]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/kern/kern_credential.c
xnu-6153.81.5.tar.gz
[apple/xnu.git] / bsd / kern / kern_credential.c
index 4a6ee0386ebcacc02a5a790cb07e6b3e16676f30..643b1cebbdafe3fcd4d33edc90d3874c82981648 100644 (file)
@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 2004-2010 Apple Inc. All rights reserved.
+ * Copyright (c) 2004-2011 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- * 
+ *
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.
- * 
+ *
  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
- * 
+ *
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
@@ -22,7 +22,7 @@
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
- * 
+ *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
@@ -37,7 +37,7 @@
  * and identity information.
  */
 
-#include <sys/param.h> /* XXX trim includes */
+#include <sys/param.h>  /* XXX trim includes */
 #include <sys/acct.h>
 #include <sys/systm.h>
 #include <sys/ucred.h>
 #include <sys/malloc.h>
 #include <sys/kauth.h>
 #include <sys/kernel.h>
+#include <sys/sdt.h>
 
 #include <security/audit/audit.h>
 
 #include <sys/mount.h>
-#include <sys/stat.h>  /* For manifest constants in posix_cred_access */
+#include <sys/stat.h>   /* For manifest constants in posix_cred_access */
 #include <sys/sysproto.h>
-#include <sys/kern_callout.h>
 #include <mach/message.h>
 #include <mach/host_security.h>
 
-/* mach_absolute_time() */
-#include <mach/clock_types.h>
-#include <mach/mach_types.h>
-#include <mach/mach_time.h>
-
-#include <libkern/OSAtomic.h>
+#include <machine/atomic.h>
 
 #include <kern/task.h>
-#include <kern/lock.h>
+#include <kern/locks.h>
 #ifdef MACH_ASSERT
 # undef MACH_ASSERT
 #endif
-#define MACH_ASSERT 1  /* XXX so bogus */
+#define MACH_ASSERT 1   /* XXX so bogus */
 #include <kern/assert.h>
 
 #if CONFIG_MACF
 #include <security/mac.h>
 #include <security/mac_framework.h>
+#include <security/_label.h>
 #endif
 
+#include <IOKit/IOBSD.h>
+
 void mach_kauth_cred_uthread_update( void );
 
-#define CRED_DIAGNOSTIC 0
+# define NULLCRED_CHECK(_c)     do {if (!IS_VALID_CRED(_c)) panic("%s: bad credential %p", __FUNCTION__,_c);} while(0)
+
+/* Set to 1 to turn on KAUTH_DEBUG for kern_credential.c */
+#if 0
+#ifdef KAUTH_DEBUG
+#undef KAUTH_DEBUG
+#endif
+
+#ifdef K_UUID_FMT
+#undef K_UUID_FMT
+#endif
+
+#ifdef K_UUID_ARG
+#undef K_UUID_ARG
+#endif
 
-# define NULLCRED_CHECK(_c)    do {if (!IS_VALID_CRED(_c)) panic("%s: bad credential %p", __FUNCTION__,_c);} while(0)
+# define K_UUID_FMT "%08x:%08x:%08x:%08x"
+# define K_UUID_ARG(_u) &_u.g_guid_asint[0],&_u.g_guid_asint[1],&_u.g_guid_asint[2],&_u.g_guid_asint[3]
+# define KAUTH_DEBUG(fmt, args...)      do { printf("%s:%d: " fmt "\n", __PRETTY_FUNCTION__, __LINE__ , ##args); } while (0)
+#endif
 
 /*
  * Credential debugging; we can track entry into a function that might
@@ -93,43 +108,44 @@ void mach_kauth_cred_uthread_update( void );
  */
 
 #if DEBUG_CRED
-#define        DEBUG_CRED_ENTER                printf
-#define        DEBUG_CRED_CHANGE               printf
+#define DEBUG_CRED_ENTER                printf
+#define DEBUG_CRED_CHANGE               printf
 extern void kauth_cred_print(kauth_cred_t cred);
 
-#include <libkern/OSDebug.h>   /* needed for get_backtrace( ) */
+#include <libkern/OSDebug.h>    /* needed for get_backtrace( ) */
 
 int is_target_cred( kauth_cred_t the_cred );
 void get_backtrace( void );
 
-static int sysctl_dump_creds( __unused struct sysctl_oid *oidp, __unused void *arg1, 
-                                                         __unused int arg2, struct sysctl_req *req );
+static int sysctl_dump_creds( __unused struct sysctl_oid *oidp, __unused void *arg1,
+    __unused int arg2, struct sysctl_req *req );
 static int
-sysctl_dump_cred_backtraces( __unused struct sysctl_oid *oidp, __unused void *arg1, 
-                                                        __unused int arg2, struct sysctl_req *req );
+sysctl_dump_cred_backtraces( __unused struct sysctl_oid *oidp, __unused void *arg1,
+    __unused int arg2, struct sysctl_req *req );
 
 #define MAX_STACK_DEPTH 8
 struct cred_backtrace {
-       int                             depth;
-       void *                  stack[ MAX_STACK_DEPTH ];
+       int                             depth;
+       void *                  stack[MAX_STACK_DEPTH];
 };
 typedef struct cred_backtrace cred_backtrace;
 
 #define MAX_CRED_BUFFER_SLOTS 200
 struct cred_debug_buffer {
-       int                             next_slot;
-       cred_backtrace  stack_buffer[ MAX_CRED_BUFFER_SLOTS ];  
+       int                             next_slot;
+       cred_backtrace  stack_buffer[MAX_CRED_BUFFER_SLOTS];
 };
 typedef struct cred_debug_buffer cred_debug_buffer;
 cred_debug_buffer * cred_debug_buf_p = NULL;
 
-#else  /* !DEBUG_CRED */
+#else   /* !DEBUG_CRED */
 
-#define        DEBUG_CRED_ENTER(fmt, ...)      do {} while (0)
-#define        DEBUG_CRED_CHANGE(fmt, ...)     do {} while (0)
+#define DEBUG_CRED_ENTER(fmt, ...)      do {} while (0)
+#define DEBUG_CRED_CHANGE(fmt, ...)     do {} while (0)
 
-#endif /* !DEBUG_CRED */
+#endif  /* !DEBUG_CRED */
 
+#if CONFIG_EXT_RESOLVER
 /*
  * Interface to external identity resolver.
  *
@@ -140,61 +156,190 @@ cred_debug_buffer * cred_debug_buf_p = NULL;
  */
 
 static lck_mtx_t *kauth_resolver_mtx;
-#define KAUTH_RESOLVER_LOCK()  lck_mtx_lock(kauth_resolver_mtx);
-#define KAUTH_RESOLVER_UNLOCK()        lck_mtx_unlock(kauth_resolver_mtx);
+#define KAUTH_RESOLVER_LOCK()   lck_mtx_lock(kauth_resolver_mtx);
+#define KAUTH_RESOLVER_UNLOCK() lck_mtx_unlock(kauth_resolver_mtx);
 
-static volatile pid_t  kauth_resolver_identity;
-static int     kauth_resolver_registered;
-static uint32_t        kauth_resolver_sequence;
-static int     kauth_resolver_timeout = 30;    /* default: 30 seconds */
+static volatile pid_t   kauth_resolver_identity;
+static int      kauth_identitysvc_has_registered;
+static int      kauth_resolver_registered;
+static uint32_t kauth_resolver_sequence;
+static int      kauth_resolver_timeout = 30;    /* default: 30 seconds */
 
 struct kauth_resolver_work {
        TAILQ_ENTRY(kauth_resolver_work) kr_link;
        struct kauth_identity_extlookup kr_work;
-       uint64_t        kr_extend;
-       uint32_t        kr_seqno;
-       uint64_t        kr_subtime;     /* submission time */
-       int             kr_refs;
-       int             kr_flags;
-#define KAUTH_REQUEST_UNSUBMITTED      (1<<0)
-#define KAUTH_REQUEST_SUBMITTED                (1<<1)
-#define KAUTH_REQUEST_DONE             (1<<2)
-       int             kr_result;
+       uint64_t        kr_extend;
+       uint32_t        kr_seqno;
+       int             kr_refs;
+       int             kr_flags;
+#define KAUTH_REQUEST_UNSUBMITTED       (1<<0)
+#define KAUTH_REQUEST_SUBMITTED         (1<<1)
+#define KAUTH_REQUEST_DONE              (1<<2)
+       int             kr_result;
 };
 
 TAILQ_HEAD(kauth_resolver_unsubmitted_head, kauth_resolver_work) kauth_resolver_unsubmitted;
-TAILQ_HEAD(kauth_resolver_submitted_head, kauth_resolver_work) kauth_resolver_submitted;
-TAILQ_HEAD(kauth_resolver_done_head, kauth_resolver_work)      kauth_resolver_done;
+TAILQ_HEAD(kauth_resolver_submitted_head, kauth_resolver_work)  kauth_resolver_submitted;
+TAILQ_HEAD(kauth_resolver_done_head, kauth_resolver_work)       kauth_resolver_done;
+
+/* Number of resolver timeouts between logged complaints */
+#define KAUTH_COMPLAINT_INTERVAL 1000
+int kauth_resolver_timeout_cnt = 0;
+
+#if DEVELOPMENT || DEBUG
+/* Internal builds get different (less ambiguous) breadcrumbs. */
+#define KAUTH_RESOLVER_FAILED_ERRCODE   EOWNERDEAD
+#else
+/* But non-Internal builds get errors that are allowed by standards. */
+#define KAUTH_RESOLVER_FAILED_ERRCODE   EIO
+#endif /* DEVELOPMENT || DEBUG */
+
+int kauth_resolver_failed_cnt = 0;
+#define RESOLVER_FAILED_MESSAGE(fmt, args...)                           \
+do {                                                                    \
+       if (!(kauth_resolver_failed_cnt++ % 100)) {                     \
+               printf("%s: " fmt "\n", __PRETTY_FUNCTION__, ##args);   \
+       }                                                               \
+} while (0)
+
+static int      kauth_resolver_submit(struct kauth_identity_extlookup *lkp, uint64_t extend_data);
+static int      kauth_resolver_complete(user_addr_t message);
+static int      kauth_resolver_getwork(user_addr_t message);
+static int      kauth_resolver_getwork2(user_addr_t message);
+static __attribute__((noinline)) int __KERNEL_IS_WAITING_ON_EXTERNAL_CREDENTIAL_RESOLVER__(
+       struct kauth_resolver_work *);
+
+#define KAUTH_CACHES_MAX_SIZE 10000 /* Max # entries for both groups and id caches */
+
+struct kauth_identity {
+       TAILQ_ENTRY(kauth_identity) ki_link;
+       int     ki_valid;
+       uid_t   ki_uid;
+       gid_t   ki_gid;
+       int     ki_supgrpcnt;
+       gid_t   ki_supgrps[NGROUPS];
+       guid_t  ki_guid;
+       ntsid_t ki_ntsid;
+       const char      *ki_name;       /* string name from string cache */
+       /*
+        * Expiry times are the earliest time at which we will disregard the
+        * cached state and go to userland.  Before then if the valid bit is
+        * set, we will return the cached value.  If it's not set, we will
+        * not go to userland to resolve, just assume that there is no answer
+        * available.
+        */
+       time_t  ki_groups_expiry;
+       time_t  ki_guid_expiry;
+       time_t  ki_ntsid_expiry;
+};
+
+static TAILQ_HEAD(kauth_identity_head, kauth_identity) kauth_identities;
+static lck_mtx_t *kauth_identity_mtx;
+#define KAUTH_IDENTITY_LOCK()   lck_mtx_lock(kauth_identity_mtx);
+#define KAUTH_IDENTITY_UNLOCK() lck_mtx_unlock(kauth_identity_mtx);
+#define KAUTH_IDENTITY_CACHEMAX_DEFAULT 100     /* XXX default sizing? */
+static int kauth_identity_cachemax = KAUTH_IDENTITY_CACHEMAX_DEFAULT;
+static int kauth_identity_count;
 
-static int     kauth_resolver_submit(struct kauth_identity_extlookup *lkp, uint64_t extend_data);
-static int     kauth_resolver_complete(user_addr_t message);
-static int     kauth_resolver_getwork(user_addr_t message);
-static int     kauth_resolver_getwork2(user_addr_t message);
+static struct kauth_identity *kauth_identity_alloc(uid_t uid, gid_t gid, guid_t *guidp, time_t guid_expiry,
+    ntsid_t *ntsidp, time_t ntsid_expiry, int supgrpcnt, gid_t *supgrps, time_t groups_expiry,
+    const char *name, int nametype);
+static void     kauth_identity_register_and_free(struct kauth_identity *kip);
+static void     kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_identity *kip, uint64_t extend_data);
+static void     kauth_identity_trimcache(int newsize);
+static void     kauth_identity_lru(struct kauth_identity *kip);
+static int      kauth_identity_guid_expired(struct kauth_identity *kip);
+static int      kauth_identity_ntsid_expired(struct kauth_identity *kip);
+static int      kauth_identity_find_uid(uid_t uid, struct kauth_identity *kir, char *getname);
+static int      kauth_identity_find_gid(gid_t gid, struct kauth_identity *kir, char *getname);
+static int      kauth_identity_find_guid(guid_t *guidp, struct kauth_identity *kir, char *getname);
+static int      kauth_identity_find_ntsid(ntsid_t *ntsid, struct kauth_identity *kir, char *getname);
+static int      kauth_identity_find_nam(char *name, int valid, struct kauth_identity *kir);
+
+struct kauth_group_membership {
+       TAILQ_ENTRY(kauth_group_membership) gm_link;
+       uid_t   gm_uid;         /* the identity whose membership we're recording */
+       gid_t   gm_gid;         /* group of which they are a member */
+       time_t  gm_expiry;      /* TTL for the membership, or 0 for persistent entries */
+       int     gm_flags;
+#define KAUTH_GROUP_ISMEMBER    (1<<0)
+};
+
+TAILQ_HEAD(kauth_groups_head, kauth_group_membership) kauth_groups;
+static lck_mtx_t *kauth_groups_mtx;
+#define KAUTH_GROUPS_LOCK()     lck_mtx_lock(kauth_groups_mtx);
+#define KAUTH_GROUPS_UNLOCK()   lck_mtx_unlock(kauth_groups_mtx);
+#define KAUTH_GROUPS_CACHEMAX_DEFAULT 100       /* XXX default sizing? */
+static int kauth_groups_cachemax = KAUTH_GROUPS_CACHEMAX_DEFAULT;
+static int kauth_groups_count;
 
-static const int kauth_cred_primes[KAUTH_CRED_PRIMES_COUNT] = KAUTH_CRED_PRIMES;
-static int     kauth_cred_primes_index = 0;
-static int     kauth_cred_table_size = 0;
+static int      kauth_groups_expired(struct kauth_group_membership *gm);
+static void     kauth_groups_lru(struct kauth_group_membership *gm);
+static void     kauth_groups_updatecache(struct kauth_identity_extlookup *el);
+static void     kauth_groups_trimcache(int newsize);
 
-TAILQ_HEAD(kauth_cred_entry_head, ucred);
-static struct kauth_cred_entry_head * kauth_cred_table_anchor = NULL;
+#endif  /* CONFIG_EXT_RESOLVER */
 
-/* Weighted moving average for resolver response time */
-static struct kco_moving_average resolver_ma;
+#define KAUTH_CRED_TABLE_SIZE 128
 
-#define KAUTH_CRED_HASH_DEBUG  0
+LIST_HEAD(kauth_cred_entry_head, ucred);
+static struct kauth_cred_entry_head
+    kauth_cred_table_anchor[KAUTH_CRED_TABLE_SIZE];
 
-static int kauth_cred_add(kauth_cred_t new_cred);
-static void kauth_cred_remove(kauth_cred_t cred);
-static inline u_long kauth_cred_hash(const uint8_t *datap, int data_len, u_long start_key);
-static u_long kauth_cred_get_hashkey(kauth_cred_t cred);
+static struct kauth_cred_entry_head *kauth_cred_get_bucket(kauth_cred_t cred);
+static kauth_cred_t kauth_cred_add(kauth_cred_t new_cred, struct kauth_cred_entry_head *bucket);
+static void kauth_cred_remove_locked(kauth_cred_t cred);
 static kauth_cred_t kauth_cred_update(kauth_cred_t old_cred, kauth_cred_t new_cred, boolean_t retain_auditinfo);
-static void kauth_cred_unref_hashlocked(kauth_cred_t *credp);
+static kauth_cred_t kauth_cred_find_and_ref(kauth_cred_t cred,
+    struct kauth_cred_entry_head *bucket);
+static bool kauth_cred_is_equal(kauth_cred_t cred1, kauth_cred_t cred2);
 
-#if KAUTH_CRED_HASH_DEBUG
-static int     kauth_cred_count = 0;
-static void kauth_cred_hash_print(void);
-static void kauth_cred_print(kauth_cred_t cred);
-#endif
+#if CONFIG_EXT_RESOLVER
+
+/*
+ *  __KERNEL_IS_WAITING_ON_EXTERNAL_CREDENTIAL_RESOLVER__
+ *
+ * Description:  Waits for the user space daemon to respond to the request
+ *               we made. Function declared non inline to be visible in
+ *               stackshots and spindumps as well as debugging.
+ *
+ * Parameters:   workp                     Work queue entry.
+ *
+ * Returns:      0                         on Success.
+ *               EIO                       if Resolver is dead.
+ *               EINTR                     thread interrupted in msleep
+ *               EWOULDBLOCK               thread timed out in msleep
+ *               ERESTART                  returned by msleep.
+ *
+ */
+static __attribute__((noinline)) int
+__KERNEL_IS_WAITING_ON_EXTERNAL_CREDENTIAL_RESOLVER__(
+       struct kauth_resolver_work  *workp)
+{
+       int error = 0;
+       struct timespec ts;
+       for (;;) {
+               /* we could compute a better timeout here */
+               ts.tv_sec = kauth_resolver_timeout;
+               ts.tv_nsec = 0;
+               error = msleep(workp, kauth_resolver_mtx, PCATCH, "kr_submit", &ts);
+               /* request has been completed? */
+               if ((error == 0) && (workp->kr_flags & KAUTH_REQUEST_DONE)) {
+                       break;
+               }
+               /* woken because the resolver has died? */
+               if (kauth_resolver_identity == 0) {
+                       RESOLVER_FAILED_MESSAGE("kauth external resolver died while while waiting for work to complete");
+                       error = KAUTH_RESOLVER_FAILED_ERRCODE;
+                       break;
+               }
+               /* an error? */
+               if (error != 0) {
+                       break;
+               }
+       }
+       return error;
+}
 
 
 /*
@@ -206,7 +351,7 @@ static void kauth_cred_print(kauth_cred_t cred);
  *
  * Returns:    (void)
  *
- * Notes:      Intialize the credential identity resolver for use; the
+ * Notes:      Initialize the credential identity resolver for use; the
  *             credential identity resolver is the KPI used by the user
  *             space credential identity resolver daemon to communicate
  *             with the kernel via the identitysvc() system call..
@@ -231,12 +376,7 @@ kauth_resolver_init(void)
        TAILQ_INIT(&kauth_resolver_submitted);
        TAILQ_INIT(&kauth_resolver_done);
        kauth_resolver_sequence = 31337;
-       kauth_resolver_mtx = lck_mtx_alloc_init(kauth_lck_grp, 0/*LCK_ATTR_NULL*/);
-
-       /*
-        * 110% of average response time is "too long" and should be reported
-        */
-       kco_ma_init(&resolver_ma, 110, KCO_MA_F_WMA);
+       kauth_resolver_mtx = lck_mtx_alloc_init(kauth_lck_grp, 0 /*LCK_ATTR_NULL*/);
 }
 
 
@@ -282,9 +422,8 @@ kauth_resolver_submit(struct kauth_identity_extlookup *lkp, uint64_t extend_data
 {
        struct kauth_resolver_work *workp, *killp;
        struct timespec ts;
-       int     error, shouldfree;
-       uint64_t        duration;
-       
+       int     error, shouldfree;
+
        /* no point actually blocking if the resolver isn't up yet */
        if (kauth_resolver_identity == 0) {
                /*
@@ -296,20 +435,21 @@ kauth_resolver_submit(struct kauth_identity_extlookup *lkp, uint64_t extend_data
                 * process, so that memberd doesn't starve while we are in a
                 * tight loop between user and kernel, eating all the CPU.
                 */
-               error = tsleep(&ts, PZERO | PCATCH, "kr_submit", hz/2);
+               error = tsleep(&ts, PZERO | PCATCH, "kr_submit", hz / 2);
                if (kauth_resolver_identity == 0) {
                        /*
                         * if things haven't changed while we were asleep,
                         * tell the caller we couldn't get an authoritative
                         * answer.
                         */
-                       return(EWOULDBLOCK);
+                       return EWOULDBLOCK;
                }
        }
-               
+
        MALLOC(workp, struct kauth_resolver_work *, sizeof(*workp), M_KAUTH, M_WAITOK);
-       if (workp == NULL)
-               return(ENOMEM);
+       if (workp == NULL) {
+               return ENOMEM;
+       }
 
        workp->kr_work = *lkp;
        workp->kr_extend = extend_data;
@@ -326,7 +466,7 @@ kauth_resolver_submit(struct kauth_identity_extlookup *lkp, uint64_t extend_data
        workp->kr_work.el_result = KAUTH_EXTLOOKUP_INPROG;
 
        /*
-        * XXX We *MUST NOT* attempt to coelesce identical work items due to
+        * XXX We *MUST NOT* attempt to coalesce identical work items due to
         * XXX the inability to ensure order of update of the request item
         * XXX extended data vs. the wakeup; instead, we let whoever is waiting
         * XXX for each item repeat the update when they wake up.
@@ -335,80 +475,52 @@ kauth_resolver_submit(struct kauth_identity_extlookup *lkp, uint64_t extend_data
 
        /*
         * Wake up an external resolver thread to deal with the new work; one
-        * may not be available, and if not, then the request will be grabed
+        * may not be available, and if not, then the request will be grabbed
         * when a resolver thread comes back into the kernel to request new
         * work.
         */
        wakeup_one((caddr_t)&kauth_resolver_unsubmitted);
-       for (;;) {
-               /* we could compute a better timeout here */
-               ts.tv_sec = kauth_resolver_timeout;
-               ts.tv_nsec = 0;
-               error = msleep(workp, kauth_resolver_mtx, PCATCH, "kr_submit", &ts);
-               /* request has been completed? */
-               if ((error == 0) && (workp->kr_flags & KAUTH_REQUEST_DONE))
-                       break;
-               /* woken because the resolver has died? */
-               if (kauth_resolver_identity == 0) {
-                       error = EIO;
-                       break;
-               }
-               /* an error? */
-               if (error != 0)
-                       break;
-       }
-
-       /*
-        * Update the moving average of how long the request took; if it
-        * took longer than the time threshold, then we complain about it
-        * being slow.
-        */
-       duration = mach_absolute_time() - workp->kr_subtime;
-       if (kco_ma_addsample(&resolver_ma, duration)) {
-               uint64_t        average;
-               uint64_t        old_average;
-               int32_t         threshold;
-               int             count;
-
-               /* If we can't get information, don't log anything */
-               if (kco_ma_info(&resolver_ma, KCO_MA_F_WMA, &average, &old_average, &threshold, &count)) {
-                       char pname[MAXCOMLEN+1] = "(NULL)";
-                       proc_name(kauth_resolver_identity, pname, sizeof(pname));
-                       // <rdar://6276265>  printf("kauth_resolver_submit: External resolver pid %d (name %s) response time %lld, average %lld new %lld threshold %d%% actual %d%% count %d\n", kauth_resolver_identity, pname, duration, old_average, average, threshold, (int)((duration * 100) / old_average), count);
-               }
-       }
+       error = __KERNEL_IS_WAITING_ON_EXTERNAL_CREDENTIAL_RESOLVER__(workp);
 
        /* if the request was processed, copy the result */
-       if (error == 0)
+       if (error == 0) {
                *lkp = workp->kr_work;
-       
-       /*
-        * If the request timed out and was never collected, the resolver
-        * is dead and probably not coming back anytime soon.  In this
-        * case we revert to no-resolver behaviour, and punt all the other
-        * sleeping requests to clear the backlog.
-        */
-       if ((error == EWOULDBLOCK) && (workp->kr_flags & KAUTH_REQUEST_UNSUBMITTED)) {
-               KAUTH_DEBUG("RESOLVER - request timed out without being collected for processing, resolver dead");
+       }
 
-               /*
-                * Make the current resolver non-authoritative, and mark it as
-                * no longer registered to prevent kauth_cred_ismember_gid()
-                * enqueueing more work until a new one is registered.  This
-                * mitigates the damage a crashing resolver may inflict.
-                */
-               kauth_resolver_identity = 0;
-               kauth_resolver_registered = 0;
+       if (error == EWOULDBLOCK) {
+               if ((kauth_resolver_timeout_cnt++ % KAUTH_COMPLAINT_INTERVAL) == 0) {
+                       printf("kauth external resolver timed out (%d timeout(s) of %d seconds).\n",
+                           kauth_resolver_timeout_cnt, kauth_resolver_timeout);
+               }
 
-               /* kill all the other requestes that are waiting as well */
-               TAILQ_FOREACH(killp, &kauth_resolver_submitted, kr_link)
-                   wakeup(killp);
-               TAILQ_FOREACH(killp, &kauth_resolver_unsubmitted, kr_link)
-                   wakeup(killp);
-               /* Cause all waiting-for-work threads to return EIO */
-               wakeup((caddr_t)&kauth_resolver_unsubmitted);
+               if (workp->kr_flags & KAUTH_REQUEST_UNSUBMITTED) {
+                       /*
+                        * If the request timed out and was never collected, the resolver
+                        * is dead and probably not coming back anytime soon.  In this
+                        * case we revert to no-resolver behaviour, and punt all the other
+                        * sleeping requests to clear the backlog.
+                        */
+                       KAUTH_DEBUG("RESOLVER - request timed out without being collected for processing, resolver dead");
+
+                       /*
+                        * Make the current resolver non-authoritative, and mark it as
+                        * no longer registered to prevent kauth_cred_ismember_gid()
+                        * enqueueing more work until a new one is registered.  This
+                        * mitigates the damage a crashing resolver may inflict.
+                        */
+                       kauth_resolver_identity = 0;
+                       kauth_resolver_registered = 0;
+
+                       /* kill all the other requestes that are waiting as well */
+                       TAILQ_FOREACH(killp, &kauth_resolver_submitted, kr_link)
+                       wakeup(killp);
+                       TAILQ_FOREACH(killp, &kauth_resolver_unsubmitted, kr_link)
+                       wakeup(killp);
+                       /* Cause all waiting-for-work threads to return EIO */
+                       wakeup((caddr_t)&kauth_resolver_unsubmitted);
+               }
        }
-       
+
        /*
         * drop our reference on the work item, and note whether we should
         * free it or not
@@ -444,7 +556,7 @@ kauth_resolver_submit(struct kauth_identity_extlookup *lkp, uint64_t extend_data
        }
 
        KAUTH_DEBUG("RESOLVER - returning %d", error);
-       return(error);
+       return error;
 }
 
 
@@ -477,9 +589,15 @@ identitysvc(__unused struct proc *p, struct identitysvc_args *uap, __unused int3
        int opcode = uap->opcode;
        user_addr_t message = uap->message;
        struct kauth_resolver_work *workp;
+       struct kauth_cache_sizes sz_arg = {};
        int error;
        pid_t new_id;
 
+       if (!IOTaskHasEntitlement(current_task(), IDENTITYSVC_ENTITLEMENT)) {
+               KAUTH_DEBUG("RESOLVER - pid %d not entitled to call identitysvc", current_proc()->p_pid);
+               return EPERM;
+       }
+
        /*
         * New server registering itself.
         */
@@ -487,7 +605,7 @@ identitysvc(__unused struct proc *p, struct identitysvc_args *uap, __unused int3
                new_id = current_proc()->p_pid;
                if ((error = kauth_authorize_generic(kauth_cred_get(), KAUTH_GENERIC_ISSUSER)) != 0) {
                        KAUTH_DEBUG("RESOLVER - pid %d refused permission to become identity resolver", new_id);
-                       return(error);
+                       return error;
                }
                KAUTH_RESOLVER_LOCK();
                if (kauth_resolver_identity != new_id) {
@@ -511,21 +629,66 @@ identitysvc(__unused struct proc *p, struct identitysvc_args *uap, __unused int3
                        }
                        kauth_resolver_identity = new_id;
                        kauth_resolver_registered = 1;
+                       kauth_identitysvc_has_registered = 1;
                        wakeup(&kauth_resolver_unsubmitted);
                }
                KAUTH_RESOLVER_UNLOCK();
-               return(0);
+               return 0;
        }
 
        /*
-        * Beyond this point, we must be the resolver process.
+        * Beyond this point, we must be the resolver process. We verify this
+        * by confirming the resolver credential and pid.
         */
-       if (current_proc()->p_pid != kauth_resolver_identity) {
+       if ((kauth_cred_getuid(kauth_cred_get()) != 0) || (current_proc()->p_pid != kauth_resolver_identity)) {
                KAUTH_DEBUG("RESOLVER - call from bogus resolver %d\n", current_proc()->p_pid);
-               return(EPERM);
+               return EPERM;
        }
 
-       if (opcode == KAUTH_EXTLOOKUP_DEREGISTER) {
+       if (opcode == KAUTH_GET_CACHE_SIZES) {
+               KAUTH_IDENTITY_LOCK();
+               sz_arg.kcs_id_size = kauth_identity_cachemax;
+               KAUTH_IDENTITY_UNLOCK();
+
+               KAUTH_GROUPS_LOCK();
+               sz_arg.kcs_group_size = kauth_groups_cachemax;
+               KAUTH_GROUPS_UNLOCK();
+
+               if ((error = copyout(&sz_arg, uap->message, sizeof(sz_arg))) != 0) {
+                       return error;
+               }
+
+               return 0;
+       } else if (opcode == KAUTH_SET_CACHE_SIZES) {
+               if ((error = copyin(uap->message, &sz_arg, sizeof(sz_arg))) != 0) {
+                       return error;
+               }
+
+               if ((sz_arg.kcs_group_size > KAUTH_CACHES_MAX_SIZE) ||
+                   (sz_arg.kcs_id_size > KAUTH_CACHES_MAX_SIZE)) {
+                       return EINVAL;
+               }
+
+               KAUTH_IDENTITY_LOCK();
+               kauth_identity_cachemax = sz_arg.kcs_id_size;
+               kauth_identity_trimcache(kauth_identity_cachemax);
+               KAUTH_IDENTITY_UNLOCK();
+
+               KAUTH_GROUPS_LOCK();
+               kauth_groups_cachemax = sz_arg.kcs_group_size;
+               kauth_groups_trimcache(kauth_groups_cachemax);
+               KAUTH_GROUPS_UNLOCK();
+
+               return 0;
+       } else if (opcode == KAUTH_CLEAR_CACHES) {
+               KAUTH_IDENTITY_LOCK();
+               kauth_identity_trimcache(0);
+               KAUTH_IDENTITY_UNLOCK();
+
+               KAUTH_GROUPS_LOCK();
+               kauth_groups_trimcache(0);
+               KAUTH_GROUPS_UNLOCK();
+       } else if (opcode == KAUTH_EXTLOOKUP_DEREGISTER) {
                /*
                 * Terminate outstanding requests; without an authoritative
                 * resolver, we are now back on our own authority.
@@ -543,37 +706,39 @@ identitysvc(__unused struct proc *p, struct identitysvc_args *uap, __unused int3
                kauth_resolver_registered = 0;
 
                TAILQ_FOREACH(killp, &kauth_resolver_submitted, kr_link)
-                   wakeup(killp);
+               wakeup(killp);
                TAILQ_FOREACH(killp, &kauth_resolver_unsubmitted, kr_link)
-                   wakeup(killp);
+               wakeup(killp);
                /* Cause all waiting-for-work threads to return EIO */
                wakeup((caddr_t)&kauth_resolver_unsubmitted);
                KAUTH_RESOLVER_UNLOCK();
        }
-       
+
        /*
         * Got a result returning?
         */
        if (opcode & KAUTH_EXTLOOKUP_RESULT) {
-               if ((error = kauth_resolver_complete(message)) != 0)
-                       return(error);
+               if ((error = kauth_resolver_complete(message)) != 0) {
+                       return error;
+               }
        }
 
        /*
         * Caller wants to take more work?
         */
        if (opcode & KAUTH_EXTLOOKUP_WORKER) {
-               if ((error = kauth_resolver_getwork(message)) != 0)
-                       return(error);
+               if ((error = kauth_resolver_getwork(message)) != 0) {
+                       return error;
+               }
        }
 
-       return(0);
+       return 0;
 }
 
 
 /*
  * kauth_resolver_getwork_continue
- *             
+ *
  * Description:        Continuation for kauth_resolver_getwork
  *
  * Parameters: result                          Error code or 0 for the sleep
@@ -595,7 +760,7 @@ kauth_resolver_getwork_continue(int result)
 
        if (result) {
                KAUTH_RESOLVER_UNLOCK();
-               return(result);
+               return result;
        }
 
        /*
@@ -612,16 +777,18 @@ kauth_resolver_getwork_continue(int result)
                 * If this is a wakeup from another thread in the resolver
                 * deregistering it, error out the request-for-work thread
                 */
-               if (!kauth_resolver_identity)
-                       error = EIO;
+               if (!kauth_resolver_identity) {
+                       RESOLVER_FAILED_MESSAGE("external resolver died");
+                       error = KAUTH_RESOLVER_FAILED_ERRCODE;
+               }
                KAUTH_RESOLVER_UNLOCK();
-               return(error);
+               return error;
        }
 
        thread = current_thread();
        ut = get_bsdthread_info(thread);
-       message = ut->uu_kauth.message;
-       return(kauth_resolver_getwork2(message));
+       message = ut->uu_save.uus_kauth.message;
+       return kauth_resolver_getwork2(message);
 }
 
 
@@ -638,7 +805,7 @@ kauth_resolver_getwork_continue(int result)
  *             EFAULT                          Bad user space message address
  *
  * Notes:      This common function exists to permit the use of continuations
- *             in the identity resoultion process.  This frees up the stack
+ *             in the identity resolution process.  This frees up the stack
  *             while we are waiting for the user space resolver to complete
  *             a request.  This is specifically used so that our per thread
  *             cost can be small, and we will therefore be willing to run a
@@ -648,7 +815,7 @@ static int
 kauth_resolver_getwork2(user_addr_t message)
 {
        struct kauth_resolver_work *workp;
-       int             error;
+       int             error;
 
        /*
         * Note: We depend on the caller protecting us from a NULL work item
@@ -670,8 +837,8 @@ kauth_resolver_getwork2(user_addr_t message)
        }
        /* AFTER FIELD */
        if ((error = copyout(&workp->kr_work.el_info_reserved_1,
-                       message + offsetof(struct kauth_identity_extlookup, el_info_reserved_1),
-               sizeof(struct kauth_identity_extlookup) - offsetof(struct kauth_identity_extlookup, el_info_reserved_1))) != 0) {
+           message + offsetof(struct kauth_identity_extlookup, el_info_reserved_1),
+           sizeof(struct kauth_identity_extlookup) - offsetof(struct kauth_identity_extlookup, el_info_reserved_1))) != 0) {
                KAUTH_DEBUG("RESOLVER - error submitting work to resolve");
                goto out;
        }
@@ -692,13 +859,13 @@ kauth_resolver_getwork2(user_addr_t message)
 
                error = copyin(message + offsetof(struct kauth_identity_extlookup, el_extend), &uaddr, sizeof(uaddr));
                if (!error) {
-                       size_t actual;  /* not used */
+                       size_t actual;  /* not used */
                        /*
                         * Use copyoutstr() to reduce the copy size; we let
                         * this catch a NULL uaddr because we shouldn't be
                         * asking in that case anyway.
                         */
-                       error = copyoutstr(CAST_DOWN(void *,workp->kr_extend), uaddr, MAXPATHLEN, &actual);
+                       error = copyoutstr(CAST_DOWN(void *, workp->kr_extend), uaddr, MAXPATHLEN, &actual);
                }
                if (error) {
                        KAUTH_DEBUG("RESOLVER - error submitting work to resolve");
@@ -708,12 +875,11 @@ kauth_resolver_getwork2(user_addr_t message)
        TAILQ_REMOVE(&kauth_resolver_unsubmitted, workp, kr_link);
        workp->kr_flags &= ~KAUTH_REQUEST_UNSUBMITTED;
        workp->kr_flags |= KAUTH_REQUEST_SUBMITTED;
-       workp->kr_subtime = mach_absolute_time();
        TAILQ_INSERT_TAIL(&kauth_resolver_submitted, workp, kr_link);
 
 out:
        KAUTH_RESOLVER_UNLOCK();
-       return(error);
+       return error;
 }
 
 
@@ -734,13 +900,13 @@ out:
  *             identity resolution daemon makes a request for work.  This
  *             permits a large number of threads to be used by the daemon,
  *             without using a lot of wired kernel memory when there are no
- *             acctual request outstanding.
+ *             actual request outstanding.
  */
 static int
 kauth_resolver_getwork(user_addr_t message)
 {
        struct kauth_resolver_work *workp;
-       int             error;
+       int             error;
 
        KAUTH_RESOLVER_LOCK();
        error = 0;
@@ -748,16 +914,18 @@ kauth_resolver_getwork(user_addr_t message)
                thread_t thread = current_thread();
                struct uthread *ut = get_bsdthread_info(thread);
 
-               ut->uu_kauth.message = message;
+               ut->uu_save.uus_kauth.message = message;
                error = msleep0(&kauth_resolver_unsubmitted, kauth_resolver_mtx, PCATCH, "GRGetWork", 0, kauth_resolver_getwork_continue);
                KAUTH_RESOLVER_UNLOCK();
                /*
                 * If this is a wakeup from another thread in the resolver
                 * deregistering it, error out the request-for-work thread
                 */
-               if (!kauth_resolver_identity)
-                       error = EIO;
-               return(error);
+               if (!kauth_resolver_identity) {
+                       printf("external resolver died");
+                       error = KAUTH_RESOLVER_FAILED_ERRCODE;
+               }
+               return error;
        }
        return kauth_resolver_getwork2(message);
 }
@@ -777,10 +945,10 @@ kauth_resolver_getwork(user_addr_t message)
 static int
 kauth_resolver_complete(user_addr_t message)
 {
-       struct kauth_identity_extlookup extl;
+       struct kauth_identity_extlookup extl;
        struct kauth_resolver_work *workp;
        struct kauth_resolver_work *killp;
-       int error, result;
+       int error, result, want_extend_data;
 
        /*
         * Copy in the mesage, including the extension field, since we are
@@ -788,7 +956,7 @@ kauth_resolver_complete(user_addr_t message)
         */
        if ((error = copyin(message, &extl, sizeof(extl))) != 0) {
                KAUTH_DEBUG("RESOLVER - error getting completed work\n");
-               return(error);
+               return error;
        }
 
        KAUTH_RESOLVER_LOCK();
@@ -814,6 +982,7 @@ kauth_resolver_complete(user_addr_t message)
        case KAUTH_EXTLOOKUP_FATAL:
                /* fatal error means the resolver is dead */
                KAUTH_DEBUG("RESOLVER - resolver %d died, waiting for a new one", kauth_resolver_identity);
+               RESOLVER_FAILED_MESSAGE("resolver %d died, waiting for a new one", kauth_resolver_identity);
                /*
                 * Terminate outstanding requests; without an authoritative
                 * resolver, we are now back on our own authority.  Tag the
@@ -825,13 +994,13 @@ kauth_resolver_complete(user_addr_t message)
                kauth_resolver_registered = 0;
 
                TAILQ_FOREACH(killp, &kauth_resolver_submitted, kr_link)
-                   wakeup(killp);
+               wakeup(killp);
                TAILQ_FOREACH(killp, &kauth_resolver_unsubmitted, kr_link)
-                   wakeup(killp);
+               wakeup(killp);
                /* Cause all waiting-for-work threads to return EIO */
                wakeup((caddr_t)&kauth_resolver_unsubmitted);
                /* and return EIO to the caller */
-               error = EIO;
+               error = KAUTH_RESOLVER_FAILED_ERRCODE;
                break;
 
        case KAUTH_EXTLOOKUP_BADRQ:
@@ -841,12 +1010,14 @@ kauth_resolver_complete(user_addr_t message)
 
        case KAUTH_EXTLOOKUP_FAILURE:
                KAUTH_DEBUG("RESOLVER - resolver reported transient failure for request %d", extl.el_seqno);
-               result = EIO;
+               RESOLVER_FAILED_MESSAGE("resolver reported transient failure for request %d", extl.el_seqno);
+               result = KAUTH_RESOLVER_FAILED_ERRCODE;
                break;
 
        default:
                KAUTH_DEBUG("RESOLVER - resolver returned unexpected status %d", extl.el_result);
-               result = EIO;
+               RESOLVER_FAILED_MESSAGE("resolver returned unexpected status %d", extl.el_result);
+               result = KAUTH_RESOLVER_FAILED_ERRCODE;
                break;
        }
 
@@ -861,6 +1032,10 @@ kauth_resolver_complete(user_addr_t message)
                TAILQ_FOREACH(workp, &kauth_resolver_submitted, kr_link) {
                        /* found it? */
                        if (workp->kr_seqno == extl.el_seqno) {
+                               /*
+                                * Do we want extend_data?
+                                */
+                               want_extend_data = (workp->kr_work.el_flags & (KAUTH_EXTLOOKUP_WANT_PWNAM | KAUTH_EXTLOOKUP_WANT_GRNAM));
 
                                /*
                                 * Get the request of the submitted queue so
@@ -898,13 +1073,23 @@ kauth_resolver_complete(user_addr_t message)
                                 * issue and is easily detectable by comparing
                                 * time to live on last response vs. time of
                                 * next request in the resolver logs.
+                                *
+                                * A malicious/faulty resolver could overwrite
+                                * part of a user's address space if they return
+                                * flags that mismatch the original request's flags.
                                 */
-                               if (extl.el_flags & (KAUTH_EXTLOOKUP_VALID_PWNAM|KAUTH_EXTLOOKUP_VALID_GRNAM)) {
-                                       size_t actual;  /* notused */
+                               if (want_extend_data && (extl.el_flags & (KAUTH_EXTLOOKUP_VALID_PWNAM | KAUTH_EXTLOOKUP_VALID_GRNAM))) {
+                                       size_t actual;  /* notused */
 
                                        KAUTH_RESOLVER_UNLOCK();
                                        error = copyinstr(extl.el_extend, CAST_DOWN(void *, workp->kr_extend), MAXPATHLEN, &actual);
+                                       KAUTH_DEBUG("RESOLVER - resolver got name :%*s: len = %d\n", (int)actual,
+                                           actual ? "null" : (char *)extl.el_extend, actual);
                                        KAUTH_RESOLVER_LOCK();
+                               } else if (extl.el_flags &  (KAUTH_EXTLOOKUP_VALID_PWNAM | KAUTH_EXTLOOKUP_VALID_GRNAM)) {
+                                       error = EFAULT;
+                                       KAUTH_DEBUG("RESOLVER - resolver returned mismatching extension flags (%d), request contained (%d)",
+                                           extl.el_flags, want_extend_data);
                                }
 
                                /*
@@ -922,63 +1107,25 @@ kauth_resolver_complete(user_addr_t message)
         * timed out the work record will be gone.
         */
        KAUTH_RESOLVER_UNLOCK();
-       
-       return(error);
+
+       return error;
 }
+#endif /* CONFIG_EXT_RESOLVER */
 
 
 /*
  * Identity cache.
  */
 
-struct kauth_identity {
-       TAILQ_ENTRY(kauth_identity) ki_link;
-       int     ki_valid;
-#define        KI_VALID_UID    (1<<0)          /* UID and GID are mutually exclusive */
-#define KI_VALID_GID   (1<<1)
-#define KI_VALID_GUID  (1<<2)
-#define KI_VALID_NTSID (1<<3)
-#define KI_VALID_PWNAM (1<<4)  /* Used for translation */
-#define KI_VALID_GRNAM (1<<5)  /* Used for translation */
-       uid_t   ki_uid;
-       gid_t   ki_gid;
-       guid_t  ki_guid;
-       ntsid_t ki_ntsid;
-       const char      *ki_name;       /* string name from string cache */
-       /*
-        * Expiry times are the earliest time at which we will disregard the
-        * cached state and go to userland.  Before then if the valid bit is
-        * set, we will return the cached value.  If it's not set, we will
-        * not go to userland to resolve, just assume that there is no answer
-        * available.
-        */
-       time_t  ki_guid_expiry;
-       time_t  ki_ntsid_expiry;
-};
-
-static TAILQ_HEAD(kauth_identity_head, kauth_identity) kauth_identities;
-#define KAUTH_IDENTITY_CACHEMAX                100     /* XXX sizing? */
-static int kauth_identity_count;
-
-static lck_mtx_t *kauth_identity_mtx;
-#define KAUTH_IDENTITY_LOCK()  lck_mtx_lock(kauth_identity_mtx);
-#define KAUTH_IDENTITY_UNLOCK()        lck_mtx_unlock(kauth_identity_mtx);
-
-
-static struct kauth_identity *kauth_identity_alloc(uid_t uid, gid_t gid, guid_t *guidp, time_t guid_expiry,
-    ntsid_t *ntsidp, time_t ntsid_expiry, const char *name, int nametype);
-static void    kauth_identity_register_and_free(struct kauth_identity *kip);
-static void    kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_identity *kip, uint64_t extend_data);
-static void    kauth_identity_lru(struct kauth_identity *kip);
-static int     kauth_identity_guid_expired(struct kauth_identity *kip);
-static int     kauth_identity_ntsid_expired(struct kauth_identity *kip);
-static int     kauth_identity_find_uid(uid_t uid, struct kauth_identity *kir, char *getname);
-static int     kauth_identity_find_gid(gid_t gid, struct kauth_identity *kir, char *getname);
-static int     kauth_identity_find_guid(guid_t *guidp, struct kauth_identity *kir, char *getname);
-static int     kauth_identity_find_ntsid(ntsid_t *ntsid, struct kauth_identity *kir, char *getname);
-static int     kauth_identity_find_nam(char *name, int valid, struct kauth_identity *kir);
-
+#define KI_VALID_UID    (1<<0)          /* UID and GID are mutually exclusive */
+#define KI_VALID_GID    (1<<1)
+#define KI_VALID_GUID   (1<<2)
+#define KI_VALID_NTSID  (1<<3)
+#define KI_VALID_PWNAM  (1<<4)  /* Used for translation */
+#define KI_VALID_GRNAM  (1<<5)  /* Used for translation */
+#define KI_VALID_GROUPS (1<<6)
 
+#if CONFIG_EXT_RESOLVER
 /*
  * kauth_identity_init
  *
@@ -988,7 +1135,7 @@ static int kauth_identity_find_nam(char *name, int valid, struct kauth_identity
  *
  * Returns:    (void)
  *
- * Notes:      Intialize the credential identity resolver for use; the
+ * Notes:      Initialize the credential identity resolver for use; the
  *             credential identity resolver is the KPI used to communicate
  *             with a user space credential identity resolver daemon.
  *
@@ -999,7 +1146,7 @@ void
 kauth_identity_init(void)
 {
        TAILQ_INIT(&kauth_identities);
-       kauth_identity_mtx = lck_mtx_alloc_init(kauth_lck_grp, 0/*LCK_ATTR_NULL*/);
+       kauth_identity_mtx = lck_mtx_alloc_init(kauth_lck_grp, 0 /*LCK_ATTR_NULL*/);
 }
 
 
@@ -1012,8 +1159,8 @@ kauth_identity_init(void)
  * Parameters: uid
  *
  * Returns:    NULL                            Insufficient memory to satisfy
- *                                             the request
- *             !NULL                           A pointer to the applocated
+ *                                             the request or bad parameters
+ *             !NULL                           A pointer to the allocated
  *                                             structure, filled in
  *
  * Notes:      It is illegal to translate between UID and GID; any given UUID
@@ -1021,10 +1168,12 @@ kauth_identity_init(void)
  *             and *either* a UID *or* a GID, but not both.
  */
 static struct kauth_identity *
-kauth_identity_alloc(uid_t uid, gid_t gid, guid_t *guidp, time_t guid_expiry, ntsid_t *ntsidp, time_t ntsid_expiry, const char *name, int nametype)
+kauth_identity_alloc(uid_t uid, gid_t gid, guid_t *guidp, time_t guid_expiry,
+    ntsid_t *ntsidp, time_t ntsid_expiry, int supgrpcnt, gid_t *supgrps, time_t groups_expiry,
+    const char *name, int nametype)
 {
        struct kauth_identity *kip;
-       
+
        /* get and fill in a new identity */
        MALLOC(kip, struct kauth_identity *, sizeof(*kip), M_KAUTH, M_WAITOK | M_ZERO);
        if (kip != NULL) {
@@ -1033,11 +1182,31 @@ kauth_identity_alloc(uid_t uid, gid_t gid, guid_t *guidp, time_t guid_expiry, nt
                        kip->ki_valid = KI_VALID_GID;
                }
                if (uid != KAUTH_UID_NONE) {
-                       if (kip->ki_valid & KI_VALID_GID)
+                       if (kip->ki_valid & KI_VALID_GID) {
                                panic("can't allocate kauth identity with both uid and gid");
+                       }
                        kip->ki_uid = uid;
                        kip->ki_valid = KI_VALID_UID;
                }
+               if (supgrpcnt) {
+                       /*
+                        * A malicious/faulty resolver could return bad values
+                        */
+                       assert(supgrpcnt >= 0);
+                       assert(supgrpcnt <= NGROUPS);
+                       assert(supgrps != NULL);
+
+                       if ((supgrpcnt < 0) || (supgrpcnt > NGROUPS) || (supgrps == NULL)) {
+                               return NULL;
+                       }
+                       if (kip->ki_valid & KI_VALID_GID) {
+                               panic("can't allocate kauth identity with both gid and supplementary groups");
+                       }
+                       kip->ki_supgrpcnt = supgrpcnt;
+                       memcpy(kip->ki_supgrps, supgrps, sizeof(supgrps[0]) * supgrpcnt);
+                       kip->ki_valid |= KI_VALID_GROUPS;
+               }
+               kip->ki_groups_expiry = groups_expiry;
                if (guidp != NULL) {
                        kip->ki_guid = *guidp;
                        kip->ki_valid |= KI_VALID_GUID;
@@ -1053,7 +1222,7 @@ kauth_identity_alloc(uid_t uid, gid_t gid, guid_t *guidp, time_t guid_expiry, nt
                        kip->ki_valid |= nametype;
                }
        }
-       return(kip);
+       return kip;
 }
 
 
@@ -1083,19 +1252,22 @@ kauth_identity_register_and_free(struct kauth_identity *kip)
        ip = NULL;
        KAUTH_IDENTITY_LOCK();
        if (kip->ki_valid & KI_VALID_UID) {
-               if (kip->ki_valid & KI_VALID_GID)
+               if (kip->ki_valid & KI_VALID_GID) {
                        panic("kauth_identity: can't insert record with both UID and GID as key");
+               }
                TAILQ_FOREACH(ip, &kauth_identities, ki_link)
-                   if ((ip->ki_valid & KI_VALID_UID) && (ip->ki_uid == kip->ki_uid))
-                               break;
+               if ((ip->ki_valid & KI_VALID_UID) && (ip->ki_uid == kip->ki_uid)) {
+                       break;
+               }
        } else if (kip->ki_valid & KI_VALID_GID) {
                TAILQ_FOREACH(ip, &kauth_identities, ki_link)
-                   if ((ip->ki_valid & KI_VALID_GID) && (ip->ki_gid == kip->ki_gid))
-                               break;
+               if ((ip->ki_valid & KI_VALID_GID) && (ip->ki_gid == kip->ki_gid)) {
+                       break;
+               }
        } else {
                panic("kauth_identity: can't insert record without UID or GID as key");
        }
-               
+
        if (ip != NULL) {
                /* we already have an entry, merge/overwrite */
                if (kip->ki_valid & KI_VALID_GUID) {
@@ -1112,8 +1284,9 @@ kauth_identity_register_and_free(struct kauth_identity *kip)
                if (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM)) {
                        /* if there's an old one, discard it */
                        const char *oname = NULL;
-                       if (ip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM))
+                       if (ip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM)) {
                                oname = ip->ki_name;
+                       }
                        ip->ki_name = kip->ki_name;
                        kip->ki_name = oname;
                }
@@ -1125,7 +1298,7 @@ kauth_identity_register_and_free(struct kauth_identity *kip)
                 * if it pushes us over our limit, discard the oldest one.
                 */
                TAILQ_INSERT_HEAD(&kauth_identities, kip, ki_link);
-               if (++kauth_identity_count > KAUTH_IDENTITY_CACHEMAX) {
+               if (++kauth_identity_count > kauth_identity_cachemax) {
                        ip = TAILQ_LAST(&kauth_identities, kauth_identity_head);
                        TAILQ_REMOVE(&kauth_identities, ip, ki_link);
                        kauth_identity_count--;
@@ -1135,8 +1308,9 @@ kauth_identity_register_and_free(struct kauth_identity *kip)
        /* have to drop lock before freeing expired entry (it may be in use) */
        if (ip != NULL) {
                /* if the ki_name field is used, clear it first */
-               if (ip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM))
+               if (ip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM)) {
                        vfs_removename(ip->ki_name);
+               }
                /* free the expired entry */
                FREE(ip, M_KAUTH);
        }
@@ -1189,26 +1363,38 @@ kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_id
         * over the allocation later.
         */
        if (elp->el_flags & (KAUTH_EXTLOOKUP_VALID_PWNAM | KAUTH_EXTLOOKUP_VALID_GRNAM)) {
-               const char *tmp = CAST_DOWN(const char *,extend_data);
+               const char *tmp = CAST_DOWN(const char *, extend_data);
                speculative_name = vfs_addname(tmp, strnlen(tmp, MAXPATHLEN - 1), 0, 0);
        }
-       
+
        /* user identity? */
        if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_UID) {
                KAUTH_IDENTITY_LOCK();
                TAILQ_FOREACH(kip, &kauth_identities, ki_link) {
                        /* matching record */
                        if ((kip->ki_valid & KI_VALID_UID) && (kip->ki_uid == elp->el_uid)) {
+                               if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_SUPGRPS) {
+                                       assert(elp->el_sup_grp_cnt <= NGROUPS);
+                                       if (elp->el_sup_grp_cnt > NGROUPS) {
+                                               KAUTH_DEBUG("CACHE - invalid sup_grp_cnt provided (%d), truncating to  %d",
+                                                   elp->el_sup_grp_cnt, NGROUPS);
+                                               elp->el_sup_grp_cnt = NGROUPS;
+                                       }
+                                       kip->ki_supgrpcnt = elp->el_sup_grp_cnt;
+                                       memcpy(kip->ki_supgrps, elp->el_sup_groups, sizeof(elp->el_sup_groups[0]) * kip->ki_supgrpcnt);
+                                       kip->ki_valid |= KI_VALID_GROUPS;
+                                       kip->ki_groups_expiry = (elp->el_member_valid) ? tv.tv_sec + elp->el_member_valid : 0;
+                               }
                                if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_UGUID) {
                                        kip->ki_guid = elp->el_uguid;
                                        kip->ki_valid |= KI_VALID_GUID;
                                }
-                               kip->ki_guid_expiry = tv.tv_sec + elp->el_uguid_valid;
+                               kip->ki_guid_expiry = (elp->el_uguid_valid) ? tv.tv_sec + elp->el_uguid_valid : 0;
                                if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_USID) {
                                        kip->ki_ntsid = elp->el_usid;
                                        kip->ki_valid |= KI_VALID_NTSID;
                                }
-                               kip->ki_ntsid_expiry = tv.tv_sec + elp->el_usid_valid;
+                               kip->ki_ntsid_expiry = (elp->el_usid_valid) ? tv.tv_sec + elp->el_usid_valid : 0;
                                if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_PWNAM) {
                                        const char *oname = kip->ki_name;
                                        kip->ki_name = speculative_name;
@@ -1223,8 +1409,9 @@ kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_id
                                        }
                                }
                                kauth_identity_lru(kip);
-                               if (rkip != NULL)
+                               if (rkip != NULL) {
                                        *rkip = *kip;
+                               }
                                KAUTH_DEBUG("CACHE - refreshed %d is " K_UUID_FMT, kip->ki_uid, K_UUID_ARG(kip->ki_guid));
                                break;
                        }
@@ -1234,16 +1421,21 @@ kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_id
                if (kip == NULL) {
                        kip = kauth_identity_alloc(elp->el_uid, KAUTH_GID_NONE,
                            (elp->el_flags & KAUTH_EXTLOOKUP_VALID_UGUID) ? &elp->el_uguid : NULL,
-                           tv.tv_sec + elp->el_uguid_valid,
+                           (elp->el_uguid_valid) ? tv.tv_sec + elp->el_uguid_valid : 0,
                            (elp->el_flags & KAUTH_EXTLOOKUP_VALID_USID) ? &elp->el_usid : NULL,
-                           tv.tv_sec + elp->el_usid_valid,
+                           (elp->el_usid_valid) ? tv.tv_sec + elp->el_usid_valid : 0,
+                           (elp->el_flags & KAUTH_EXTLOOKUP_VALID_SUPGRPS) ? elp->el_sup_grp_cnt : 0,
+                           (elp->el_flags & KAUTH_EXTLOOKUP_VALID_SUPGRPS) ? elp->el_sup_groups : NULL,
+                           (elp->el_member_valid) ? tv.tv_sec + elp->el_member_valid : 0,
                            (elp->el_flags & KAUTH_EXTLOOKUP_VALID_PWNAM) ? speculative_name : NULL,
                            KI_VALID_PWNAM);
                        if (kip != NULL) {
-                               if (rkip != NULL)
+                               if (rkip != NULL) {
                                        *rkip = *kip;
-                               if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_PWNAM)
+                               }
+                               if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_PWNAM) {
                                        speculative_name = NULL;
+                               }
                                KAUTH_DEBUG("CACHE - learned %d is " K_UUID_FMT, kip->ki_uid, K_UUID_ARG(kip->ki_guid));
                                kauth_identity_register_and_free(kip);
                        }
@@ -1260,12 +1452,12 @@ kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_id
                                        kip->ki_guid = elp->el_gguid;
                                        kip->ki_valid |= KI_VALID_GUID;
                                }
-                               kip->ki_guid_expiry = tv.tv_sec + elp->el_gguid_valid;
+                               kip->ki_guid_expiry = (elp->el_gguid_valid) ? tv.tv_sec + elp->el_gguid_valid : 0;
                                if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GSID) {
                                        kip->ki_ntsid = elp->el_gsid;
                                        kip->ki_valid |= KI_VALID_NTSID;
                                }
-                               kip->ki_ntsid_expiry = tv.tv_sec + elp->el_gsid_valid;
+                               kip->ki_ntsid_expiry = (elp->el_gsid_valid) ? tv.tv_sec + elp->el_gsid_valid : 0;
                                if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GRNAM) {
                                        const char *oname = kip->ki_name;
                                        kip->ki_name = speculative_name;
@@ -1280,8 +1472,9 @@ kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_id
                                        }
                                }
                                kauth_identity_lru(kip);
-                               if (rkip != NULL)
+                               if (rkip != NULL) {
                                        *rkip = *kip;
+                               }
                                KAUTH_DEBUG("CACHE - refreshed %d is " K_UUID_FMT, kip->ki_uid, K_UUID_ARG(kip->ki_guid));
                                break;
                        }
@@ -1291,16 +1484,21 @@ kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_id
                if (kip == NULL) {
                        kip = kauth_identity_alloc(KAUTH_UID_NONE, elp->el_gid,
                            (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GGUID) ? &elp->el_gguid : NULL,
-                           tv.tv_sec + elp->el_gguid_valid,
+                           (elp->el_gguid_valid) ? tv.tv_sec + elp->el_gguid_valid : 0,
                            (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GSID) ? &elp->el_gsid : NULL,
-                           tv.tv_sec + elp->el_gsid_valid,
+                           (elp->el_gsid_valid) ? tv.tv_sec + elp->el_gsid_valid : 0,
+                           (elp->el_flags & KAUTH_EXTLOOKUP_VALID_SUPGRPS) ? elp->el_sup_grp_cnt : 0,
+                           (elp->el_flags & KAUTH_EXTLOOKUP_VALID_SUPGRPS) ? elp->el_sup_groups : NULL,
+                           (elp->el_member_valid) ? tv.tv_sec + elp->el_member_valid : 0,
                            (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GRNAM) ? speculative_name : NULL,
                            KI_VALID_GRNAM);
                        if (kip != NULL) {
-                               if (rkip != NULL)
+                               if (rkip != NULL) {
                                        *rkip = *kip;
-                               if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GRNAM)
+                               }
+                               if (elp->el_flags & KAUTH_EXTLOOKUP_VALID_GRNAM) {
                                        speculative_name = NULL;
+                               }
                                KAUTH_DEBUG("CACHE - learned %d is " K_UUID_FMT, kip->ki_uid, K_UUID_ARG(kip->ki_guid));
                                kauth_identity_register_and_free(kip);
                        }
@@ -1314,6 +1512,26 @@ kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_id
 }
 
 
+/*
+ * Trim older entries from the identity cache.
+ *
+ * Must be called with the identity cache lock held.
+ */
+static void
+kauth_identity_trimcache(int newsize)
+{
+       struct kauth_identity           *kip;
+
+       lck_mtx_assert(kauth_identity_mtx, LCK_MTX_ASSERT_OWNED);
+
+       while (kauth_identity_count > newsize) {
+               kip = TAILQ_LAST(&kauth_identities, kauth_identity_head);
+               TAILQ_REMOVE(&kauth_identities, kip, ki_link);
+               kauth_identity_count--;
+               FREE(kip, M_KAUTH);
+       }
+}
+
 /*
  * kauth_identity_lru
  *
@@ -1357,9 +1575,17 @@ kauth_identity_guid_expired(struct kauth_identity *kip)
 {
        struct timeval tv;
 
+       /*
+        * Expiration time of 0 means this entry is persistent.
+        */
+       if (kip->ki_guid_expiry == 0) {
+               return 0;
+       }
+
        microuptime(&tv);
-       KAUTH_DEBUG("CACHE - GUID expires @ %d now %d", kip->ki_guid_expiry, tv.tv_sec);
-       return((kip->ki_guid_expiry <= tv.tv_sec) ? 1 : 0);
+       KAUTH_DEBUG("CACHE - GUID expires @ %ld now %ld", kip->ki_guid_expiry, tv.tv_sec);
+
+       return (kip->ki_guid_expiry <= tv.tv_sec) ? 1 : 0;
 }
 
 
@@ -1379,11 +1605,47 @@ kauth_identity_ntsid_expired(struct kauth_identity *kip)
 {
        struct timeval tv;
 
+       /*
+        * Expiration time of 0 means this entry is persistent.
+        */
+       if (kip->ki_ntsid_expiry == 0) {
+               return 0;
+       }
+
        microuptime(&tv);
-       KAUTH_DEBUG("CACHE - NTSID expires @ %d now %d", kip->ki_ntsid_expiry, tv.tv_sec);
-       return((kip->ki_ntsid_expiry <= tv.tv_sec) ? 1 : 0);
+       KAUTH_DEBUG("CACHE - NTSID expires @ %ld now %ld", kip->ki_ntsid_expiry, tv.tv_sec);
+
+       return (kip->ki_ntsid_expiry <= tv.tv_sec) ? 1 : 0;
 }
 
+/*
+ * kauth_identity_groups_expired
+ *
+ * Description:        Handle lazy expiration of supplemental group translations.
+ *
+ * Parameters: kip                             kauth identity to check for
+ *                                             groups expiration
+ *
+ * Returns:    1                               Expired
+ *             0                               Not expired
+ */
+static int
+kauth_identity_groups_expired(struct kauth_identity *kip)
+{
+       struct timeval tv;
+
+       /*
+        * Expiration time of 0 means this entry is persistent.
+        */
+       if (kip->ki_groups_expiry == 0) {
+               return 0;
+       }
+
+       microuptime(&tv);
+       KAUTH_DEBUG("CACHE - GROUPS expires @ %ld now %ld\n", kip->ki_groups_expiry, tv.tv_sec);
+
+       return (kip->ki_groups_expiry <= tv.tv_sec) ? 1 : 0;
+}
 
 /*
  * kauth_identity_find_uid
@@ -1412,13 +1674,14 @@ kauth_identity_find_uid(uid_t uid, struct kauth_identity *kir, char *getname)
                        /* Copy via structure assignment */
                        *kir = *kip;
                        /* If a name is wanted and one exists, copy it out */
-                       if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM)))
+                       if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM))) {
                                strlcpy(getname, kip->ki_name, MAXPATHLEN);
+                       }
                        break;
                }
        }
        KAUTH_IDENTITY_UNLOCK();
-       return((kip == NULL) ? ENOENT : 0);
+       return (kip == NULL) ? ENOENT : 0;
 }
 
 
@@ -1449,13 +1712,14 @@ kauth_identity_find_gid(uid_t gid, struct kauth_identity *kir, char *getname)
                        /* Copy via structure assignment */
                        *kir = *kip;
                        /* If a name is wanted and one exists, copy it out */
-                       if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM)))
+                       if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM))) {
                                strlcpy(getname, kip->ki_name, MAXPATHLEN);
+                       }
                        break;
                }
        }
        KAUTH_IDENTITY_UNLOCK();
-       return((kip == NULL) ? ENOENT : 0);
+       return (kip == NULL) ? ENOENT : 0;
 }
 
 
@@ -1489,13 +1753,14 @@ kauth_identity_find_guid(guid_t *guidp, struct kauth_identity *kir, char *getnam
                        /* Copy via structure assignment */
                        *kir = *kip;
                        /* If a name is wanted and one exists, copy it out */
-                       if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM)))
+                       if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM))) {
                                strlcpy(getname, kip->ki_name, MAXPATHLEN);
+                       }
                        break;
                }
        }
        KAUTH_IDENTITY_UNLOCK();
-       return((kip == NULL) ? ENOENT : 0);
+       return (kip == NULL) ? ENOENT : 0;
 }
 
 /*
@@ -1505,7 +1770,7 @@ kauth_identity_find_guid(guid_t *guidp, struct kauth_identity *kir, char *getnam
  *
  * Parameters: name                            Pointer to name to find
  *             valid                           KI_VALID_PWNAM or KI_VALID_GRNAM
- *             kir                             Pointer to return aread
+ *             kir                             Pointer to return area
  *
  * Returns:    0                               Found
  *             ENOENT                          Not found
@@ -1528,7 +1793,7 @@ kauth_identity_find_nam(char *name, int valid, struct kauth_identity *kir)
                }
        }
        KAUTH_IDENTITY_UNLOCK();
-       return((kip == NULL) ? ENOENT : 0);
+       return (kip == NULL) ? ENOENT : 0;
 }
 
 
@@ -1562,14 +1827,16 @@ kauth_identity_find_ntsid(ntsid_t *ntsid, struct kauth_identity *kir, char *getn
                        /* Copy via structure assignment */
                        *kir = *kip;
                        /* If a name is wanted and one exists, copy it out */
-                       if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM)))
+                       if (getname != NULL && (kip->ki_valid & (KI_VALID_PWNAM | KI_VALID_GRNAM))) {
                                strlcpy(getname, kip->ki_name, MAXPATHLEN);
+                       }
                        break;
                }
        }
        KAUTH_IDENTITY_UNLOCK();
-       return((kip == NULL) ? ENOENT : 0);
+       return (kip == NULL) ? ENOENT : 0;
 }
+#endif  /* CONFIG_EXT_RESOLVER */
 
 
 /*
@@ -1586,13 +1853,13 @@ guid_t kauth_null_guid;
  * Parameters: guid1                           Pointer to first GUID
  *             guid2                           Pointer to second GUID
  *
- * Returns:    0                               If GUIDs are inequal
+ * Returns:    0                               If GUIDs are unequal
  *             !0                              If GUIDs are equal
  */
 int
 kauth_guid_equal(guid_t *guid1, guid_t *guid2)
 {
-       return(bcmp(guid1, guid2, sizeof(*guid1)) == 0);
+       return bcmp(guid1, guid2, sizeof(*guid1)) == 0;
 }
 
 
@@ -1603,7 +1870,7 @@ kauth_guid_equal(guid_t *guid1, guid_t *guid2)
  *
  * Parameters: guid                            Pointer to GUID to check
  *
- * Returns:    KAUTH_WKG_NOT                   Not a wel known GUID
+ * Returns:    KAUTH_WKG_NOT                   Not a well known GUID
  *             KAUTH_WKG_EVERYBODY             "Everybody"
  *             KAUTH_WKG_NOBODY                "Nobody"
  *             KAUTH_WKG_OWNER                 "Other"
@@ -1612,8 +1879,8 @@ kauth_guid_equal(guid_t *guid1, guid_t *guid2)
 int
 kauth_wellknown_guid(guid_t *guid)
 {
-       static char     fingerprint[] = {0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef};
-       uint32_t                code;
+       static char     fingerprint[] = {0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef};
+       uint32_t                code;
        /*
         * All WKGs begin with the same 12 bytes.
         */
@@ -1622,30 +1889,30 @@ kauth_wellknown_guid(guid_t *guid)
                 * The final 4 bytes are our code (in network byte order).
                 */
                code = OSSwapHostToBigInt32(*(uint32_t *)&guid->g_guid[12]);
-               switch(code) {
+               switch (code) {
                case 0x0000000c:
-                       return(KAUTH_WKG_EVERYBODY);
+                       return KAUTH_WKG_EVERYBODY;
                case 0xfffffffe:
-                       return(KAUTH_WKG_NOBODY);
+                       return KAUTH_WKG_NOBODY;
                case 0x0000000a:
-                       return(KAUTH_WKG_OWNER);
+                       return KAUTH_WKG_OWNER;
                case 0x00000010:
-                       return(KAUTH_WKG_GROUP);
+                       return KAUTH_WKG_GROUP;
                }
        }
-       return(KAUTH_WKG_NOT);
+       return KAUTH_WKG_NOT;
 }
 
 
 /*
  * kauth_ntsid_equal
  *
- * Description:        Determine the equality of two NTSIDs (NT Security Identifiers) 
+ * Description:        Determine the equality of two NTSIDs (NT Security Identifiers)
  *
- * Paramters:  sid1                            Pointer to first NTSID
+ * Parameters: sid1                            Pointer to first NTSID
  *             sid2                            Pointer to second NTSID
  *
- * Returns:    0                               If GUIDs are inequal
+ * Returns:    0                               If GUIDs are unequal
  *             !0                              If GUIDs are equal
  */
 int
@@ -1654,9 +1921,10 @@ kauth_ntsid_equal(ntsid_t *sid1, ntsid_t *sid2)
        /* check sizes for equality, also sanity-check size while we're at it */
        if ((KAUTH_NTSID_SIZE(sid1) == KAUTH_NTSID_SIZE(sid2)) &&
            (KAUTH_NTSID_SIZE(sid1) <= sizeof(*sid1)) &&
-           bcmp(sid1, sid2, KAUTH_NTSID_SIZE(sid1)) == 0)
-               return(1);
-       return(0);
+           bcmp(sid1, sid2, KAUTH_NTSID_SIZE(sid1)) == 0) {
+               return 1;
+       }
+       return 0;
 }
 
 
@@ -1673,7 +1941,6 @@ kauth_ntsid_equal(ntsid_t *sid1, ntsid_t *sid2)
  * be done using it.
  */
 
-static int     kauth_cred_cache_lookup(int from, int to, void *src, void *dst);
 
 
 /*
@@ -1702,12 +1969,12 @@ static int      kauth_cred_cache_lookup(int from, int to, void *src, void *dst);
 static int
 kauth_cred_change_egid(kauth_cred_t cred, gid_t new_egid)
 {
-       int     i;
-       int     displaced = 1;
+       int     i;
+       int     displaced = 1;
 #if radar_4600026
-       int     is_member;
-#endif /* radar_4600026 */
-       gid_t   old_egid = kauth_cred_getgid(cred);
+       int     is_member;
+#endif  /* radar_4600026 */
+       gid_t   old_egid = kauth_cred_getgid(cred);
        posix_cred_t pcred = posix_cred_get(cred);
 
        /* Ignoring the first entry, scan for a match for the new egid */
@@ -1728,12 +1995,12 @@ kauth_cred_change_egid(kauth_cred_t cred, gid_t new_egid)
 #error Fix radar 4600026 first!!!
 
 /*
-This is correct for memberd behaviour, but incorrect for POSIX; to address
-this, we would need to automatically opt-out any SUID/SGID binary, and force
-it to use initgroups to opt back in.  We take the approach of considering it
-opt'ed out in any group of 16 displacement instead, since it's a much more
-conservative approach (i.e. less likely to cause things to break).
-*/
+ *  This is correct for memberd behaviour, but incorrect for POSIX; to address
+ *  this, we would need to automatically opt-out any SUID/SGID binary, and force
+ *  it to use initgroups to opt back in.  We take the approach of considering it
+ *  opt'ed out in any group of 16 displacement instead, since it's a much more
+ *  conservative approach (i.e. less likely to cause things to break).
+ */
 
        /*
         * If we displaced a member of the supplementary groups list of the
@@ -1746,15 +2013,15 @@ conservative approach (i.e. less likely to cause things to break).
        if (displaced && !(pcred->cr_flags & CRF_NOMEMBERD) &&
            kauth_cred_ismember_gid(cred, new_egid, &is_member) == 0 &&
            is_member) {
-               displaced = 0;
+               displaced = 0;
                DEBUG_CRED_CHANGE("kauth_cred_change_egid: reset displaced\n");
        }
-#endif /* radar_4600026 */
+#endif  /* radar_4600026 */
 
        /* set the new EGID into the old spot */
        pcred->cr_groups[0] = new_egid;
 
-       return (displaced);
+       return displaced;
 }
 
 
@@ -1771,7 +2038,7 @@ uid_t
 kauth_cred_getuid(kauth_cred_t cred)
 {
        NULLCRED_CHECK(cred);
-       return(posix_cred_get(cred)->cr_uid);
+       return posix_cred_get(cred)->cr_uid;
 }
 
 
@@ -1788,7 +2055,7 @@ uid_t
 kauth_cred_getruid(kauth_cred_t cred)
 {
        NULLCRED_CHECK(cred);
-       return(posix_cred_get(cred)->cr_ruid);
+       return posix_cred_get(cred)->cr_ruid;
 }
 
 
@@ -1805,7 +2072,7 @@ uid_t
 kauth_cred_getsvuid(kauth_cred_t cred)
 {
        NULLCRED_CHECK(cred);
-       return(posix_cred_get(cred)->cr_svuid);
+       return posix_cred_get(cred)->cr_svuid;
 }
 
 
@@ -1822,7 +2089,7 @@ gid_t
 kauth_cred_getgid(kauth_cred_t cred)
 {
        NULLCRED_CHECK(cred);
-       return(posix_cred_get(cred)->cr_gid);
+       return posix_cred_get(cred)->cr_gid;
 }
 
 
@@ -1839,7 +2106,7 @@ gid_t
 kauth_cred_getrgid(kauth_cred_t cred)
 {
        NULLCRED_CHECK(cred);
-       return(posix_cred_get(cred)->cr_rgid);
+       return posix_cred_get(cred)->cr_rgid;
 }
 
 
@@ -1856,17 +2123,126 @@ gid_t
 kauth_cred_getsvgid(kauth_cred_t cred)
 {
        NULLCRED_CHECK(cred);
-       return(posix_cred_get(cred)->cr_svgid);
+       return posix_cred_get(cred)->cr_svgid;
 }
 
 
+static int      kauth_cred_cache_lookup(int from, int to, void *src, void *dst);
+
+#if CONFIG_EXT_RESOLVER == 0
 /*
- * kauth_cred_guid2pwnam
- *
- * Description:        Fetch PWNAM from GUID
- *
- * Parameters: guidp                           Pointer to GUID to examine
- *             pwnam                           Pointer to user@domain buffer
+ * If there's no resolver, only support a subset of the kauth_cred_x2y() lookups.
+ */
+static __inline int
+kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
+{
+       /* NB: These must match the definitions used by Libinfo's mbr_identifier_translate(). */
+       static const uuid_t _user_compat_prefix = {0xff, 0xff, 0xee, 0xee, 0xdd, 0xdd, 0xcc, 0xcc, 0xbb, 0xbb, 0xaa, 0xaa, 0x00, 0x00, 0x00, 0x00};
+       static const uuid_t _group_compat_prefix = {0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0x00, 0x00, 0x00, 0x00};
+#define COMPAT_PREFIX_LEN       (sizeof(uuid_t) - sizeof(id_t))
+
+       assert(from != to);
+
+       switch (from) {
+       case KI_VALID_UID: {
+               id_t uid = htonl(*(id_t *)src);
+
+               if (to == KI_VALID_GUID) {
+                       uint8_t *uu = dst;
+                       memcpy(uu, _user_compat_prefix, sizeof(_user_compat_prefix));
+                       memcpy(&uu[COMPAT_PREFIX_LEN], &uid, sizeof(uid));
+                       return 0;
+               }
+               break;
+       }
+       case KI_VALID_GID: {
+               id_t gid = htonl(*(id_t *)src);
+
+               if (to == KI_VALID_GUID) {
+                       uint8_t *uu = dst;
+                       memcpy(uu, _group_compat_prefix, sizeof(_group_compat_prefix));
+                       memcpy(&uu[COMPAT_PREFIX_LEN], &gid, sizeof(gid));
+                       return 0;
+               }
+               break;
+       }
+       case KI_VALID_GUID: {
+               const uint8_t *uu = src;
+
+               if (to == KI_VALID_UID) {
+                       if (memcmp(uu, _user_compat_prefix, COMPAT_PREFIX_LEN) == 0) {
+                               id_t uid;
+                               memcpy(&uid, &uu[COMPAT_PREFIX_LEN], sizeof(uid));
+                               *(id_t *)dst = ntohl(uid);
+                               return 0;
+                       }
+               } else if (to == KI_VALID_GID) {
+                       if (memcmp(uu, _group_compat_prefix, COMPAT_PREFIX_LEN) == 0) {
+                               id_t gid;
+                               memcpy(&gid, &uu[COMPAT_PREFIX_LEN], sizeof(gid));
+                               *(id_t *)dst = ntohl(gid);
+                               return 0;
+                       }
+               }
+               break;
+       }
+       default:
+               /* NOT IMPLEMENTED */
+               break;
+       }
+       return ENOENT;
+}
+#endif
+
+#if defined(CONFIG_EXT_RESOLVER) && (CONFIG_EXT_RESOLVER)
+/*
+ * Structure to hold supplemental groups. Used for impedance matching with
+ * kauth_cred_cache_lookup below.
+ */
+struct supgroups {
+       int *count;
+       gid_t *groups;
+};
+
+/*
+ * kauth_cred_uid2groups
+ *
+ * Description:        Fetch supplemental GROUPS from UID
+ *
+ * Parameters: uid                             UID to examine
+ *             groups                          pointer to an array of gid_ts
+ *             gcount                          pointer to the number of groups wanted/returned
+ *
+ * Returns:    0                               Success
+ *     kauth_cred_cache_lookup:EINVAL
+ *
+ * Implicit returns:
+ *             *groups                         Modified, if successful
+ *             *gcount                         Modified, if successful
+ *
+ */
+static int
+kauth_cred_uid2groups(uid_t *uid, gid_t *groups, int *gcount)
+{
+       int rv;
+
+       struct supgroups supgroups;
+       supgroups.count = gcount;
+       supgroups.groups = groups;
+
+       rv = kauth_cred_cache_lookup(KI_VALID_UID, KI_VALID_GROUPS, uid, &supgroups);
+
+       return rv;
+}
+#endif
+
+/*
+ * kauth_cred_guid2pwnam
+ *
+ * Description:        Fetch PWNAM from GUID
+ *
+ * Parameters: guidp                           Pointer to GUID to examine
+ *             pwnam                           Pointer to user@domain buffer
  *
  * Returns:    0                               Success
  *     kauth_cred_cache_lookup:EINVAL
@@ -1879,7 +2255,7 @@ kauth_cred_getsvgid(kauth_cred_t cred)
 int
 kauth_cred_guid2pwnam(guid_t *guidp, char *pwnam)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_PWNAM, guidp, pwnam));
+       return kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_PWNAM, guidp, pwnam);
 }
 
 
@@ -1902,7 +2278,7 @@ kauth_cred_guid2pwnam(guid_t *guidp, char *pwnam)
 int
 kauth_cred_guid2grnam(guid_t *guidp, char *grnam)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_GRNAM, guidp, grnam));
+       return kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_GRNAM, guidp, grnam);
 }
 
 
@@ -1926,7 +2302,7 @@ kauth_cred_guid2grnam(guid_t *guidp, char *grnam)
 int
 kauth_cred_pwnam2guid(char *pwnam, guid_t *guidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_PWNAM, KI_VALID_GUID, pwnam, guidp));
+       return kauth_cred_cache_lookup(KI_VALID_PWNAM, KI_VALID_GUID, pwnam, guidp);
 }
 
 
@@ -1950,7 +2326,7 @@ kauth_cred_pwnam2guid(char *pwnam, guid_t *guidp)
 int
 kauth_cred_grnam2guid(char *grnam, guid_t *guidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_GRNAM, KI_VALID_GUID, grnam, guidp));
+       return kauth_cred_cache_lookup(KI_VALID_GRNAM, KI_VALID_GUID, grnam, guidp);
 }
 
 
@@ -1971,7 +2347,7 @@ kauth_cred_grnam2guid(char *grnam, guid_t *guidp)
 int
 kauth_cred_guid2uid(guid_t *guidp, uid_t *uidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_UID, guidp, uidp));
+       return kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_UID, guidp, uidp);
 }
 
 
@@ -1992,9 +2368,48 @@ kauth_cred_guid2uid(guid_t *guidp, uid_t *uidp)
 int
 kauth_cred_guid2gid(guid_t *guidp, gid_t *gidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_GID, guidp, gidp));
+       return kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_GID, guidp, gidp);
+}
+
+/*
+ * kauth_cred_nfs4domain2dsnode
+ *
+ * Description: Fetch dsnode from nfs4domain
+ *
+ * Parameters: nfs4domain                      Pointer to a string nfs4 domain
+ *             dsnode                          Pointer to buffer for dsnode
+ *
+ * Returns:    0                               Success
+ *             ENOENT                          For now just a stub that always fails
+ *
+ * Implicit returns:
+ *             *dsnode                         Modified, if successuful
+ */
+int
+kauth_cred_nfs4domain2dsnode(__unused char *nfs4domain, __unused char *dsnode)
+{
+       return ENOENT;
 }
 
+/*
+ * kauth_cred_dsnode2nfs4domain
+ *
+ * Description: Fetch nfs4domain from dsnode
+ *
+ * Parameters: nfs4domain                      Pointer to  string dsnode
+ *             dsnode                          Pointer to buffer for nfs4domain
+ *
+ * Returns:    0                               Success
+ *             ENOENT                          For now just a stub that always fails
+ *
+ * Implicit returns:
+ *             *nfs4domain                     Modified, if successuful
+ */
+int
+kauth_cred_dsnode2nfs4domain(__unused char *dsnode, __unused char *nfs4domain)
+{
+       return ENOENT;
+}
 
 /*
  * kauth_cred_ntsid2uid
@@ -2013,7 +2428,7 @@ kauth_cred_guid2gid(guid_t *guidp, gid_t *gidp)
 int
 kauth_cred_ntsid2uid(ntsid_t *sidp, uid_t *uidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_NTSID, KI_VALID_UID, sidp, uidp));
+       return kauth_cred_cache_lookup(KI_VALID_NTSID, KI_VALID_UID, sidp, uidp);
 }
 
 
@@ -2034,7 +2449,7 @@ kauth_cred_ntsid2uid(ntsid_t *sidp, uid_t *uidp)
 int
 kauth_cred_ntsid2gid(ntsid_t *sidp, gid_t *gidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_NTSID, KI_VALID_GID, sidp, gidp));
+       return kauth_cred_cache_lookup(KI_VALID_NTSID, KI_VALID_GID, sidp, gidp);
 }
 
 
@@ -2055,7 +2470,7 @@ kauth_cred_ntsid2gid(ntsid_t *sidp, gid_t *gidp)
 int
 kauth_cred_ntsid2guid(ntsid_t *sidp, guid_t *guidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_NTSID, KI_VALID_GUID, sidp, guidp));
+       return kauth_cred_cache_lookup(KI_VALID_NTSID, KI_VALID_GUID, sidp, guidp);
 }
 
 
@@ -2076,7 +2491,7 @@ kauth_cred_ntsid2guid(ntsid_t *sidp, guid_t *guidp)
 int
 kauth_cred_uid2guid(uid_t uid, guid_t *guidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_UID, KI_VALID_GUID, &uid, guidp));
+       return kauth_cred_cache_lookup(KI_VALID_UID, KI_VALID_GUID, &uid, guidp);
 }
 
 
@@ -2098,7 +2513,7 @@ int
 kauth_cred_getguid(kauth_cred_t cred, guid_t *guidp)
 {
        NULLCRED_CHECK(cred);
-       return(kauth_cred_uid2guid(kauth_cred_getuid(cred), guidp));
+       return kauth_cred_uid2guid(kauth_cred_getuid(cred), guidp);
 }
 
 
@@ -2119,7 +2534,7 @@ kauth_cred_getguid(kauth_cred_t cred, guid_t *guidp)
 int
 kauth_cred_gid2guid(gid_t gid, guid_t *guidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_GID, KI_VALID_GUID, &gid, guidp));
+       return kauth_cred_cache_lookup(KI_VALID_GID, KI_VALID_GUID, &gid, guidp);
 }
 
 
@@ -2140,7 +2555,7 @@ kauth_cred_gid2guid(gid_t gid, guid_t *guidp)
 int
 kauth_cred_uid2ntsid(uid_t uid, ntsid_t *sidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_UID, KI_VALID_NTSID, &uid, sidp));
+       return kauth_cred_cache_lookup(KI_VALID_UID, KI_VALID_NTSID, &uid, sidp);
 }
 
 
@@ -2162,7 +2577,7 @@ int
 kauth_cred_getntsid(kauth_cred_t cred, ntsid_t *sidp)
 {
        NULLCRED_CHECK(cred);
-       return(kauth_cred_uid2ntsid(kauth_cred_getuid(cred), sidp));
+       return kauth_cred_uid2ntsid(kauth_cred_getuid(cred), sidp);
 }
 
 
@@ -2183,7 +2598,7 @@ kauth_cred_getntsid(kauth_cred_t cred, ntsid_t *sidp)
 int
 kauth_cred_gid2ntsid(gid_t gid, ntsid_t *sidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_GID, KI_VALID_NTSID, &gid, sidp));
+       return kauth_cred_cache_lookup(KI_VALID_GID, KI_VALID_NTSID, &gid, sidp);
 }
 
 
@@ -2204,7 +2619,7 @@ kauth_cred_gid2ntsid(gid_t gid, ntsid_t *sidp)
 int
 kauth_cred_guid2ntsid(guid_t *guidp, ntsid_t *sidp)
 {
-       return(kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_NTSID, guidp, sidp));
+       return kauth_cred_cache_lookup(KI_VALID_GUID, KI_VALID_NTSID, guidp, sidp);
 }
 
 
@@ -2225,6 +2640,7 @@ kauth_cred_guid2ntsid(guid_t *guidp, ntsid_t *sidp)
  * Returns:    0                               Success
  *             EINVAL                          Unknown source identity type
  */
+#if CONFIG_EXT_RESOLVER
 static int
 kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
 {
@@ -2236,7 +2652,7 @@ kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
        char *namebuf = NULL;
 
        KAUTH_DEBUG("CACHE - translate %d to %d", from, to);
-       
+
        /*
         * Look for an existing cache entry for this association.
         * If the entry has not expired, return the cached information.
@@ -2245,10 +2661,14 @@ kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
         * atomically.
         */
        if (to == KI_VALID_PWNAM || to == KI_VALID_GRNAM) {
+               if (dst == NULL) {
+                       return EINVAL;
+               }
                namebuf = dst;
+               *namebuf = '\0';
        }
        ki.ki_valid = 0;
-       switch(from) {
+       switch (from) {
        case KI_VALID_UID:
                error = kauth_identity_find_uid(*(uid_t *)src, &ki, namebuf);
                break;
@@ -2267,7 +2687,11 @@ kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
                error = kauth_identity_find_nam((char *)src, from, &ki);
                break;
        default:
-               return(EINVAL);
+               return EINVAL;
+       }
+       /* If we didn't get what we're asking for. Call the resolver */
+       if (!error && !(to & ki.ki_valid)) {
+               error = ENOENT;
        }
        /* lookup failure or error */
        if (error != 0) {
@@ -2275,19 +2699,22 @@ kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
                if (error != ENOENT) {
                        /* XXX bogus check - this is not possible */
                        KAUTH_DEBUG("CACHE - cache search error %d", error);
-                       return(error);
+                       return error;
                }
        } else {
                /* found a valid cached entry, check expiry */
-               switch(to) {
+               switch (to) {
                case KI_VALID_GUID:
                        expired = kauth_identity_guid_expired;
                        break;
                case KI_VALID_NTSID:
                        expired = kauth_identity_ntsid_expired;
                        break;
+               case KI_VALID_GROUPS:
+                       expired = kauth_identity_groups_expired;
+                       break;
                default:
-                       switch(from) {
+                       switch (from) {
                        case KI_VALID_GUID:
                                expired = kauth_identity_guid_expired;
                                break;
@@ -2314,40 +2741,41 @@ kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
                                 * get a result from the resolver, we will use it as
                                 * a better-than nothing alternative.
                                 */
-                               
+
                                KAUTH_DEBUG("CACHE - expired entry found");
                        }
                } else {
                        KAUTH_DEBUG("CACHE - no expiry function");
                }
-               
+
                if (!expired) {
                        /* do we have a translation? */
                        if (ki.ki_valid & to) {
                                KAUTH_DEBUG("CACHE - found matching entry with valid 0x%08x", ki.ki_valid);
+                               DTRACE_PROC4(kauth__identity__cache__hit, int, from, int, to, void *, src, void *, dst);
                                goto found;
                        } else {
                                /*
-                                * GUIDs and NTSIDs map to either a UID or a GID, but not both. 
-                                * If we went looking for a translation from GUID or NTSID and 
-                                * found a translation that wasn't for our desired type, then 
-                                * don't bother calling the resolver. We know that this 
+                                * GUIDs and NTSIDs map to either a UID or a GID, but not both.
+                                * If we went looking for a translation from GUID or NTSID and
+                                * found a translation that wasn't for our desired type, then
+                                * don't bother calling the resolver. We know that this
                                 * GUID/NTSID can't translate to our desired type.
                                 */
-                               switch(from) {
+                               switch (from) {
                                case KI_VALID_GUID:
                                case KI_VALID_NTSID:
-                                       switch(to) {
+                                       switch (to) {
                                        case KI_VALID_GID:
                                                if ((ki.ki_valid & KI_VALID_UID)) {
                                                        KAUTH_DEBUG("CACHE - unexpected entry 0x%08x & %x", ki.ki_valid, KI_VALID_GID);
-                                                       return (ENOENT);
+                                                       return ENOENT;
                                                }
                                                break;
                                        case KI_VALID_UID:
                                                if ((ki.ki_valid & KI_VALID_GID)) {
                                                        KAUTH_DEBUG("CACHE - unexpected entry 0x%08x & %x", ki.ki_valid, KI_VALID_UID);
-                                                       return (ENOENT);
+                                                       return ENOENT;
                                                }
                                                break;
                                        }
@@ -2368,7 +2796,7 @@ kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
         */
        bzero(&el, sizeof(el));
        el.el_info_pid = current_proc()->p_pid;
-       switch(from) {
+       switch (from) {
        case KI_VALID_UID:
                el.el_flags = KAUTH_EXTLOOKUP_VALID_UID;
                el.el_uid = *(uid_t *)src;
@@ -2398,7 +2826,7 @@ kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
                extend_data = CAST_USER_ADDR_T(src);
                break;
        default:
-               return(EINVAL);
+               return EINVAL;
        }
        /*
         * Here we ask for everything all at once, to avoid having to work
@@ -2422,10 +2850,43 @@ kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
                el.el_flags |= KAUTH_EXTLOOKUP_WANT_GRNAM;
                extend_data = CAST_USER_ADDR_T(dst);
        }
+       if (to == KI_VALID_GROUPS) {
+               /* Expensive and only useful for an NFS client not using kerberos */
+               el.el_flags |= KAUTH_EXTLOOKUP_WANT_SUPGRPS;
+               if (ki.ki_valid & KI_VALID_GROUPS) {
+                       /*
+                        * Copy the current supplemental groups for the resolver.
+                        * The resolver should check these groups first and if
+                        * the user (uid) is still a member it should endeavor to
+                        * keep them in the list. Otherwise NFS clients could get
+                        * changing access to server file system objects on each
+                        * expiration.
+                        */
+                       if (ki.ki_supgrpcnt > NGROUPS) {
+                               panic("kauth data structure corrupted. kauth identity 0x%p with %d groups, greater than max of %d",
+                                   &ki, ki.ki_supgrpcnt, NGROUPS);
+                       }
+
+                       el.el_sup_grp_cnt = ki.ki_supgrpcnt;
+
+                       memcpy(el.el_sup_groups, ki.ki_supgrps, sizeof(el.el_sup_groups[0]) * ki.ki_supgrpcnt);
+                       /* Let the resolver know these were the previous valid groups */
+                       el.el_flags |= KAUTH_EXTLOOKUP_VALID_SUPGRPS;
+                       KAUTH_DEBUG("GROUPS: Sending previously valid GROUPS");
+               } else {
+                       KAUTH_DEBUG("GROUPS: no valid groups to send");
+               }
+       }
 
        /* Call resolver */
        KAUTH_DEBUG("CACHE - calling resolver for %x", el.el_flags);
+
+       DTRACE_PROC3(kauth__id__resolver__submitted, int, from, int, to, uintptr_t, src);
+
        error = kauth_resolver_submit(&el, extend_data);
+
+       DTRACE_PROC2(kauth__id__resolver__returned, int, error, struct kauth_identity_extlookup *, &el)
+
        KAUTH_DEBUG("CACHE - resolver returned %d", error);
 
        /* was the external lookup successful? */
@@ -2437,10 +2898,11 @@ kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
                 *
                 * If we came from a name, we know the extend_data is valid.
                 */
-               if (from == KI_VALID_PWNAM)
+               if (from == KI_VALID_PWNAM) {
                        el.el_flags |= KAUTH_EXTLOOKUP_VALID_PWNAM;
-               else if (from == KI_VALID_GRNAM)
+               } else if (from == KI_VALID_GRNAM) {
                        el.el_flags |= KAUTH_EXTLOOKUP_VALID_GRNAM;
+               }
 
                kauth_identity_updatecache(&el, &ki, extend_data);
 
@@ -2452,14 +2914,15 @@ kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
                        error = ENOENT;
                }
        }
-       if (error)
-               return(error);
+       if (error) {
+               return error;
+       }
 found:
        /*
         * Copy from the appropriate struct kauth_identity cache entry
         * structure into the destination buffer area.
         */
-       switch(to) {
+       switch (to) {
        case KI_VALID_UID:
                *(uid_t *)dst = ki.ki_uid;
                break;
@@ -2472,15 +2935,27 @@ found:
        case KI_VALID_NTSID:
                *(ntsid_t *)dst = ki.ki_ntsid;
                break;
+       case KI_VALID_GROUPS: {
+               struct supgroups *gp = (struct supgroups *)dst;
+               u_int32_t limit = ki.ki_supgrpcnt;
+
+               if (gp->count) {
+                       limit = MIN(ki.ki_supgrpcnt, *gp->count);
+                       *gp->count = limit;
+               }
+
+               memcpy(gp->groups, ki.ki_supgrps, sizeof(gid_t) * limit);
+       }
+       break;
        case KI_VALID_PWNAM:
        case KI_VALID_GRNAM:
                /* handled in kauth_resolver_complete() */
                break;
        default:
-               return(EINVAL);
+               return EINVAL;
        }
        KAUTH_DEBUG("CACHE - returned successfully");
-       return(0);
+       return 0;
 }
 
 
@@ -2490,28 +2965,6 @@ found:
  * XXX the linked-list implementation here needs to be optimized.
  */
 
-struct kauth_group_membership {
-       TAILQ_ENTRY(kauth_group_membership) gm_link;
-       uid_t   gm_uid;         /* the identity whose membership we're recording */
-       gid_t   gm_gid;         /* group of which they are a member */
-       time_t  gm_expiry;      /* TTL for the membership */
-       int     gm_flags;
-#define KAUTH_GROUP_ISMEMBER   (1<<0)
-};
-
-TAILQ_HEAD(kauth_groups_head, kauth_group_membership) kauth_groups;
-#define KAUTH_GROUPS_CACHEMAX          100     /* XXX sizing? */
-static int kauth_groups_count;
-
-static lck_mtx_t *kauth_groups_mtx;
-#define KAUTH_GROUPS_LOCK()    lck_mtx_lock(kauth_groups_mtx);
-#define KAUTH_GROUPS_UNLOCK()  lck_mtx_unlock(kauth_groups_mtx);
-
-static int     kauth_groups_expired(struct kauth_group_membership *gm);
-static void    kauth_groups_lru(struct kauth_group_membership *gm);
-static void    kauth_groups_updatecache(struct kauth_identity_extlookup *el);
-
-
 /*
  * kauth_groups_init
  *
@@ -2521,7 +2974,7 @@ static void       kauth_groups_updatecache(struct kauth_identity_extlookup *el);
  *
  * Returns:    (void)
  *
- * Notes:      Intialize the groups cache for use; the group cache is used
+ * Notes:      Initialize the groups cache for use; the group cache is used
  *             to avoid unnecessary calls out to user space.
  *
  *             This function is called from kauth_init() in the file
@@ -2531,7 +2984,7 @@ void
 kauth_groups_init(void)
 {
        TAILQ_INIT(&kauth_groups);
-       kauth_groups_mtx = lck_mtx_alloc_init(kauth_lck_grp, 0/*LCK_ATTR_NULL*/);
+       kauth_groups_mtx = lck_mtx_alloc_init(kauth_lck_grp, 0 /*LCK_ATTR_NULL*/);
 }
 
 
@@ -2551,8 +3004,16 @@ kauth_groups_expired(struct kauth_group_membership *gm)
 {
        struct timeval tv;
 
+       /*
+        * Expiration time of 0 means this entry is persistent.
+        */
+       if (gm->gm_expiry == 0) {
+               return 0;
+       }
+
        microuptime(&tv);
-       return((gm->gm_expiry <= tv.tv_sec) ? 1 : 0);
+
+       return (gm->gm_expiry <= tv.tv_sec) ? 1 : 0;
 }
 
 
@@ -2601,12 +3062,13 @@ kauth_groups_updatecache(struct kauth_identity_extlookup *el)
 {
        struct kauth_group_membership *gm;
        struct timeval tv;
-       
+
        /* need a valid response if we are to cache anything */
        if ((el->el_flags &
-               (KAUTH_EXTLOOKUP_VALID_UID | KAUTH_EXTLOOKUP_VALID_GID | KAUTH_EXTLOOKUP_VALID_MEMBERSHIP)) !=
-           (KAUTH_EXTLOOKUP_VALID_UID | KAUTH_EXTLOOKUP_VALID_GID | KAUTH_EXTLOOKUP_VALID_MEMBERSHIP))
+           (KAUTH_EXTLOOKUP_VALID_UID | KAUTH_EXTLOOKUP_VALID_GID | KAUTH_EXTLOOKUP_VALID_MEMBERSHIP)) !=
+           (KAUTH_EXTLOOKUP_VALID_UID | KAUTH_EXTLOOKUP_VALID_GID | KAUTH_EXTLOOKUP_VALID_MEMBERSHIP)) {
                return;
+       }
 
        microuptime(&tv);
 
@@ -2623,7 +3085,7 @@ kauth_groups_updatecache(struct kauth_identity_extlookup *el)
                        } else {
                                gm->gm_flags &= ~KAUTH_GROUP_ISMEMBER;
                        }
-                       gm->gm_expiry = el->el_member_valid + tv.tv_sec;
+                       gm->gm_expiry = (el->el_member_valid) ? el->el_member_valid + tv.tv_sec : 0;
                        kauth_groups_lru(gm);
                        break;
                }
@@ -2631,8 +3093,9 @@ kauth_groups_updatecache(struct kauth_identity_extlookup *el)
        KAUTH_GROUPS_UNLOCK();
 
        /* if we found an entry to update, stop here */
-       if (gm != NULL)
+       if (gm != NULL) {
                return;
+       }
 
        /* allocate a new record */
        MALLOC(gm, struct kauth_group_membership *, sizeof(*gm), M_KAUTH, M_WAITOK);
@@ -2644,8 +3107,8 @@ kauth_groups_updatecache(struct kauth_identity_extlookup *el)
                } else {
                        gm->gm_flags &= ~KAUTH_GROUP_ISMEMBER;
                }
-               gm->gm_expiry = el->el_member_valid + tv.tv_sec;
-       }               
+               gm->gm_expiry = (el->el_member_valid) ? el->el_member_valid + tv.tv_sec : 0;
+       }
 
        /*
         * Insert the new entry.  Note that it's possible to race ourselves
@@ -2655,7 +3118,7 @@ kauth_groups_updatecache(struct kauth_identity_extlookup *el)
         */
        KAUTH_GROUPS_LOCK();
        TAILQ_INSERT_HEAD(&kauth_groups, gm, gm_link);
-       if (kauth_groups_count++ > KAUTH_GROUPS_CACHEMAX) {
+       if (++kauth_groups_count > kauth_groups_cachemax) {
                gm = TAILQ_LAST(&kauth_groups, kauth_groups_head);
                TAILQ_REMOVE(&kauth_groups, gm, gm_link);
                kauth_groups_count--;
@@ -2665,10 +3128,31 @@ kauth_groups_updatecache(struct kauth_identity_extlookup *el)
        KAUTH_GROUPS_UNLOCK();
 
        /* free expired cache entry */
-       if (gm != NULL)
+       if (gm != NULL) {
                FREE(gm, M_KAUTH);
+       }
 }
 
+/*
+ * Trim older entries from the group membership cache.
+ *
+ * Must be called with the group cache lock held.
+ */
+static void
+kauth_groups_trimcache(int new_size)
+{
+       struct kauth_group_membership *gm;
+
+       lck_mtx_assert(kauth_groups_mtx, LCK_MTX_ASSERT_OWNED);
+
+       while (kauth_groups_count > new_size) {
+               gm = TAILQ_LAST(&kauth_groups, kauth_groups_head);
+               TAILQ_REMOVE(&kauth_groups, gm, gm_link);
+               kauth_groups_count--;
+               FREE(gm, M_KAUTH);
+       }
+}
+#endif  /* CONFIG_EXT_RESOLVER */
 
 /*
  * Group membership KPI
@@ -2687,7 +3171,7 @@ kauth_groups_updatecache(struct kauth_identity_extlookup *el)
  *                                             result of the call
  *
  * Returns:    0                               Success
- *             ENOENT                          Could not proform lookup
+ *             ENOENT                          Could not perform lookup
  *     kauth_resolver_submit:EWOULDBLOCK
  *     kauth_resolver_submit:EINTR
  *     kauth_resolver_submit:ENOMEM
@@ -2702,16 +3186,14 @@ kauth_groups_updatecache(struct kauth_identity_extlookup *el)
  * Notes:      This function guarantees not to modify resultp when returning
  *             an error.
  *
- *             This function effectively checkes the EGID as well, since the
+ *             This function effectively checks the EGID as well, since the
  *             EGID is cr_groups[0] as an implementation detail.
  */
 int
 kauth_cred_ismember_gid(kauth_cred_t cred, gid_t gid, int *resultp)
 {
        posix_cred_t pcred = posix_cred_get(cred);
-       struct kauth_group_membership *gm;
-       struct kauth_identity_extlookup el;
-       int i, error;
+       int i;
 
        /*
         * Check the per-credential list of override groups.
@@ -2722,7 +3204,7 @@ kauth_cred_ismember_gid(kauth_cred_t cred, gid_t gid, int *resultp)
        for (i = 0; i < pcred->cr_ngroups; i++) {
                if (gid == pcred->cr_groups[i]) {
                        *resultp = 1;
-                       return(0);
+                       return 0;
                }
        }
 
@@ -2732,19 +3214,23 @@ kauth_cred_ismember_gid(kauth_cred_t cred, gid_t gid, int *resultp)
         */
        if (pcred->cr_gmuid == KAUTH_UID_NONE) {
                *resultp = 0;
-               return(0);
+               return 0;
        }
-               
-       
+
+#if CONFIG_EXT_RESOLVER
+       struct kauth_group_membership *gm;
+       struct kauth_identity_extlookup el;
+       int error;
+
        /*
         * If the resolver hasn't checked in yet, we are early in the boot
         * phase and the local group list is complete and authoritative.
         */
        if (!kauth_resolver_registered) {
                *resultp = 0;
-               return(0);
+               return 0;
        }
-       
+
        /* TODO: */
        /* XXX check supplementary groups */
        /* XXX check whiteout groups */
@@ -2762,37 +3248,50 @@ kauth_cred_ismember_gid(kauth_cred_t cred, gid_t gid, int *resultp)
        }
 
        /* did we find a membership entry? */
-       if (gm != NULL)
+       if (gm != NULL) {
                *resultp = (gm->gm_flags & KAUTH_GROUP_ISMEMBER) ? 1 : 0;
+       }
        KAUTH_GROUPS_UNLOCK();
 
        /* if we did, we can return now */
-       if (gm != NULL)
-               return(0);
-       
+       if (gm != NULL) {
+               DTRACE_PROC2(kauth__group__cache__hit, int, pcred->cr_gmuid, int, gid);
+               return 0;
+       }
+
        /* nothing in the cache, need to go to userland */
        bzero(&el, sizeof(el));
        el.el_info_pid = current_proc()->p_pid;
        el.el_flags = KAUTH_EXTLOOKUP_VALID_UID | KAUTH_EXTLOOKUP_VALID_GID | KAUTH_EXTLOOKUP_WANT_MEMBERSHIP;
        el.el_uid = pcred->cr_gmuid;
        el.el_gid = gid;
-       el.el_member_valid = 0;         /* XXX set by resolver? */
+       el.el_member_valid = 0;         /* XXX set by resolver? */
+
+       DTRACE_PROC2(kauth__group__resolver__submitted, int, el.el_uid, int, el.el_gid);
+
        error = kauth_resolver_submit(&el, 0ULL);
-       if (error != 0)
-               return(error);
+
+       DTRACE_PROC2(kauth__group__resolver__returned, int, error, int, el.el_flags);
+
+       if (error != 0) {
+               return error;
+       }
        /* save the results from the lookup */
        kauth_groups_updatecache(&el);
 
        /* if we successfully ascertained membership, report */
        if (el.el_flags & KAUTH_EXTLOOKUP_VALID_MEMBERSHIP) {
                *resultp = (el.el_flags & KAUTH_EXTLOOKUP_ISMEMBER) ? 1 : 0;
-               return(0);
+               return 0;
        }
 
-       return(ENOENT);
+       return ENOENT;
+#else
+       *resultp = 0;
+       return 0;
+#endif
 }
 
-
 /*
  * kauth_cred_ismember_guid
  *
@@ -2820,15 +3319,11 @@ kauth_cred_ismember_gid(kauth_cred_t cred, gid_t gid, int *resultp)
  *                                     0       Is not member
  */
 int
-kauth_cred_ismember_guid(kauth_cred_t cred, guid_t *guidp, int *resultp)
+kauth_cred_ismember_guid(__unused kauth_cred_t cred, guid_t *guidp, int *resultp)
 {
-       struct kauth_identity ki;
-       gid_t gid;
-       int error, wkg;
+       int error = 0;
 
-       error = 0;
-       wkg = kauth_wellknown_guid(guidp);
-       switch(wkg) {
+       switch (kauth_wellknown_guid(guidp)) {
        case KAUTH_WKG_NOBODY:
                *resultp = 0;
                break;
@@ -2836,7 +3331,11 @@ kauth_cred_ismember_guid(kauth_cred_t cred, guid_t *guidp, int *resultp)
                *resultp = 1;
                break;
        default:
-#if 6603280
+       {
+               gid_t gid;
+#if CONFIG_EXT_RESOLVER
+               struct kauth_identity ki;
+
                /*
                 * Grovel the identity cache looking for this GUID.
                 * If we find it, and it is for a user record, return
@@ -2860,10 +3359,10 @@ kauth_cred_ismember_guid(kauth_cred_t cred, guid_t *guidp, int *resultp)
                        }
                        if (ki.ki_valid & KI_VALID_UID) {
                                *resultp = 0;
-                               return (0);
+                               return 0;
                        }
                }
-#endif /* 6603280 */
+#endif /* CONFIG_EXT_RESOLVER */
                /*
                 * Attempt to translate the GUID to a GID.  Even if
                 * this fails, we will have primed the cache if it is
@@ -2880,21 +3379,25 @@ kauth_cred_ismember_guid(kauth_cred_t cred, guid_t *guidp, int *resultp)
                                error = 0;
                        }
                } else {
- do_check:
+#if CONFIG_EXT_RESOLVER
+do_check:
+#endif /* CONFIG_EXT_RESOLVER */
                        error = kauth_cred_ismember_gid(cred, gid, resultp);
                }
        }
-       return(error);
+       break;
+       }
+       return error;
 }
 
 /*
  * kauth_cred_gid_subset
  *
- * Description:        Given two credentials, determine if all GIDs associated with 
- *             the first are also associated with the second
+ * Description:        Given two credentials, determine if all GIDs associated with
+ *              the first are also associated with the second
  *
  * Parameters: cred1                           Credential to check for
- *             cred2                           Credential to check in
+ *              cred2                          Credential to check in
  *             resultp                         Pointer to int to contain the
  *                                             result of the call
  *
@@ -2909,7 +3412,7 @@ kauth_cred_ismember_guid(kauth_cred_t cred, guid_t *guidp, int *resultp)
  * Notes:      This function guarantees not to modify resultp when returning
  *             an error.
  */
-int    
+int
 kauth_cred_gid_subset(kauth_cred_t cred1, kauth_cred_t cred2, int *resultp)
 {
        int i, err, res = 1;
@@ -2936,18 +3439,18 @@ kauth_cred_gid_subset(kauth_cred_t cred1, kauth_cred_t cred2, int *resultp)
        }
 
        if (!res && pcred1->cr_rgid != pcred2->cr_rgid &&
-                       pcred1->cr_rgid != pcred2->cr_svgid) {
+           pcred1->cr_rgid != pcred2->cr_svgid) {
                *resultp = 0;
                return 0;
        }
 
        /* Finally, check saved gid */
-       if ((err = kauth_cred_ismember_gid(cred2, pcred1->cr_svgid, &res)) != 0){
+       if ((err = kauth_cred_ismember_gid(cred2, pcred1->cr_svgid, &res)) != 0) {
                return err;
        }
 
        if (!res && pcred1->cr_svgid != pcred2->cr_rgid &&
-                       pcred1->cr_svgid != pcred2->cr_svgid) {
+           pcred1->cr_svgid != pcred2->cr_svgid) {
                *resultp = 0;
                return 0;
        }
@@ -2974,7 +3477,7 @@ kauth_cred_gid_subset(kauth_cred_t cred1, kauth_cred_t cred2, int *resultp)
 int
 kauth_cred_issuser(kauth_cred_t cred)
 {
-       return(kauth_cred_getuid(cred) == 0);
+       return kauth_cred_getuid(cred) == 0;
 }
 
 
@@ -2983,14 +3486,10 @@ kauth_cred_issuser(kauth_cred_t cred)
  */
 
 /* lock protecting credential hash table */
-static lck_mtx_t *kauth_cred_hash_mtx;
-#define KAUTH_CRED_HASH_LOCK()         lck_mtx_lock(kauth_cred_hash_mtx);
-#define KAUTH_CRED_HASH_UNLOCK()       lck_mtx_unlock(kauth_cred_hash_mtx);
-#if KAUTH_CRED_HASH_DEBUG
-#define KAUTH_CRED_HASH_LOCK_ASSERT()  lck_mtx_assert(kauth_cred_hash_mtx, LCK_MTX_ASSERT_OWNED)
-#else  /* !KAUTH_CRED_HASH_DEBUG */
-#define KAUTH_CRED_HASH_LOCK_ASSERT()
-#endif /* !KAUTH_CRED_HASH_DEBUG */
+static lck_mtx_t kauth_cred_hash_mtx;
+#define KAUTH_CRED_HASH_LOCK()          lck_mtx_lock(&kauth_cred_hash_mtx);
+#define KAUTH_CRED_HASH_UNLOCK()        lck_mtx_unlock(&kauth_cred_hash_mtx);
+#define KAUTH_CRED_HASH_LOCK_ASSERT()   LCK_MTX_ASSERT(&kauth_cred_hash_mtx, LCK_MTX_ASSERT_OWNED)
 
 
 /*
@@ -3027,19 +3526,10 @@ static lck_mtx_t *kauth_cred_hash_mtx;
 void
 kauth_cred_init(void)
 {
-       int             i;
-       
-       kauth_cred_hash_mtx = lck_mtx_alloc_init(kauth_lck_grp, 0/*LCK_ATTR_NULL*/);
-       kauth_cred_table_size = kauth_cred_primes[kauth_cred_primes_index];
-
-       /*allocate credential hash table */
-       MALLOC(kauth_cred_table_anchor, struct kauth_cred_entry_head *, 
-                       (sizeof(struct kauth_cred_entry_head) * kauth_cred_table_size), 
-                       M_KAUTH, M_WAITOK | M_ZERO);
-       if (kauth_cred_table_anchor == NULL)
-               panic("startup: kauth_cred_init");
-       for (i = 0; i < kauth_cred_table_size; i++) {
-               TAILQ_INIT(&kauth_cred_table_anchor[i]);
+       lck_mtx_init(&kauth_cred_hash_mtx, kauth_lck_grp, 0 /*LCK_ATTR_NULL*/);
+
+       for (int i = 0; i < KAUTH_CRED_TABLE_SIZE; i++) {
+               LIST_INIT(&kauth_cred_table_anchor[i]);
        }
 }
 
@@ -3057,7 +3547,7 @@ kauth_cred_init(void)
 uid_t
 kauth_getuid(void)
 {
-       return(kauth_cred_getuid(kauth_cred_get()));
+       return kauth_cred_getuid(kauth_cred_get());
 }
 
 
@@ -3074,7 +3564,7 @@ kauth_getuid(void)
 uid_t
 kauth_getruid(void)
 {
-       return(kauth_cred_getruid(kauth_cred_get()));
+       return kauth_cred_getruid(kauth_cred_get());
 }
 
 
@@ -3091,7 +3581,7 @@ kauth_getruid(void)
 gid_t
 kauth_getgid(void)
 {
-       return(kauth_cred_getgid(kauth_cred_get()));
+       return kauth_cred_getgid(kauth_cred_get());
 }
 
 
@@ -3108,7 +3598,7 @@ kauth_getgid(void)
 gid_t
 kauth_getrgid(void)
 {
-       return(kauth_cred_getrgid(kauth_cred_get()));
+       return kauth_cred_getrgid(kauth_cred_get());
 }
 
 
@@ -3142,8 +3632,9 @@ kauth_cred_get(void)
 
        uthread = get_bsdthread_info(current_thread());
        /* sanity */
-       if (uthread == NULL)
+       if (uthread == NULL) {
                panic("thread wants credential but has no BSD thread info");
+       }
        /*
         * We can lazy-bind credentials to threads, as long as their processes
         * have them.
@@ -3152,11 +3643,12 @@ kauth_cred_get(void)
         * XXX should probably be called out in a function.
         */
        if (uthread->uu_ucred == NOCRED) {
-               if ((p = (proc_t) get_bsdtask_info(get_threadtask(current_thread()))) == NULL)
+               if ((p = (proc_t) get_bsdtask_info(get_threadtask(current_thread()))) == NULL) {
                        panic("thread wants credential but has no BSD process");
+               }
                uthread->uu_ucred = kauth_cred_proc_ref(p);
        }
-       return(uthread->uu_ucred);
+       return uthread->uu_ucred;
 }
 
 void
@@ -3195,8 +3687,9 @@ kauth_cred_uthread_update(uthread_t uthread, proc_t proc)
            (uthread->uu_flag & UT_SETUID) == 0) {
                kauth_cred_t old = uthread->uu_ucred;
                uthread->uu_ucred = kauth_cred_proc_ref(proc);
-               if (IS_VALID_CRED(old))
+               if (IS_VALID_CRED(old)) {
                        kauth_cred_unref(&old);
+               }
        }
 }
 
@@ -3228,15 +3721,7 @@ kauth_cred_uthread_update(uthread_t uthread, proc_t proc)
 kauth_cred_t
 kauth_cred_get_with_ref(void)
 {
-       struct proc *procp;
-       struct uthread *uthread;
-
-       uthread = get_bsdthread_info(current_thread());
-       /* sanity checks */
-       if (uthread == NULL)
-               panic("%s - thread wants credential but has no BSD thread info", __FUNCTION__);
-       if ((procp = (proc_t) get_bsdtask_info(get_threadtask(current_thread()))) == NULL)
-               panic("%s - thread wants credential but has no BSD process", __FUNCTION__);
+       struct uthread *uthread = current_uthread();
 
        /*
         * We can lazy-bind credentials to threads, as long as their processes
@@ -3247,11 +3732,11 @@ kauth_cred_get_with_ref(void)
         */
        if (uthread->uu_ucred == NOCRED) {
                /* take reference for new cred in thread */
-               uthread->uu_ucred = kauth_cred_proc_ref(procp);
+               uthread->uu_ucred = kauth_cred_proc_ref(current_proc());
        }
        /* take a reference for our caller */
        kauth_cred_ref(uthread->uu_ucred);
-       return(uthread->uu_ucred);
+       return uthread->uu_ucred;
 }
 
 
@@ -3267,7 +3752,7 @@ kauth_cred_get_with_ref(void)
  * Returns:    (kauth_cred_t)                  Pointer to the process's
  *                                             newly referenced credential
  *
- * Locks:      PROC_LOCK is held before taking the reference and released
+ * Locks:      PROC_UCRED_LOCK is held before taking the reference and released
  *             after the refeence is taken to protect the p_ucred field of
  *             the process referred to by procp.
  *
@@ -3287,16 +3772,15 @@ kauth_cred_get_with_ref(void)
 kauth_cred_t
 kauth_cred_proc_ref(proc_t procp)
 {
-       kauth_cred_t    cred;
-       
-       proc_lock(procp);
+       kauth_cred_t    cred;
+
+       proc_ucred_lock(procp);
        cred = proc_ucred(procp);
        kauth_cred_ref(cred);
-       proc_unlock(procp);
-       return(cred);
+       proc_ucred_unlock(procp);
+       return cred;
 }
 
-
 /*
  * kauth_cred_alloc
  *
@@ -3309,8 +3793,8 @@ kauth_cred_proc_ref(proc_t procp)
  *
  * Notes:      The newly allocated credential is zero'ed as part of the
  *             allocation process, with the exception of the reference
- *             count, which is set to 1 to indicate a single reference
- *             held by the caller.
+ *             count, which is set to 0 to indicate the caller still has
+ *             to call kauth_cred_add().
  *
  *             Since newly allocated credentials have no external pointers
  *             referencing them, prior to making them visible in an externally
@@ -3337,37 +3821,44 @@ kauth_cred_proc_ref(proc_t procp)
  *             than returning a NULL pointer; the code that calls this
  *             function needs to be audited before this can be changed.
  */
-kauth_cred_t
+static kauth_cred_t
 kauth_cred_alloc(void)
 {
        kauth_cred_t newcred;
-       
-       MALLOC_ZONE(newcred, kauth_cred_t, sizeof(*newcred), M_CRED, M_WAITOK);
+
+       MALLOC_ZONE(newcred, kauth_cred_t, sizeof(*newcred), M_CRED, M_WAITOK | M_ZERO);
+       assert(newcred);
        if (newcred != 0) {
                posix_cred_t newpcred = posix_cred_get(newcred);
-               bzero(newcred, sizeof(*newcred));
-               newcred->cr_ref = 1;
                newcred->cr_audit.as_aia_p = audit_default_aia_p;
                /* must do this, or cred has same group membership as uid 0 */
                newpcred->cr_gmuid = KAUTH_UID_NONE;
-#if CRED_DIAGNOSTIC
-       } else {
-               panic("kauth_cred_alloc: couldn't allocate credential");
-#endif         
+#if CONFIG_MACF
+               mac_cred_label_init(newcred);
+#endif
        }
+       return newcred;
+}
 
-#if KAUTH_CRED_HASH_DEBUG
-       kauth_cred_count++;
-#endif
 
+/*
+ * kauth_cred_free
+ *
+ * Description: Destroy a credential
+ *
+ * Parameters: cred                            Credential to destroy.
+ */
+static void
+kauth_cred_free(kauth_cred_t cred)
+{
+       assert(os_atomic_load(&cred->cr_ref, relaxed) == 0);
 #if CONFIG_MACF
-       mac_cred_label_init(newcred);
+       mac_cred_label_destroy(cred);
 #endif
-
-       return(newcred);
+       AUDIT_SESSION_UNREF(cred);
+       FREE_ZONE(cred, sizeof(*cred), M_CRED);
 }
 
-
 /*
  * kauth_cred_create
  *
@@ -3388,21 +3879,14 @@ kauth_cred_alloc(void)
  *             maintain this field, we can't expect callers to know how it
  *             needs to be set.  Callers should be prepared for this field
  *             to be overwritten.
- *
- * XXX:                This code will tight-loop if memory for a new credential is
- *             persistently unavailable; this is perhaps not the wisest way
- *             to handle this condition, but current callers do not expect
- *             a failure.
  */
 kauth_cred_t
 kauth_cred_create(kauth_cred_t cred)
 {
-       kauth_cred_t    found_cred, new_cred = NULL;
-       posix_cred_t    pcred = posix_cred_get(cred);
+       kauth_cred_t    found_cred, new_cred = NULL;
+       posix_cred_t    pcred = posix_cred_get(cred);
        int is_member = 0;
 
-       KAUTH_CRED_HASH_LOCK_ASSERT();
-
        if (pcred->cr_flags & CRF_NOMEMBERD) {
                pcred->cr_gmuid = KAUTH_UID_NONE;
        } else {
@@ -3440,63 +3924,33 @@ kauth_cred_create(kauth_cred_t cred)
        }
 
        /* Caller *must* specify at least the egid in cr_groups[0] */
-       if (pcred->cr_ngroups < 1)
-               return(NULL);
-       
-       for (;;) {
-               KAUTH_CRED_HASH_LOCK();
-               found_cred = kauth_cred_find(cred);
-               if (found_cred != NULL) {
-                       /*
-                        * Found an existing credential so we'll bump
-                        * reference count and return
-                        */
-                       kauth_cred_ref(found_cred);
-                       KAUTH_CRED_HASH_UNLOCK();
-                       return(found_cred);
-               }
-               KAUTH_CRED_HASH_UNLOCK();
-       
-               /*
-                * No existing credential found.  Create one and add it to
-                * our hash table.
-                */
-               new_cred = kauth_cred_alloc();
-               if (new_cred != NULL) {
-                       int             err;
-                       posix_cred_t    new_pcred = posix_cred_get(new_cred);
-                       new_pcred->cr_uid = pcred->cr_uid;
-                       new_pcred->cr_ruid = pcred->cr_ruid;
-                       new_pcred->cr_svuid = pcred->cr_svuid;
-                       new_pcred->cr_rgid = pcred->cr_rgid;
-                       new_pcred->cr_svgid = pcred->cr_svgid;
-                       new_pcred->cr_gmuid = pcred->cr_gmuid;
-                       new_pcred->cr_ngroups = pcred->cr_ngroups;      
-                       bcopy(&pcred->cr_groups[0], &new_pcred->cr_groups[0], sizeof(new_pcred->cr_groups));
+       if (pcred->cr_ngroups < 1) {
+               return NULL;
+       }
+
+       struct kauth_cred_entry_head *bucket = kauth_cred_get_bucket(cred);
+
+       KAUTH_CRED_HASH_LOCK();
+       found_cred = kauth_cred_find_and_ref(cred, bucket);
+       KAUTH_CRED_HASH_UNLOCK();
+       if (found_cred != NULL) {
+               return found_cred;
+       }
+
+       /*
+        * No existing credential found.  Create one and add it to
+        * our hash table.
+        */
+       new_cred = kauth_cred_alloc();
+       if (new_cred != NULL) {
+               *posix_cred_get(new_cred) = *pcred;
 #if CONFIG_AUDIT
-                       bcopy(&cred->cr_audit, &new_cred->cr_audit, 
-                           sizeof(new_cred->cr_audit));
-#endif
-                       new_pcred->cr_flags = pcred->cr_flags;
-                       
-                       KAUTH_CRED_HASH_LOCK();
-                       err = kauth_cred_add(new_cred);
-                       KAUTH_CRED_HASH_UNLOCK();
-                       
-                       /* Retry if kauth_cred_add returns non zero value */
-                       if (err == 0)
-                               break;
-#if CONFIG_MACF
-                       mac_cred_label_destroy(new_cred);
+               new_cred->cr_audit = cred->cr_audit;
 #endif
-                       AUDIT_SESSION_UNREF(new_cred);
-
-                       FREE_ZONE(new_cred, sizeof(*new_cred), M_CRED);
-                       new_cred = NULL;
-               }
+               new_cred = kauth_cred_add(new_cred, bucket);
        }
 
-       return(new_cred);
+       return new_cred;
 }
 
 
@@ -3550,7 +4004,7 @@ kauth_cred_setresuid(kauth_cred_t cred, uid_t ruid, uid_t euid, uid_t svuid, uid
            (svuid == KAUTH_UID_NONE || pcred->cr_svuid == svuid) &&
            (pcred->cr_gmuid == gmuid)) {
                /* no change needed */
-               return(cred);
+               return cred;
        }
 
        /*
@@ -3577,7 +4031,7 @@ kauth_cred_setresuid(kauth_cred_t cred, uid_t ruid, uid_t euid, uid_t svuid, uid
                temp_pcred->cr_flags |= CRF_NOMEMBERD;
        }
 
-       return(kauth_cred_update(cred, &temp_cred, TRUE));
+       return kauth_cred_update(cred, &temp_cred, TRUE);
 }
 
 
@@ -3610,7 +4064,7 @@ kauth_cred_setresuid(kauth_cred_t cred, uid_t ruid, uid_t euid, uid_t svuid, uid
 kauth_cred_t
 kauth_cred_setresgid(kauth_cred_t cred, gid_t rgid, gid_t egid, gid_t svgid)
 {
-       struct ucred    temp_cred;
+       struct ucred    temp_cred;
        posix_cred_t temp_pcred = posix_cred_get(&temp_cred);
        posix_cred_t pcred = posix_cred_get(cred);
 
@@ -3618,14 +4072,14 @@ kauth_cred_setresgid(kauth_cred_t cred, gid_t rgid, gid_t egid, gid_t svgid)
        DEBUG_CRED_ENTER("kauth_cred_setresgid %p %d %d %d\n", cred, rgid, egid, svgid);
 
        /*
-        * We don't need to do anything if the given GID are already the 
+        * We don't need to do anything if the given GID are already the
         * same as the GIDs in the credential.
         */
        if (pcred->cr_groups[0] == egid &&
            pcred->cr_rgid == rgid &&
            pcred->cr_svgid == svgid) {
                /* no change needed */
-               return(cred);
+               return cred;
        }
 
        /*
@@ -3650,13 +4104,13 @@ kauth_cred_setresgid(kauth_cred_t cred, gid_t rgid, gid_t egid, gid_t svgid)
                temp_pcred->cr_svgid = svgid;
        }
 
-       return(kauth_cred_update(cred, &temp_cred, TRUE));
+       return kauth_cred_update(cred, &temp_cred, TRUE);
 }
 
 
 /*
- * Update the given credential with the given groups.  We only allocate a new 
- *     credential when the given gid actually results in changes to the existing 
+ * Update the given credential with the given groups.  We only allocate a new
+ *     credential when the given gid actually results in changes to the existing
  *     credential.
  *     The gmuid argument supplies a new uid (or KAUTH_UID_NONE to opt out)
  *     which will be used for group membership checking.
@@ -3670,7 +4124,7 @@ kauth_cred_setresgid(kauth_cred_t cred, gid_t rgid, gid_t egid, gid_t svgid)
  * Parameters: cred                            The original credential
  *             groups                          Pointer to gid_t array which
  *                                             contains the new group list
- *             groupcount                      The cound of valid groups which
+ *             groupcount                      The count of valid groups which
  *                                             are contained in 'groups'
  *             gmuid                           KAUTH_UID_NONE -or- the new
  *                                             group membership UID
@@ -3693,7 +4147,7 @@ kauth_cred_setresgid(kauth_cred_t cred, gid_t rgid, gid_t egid, gid_t svgid)
  *             that is returned to them, if it is not intended to be a
  *             persistent reference.
  *
- * XXX:                Changes are determined in ordinal order - if the caller pasess
+ * XXX:                Changes are determined in ordinal order - if the caller passes
  *             in the same groups list that is already present in the
  *             credential, but the members are in a different order, even if
  *             the EGID is not modified (i.e. cr_groups[0] is the same), it
@@ -3706,7 +4160,7 @@ kauth_cred_setresgid(kauth_cred_t cred, gid_t rgid, gid_t egid, gid_t svgid)
 kauth_cred_t
 kauth_cred_setgroups(kauth_cred_t cred, gid_t *groups, int groupcount, uid_t gmuid)
 {
-       int             i;
+       int             i;
        struct ucred temp_cred;
        posix_cred_t temp_pcred = posix_cred_get(&temp_cred);
        posix_cred_t pcred;
@@ -3721,12 +4175,13 @@ kauth_cred_setgroups(kauth_cred_t cred, gid_t *groups, int groupcount, uid_t gmu
         */
        if ((pcred->cr_gmuid == gmuid) && (pcred->cr_ngroups == groupcount)) {
                for (i = 0; i < groupcount; i++) {
-                       if (pcred->cr_groups[i] != groups[i])
+                       if (pcred->cr_groups[i] != groups[i]) {
                                break;
+                       }
                }
                if (i == groupcount) {
                        /* no change needed */
-                       return(cred);
+                       return cred;
                }
        }
 
@@ -3741,26 +4196,53 @@ kauth_cred_setgroups(kauth_cred_t cred, gid_t *groups, int groupcount, uid_t gmu
        temp_pcred->cr_ngroups = groupcount;
        bcopy(groups, temp_pcred->cr_groups, sizeof(temp_pcred->cr_groups));
        temp_pcred->cr_gmuid = gmuid;
-       if (gmuid == KAUTH_UID_NONE)
+       if (gmuid == KAUTH_UID_NONE) {
                temp_pcred->cr_flags |= CRF_NOMEMBERD;
-       else
+       } else {
                temp_pcred->cr_flags &= ~CRF_NOMEMBERD;
+       }
 
-       return(kauth_cred_update(cred, &temp_cred, TRUE));
+       return kauth_cred_update(cred, &temp_cred, TRUE);
 }
 
 /*
- * XXX temporary, for NFS support until we can come up with a better
- * XXX enumeration/comparison mechanism
- *
- * Notes:      The return value exists to account for the possbility of a
+ * Notes:      The return value exists to account for the possibility of a
  *             kauth_cred_t without a POSIX label.  This will be the case in
  *             the future (see posix_cred_get() below, for more details).
  */
+#if CONFIG_EXT_RESOLVER
+int kauth_external_supplementary_groups_supported = 1;
+
+SYSCTL_INT(_kern, OID_AUTO, ds_supgroups_supported, CTLFLAG_RW | CTLFLAG_LOCKED, &kauth_external_supplementary_groups_supported, 0, "");
+#endif
+
 int
 kauth_cred_getgroups(kauth_cred_t cred, gid_t *grouplist, int *countp)
 {
        int limit = NGROUPS;
+       posix_cred_t pcred;
+
+       pcred = posix_cred_get(cred);
+
+#if CONFIG_EXT_RESOLVER
+       /*
+        * If we've not opted out of using the resolver, then convert the cred to a list
+        * of supplemental groups. We do this only if there has been a resolver to talk to,
+        * since we may be too early in boot, or in an environment that isn't using DS.
+        */
+       if (kauth_identitysvc_has_registered && kauth_external_supplementary_groups_supported && (pcred->cr_flags & CRF_NOMEMBERD) == 0) {
+               uid_t uid = kauth_cred_getuid(cred);
+               int err;
+
+               err = kauth_cred_uid2groups(&uid, grouplist, countp);
+               if (!err) {
+                       return 0;
+               }
+
+               /* On error just fall through */
+               KAUTH_DEBUG("kauth_cred_getgroups failed %d\n", err);
+       }
+#endif /* CONFIG_EXT_RESOLVER */
 
        /*
         * If they just want a copy of the groups list, they may not care
@@ -3769,11 +4251,11 @@ kauth_cred_getgroups(kauth_cred_t cred, gid_t *grouplist, int *countp)
         * and limit the returned list to that size.
         */
        if (countp) {
-               limit = MIN(*countp, cred->cr_posix.cr_ngroups);
+               limit = MIN(*countp, pcred->cr_ngroups);
                *countp = limit;
        }
 
-       memcpy(grouplist, cred->cr_posix.cr_groups, sizeof(gid_t) * limit);
+       memcpy(grouplist, pcred->cr_groups, sizeof(gid_t) * limit);
 
        return 0;
 }
@@ -3830,9 +4312,9 @@ kauth_cred_setuidgid(kauth_cred_t cred, uid_t uid, gid_t gid)
         * user IDs are already the same as the user ID passed into us.
         */
        if (pcred->cr_uid == uid && pcred->cr_ruid == uid && pcred->cr_svuid == uid &&
-               pcred->cr_gid == gid && pcred->cr_rgid == gid && pcred->cr_svgid == gid) {
+           pcred->cr_gid == gid && pcred->cr_rgid == gid && pcred->cr_svgid == gid) {
                /* no change needed */
-               return(cred);
+               return cred;
        }
 
        /*
@@ -3864,7 +4346,7 @@ kauth_cred_setuidgid(kauth_cred_t cred, uid_t uid, gid_t gid)
        temp_cred.cr_label = cred->cr_label;
 #endif
 
-       return(kauth_cred_update(cred, &temp_cred, TRUE));
+       return kauth_cred_update(cred, &temp_cred, TRUE);
 }
 
 
@@ -3912,7 +4394,7 @@ kauth_cred_setsvuidgid(kauth_cred_t cred, uid_t uid, gid_t gid)
         */
        if (pcred->cr_svuid == uid && pcred->cr_svgid == gid) {
                /* no change needed */
-               return(cred);
+               return cred;
        }
        DEBUG_CRED_CHANGE("kauth_cred_setsvuidgid: cred change\n");
 
@@ -3923,13 +4405,13 @@ kauth_cred_setsvuidgid(kauth_cred_t cred, uid_t uid, gid_t gid)
        temp_pcred->cr_svuid = uid;
        temp_pcred->cr_svgid = gid;
 
-       return(kauth_cred_update(cred, &temp_cred, TRUE));
+       return kauth_cred_update(cred, &temp_cred, TRUE);
 }
 
 
 /*
  * kauth_cred_setauditinfo
- * 
+ *
  * Description:        Update the given credential using the given au_session_t.
  *
  * Parameters: cred                            The original credential
@@ -3962,19 +4444,19 @@ kauth_cred_setauditinfo(kauth_cred_t cred, au_session_t *auditinfo_p)
         */
        if (bcmp(&cred->cr_audit, auditinfo_p, sizeof(cred->cr_audit)) == 0) {
                /* no change needed */
-               return(cred);
+               return cred;
        }
 
        bcopy(cred, &temp_cred, sizeof(temp_cred));
        bcopy(auditinfo_p, &temp_cred.cr_audit, sizeof(temp_cred.cr_audit));
 
-       return(kauth_cred_update(cred, &temp_cred, FALSE));
+       return kauth_cred_update(cred, &temp_cred, FALSE);
 }
 
 #if CONFIG_MACF
 /*
  * kauth_cred_label_update
- * 
+ *
  * Description:        Update the MAC label associated with a credential
  *
  * Parameters: cred                            The original credential
@@ -4008,12 +4490,12 @@ kauth_cred_label_update(kauth_cred_t cred, struct label *label)
 
        newcred = kauth_cred_update(cred, &temp_cred, TRUE);
        mac_cred_label_destroy(&temp_cred);
-       return (newcred);
+       return newcred;
 }
 
 /*
  * kauth_cred_label_update_execve
- * 
+ *
  * Description:        Update the MAC label associated with a credential as
  *             part of exec
  *
@@ -4042,11 +4524,12 @@ kauth_cred_label_update(kauth_cred_t cred, struct label *label)
  *             that is returned to them, if it is not intended to be a
  *             persistent reference.
  */
+
 static
 kauth_cred_t
 kauth_cred_label_update_execve(kauth_cred_t cred, vfs_context_t ctx,
-       struct vnode *vp, struct label *scriptl, struct label *execl,
-       int *disjointp)
+    struct vnode *vp, off_t offset, struct vnode *scriptvp, struct label *scriptl,
+    struct label *execl, unsigned int *csflags, void *macextensions, int *disjointp, int *labelupdateerror)
 {
        kauth_cred_t newcred;
        struct ucred temp_cred;
@@ -4055,12 +4538,13 @@ kauth_cred_label_update_execve(kauth_cred_t cred, vfs_context_t ctx,
 
        mac_cred_label_init(&temp_cred);
        mac_cred_label_associate(cred, &temp_cred);
-       *disjointp = mac_cred_label_update_execve(ctx, &temp_cred, 
-                                                    vp, scriptl, execl);
+       mac_cred_label_update_execve(ctx, &temp_cred,
+           vp, offset, scriptvp, scriptl, execl, csflags,
+           macextensions, disjointp, labelupdateerror);
 
        newcred = kauth_cred_update(cred, &temp_cred, TRUE);
        mac_cred_label_destroy(&temp_cred);
-       return (newcred);
+       return newcred;
 }
 
 /*
@@ -4075,7 +4559,8 @@ kauth_cred_label_update_execve(kauth_cred_t cred, vfs_context_t ctx,
  *                             of this call.  The caller should not assume the process reference to
  *                             the old credential still exists.
  */
-int kauth_proc_label_update(struct proc *p, struct label *label)
+int
+kauth_proc_label_update(struct proc *p, struct label *label)
 {
        kauth_cred_t my_cred, my_new_cred;
 
@@ -4085,20 +4570,18 @@ int kauth_proc_label_update(struct proc *p, struct label *label)
 
        /* get current credential and take a reference while we muck with it */
        for (;;) {
-
-               /* 
+               /*
                 * Set the credential with new info.  If there is no change,
                 * we get back the same credential we passed in; if there is
                 * a change, we drop the reference on the credential we
                 * passed in.  The subsequent compare is safe, because it is
                 * a pointer compare rather than a contents compare.
-                */
+                */
                my_new_cred = kauth_cred_label_update(my_cred, label);
                if (my_cred != my_new_cred) {
-
                        DEBUG_CRED_CHANGE("kauth_proc_setlabel_unlocked CH(%d): %p/0x%08x -> %p/0x%08x\n", p->p_pid, my_cred, my_cred->cr_flags, my_new_cred, my_new_cred->cr_flags);
 
-                       proc_lock(p);
+                       proc_ucred_lock(p);
                        /*
                         * We need to protect for a race where another thread
                         * also changed the credential after we took our
@@ -4106,7 +4589,7 @@ int kauth_proc_label_update(struct proc *p, struct label *label)
                         * restart this again with the new cred.
                         */
                        if (p->p_ucred != my_cred) {
-                               proc_unlock(p);
+                               proc_ucred_unlock(p);
                                kauth_cred_unref(&my_new_cred);
                                my_cred = kauth_cred_proc_ref(p);
                                /* try again */
@@ -4116,15 +4599,14 @@ int kauth_proc_label_update(struct proc *p, struct label *label)
                        /* update cred on proc */
                        PROC_UPDATE_CREDS_ONPROC(p);
 
-                       mac_proc_set_enforce(p, MAC_ALL_ENFORCE);
-                       proc_unlock(p);
+                       proc_ucred_unlock(p);
                }
                break;
        }
        /* Drop old proc reference or our extra reference */
        kauth_cred_unref(&my_cred);
-       
-       return (0);
+
+       return 0;
 }
 
 /*
@@ -4140,6 +4622,8 @@ int kauth_proc_label_update(struct proc *p, struct label *label)
  *             vp                      The vnode being exec'ed
  *             scriptl                 The script MAC label
  *             execl                   The executable MAC label
+ *             lupdateerror    The error place holder for MAC label authority
+ *                                             to update about possible termination
  *
  * Returns:    0                       Label update did not make credential
  *                                     disjoint
@@ -4150,33 +4634,31 @@ int kauth_proc_label_update(struct proc *p, struct label *label)
  *             result of this call.  The caller should not assume the process
  *             reference to the old credential still exists.
  */
-int
+
+void
 kauth_proc_label_update_execve(struct proc *p, vfs_context_t ctx,
-       struct vnode *vp, struct label *scriptl, struct label *execl)
+    struct vnode *vp, off_t offset, struct vnode *scriptvp, struct label *scriptl,
+    struct label *execl, unsigned int *csflags, void *macextensions, int *disjoint, int *update_return)
 {
        kauth_cred_t my_cred, my_new_cred;
-       int disjoint = 0;
-
        my_cred = kauth_cred_proc_ref(p);
 
        DEBUG_CRED_ENTER("kauth_proc_label_update_execve: %p\n", my_cred);
 
        /* get current credential and take a reference while we muck with it */
        for (;;) {
-
-               /* 
+               /*
                 * Set the credential with new info.  If there is no change,
                 * we get back the same credential we passed in; if there is
                 * a change, we drop the reference on the credential we
                 * passed in.  The subsequent compare is safe, because it is
                 * a pointer compare rather than a contents compare.
-                */
-               my_new_cred = kauth_cred_label_update_execve(my_cred, ctx, vp, scriptl, execl, &disjoint);
+                */
+               my_new_cred = kauth_cred_label_update_execve(my_cred, ctx, vp, offset, scriptvp, scriptl, execl, csflags, macextensions, disjoint, update_return);
                if (my_cred != my_new_cred) {
-
                        DEBUG_CRED_CHANGE("kauth_proc_label_update_execve_unlocked CH(%d): %p/0x%08x -> %p/0x%08x\n", p->p_pid, my_cred, my_cred->cr_flags, my_new_cred, my_new_cred->cr_flags);
 
-                       proc_lock(p);
+                       proc_ucred_lock(p);
                        /*
                         * We need to protect for a race where another thread
                         * also changed the credential after we took our
@@ -4184,7 +4666,7 @@ kauth_proc_label_update_execve(struct proc *p, vfs_context_t ctx,
                         * restart this again with the new cred.
                         */
                        if (p->p_ucred != my_cred) {
-                               proc_unlock(p);
+                               proc_ucred_unlock(p);
                                kauth_cred_unref(&my_new_cred);
                                my_cred = kauth_cred_proc_ref(p);
                                /* try again */
@@ -4193,22 +4675,19 @@ kauth_proc_label_update_execve(struct proc *p, vfs_context_t ctx,
                        p->p_ucred = my_new_cred;
                        /* update cred on proc */
                        PROC_UPDATE_CREDS_ONPROC(p);
-                       mac_proc_set_enforce(p, MAC_ALL_ENFORCE);
-                       proc_unlock(p);
+                       proc_ucred_unlock(p);
                }
                break;
        }
        /* Drop old proc reference or our extra reference */
        kauth_cred_unref(&my_cred);
-       
-       return (disjoint);
 }
 
 #if 1
 /*
  * for temporary binary compatibility
  */
-kauth_cred_t   kauth_cred_setlabel(kauth_cred_t cred, struct label *label);
+kauth_cred_t    kauth_cred_setlabel(kauth_cred_t cred, struct label *label);
 kauth_cred_t
 kauth_cred_setlabel(kauth_cred_t cred, struct label *label)
 {
@@ -4225,27 +4704,27 @@ kauth_proc_setlabel(struct proc *p, struct label *label)
 
 #else
 
-/* this is a temp hack to cover us when MACF is not built in a kernel configuration. 
+/* this is a temp hack to cover us when MACF is not built in a kernel configuration.
  * Since we cannot build our export lists based on the kernel configuration we need
- * to define a stub. 
+ * to define a stub.
  */
 kauth_cred_t
 kauth_cred_label_update(__unused kauth_cred_t cred, __unused void *label)
 {
-       return(NULL);
+       return NULL;
 }
 
 int
 kauth_proc_label_update(__unused struct proc *p, __unused void *label)
 {
-       return (0);
+       return 0;
 }
 
 #if 1
 /*
  * for temporary binary compatibility
  */
-kauth_cred_t   kauth_cred_setlabel(kauth_cred_t cred, void *label);
+kauth_cred_t    kauth_cred_setlabel(kauth_cred_t cred, void *label);
 kauth_cred_t
 kauth_cred_setlabel(__unused kauth_cred_t cred, __unused void *label)
 {
@@ -4256,11 +4735,72 @@ int kauth_proc_setlabel(struct proc *p, void *label);
 int
 kauth_proc_setlabel(__unused struct proc *p, __unused void *label)
 {
-       return (0);
+       return 0;
 }
 #endif
 #endif
 
+// TODO: move to os_refcnt once the ABI issue is resolved
+
+#define KAUTH_CRED_REF_MAX 0x0ffffffful
+
+__attribute__((noinline, cold, noreturn))
+static void
+kauth_cred_panic_resurrection(kauth_cred_t cred)
+{
+       panic("kauth_cred_unref: cred %p resurrected", cred);
+       __builtin_unreachable();
+}
+
+__attribute__((noinline, cold, noreturn))
+static void
+kauth_cred_panic_over_released(kauth_cred_t cred)
+{
+       panic("kauth_cred_unref: cred %p over-released", cred);
+       __builtin_unreachable();
+}
+
+__attribute__((noinline, cold, noreturn))
+static void
+kauth_cred_panic_over_retain(kauth_cred_t cred)
+{
+       panic("kauth_cred_ref: cred %p over-retained", cred);
+       __builtin_unreachable();
+}
+
+/*
+ * kauth_cred_tryref
+ *
+ * Description:        Tries to take a reference, used from kauth_cred_find_and_ref
+ *             to debounce the race with kauth_cred_unref.
+ *
+ * Parameters: cred                            The credential to reference
+ *
+ * Returns:    (bool)                          Whether the reference was taken
+ */
+static inline bool
+kauth_cred_tryref(kauth_cred_t cred)
+{
+       u_long old_ref, new_ref;
+       os_atomic_rmw_loop(&cred->cr_ref, old_ref, new_ref, relaxed, {
+               if (old_ref == 0) {
+                       os_atomic_rmw_loop_give_up(return false);
+               }
+               new_ref = old_ref + 1;
+       });
+       if (__improbable(old_ref >= KAUTH_CRED_REF_MAX)) {
+               kauth_cred_panic_over_retain(cred);
+       }
+
+#if 0 // use this to watch a specific credential
+       if (is_target_cred( *credp ) != 0) {
+               get_backtrace();
+       }
+#endif
+
+       return true;
+}
+
 /*
  * kauth_cred_ref
  *
@@ -4269,112 +4809,60 @@ kauth_proc_setlabel(__unused struct proc *p, __unused void *label)
  * Parameters: cred                            The credential to reference
  *
  * Returns:    (void)
- *
- * Notes:      This function adds a reference to the provided credential;
- *             the existing reference on the credential is assumed to be
- *             held stable over this operation by taking the appropriate
- *             lock to protect the pointer from which it is being referenced,
- *             if necessary (e.g. the proc lock is held over the call if the
- *             credential being referenced is from p_ucred, the vnode lock
- *             if from the per vnode name cache cred cache, and so on).
- *
- *             This is safe from the kauth_cred_unref() path, since an atomic
- *             add is used, and the unref path specifically checks to see that
- *             the value has not been changed to add a reference between the
- *             time the credential is unreferenced by another pointer and the
- *             time it is unreferenced from the cred hash cache.
  */
 void
 kauth_cred_ref(kauth_cred_t cred)
 {
-       int             old_value;
-       
-       NULLCRED_CHECK(cred);
-
-       old_value = OSAddAtomicLong(1, (long*)&cred->cr_ref);
+       u_long old_ref = os_atomic_inc_orig(&cred->cr_ref, relaxed);
 
-       if (old_value < 1)
-               panic("kauth_cred_ref: trying to take a reference on a cred with no references");
+       if (__improbable(old_ref < 1)) {
+               kauth_cred_panic_resurrection(cred);
+       }
+       if (__improbable(old_ref >= KAUTH_CRED_REF_MAX)) {
+               kauth_cred_panic_over_retain(cred);
+       }
 
 #if 0 // use this to watch a specific credential
-       if ( is_target_cred( cred ) != 0 ) {
-               get_backtrace( );
+       if (is_target_cred( cred ) != 0) {
+               get_backtrace();
        }
 #endif
-               
-       return;
 }
 
-
 /*
- * kauth_cred_unref_hashlocked
+ * kauth_cred_unref_fast
  *
- * Description:        release a credential reference; when the last reference is
- *             released, the credential will be freed.
+ * Description:        Release a credential reference.
  *
  * Parameters: credp                           Pointer to address containing
  *                                             credential to be freed
  *
- * Returns:    (void)
- *
- * Implicit returns:
- *             *credp                          Set to NOCRED
- *
- * Notes:      This function assumes the credential hash lock is held.
- *
- *             This function is internal use only, since the hash lock is
- *             scoped to this compilation unit.
- *
- *             This function destroys the contents of the pointer passed by
- *             the caller to prevent the caller accidently attempting to
- *             release a given reference twice in error.
+ * Returns:    true                            This was the last reference.
+ *             false                           The object has more refs.
  *
- *             The last reference is considered to be released when a release
- *             of a credential of a reference count of 2 occurs; this is an
- *             intended effect, to take into accout the reference held by
- *             the credential hash, which is released at the same time.
  */
-static void
-kauth_cred_unref_hashlocked(kauth_cred_t *credp)
+static inline bool
+kauth_cred_unref_fast(kauth_cred_t cred)
 {
-       int             old_value;
-
-       KAUTH_CRED_HASH_LOCK_ASSERT();
-       NULLCRED_CHECK(*credp);
-
-       old_value = OSAddAtomicLong(-1, (long*)&(*credp)->cr_ref);
-
-#if DIAGNOSTIC
-       if (old_value == 0)
-               panic("%s:0x%08x kauth_cred_unref_hashlocked: dropping a reference on a cred with no references", current_proc()->p_comm, *credp);
-       if (old_value == 1)
-               panic("%s:0x%08x kauth_cred_unref_hashlocked: dropping a reference on a cred with no hash entry", current_proc()->p_comm, *credp);
-#endif
+       u_long old_ref = os_atomic_dec_orig(&cred->cr_ref, relaxed);
 
 #if 0 // use this to watch a specific credential
-       if ( is_target_cred( *credp ) != 0 ) {
-               get_backtrace( );
+       if (is_target_cred( *credp ) != 0) {
+               get_backtrace();
        }
 #endif
 
-       /*
-        * If the old_value is 2, then we have just released the last external
-        * reference to this credential
-        */
-       if (old_value < 3) {
-               /* The last absolute reference is our credential hash table */
-               kauth_cred_remove(*credp);
+       if (__improbable(old_ref <= 0)) {
+               kauth_cred_panic_over_released(cred);
        }
-       *credp = NOCRED;
+       return old_ref == 1;
 }
 
-
 /*
  * kauth_cred_unref
  *
- * Description:        Release a credential reference while holding the credential
- *             hash lock; when the last reference is released, the credential
- *             will be freed.
+ * Description:        Release a credential reference.
+ *             Frees the credential if it is the last ref.
  *
  * Parameters: credp                           Pointer to address containing
  *                                             credential to be freed
@@ -4384,15 +4872,18 @@ kauth_cred_unref_hashlocked(kauth_cred_t *credp)
  * Implicit returns:
  *             *credp                          Set to NOCRED
  *
- * Notes:      See kauth_cred_unref_hashlocked() for more information.
- *
  */
 void
 kauth_cred_unref(kauth_cred_t *credp)
 {
-       KAUTH_CRED_HASH_LOCK();
-       kauth_cred_unref_hashlocked(credp);
-       KAUTH_CRED_HASH_UNLOCK();
+       if (kauth_cred_unref_fast(*credp)) {
+               KAUTH_CRED_HASH_LOCK();
+               kauth_cred_remove_locked(*credp);
+               KAUTH_CRED_HASH_UNLOCK();
+               kauth_cred_free(*credp);
+       }
+
+       *credp = NOCRED;
 }
 
 
@@ -4440,18 +4931,18 @@ kauth_cred_rele(kauth_cred_t cred)
  *
  *             The newly allocated credential is copied as part of the
  *             allocation process, with the exception of the reference
- *             count, which is set to 1 to indicate a single reference
- *             held by the caller.
+ *             count, which is set to 0 to indicate the caller still has
+ *             to call kauth_cred_add().
  *
  *             Since newly allocated credentials have no external pointers
  *             referencing them, prior to making them visible in an externally
  *             visible pointer (e.g. by adding them to the credential hash
  *             cache) is the only legal time in which an existing credential
- *             can be safely iinitialized or modified directly.
+ *             can be safely initialized or modified directly.
  *
  *             After initialization, the caller is expected to call the
  *             function kauth_cred_add() to add the credential to the hash
- *             cache, after which time it's frozen and becomes publically
+ *             cache, after which time it's frozen and becomes publicly
  *             visible.
  *
  *             The release protocol depends on kauth_hash_add() being called
@@ -4459,32 +4950,24 @@ kauth_cred_rele(kauth_cred_t cred)
  *             will trigger if this protocol is not observed).
  *
  */
-kauth_cred_t
+static kauth_cred_t
 kauth_cred_dup(kauth_cred_t cred)
 {
        kauth_cred_t newcred;
-#if CONFIG_MACF
-       struct label *temp_label;
-#endif
-       
-#if CRED_DIAGNOSTIC
-       if (cred == NOCRED || cred == FSCRED)
-               panic("kauth_cred_dup: bad credential");
-#endif
+
+       assert(cred != NOCRED && cred != FSCRED);
        newcred = kauth_cred_alloc();
        if (newcred != NULL) {
-#if CONFIG_MACF
-               temp_label = newcred->cr_label;
+               newcred->cr_posix = cred->cr_posix;
+#if CONFIG_AUDIT
+               newcred->cr_audit = cred->cr_audit;
 #endif
-               bcopy(cred, newcred, sizeof(*newcred));
 #if CONFIG_MACF
-               newcred->cr_label = temp_label;
                mac_cred_label_associate(cred, newcred);
 #endif
                AUDIT_SESSION_REF(cred);
-               newcred->cr_ref = 1;
        }
-       return(newcred);
+       return newcred;
 }
 
 /*
@@ -4502,7 +4985,7 @@ kauth_cred_dup(kauth_cred_t cred)
  *             result, the caller is responsible for dropping BOTH the
  *             additional reference on the passed cred (if any), and the
  *             credential returned by this function.  The drop should be
- *             via the satnadr kauth_cred_unref() KPI.
+ *             via the kauth_cred_unref() KPI.
  */
 kauth_cred_t
 kauth_cred_copy_real(kauth_cred_t cred)
@@ -4516,7 +4999,7 @@ kauth_cred_copy_real(kauth_cred_t cred)
        if ((pcred->cr_ruid == pcred->cr_uid) &&
            (pcred->cr_rgid == pcred->cr_gid)) {
                kauth_cred_ref(cred);
-               return(cred);
+               return cred;
        }
 
        /*
@@ -4534,50 +5017,26 @@ kauth_cred_copy_real(kauth_cred_t cred)
         * If the cred is not opted out, make sure we are using the r/euid
         * for group checks
         */
-       if (temp_pcred->cr_gmuid != KAUTH_UID_NONE)
+       if (temp_pcred->cr_gmuid != KAUTH_UID_NONE) {
                temp_pcred->cr_gmuid = pcred->cr_ruid;
+       }
 
-       for (;;) {
-               int             err;
-               
-               KAUTH_CRED_HASH_LOCK();
-               found_cred = kauth_cred_find(&temp_cred);
-               if (found_cred == cred) {
-                       /* same cred so just bail */
-                       KAUTH_CRED_HASH_UNLOCK();
-                       return(cred); 
-               }
-               if (found_cred != NULL) {
-                       /*
-                        * Found a match so we bump reference count on new
-                        * one.  We leave the old one alone.
-                        */
-                       kauth_cred_ref(found_cred);
-                       KAUTH_CRED_HASH_UNLOCK();
-                       return(found_cred);
-               }
-       
-               /*
-                * Must allocate a new credential, copy in old credential
-                * data and update the real user and group IDs.
-                */
-               newcred = kauth_cred_dup(&temp_cred);
-               err = kauth_cred_add(newcred);
-               KAUTH_CRED_HASH_UNLOCK();
+       struct kauth_cred_entry_head *bucket = kauth_cred_get_bucket(cred);
 
-               /* Retry if kauth_cred_add() fails */
-               if (err == 0)
-                       break;
-#if CONFIG_MACF
-               mac_cred_label_destroy(newcred);
-#endif
-               AUDIT_SESSION_UNREF(newcred);
+       KAUTH_CRED_HASH_LOCK();
+       found_cred = kauth_cred_find_and_ref(&temp_cred, bucket);
+       KAUTH_CRED_HASH_UNLOCK();
 
-               FREE_ZONE(newcred, sizeof(*newcred), M_CRED);
-               newcred = NULL;
+       if (found_cred) {
+               return found_cred;
        }
-       
-       return(newcred);
+
+       /*
+        * Must allocate a new credential, copy in old credential
+        * data and update the real user and group IDs.
+        */
+       newcred = kauth_cred_dup(&temp_cred);
+       return kauth_cred_add(newcred, bucket);
 }
 
 
@@ -4612,64 +5071,65 @@ kauth_cred_copy_real(kauth_cred_t cred)
  */
 static kauth_cred_t
 kauth_cred_update(kauth_cred_t old_cred, kauth_cred_t model_cred,
-       boolean_t retain_auditinfo)
-{      
-       kauth_cred_t found_cred, new_cred = NULL;
-       
+    boolean_t retain_auditinfo)
+{
+       kauth_cred_t cred;
+
        /*
         * Make sure we carry the auditinfo forward to the new credential
         * unless we are actually updating the auditinfo.
         */
        if (retain_auditinfo) {
-               bcopy(&old_cred->cr_audit, &model_cred->cr_audit, 
-                   sizeof(model_cred->cr_audit));
+               model_cred->cr_audit = old_cred->cr_audit;
        }
-       
-       for (;;) {
-               int             err;
 
-               KAUTH_CRED_HASH_LOCK();
-               found_cred = kauth_cred_find(model_cred);
-               if (found_cred == old_cred) {
-                       /* same cred so just bail */
-                       KAUTH_CRED_HASH_UNLOCK();
-                       return(old_cred); 
-               }
-               if (found_cred != NULL) {
-                       DEBUG_CRED_CHANGE("kauth_cred_update(cache hit): %p -> %p\n", old_cred, found_cred);
-                       /*
-                        * Found a match so we bump reference count on new
-                        * one and decrement reference count on the old one.
-                        */
-                       kauth_cred_ref(found_cred);
-                       kauth_cred_unref_hashlocked(&old_cred);
-                       KAUTH_CRED_HASH_UNLOCK();
-                       return(found_cred);
-               }
-       
+       if (kauth_cred_is_equal(old_cred, model_cred)) {
+               return old_cred;
+       }
+
+       struct kauth_cred_entry_head *bucket = kauth_cred_get_bucket(model_cred);
+
+       KAUTH_CRED_HASH_LOCK();
+       cred = kauth_cred_find_and_ref(model_cred, bucket);
+       if (cred != NULL) {
                /*
-                * Must allocate a new credential using the model.  also
-                * adds the new credential to the credential hash table.
+                * We found a hit, so we can get rid of the old_cred.
+                * If we didn't, then we need to keep the old_cred around,
+                * because `model_cred` has copies of things such as the cr_label
+                * or audit session that it has not refcounts for.
                 */
-               new_cred = kauth_cred_dup(model_cred);
-               err = kauth_cred_add(new_cred);
+               bool needs_free = kauth_cred_unref_fast(old_cred);
+               if (needs_free) {
+                       kauth_cred_remove_locked(old_cred);
+               }
                KAUTH_CRED_HASH_UNLOCK();
 
-               /* retry if kauth_cred_add returns non zero value */
-               if (err == 0)
-                       break;
-#if CONFIG_MACF
-               mac_cred_label_destroy(new_cred);
-#endif
-               AUDIT_SESSION_UNREF(new_cred);
-
-               FREE_ZONE(new_cred, sizeof(*new_cred), M_CRED);
-               new_cred = NULL;
+               DEBUG_CRED_CHANGE("kauth_cred_update(cache hit): %p -> %p\n",
+                   old_cred, cred);
+               if (needs_free) {
+                       kauth_cred_free(old_cred);
+               }
+               return cred;
        }
 
-       DEBUG_CRED_CHANGE("kauth_cred_update(cache miss): %p -> %p\n", old_cred, new_cred);
+       KAUTH_CRED_HASH_UNLOCK();
+
+       /*
+        * Must allocate a new credential using the model.  also
+        * adds the new credential to the credential hash table.
+        */
+       cred = kauth_cred_dup(model_cred);
+       cred = kauth_cred_add(cred, bucket);
+       DEBUG_CRED_CHANGE("kauth_cred_update(cache miss): %p -> %p\n",
+           old_cred, cred);
+
+
+       /*
+        * This can't be done before the kauth_cred_dup() as the model_cred
+        * has pointers that old_cred owns references for.
+        */
        kauth_cred_unref(&old_cred);
-       return(new_cred);
+       return cred;
 }
 
 
@@ -4677,108 +5137,105 @@ kauth_cred_update(kauth_cred_t old_cred, kauth_cred_t model_cred,
  * kauth_cred_add
  *
  * Description:        Add the given credential to our credential hash table and
- *             take an additional reference to account for our use of the
- *             credential in the hash table
+ *             take an initial reference to account for the object being
+ *             now valid.
  *
  * Parameters: new_cred                        Credential to insert into cred
- *                                             hash cache
+ *                                             hash cache, or to destroy when
+ *                                             a collision is detected.
  *
- * Returns:    0                               Success
- *             -1                              Hash insertion failed: caller
- *                                             should retry
- *
- * Locks:      Caller is expected to hold KAUTH_CRED_HASH_LOCK
+ * Returns:    (kauth_thread_t)                The inserted cred, or the
+ *                                             collision that was found.
  *
  * Notes:      The 'new_cred' MUST NOT already be in the cred hash cache
  */
-static int
-kauth_cred_add(kauth_cred_t new_cred)
+static kauth_cred_t
+kauth_cred_add(kauth_cred_t new_cred, struct kauth_cred_entry_head *bucket)
 {
-       u_long                  hash_key;
+       kauth_cred_t found_cred;
+       u_long old_ref;
 
-       KAUTH_CRED_HASH_LOCK_ASSERT();
-
-       hash_key = kauth_cred_get_hashkey(new_cred);
-       hash_key %= kauth_cred_table_size;
+       KAUTH_CRED_HASH_LOCK();
+       found_cred = kauth_cred_find_and_ref(new_cred, bucket);
+       if (found_cred) {
+               KAUTH_CRED_HASH_UNLOCK();
+               kauth_cred_free(new_cred);
+               return found_cred;
+       }
 
-       /* race fix - there is a window where another matching credential 
-        * could have been inserted between the time this one was created and we
-        * got the hash lock.  If we find a match return an error and have the 
-        * the caller retry.
-        */
-       if (kauth_cred_find(new_cred) != NULL) {
-               return(-1);
+       old_ref = os_atomic_xchg(&new_cred->cr_ref, 1, relaxed);
+       if (old_ref != 0) {
+               panic("kauth_cred_add: invalid cred %p", new_cred);
        }
-       
-       /* take a reference for our use in credential hash table */ 
-       kauth_cred_ref(new_cred);
 
        /* insert the credential into the hash table */
-       TAILQ_INSERT_HEAD(&kauth_cred_table_anchor[hash_key], new_cred, cr_link);
-       
-       return(0);
-}
+       LIST_INSERT_HEAD(bucket, new_cred, cr_link);
 
+       KAUTH_CRED_HASH_UNLOCK();
+       return new_cred;
+}
 
-/* 
- * kauth_cred_remove
- *
- * Description:        Remove the given credential from our credential hash table
+/*
+ * kauth_cred_remove_locked
  *
- * Parameters: cred                            Credential to remove from cred
- *                                             hash cache
+ * Description:        Remove the given credential from our credential hash table.
  *
- * Returns:    (void)
+ * Parameters: cred                            Credential to remove.
  *
  * Locks:      Caller is expected to hold KAUTH_CRED_HASH_LOCK
- *
- * Notes:      The check for the reference increment after entry is generally
- *             agree to be safe, since we use atomic operations, and the
- *             following code occurs with the hash lock held; in theory, this
- *             protects us from the 2->1 reference that gets us here.
  */
 static void
-kauth_cred_remove(kauth_cred_t cred)
+kauth_cred_remove_locked(kauth_cred_t cred)
 {
-       u_long                  hash_key;
-       kauth_cred_t    found_cred;
-
-       hash_key = kauth_cred_get_hashkey(cred);
-       hash_key %= kauth_cred_table_size;
-
-       /* Avoid race */
-       if (cred->cr_ref < 1)
-               panic("cred reference underflow");
-       if (cred->cr_ref > 1)
-               return;         /* someone else got a ref */
-               
-       /* Find cred in the credential hash table */
-       TAILQ_FOREACH(found_cred, &kauth_cred_table_anchor[hash_key], cr_link) {
-               if (found_cred == cred) {
-                       /* found a match, remove it from the hash table */
-                       TAILQ_REMOVE(&kauth_cred_table_anchor[hash_key], found_cred, cr_link);
-#if CONFIG_MACF
-                       mac_cred_label_destroy(cred);
-#endif
-                       AUDIT_SESSION_UNREF(cred);
+       KAUTH_CRED_HASH_LOCK_ASSERT();
 
-                       cred->cr_ref = 0;
-                       FREE_ZONE(cred, sizeof(*cred), M_CRED);
-#if KAUTH_CRED_HASH_DEBUG
-                       kauth_cred_count--;
-#endif
-                       return;
-               }
+       if (cred->cr_link.le_prev == NULL) {
+               panic("kauth_cred_unref: cred %p never added", cred);
        }
 
-       /* Did not find a match... this should not happen! XXX Make panic? */
-       printf("%s:%d - %s - %s - did not find a match for %p\n", __FILE__, __LINE__, __FUNCTION__, current_proc()->p_comm, cred);
-       return;
+       LIST_REMOVE(cred, cr_link);
 }
 
+/*
+ * kauth_cred_is_equal
+ *
+ * Description:        Returns whether two credentions are identical.
+ *
+ * Parameters: cred1                           Credential to compare
+ *              cred2                          Credential to compare
+ *
+ * Returns:    true                            Credentials are equal
+ *             false                           Credentials are different
+ */
+static bool
+kauth_cred_is_equal(kauth_cred_t cred1, kauth_cred_t cred2)
+{
+       posix_cred_t pcred1 = posix_cred_get(cred1);
+       posix_cred_t pcred2 = posix_cred_get(cred2);
 
-/* 
- * kauth_cred_find
+       /*
+        * don't worry about the label unless the flags in
+        * either credential tell us to.
+        */
+       if (memcmp(pcred1, pcred2, sizeof(*pcred1))) {
+               return false;
+       }
+       if (memcmp(&cred1->cr_audit, &cred2->cr_audit, sizeof(cred1->cr_audit))) {
+               return false;
+       }
+#if CONFIG_MACF
+       /* Note: we know the flags are equal, so we only need to test one */
+       if (pcred1->cr_flags & CRF_MAC_ENFORCE) {
+               if (!mac_cred_label_compare(cred1->cr_label, cred2->cr_label)) {
+                       return false;
+               }
+       }
+#endif
+       return true;
+}
+
+/*
+ * kauth_cred_find_and_ref
  *
  * Description:        Using the given credential data, look for a match in our
  *             credential hash table
@@ -4787,64 +5244,67 @@ kauth_cred_remove(kauth_cred_t cred)
  *                                             hash cache
  *
  * Returns:    NULL                            Not found
- *             !NULL                           Matching cedential already in
- *                                             cred hash cache
+ *             !NULL                           Matching credential already in
+ *                                             cred hash cache, with a +1 ref
  *
  * Locks:      Caller is expected to hold KAUTH_CRED_HASH_LOCK
  */
-kauth_cred_t
-kauth_cred_find(kauth_cred_t cred)
+static kauth_cred_t
+kauth_cred_find_and_ref(kauth_cred_t cred, struct kauth_cred_entry_head *bucket)
 {
-       u_long                  hash_key;
-       kauth_cred_t    found_cred;
-       posix_cred_t pcred = posix_cred_get(cred);
+       kauth_cred_t found_cred;
 
        KAUTH_CRED_HASH_LOCK_ASSERT();
 
-#if KAUTH_CRED_HASH_DEBUG
-       static int              test_count = 0; 
-
-       test_count++;
-       if ((test_count % 200) == 0) {
-               kauth_cred_hash_print();
+       /* Find cred in the credential hash table */
+       LIST_FOREACH(found_cred, bucket, cr_link) {
+               if (kauth_cred_is_equal(found_cred, cred)) {
+                       /*
+                        * newer entries are inserted at the head,
+                        * no hit further in the chain can possibly
+                        * be successfully retained.
+                        */
+                       if (!kauth_cred_tryref(found_cred)) {
+                               found_cred = NULL;
+                       }
+                       break;
+               }
        }
-#endif
 
-       hash_key = kauth_cred_get_hashkey(cred);
-       hash_key %= kauth_cred_table_size;
+       return found_cred;
+}
 
-       /* Find cred in the credential hash table */
-       TAILQ_FOREACH(found_cred, &kauth_cred_table_anchor[hash_key], cr_link) {
-               boolean_t match;
-               posix_cred_t found_pcred = posix_cred_get(found_cred);
+/*
+ * kauth_cred_find
+ *
+ * Description:        This interface is sadly KPI but people can't possibly use it,
+ *             as they need to hold a lock that isn't exposed.
+ *
+ * Parameters: cred                            Credential to lookup in cred
+ *                                             hash cache
+ *
+ * Returns:    NULL                            Not found
+ *             !NULL                           Matching credential already in
+ *                                             cred hash cache
+ *
+ * Locks:      Caller is expected to hold KAUTH_CRED_HASH_LOCK
+ */
+kauth_cred_t
+kauth_cred_find(kauth_cred_t cred)
+{
+       struct kauth_cred_entry_head *bucket = kauth_cred_get_bucket(cred);
+       kauth_cred_t found_cred;
 
-               /*
-                * don't worry about the label unless the flags in
-                * either credential tell us to.
-                */
-               if ((found_pcred->cr_flags & CRF_MAC_ENFORCE) != 0 ||
-                   (pcred->cr_flags & CRF_MAC_ENFORCE) != 0) {
-                       /* include the label pointer in the compare */
-                       match = (bcmp(&found_pcred->cr_uid, &pcred->cr_uid,
-                                (sizeof(struct ucred) -
-                                 offsetof(struct ucred, cr_posix))) == 0);
-               } else {
-                       /* flags have to match, but skip the label in bcmp */
-                       match = (found_pcred->cr_flags == pcred->cr_flags &&
-                                bcmp(&found_pcred->cr_uid, &pcred->cr_uid,
-                                     sizeof(struct posix_cred)) == 0 &&
-                                bcmp(&found_cred->cr_audit, &cred->cr_audit,
-                                     sizeof(cred->cr_audit)) == 0);
+       KAUTH_CRED_HASH_LOCK_ASSERT();
 
-               }
-               if (match) {
-                       /* found a match */
-                       return(found_cred);
+       /* Find cred in the credential hash table */
+       LIST_FOREACH(found_cred, bucket, cr_link) {
+               if (kauth_cred_is_equal(found_cred, cred)) {
+                       break;
                }
        }
-       /* No match found */
 
-       return(NULL);
+       return found_cred;
 }
 
 
@@ -4863,8 +5323,8 @@ kauth_cred_find(kauth_cred_t cred)
 static inline u_long
 kauth_cred_hash(const uint8_t *datap, int data_len, u_long start_key)
 {
-       u_long  hash_key = start_key;
-       u_long  temp;
+       u_long  hash_key = start_key;
+       u_long  temp;
 
        while (data_len > 0) {
                hash_key = (hash_key << 4) + *datap++;
@@ -4875,90 +5335,56 @@ kauth_cred_hash(const uint8_t *datap, int data_len, u_long start_key)
                hash_key &= ~temp;
                data_len--;
        }
-       return(hash_key);
+       return hash_key;
 }
 
 
 /*
- * kauth_cred_get_hashkey
+ * kauth_cred_get_bucket
  *
  * Description:        Generate a hash key using data that makes up a credential;
  *             based on ElfHash.  We hash on the entire credential data,
  *             not including the ref count or the TAILQ, which are mutable;
  *             everything else isn't.
  *
+ *             Returns the bucket correspondong to this hash key.
+ *
  * Parameters: cred                            Credential for which hash is
  *                                             desired
  *
- * Returns:    (u_long)                        Returned hash key
+ * Returns:    (kauth_cred_entry_head *)       Returned bucket.
  *
  * Notes:      When actually moving the POSIX credential into a real label,
  *             remember to update this hash computation.
  */
-static u_long
-kauth_cred_get_hashkey(kauth_cred_t cred)
+static struct kauth_cred_entry_head *
+kauth_cred_get_bucket(kauth_cred_t cred)
 {
+#if CONFIG_MACF
        posix_cred_t pcred = posix_cred_get(cred);
-       u_long  hash_key = 0;
-
+#endif
+       u_long  hash_key = 0;
+
+       hash_key = kauth_cred_hash((uint8_t *)&cred->cr_posix,
+           sizeof(struct posix_cred),
+           hash_key);
+       hash_key = kauth_cred_hash((uint8_t *)&cred->cr_audit,
+           sizeof(struct au_session),
+           hash_key);
+#if CONFIG_MACF
        if (pcred->cr_flags & CRF_MAC_ENFORCE) {
-               hash_key = kauth_cred_hash((uint8_t *)&cred->cr_posix, 
-                                                                  sizeof(struct ucred) - offsetof(struct ucred, cr_posix),
-                                                                  hash_key);
-       } else {
-               /* skip label */
-               hash_key = kauth_cred_hash((uint8_t *)&cred->cr_posix, 
-                                                                  sizeof(struct posix_cred),
-                                                                  hash_key);
-               hash_key = kauth_cred_hash((uint8_t *)&cred->cr_audit, 
-                                                                  sizeof(struct au_session),
-                                                                  hash_key);
-       }
-       return(hash_key);
-}
-
-
-#if KAUTH_CRED_HASH_DEBUG
-/*
- * kauth_cred_hash_print
- *
- * Description:        Print out cred hash cache table information for debugging
- *             purposes, including the credential contents
- *
- * Parameters: (void)
- *
- * Returns:    (void)
- *
- * Implicit returns:   Results in console output
- */
-static void
-kauth_cred_hash_print(void) 
-{
-       int                     i, j;
-       kauth_cred_t    found_cred;
-               
-       printf("\n\t kauth credential hash table statistics - current cred count %d \n", kauth_cred_count);
-       /* count slot hits, misses, collisions, and max depth */
-       for (i = 0; i < kauth_cred_table_size; i++) {
-               printf("[%02d] ", i);
-               j = 0;
-               TAILQ_FOREACH(found_cred, &kauth_cred_table_anchor[i], cr_link) {
-                       if (j > 0) {
-                               printf("---- ");
-                       }
-                       j++;
-                       kauth_cred_print(found_cred);
-                       printf("\n");
-               }
-               if (j == 0) {
-                       printf("NOCRED \n");
-               }
+               hash_key = kauth_cred_hash((uint8_t *)cred->cr_label,
+                   sizeof(struct label),
+                   hash_key);
        }
+#endif
+
+       hash_key %= KAUTH_CRED_TABLE_SIZE;
+       return &kauth_cred_table_anchor[hash_key];
 }
-#endif /* KAUTH_CRED_HASH_DEBUG */
 
 
-#if (defined(KAUTH_CRED_HASH_DEBUG) && (KAUTH_CRED_HASH_DEBUG != 0)) || defined(DEBUG_CRED)
+#ifdef DEBUG_CRED
 /*
  * kauth_cred_print
  *
@@ -4972,112 +5398,134 @@ kauth_cred_hash_print(void)
  * Implicit returns:   Results in console output
  */
 void
-kauth_cred_print(kauth_cred_t cred) 
+kauth_cred_print(kauth_cred_t cred)
 {
-       int     i;
+       int     i;
 
        printf("%p - refs %lu flags 0x%08x uids e%d r%d sv%d gm%d ", cred, cred->cr_ref, cred->cr_flags, cred->cr_uid, cred->cr_ruid, cred->cr_svuid, cred->cr_gmuid);
        printf("group count %d gids ", cred->cr_ngroups);
        for (i = 0; i < NGROUPS; i++) {
-               if (i == 0)
+               if (i == 0) {
                        printf("e");
+               }
                printf("%d ", cred->cr_groups[i]);
        }
        printf("r%d sv%d ", cred->cr_rgid, cred->cr_svgid);
-       printf("auditinfo_addr %d %d %d %d %d %d\n", 
-               cred->cr_audit.s_aia_p->ai_auid,
-               cred->cr_audit.as_mask.am_success,
-               cred->cr_audit.as_mask.am_failure,
-               cred->cr_audit.as_aia_p->ai_termid.at_port,
-               cred->cr_audit.as_aia_p->ai_termid.at_addr[0],
-               cred->cr_audit.as_aia_p->ai_asid);
+       printf("auditinfo_addr %d %d %d %d %d %d\n",
+           cred->cr_audit.s_aia_p->ai_auid,
+           cred->cr_audit.as_mask.am_success,
+           cred->cr_audit.as_mask.am_failure,
+           cred->cr_audit.as_aia_p->ai_termid.at_port,
+           cred->cr_audit.as_aia_p->ai_termid.at_addr[0],
+           cred->cr_audit.as_aia_p->ai_asid);
 }
 
-int is_target_cred( kauth_cred_t the_cred )
+int
+is_target_cred( kauth_cred_t the_cred )
 {
-       if ( the_cred->cr_uid != 0 ) 
-               return( 0 );
-       if ( the_cred->cr_ruid != 0 ) 
-               return( 0 );
-       if ( the_cred->cr_svuid != 0 ) 
-               return( 0 );
-       if ( the_cred->cr_ngroups != 11 ) 
-               return( 0 );
-       if ( the_cred->cr_groups[0] != 11 ) 
-               return( 0 );
-       if ( the_cred->cr_groups[1] != 81 ) 
-               return( 0 );
-       if ( the_cred->cr_groups[2] != 63947 ) 
-               return( 0 );
-       if ( the_cred->cr_groups[3] != 80288 ) 
-               return( 0 );
-       if ( the_cred->cr_groups[4] != 89006 ) 
-               return( 0 );
-       if ( the_cred->cr_groups[5] != 52173 ) 
-               return( 0 );
-       if ( the_cred->cr_groups[6] != 84524 ) 
-               return( 0 );
-       if ( the_cred->cr_groups[7] != 79 ) 
-               return( 0 );
-       if ( the_cred->cr_groups[8] != 80292 ) 
-               return( 0 );
-       if ( the_cred->cr_groups[9] != 80 ) 
-               return( 0 );
-       if ( the_cred->cr_groups[10] != 90824 ) 
-               return( 0 );
-       if ( the_cred->cr_rgid != 11 ) 
-               return( 0 );
-       if ( the_cred->cr_svgid != 11 ) 
-               return( 0 );
-       if ( the_cred->cr_gmuid != 3475 ) 
-               return( 0 );
-       if ( the_cred->cr_audit.as_aia_p->ai_auid != 3475 ) 
-               return( 0 );
+       if (the_cred->cr_uid != 0) {
+               return 0;
+       }
+       if (the_cred->cr_ruid != 0) {
+               return 0;
+       }
+       if (the_cred->cr_svuid != 0) {
+               return 0;
+       }
+       if (the_cred->cr_ngroups != 11) {
+               return 0;
+       }
+       if (the_cred->cr_groups[0] != 11) {
+               return 0;
+       }
+       if (the_cred->cr_groups[1] != 81) {
+               return 0;
+       }
+       if (the_cred->cr_groups[2] != 63947) {
+               return 0;
+       }
+       if (the_cred->cr_groups[3] != 80288) {
+               return 0;
+       }
+       if (the_cred->cr_groups[4] != 89006) {
+               return 0;
+       }
+       if (the_cred->cr_groups[5] != 52173) {
+               return 0;
+       }
+       if (the_cred->cr_groups[6] != 84524) {
+               return 0;
+       }
+       if (the_cred->cr_groups[7] != 79) {
+               return 0;
+       }
+       if (the_cred->cr_groups[8] != 80292) {
+               return 0;
+       }
+       if (the_cred->cr_groups[9] != 80) {
+               return 0;
+       }
+       if (the_cred->cr_groups[10] != 90824) {
+               return 0;
+       }
+       if (the_cred->cr_rgid != 11) {
+               return 0;
+       }
+       if (the_cred->cr_svgid != 11) {
+               return 0;
+       }
+       if (the_cred->cr_gmuid != 3475) {
+               return 0;
+       }
+       if (the_cred->cr_audit.as_aia_p->ai_auid != 3475) {
+               return 0;
+       }
 /*
-       if ( the_cred->cr_audit.as_mask.am_success != 0 ) 
-               return( 0 );
-       if ( the_cred->cr_audit.as_mask.am_failure != 0 ) 
-               return( 0 );
-       if ( the_cred->cr_audit.as_aia_p->ai_termid.at_port != 0 ) 
-               return( 0 );
-       if ( the_cred->cr_audit.as_aia_p->ai_termid.at_addr[0] != 0 ) 
-               return( 0 );
-       if ( the_cred->cr_audit.as_aia_p->ai_asid != 0 ) 
-               return( 0 );
-       if ( the_cred->cr_flags != 0 ) 
-               return( 0 );
-*/
-       return( -1 ); // found target cred
+ *       if ( the_cred->cr_audit.as_mask.am_success != 0 )
              return( 0 );
+ *       if ( the_cred->cr_audit.as_mask.am_failure != 0 )
              return( 0 );
+ *       if ( the_cred->cr_audit.as_aia_p->ai_termid.at_port != 0 )
              return( 0 );
+ *       if ( the_cred->cr_audit.as_aia_p->ai_termid.at_addr[0] != 0 )
              return( 0 );
+ *       if ( the_cred->cr_audit.as_aia_p->ai_asid != 0 )
              return( 0 );
+ *       if ( the_cred->cr_flags != 0 )
              return( 0 );
+ */
+       return -1;  // found target cred
 }
 
-void get_backtrace( void )
+void
+get_backtrace( void )
 {
-       int                             my_slot;
-       void *                  my_stack[ MAX_STACK_DEPTH ];
-       int                             i, my_depth;
-       
-       if ( cred_debug_buf_p == NULL ) {
+       int                             my_slot;
+       void *                  my_stack[MAX_STACK_DEPTH];
+       int                             i, my_depth;
+
+       if (cred_debug_buf_p == NULL) {
                MALLOC(cred_debug_buf_p, cred_debug_buffer *, sizeof(*cred_debug_buf_p), M_KAUTH, M_WAITOK);
                bzero(cred_debug_buf_p, sizeof(*cred_debug_buf_p));
-       }       
+       }
 
-       if ( cred_debug_buf_p->next_slot > (MAX_CRED_BUFFER_SLOTS - 1) ) {
+       if (cred_debug_buf_p->next_slot > (MAX_CRED_BUFFER_SLOTS - 1)) {
                /* buffer is full */
                return;
        }
-       
+
        my_depth = OSBacktrace(&my_stack[0], MAX_STACK_DEPTH);
-       if ( my_depth == 0 ) {
+       if (my_depth == 0) {
                printf("%s - OSBacktrace failed \n", __FUNCTION__);
                return;
        }
-       
+
        /* fill new backtrace */
        my_slot = cred_debug_buf_p->next_slot;
        cred_debug_buf_p->next_slot++;
-       cred_debug_buf_p->stack_buffer[ my_slot ].depth = my_depth;
-       for ( i = 0; i < my_depth; i++ ) {
-               cred_debug_buf_p->stack_buffer[ my_slot ].stack[ i ] = my_stack[ i ];
+       cred_debug_buf_p->stack_buffer[my_slot].depth = my_depth;
+       for (i = 0; i < my_depth; i++) {
+               cred_debug_buf_p->stack_buffer[my_slot].stack[i] = my_stack[i];
        }
 
        return;
@@ -5086,45 +5534,46 @@ void get_backtrace( void )
 
 /* subset of struct ucred for use in sysctl_dump_creds */
 struct debug_ucred {
-       void    *credp;
-       u_long  cr_ref;                         /* reference count */
-       uid_t   cr_uid;                         /* effective user id */
-       uid_t   cr_ruid;                        /* real user id */
-       uid_t   cr_svuid;                       /* saved user id */
-       short   cr_ngroups;                     /* number of groups in advisory list */
-       gid_t   cr_groups[NGROUPS];     /* advisory group list */
-       gid_t   cr_rgid;                        /* real group id */
-       gid_t   cr_svgid;                       /* saved group id */
-       uid_t   cr_gmuid;                       /* UID for group membership purposes */
-       struct auditinfo_addr cr_audit; /* user auditing data. */
-       void    *cr_label;                      /* MACF label */
-       int             cr_flags;                       /* flags on credential */
+       void    *credp;
+       u_long  cr_ref;                         /* reference count */
+       uid_t   cr_uid;                         /* effective user id */
+       uid_t   cr_ruid;                        /* real user id */
+       uid_t   cr_svuid;                       /* saved user id */
+       short   cr_ngroups;                     /* number of groups in advisory list */
+       gid_t   cr_groups[NGROUPS];     /* advisory group list */
+       gid_t   cr_rgid;                        /* real group id */
+       gid_t   cr_svgid;                       /* saved group id */
+       uid_t   cr_gmuid;                       /* UID for group membership purposes */
+       struct auditinfo_addr cr_audit; /* user auditing data. */
+       void    *cr_label;                      /* MACF label */
+       int             cr_flags;                       /* flags on credential */
 };
 typedef struct debug_ucred debug_ucred;
 
 SYSCTL_PROC(_kern, OID_AUTO, dump_creds, CTLFLAG_RD,
     NULL, 0, sysctl_dump_creds, "S,debug_ucred", "List of credentials in the cred hash");
 
-/*     accessed by:      
+/*     accessed by:
  *     err = sysctlbyname( "kern.dump_creds", bufp, &len, NULL, 0 );
  */
 
 static int
 sysctl_dump_creds( __unused struct sysctl_oid *oidp, __unused void *arg1, __unused int arg2, struct sysctl_req *req )
 {
-       int                     i, j, counter = 0;
-       int                             error;
-       size_t                  space;
-       kauth_cred_t    found_cred;
-       debug_ucred *   cred_listp;
-       debug_ucred *   nextp;
+       int                     i, j, counter = 0;
+       int                             error;
+       size_t                  space;
+       kauth_cred_t    found_cred;
+       debug_ucred *   cred_listp;
+       debug_ucred *   nextp;
 
        /* This is a readonly node. */
-       if (req->newptr != USER_ADDR_NULL)
-               return (EPERM);
+       if (req->newptr != USER_ADDR_NULL) {
+               return EPERM;
+       }
 
        /* calculate space needed */
-       for (i = 0; i < kauth_cred_table_size; i++) {
+       for (i = 0; i < KAUTH_CRED_TABLE_SIZE; i++) {
                TAILQ_FOREACH(found_cred, &kauth_cred_table_anchor[i], cr_link) {
                        counter++;
                }
@@ -5137,15 +5586,15 @@ sysctl_dump_creds( __unused struct sysctl_oid *oidp, __unused void *arg1, __unus
                return 0;
        }
 
-       MALLOC( cred_listp, debug_ucred *, req->oldlen, M_TEMP, M_WAITOK );
-       if ( cred_listp == NULL ) {
-               return (ENOMEM);
+       MALLOC( cred_listp, debug_ucred *, req->oldlen, M_TEMP, M_WAITOK | M_ZERO);
+       if (cred_listp == NULL) {
+               return ENOMEM;
        }
-       
+
        /* fill in creds to send back */
        nextp = cred_listp;
        space = 0;
-       for (i = 0; i < kauth_cred_table_size; i++) {
+       for (i = 0; i < KAUTH_CRED_TABLE_SIZE; i++) {
                TAILQ_FOREACH(found_cred, &kauth_cred_table_anchor[i], cr_link) {
                        nextp->credp = found_cred;
                        nextp->cr_ref = found_cred->cr_ref;
@@ -5153,8 +5602,8 @@ sysctl_dump_creds( __unused struct sysctl_oid *oidp, __unused void *arg1, __unus
                        nextp->cr_ruid = found_cred->cr_ruid;
                        nextp->cr_svuid = found_cred->cr_svuid;
                        nextp->cr_ngroups = found_cred->cr_ngroups;
-                       for ( j = 0; j < nextp->cr_ngroups; j++ ) {
-                               nextp->cr_groups[ j ] = found_cred->cr_groups[ j ];
+                       for (j = 0; j < nextp->cr_ngroups; j++) {
+                               nextp->cr_groups[j] = found_cred->cr_groups[j];
                        }
                        nextp->cr_rgid = found_cred->cr_rgid;
                        nextp->cr_svgid = found_cred->cr_svgid;
@@ -5185,46 +5634,47 @@ sysctl_dump_creds( __unused struct sysctl_oid *oidp, __unused void *arg1, __unus
                        nextp->cr_flags = found_cred->cr_flags;
                        nextp++;
                        space += sizeof(debug_ucred);
-                       if ( space > req->oldlen ) {
+                       if (space > req->oldlen) {
                                FREE(cred_listp, M_TEMP);
-                               return (ENOMEM);
+                               return ENOMEM;
                        }
                }
        }
        req->oldlen = space;
        error = SYSCTL_OUT(req, cred_listp, req->oldlen);
        FREE(cred_listp, M_TEMP);
-       return (error);
+       return error;
 }
 
 
 SYSCTL_PROC(_kern, OID_AUTO, cred_bt, CTLFLAG_RD,
     NULL, 0, sysctl_dump_cred_backtraces, "S,cred_debug_buffer", "dump credential backtrace");
 
-/*     accessed by:      
+/*     accessed by:
  *     err = sysctlbyname( "kern.cred_bt", bufp, &len, NULL, 0 );
  */
 
 static int
 sysctl_dump_cred_backtraces( __unused struct sysctl_oid *oidp, __unused void *arg1, __unused int arg2, struct sysctl_req *req )
 {
-       int                     i, j;
-       int                             error;
-       size_t                  space;
-       cred_debug_buffer *     bt_bufp;
-       cred_backtrace *        nextp;
+       int                     i, j;
+       int                             error;
+       size_t                  space;
+       cred_debug_buffer *     bt_bufp;
+       cred_backtrace *        nextp;
 
        /* This is a readonly node. */
-       if (req->newptr != USER_ADDR_NULL)
-               return (EPERM);
+       if (req->newptr != USER_ADDR_NULL) {
+               return EPERM;
+       }
 
-       if ( cred_debug_buf_p == NULL ) {
-               return (EAGAIN);
+       if (cred_debug_buf_p == NULL) {
+               return EAGAIN;
        }
 
        /* calculate space needed */
-       space = sizeof( cred_debug_buf_p->next_slot );
-       space += (sizeof( cred_backtrace ) * cred_debug_buf_p->next_slot);
+       space = sizeof(cred_debug_buf_p->next_slot);
+       space += (sizeof(cred_backtrace) * cred_debug_buf_p->next_slot);
 
        /* they are querying us so just return the space required. */
        if (req->oldptr == USER_ADDR_NULL) {
@@ -5232,24 +5682,24 @@ sysctl_dump_cred_backtraces( __unused struct sysctl_oid *oidp, __unused void *ar
                return 0;
        }
 
-       if ( space > req->oldlen ) {
-               return (ENOMEM);
+       if (space > req->oldlen) {
+               return ENOMEM;
        }
 
-       MALLOC( bt_bufp, cred_debug_buffer *, req->oldlen, M_TEMP, M_WAITOK );
-       if ( bt_bufp == NULL ) {
-               return (ENOMEM);
+       MALLOC( bt_bufp, cred_debug_buffer *, req->oldlen, M_TEMP, M_WAITOK | M_ZERO);
+       if (bt_bufp == NULL) {
+               return ENOMEM;
        }
-       
+
        /* fill in backtrace info to send back */
        bt_bufp->next_slot = cred_debug_buf_p->next_slot;
        space = sizeof(bt_bufp->next_slot);
-       
-       nextp = &bt_bufp->stack_buffer[ 0 ];
+
+       nextp = &bt_bufp->stack_buffer[0];
        for (i = 0; i < cred_debug_buf_p->next_slot; i++) {
-               nextp->depth = cred_debug_buf_p->stack_buffer[ i ].depth;
-               for ( j = 0; j < nextp->depth; j++ ) {
-                       nextp->stack[ j ] = cred_debug_buf_p->stack_buffer[ i ].stack[ j ];
+               nextp->depth = cred_debug_buf_p->stack_buffer[i].depth;
+               for (j = 0; j < nextp->depth; j++) {
+                       nextp->stack[j] = cred_debug_buf_p->stack_buffer[i].stack[j];
                }
                space += sizeof(*nextp);
                nextp++;
@@ -5257,10 +5707,10 @@ sysctl_dump_cred_backtraces( __unused struct sysctl_oid *oidp, __unused void *ar
        req->oldlen = space;
        error = SYSCTL_OUT(req, bt_bufp, req->oldlen);
        FREE(bt_bufp, M_TEMP);
-       return (error);
+       return error;
 }
 
-#endif /* KAUTH_CRED_HASH_DEBUG || DEBUG_CRED */
+#endif  /* DEBUG_CRED */
 
 
 /*
@@ -5286,9 +5736,9 @@ sysctl_dump_cred_backtraces( __unused struct sysctl_oid *oidp, __unused void *ar
  *                                     attach a label to the new credential
  *
  * Notes:      This function currently wraps kauth_cred_create(), and is the
- *             only consume of tht ill-fated function, apart from bsd_init().
+ *             only consumer of that ill-fated function, apart from bsd_init().
  *             It exists solely to support the NFS server code creation of
- *             credentials based on the over-the-wire RPC cals containing
+ *             credentials based on the over-the-wire RPC calls containing
  *             traditional POSIX credential information being tunneled to
  *             the server host from the client machine.
  *
@@ -5296,7 +5746,7 @@ sysctl_dump_cred_backtraces( __unused struct sysctl_oid *oidp, __unused void *ar
  *
  *             In the short term, it creates a temporary credential, puts
  *             the POSIX information from NFS into it, and then calls
- *             kauth_cred_create(), as an internal implementaiton detail.
+ *             kauth_cred_create(), as an internal implementation detail.
  *
  *             If we have to keep it around in the medium term, it will
  *             create a new kauth_cred_t, then label it with a POSIX label
@@ -5332,7 +5782,7 @@ posix_cred_create(posix_cred_t pcred)
  *             this function will return a pointer to a posix_cred_t which
  *             GRANTS all access (effectively, a "root" credential).  This is
  *             necessary to support legacy code which insists on tightly
- *             integrating POSIX credentails into its APIs, including, but
+ *             integrating POSIX credentials into its APIs, including, but
  *             not limited to, System V IPC mechanisms, POSIX IPC mechanisms,
  *             NFSv3, signals, dtrace, and a large number of kauth routines
  *             used to implement POSIX permissions related system calls.
@@ -5354,7 +5804,7 @@ posix_cred_create(posix_cred_t pcred)
 posix_cred_t
 posix_cred_get(kauth_cred_t cred)
 {
-       return(&cred->cr_posix);
+       return &cred->cr_posix;
 }
 
 
@@ -5369,20 +5819,20 @@ posix_cred_get(kauth_cred_t cred)
  * Returns:    (void)
  *
  * Notes:      This function is currently void in order to permit it to fit
- *             in with the currrent MACF framework label methods which allow
- *             labelling to fail silently.  This is like acceptable for
+ *             in with the current MACF framework label methods which allow
+ *             labeling to fail silently.  This is like acceptable for
  *             mandatory access controls, but not for POSIX, since those
  *             access controls are advisory.  We will need to consider a
  *             return value in a future version of the MACF API.
  *
- *             This operation currenty can not fail, as currently the POSIX
+ *             This operation currently cannot fail, as currently the POSIX
  *             credential is a subfield of the kauth_cred_t (ucred), which
  *             MUST be valid.  In the future, this will not be the case.
  */
 void
 posix_cred_label(kauth_cred_t cred, posix_cred_t pcred)
 {
-       cred->cr_posix = *pcred;        /* structure assign for now */
+       cred->cr_posix = *pcred;        /* structure assign for now */
 }
 
 
@@ -5416,8 +5866,9 @@ posix_cred_access(kauth_cred_t cred, id_t object_uid, id_t object_gid, mode_t ob
        /*
         * Check first for owner rights
         */
-       if (kauth_cred_getuid(cred) == object_uid && (mode_req & mode_owner) == mode_req)
-               return (0);
+       if (kauth_cred_getuid(cred) == object_uid && (mode_req & mode_owner) == mode_req) {
+               return 0;
+       }
 
        /*
         * Combined group and world rights check, if we don't have owner rights
@@ -5427,7 +5878,7 @@ posix_cred_access(kauth_cred_t cred, id_t object_uid, id_t object_gid, mode_t ob
         * world rights, avoiding a group membership check, which is expensive.
         */
        if ((mode_req & mode_group & mode_world) == mode_req) {
-               return (0);
+               return 0;
        } else {
                /*
                 * NON-OPTIMIZED: requires group membership check.
@@ -5442,18 +5893,18 @@ posix_cred_access(kauth_cred_t cred, id_t object_uid, id_t object_gid, mode_t ob
                                /*
                                 * DENY: +group denies
                                 */
-                               return (EACCES);
+                               return EACCES;
                        } else {
                                if ((mode_req & mode_world) != mode_req) {
                                        /*
                                         * DENY: both -group & world would deny
                                         */
-                                       return (EACCES);
+                                       return EACCES;
                                } else {
                                        /*
                                         * ALLOW: allowed by -group and +world
                                         */
-                                       return (0);
+                                       return 0;
                                }
                        }
                } else {
@@ -5467,18 +5918,18 @@ posix_cred_access(kauth_cred_t cred, id_t object_uid, id_t object_gid, mode_t ob
                                /*
                                 * ALLOW: allowed by +group
                                 */
-                               return (0);
+                               return 0;
                        } else {
                                if ((mode_req & mode_world) != mode_req) {
                                        /*
                                         * DENY: both -group & world would deny
                                         */
-                                       return (EACCES);
+                                       return EACCES;
                                } else {
                                        /*
                                         * ALLOW: allowed by -group and +world
                                         */
-                                       return (0);
+                                       return 0;
                                }
                        }
                }