]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/kern/kern_credential.c
xnu-3789.31.2.tar.gz
[apple/xnu.git] / bsd / kern / kern_credential.c
index 0098c54d3a8b731ddc1c54773e88d20f3a98534b..1376ff3c53e4eb50c6dffffa875b2b67c3145b9b 100644 (file)
@@ -61,7 +61,7 @@
 #include <libkern/OSAtomic.h>
 
 #include <kern/task.h>
-#include <kern/lock.h>
+#include <kern/locks.h>
 #ifdef MACH_ASSERT
 # undef MACH_ASSERT
 #endif
@@ -264,9 +264,7 @@ static void kauth_groups_trimcache(int newsize);
 
 #endif /* CONFIG_EXT_RESOLVER */
 
-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;
+#define KAUTH_CRED_TABLE_SIZE 97
 
 TAILQ_HEAD(kauth_cred_entry_head, ucred);
 static struct kauth_cred_entry_head * kauth_cred_table_anchor = NULL;
@@ -619,9 +617,10 @@ identitysvc(__unused struct proc *p, struct identitysvc_args *uap, __unused int3
        }
 
        /*
-        * 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);
        }
@@ -923,7 +922,7 @@ kauth_resolver_complete(user_addr_t message)
        struct kauth_identity_extlookup extl;
        struct kauth_resolver_work *workp;
        struct kauth_resolver_work *killp;
-       int error, result;
+       int error, result, request_flags;
 
        /*
         * Copy in the mesage, including the extension field, since we are
@@ -1004,6 +1003,10 @@ kauth_resolver_complete(user_addr_t message)
                TAILQ_FOREACH(workp, &kauth_resolver_submitted, kr_link) {
                        /* found it? */
                        if (workp->kr_seqno == extl.el_seqno) {
+                               /*
+                                * Take a snapshot of the original request flags.
+                                */
+                               request_flags = workp->kr_work.el_flags;
 
                                /*
                                 * Get the request of the submitted queue so
@@ -1041,13 +1044,21 @@ 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)) {
+                               if ((extl.el_flags & request_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_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, request_flags);
                                }
 
                                /*
@@ -1117,7 +1128,7 @@ kauth_identity_init(void)
  * Parameters: uid
  *
  * Returns:    NULL                            Insufficient memory to satisfy
- *                                             the request
+ *                                             the request or bad parameters
  *             !NULL                           A pointer to the allocated
  *                                             structure, filled in
  *
@@ -1146,8 +1157,16 @@ kauth_identity_alloc(uid_t uid, gid_t gid, guid_t *guidp, time_t guid_expiry,
                        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;
@@ -1318,6 +1337,11 @@ kauth_identity_updatecache(struct kauth_identity_extlookup *elp, struct kauth_id
                        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;
@@ -2054,14 +2078,66 @@ static int      kauth_cred_cache_lookup(int from, int to, void *src, void *dst);
 
 #if CONFIG_EXT_RESOLVER == 0
 /*
- * If there's no resolver, short-circuit the kauth_cred_x2y() lookups.
+ * If there's no resolver, only support a subset of the kauth_cred_x2y() lookups.
  */
 static __inline int
-kauth_cred_cache_lookup(__unused int from, __unused int to,
-       __unused void *src, __unused void *dst)
+kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
 {
-       return (EWOULDBLOCK);
-
+       /* 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
 
@@ -2242,6 +2318,45 @@ kauth_cred_guid2gid(guid_t *guidp, gid_t *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
@@ -2686,6 +2801,11 @@ kauth_cred_cache_lookup(int from, int to, void *src, void *dst)
                         * 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);
@@ -3140,11 +3260,11 @@ kauth_cred_ismember_guid(__unused kauth_cred_t cred, guid_t *guidp, int *resultp
                *resultp = 1;
                break;
        default:
-#if CONFIG_EXT_RESOLVER
        {
-               struct kauth_identity ki;
                gid_t gid;
-#if 6603280
+#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
@@ -3171,7 +3291,7 @@ kauth_cred_ismember_guid(__unused kauth_cred_t cred, guid_t *guidp, int *resultp
                                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
@@ -3188,13 +3308,12 @@ kauth_cred_ismember_guid(__unused kauth_cred_t cred, guid_t *guidp, int *resultp
                                error = 0;
                        }
                } else {
+#if CONFIG_EXT_RESOLVER
  do_check:
+#endif /* CONFIG_EXT_RESOLVER */
                        error = kauth_cred_ismember_gid(cred, gid, resultp);
                }
        }
-#else  /* CONFIG_EXT_RESOLVER */
-               error = ENOENT;
-#endif /* CONFIG_EXT_RESOLVER */
                break;
        }
        return(error);
@@ -3343,15 +3462,14 @@ 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), 
+                       (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++) {
+       for (i = 0; i < KAUTH_CRED_TABLE_SIZE; i++) {
                TAILQ_INIT(&kauth_cred_table_anchor[i]);
        }
 }
@@ -3580,7 +3698,7 @@ 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.
  *
@@ -3602,10 +3720,10 @@ kauth_cred_proc_ref(proc_t procp)
 {
        kauth_cred_t    cred;
        
-       proc_lock(procp);
+       proc_ucred_lock(procp);
        cred = proc_ucred(procp);
        kauth_cred_ref(cred);
-       proc_unlock(procp);
+       proc_ucred_unlock(procp);
        return(cred);
 }
 
@@ -4380,11 +4498,12 @@ 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 vnode *scriptvp, struct label *scriptl,
-       struct label *execl, void *macextensions, 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;
@@ -4393,9 +4512,9 @@ 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, scriptvp, scriptl, execl,
-                                                 macextensions);
+       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);
@@ -4437,7 +4556,7 @@ int kauth_proc_label_update(struct proc *p, struct label *label)
 
                        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
@@ -4445,7 +4564,7 @@ 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 */
@@ -4456,7 +4575,7 @@ int kauth_proc_label_update(struct proc *p, struct label *label)
                        PROC_UPDATE_CREDS_ONPROC(p);
 
                        mac_proc_set_enforce(p, MAC_ALL_ENFORCE);
-                       proc_unlock(p);
+                       proc_ucred_unlock(p);
                }
                break;
        }
@@ -4479,6 +4598,8 @@ 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
@@ -4489,14 +4610,13 @@ 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 vnode *scriptvp, struct label *scriptl,
-       struct label *execl, void *macextensions)
+       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);
@@ -4511,12 +4631,12 @@ kauth_proc_label_update_execve(struct proc *p, vfs_context_t ctx,
                 * 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, scriptvp, scriptl, execl, macextensions, &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
@@ -4524,7 +4644,7 @@ 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 */
@@ -4534,14 +4654,12 @@ kauth_proc_label_update_execve(struct proc *p, vfs_context_t ctx,
                        /* 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
@@ -5074,7 +5192,7 @@ kauth_cred_add(kauth_cred_t new_cred)
        KAUTH_CRED_HASH_LOCK_ASSERT();
 
        hash_key = kauth_cred_get_hashkey(new_cred);
-       hash_key %= kauth_cred_table_size;
+       hash_key %= KAUTH_CRED_TABLE_SIZE;
 
        /* race fix - there is a window where another matching credential 
         * could have been inserted between the time this one was created and we
@@ -5119,7 +5237,7 @@ kauth_cred_remove(kauth_cred_t cred)
        kauth_cred_t    found_cred;
 
        hash_key = kauth_cred_get_hashkey(cred);
-       hash_key %= kauth_cred_table_size;
+       hash_key %= KAUTH_CRED_TABLE_SIZE;
 
        /* Avoid race */
        if (cred->cr_ref < 1)
@@ -5179,7 +5297,7 @@ kauth_cred_find(kauth_cred_t cred)
 #endif
 
        hash_key = kauth_cred_get_hashkey(cred);
-       hash_key %= kauth_cred_table_size;
+       hash_key %= KAUTH_CRED_TABLE_SIZE;
 
        /* Find cred in the credential hash table */
        TAILQ_FOREACH(found_cred, &kauth_cred_table_anchor[hash_key], cr_link) {
@@ -5304,7 +5422,7 @@ kauth_cred_hash_print(void)
                
        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++) {
+       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) {
@@ -5489,7 +5607,7 @@ sysctl_dump_creds( __unused struct sysctl_oid *oidp, __unused void *arg1, __unus
                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++;
                }
@@ -5510,7 +5628,7 @@ sysctl_dump_creds( __unused struct sysctl_oid *oidp, __unused void *arg1, __unus
        /* 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;