xnu-7195.81.3.tar.gz
[apple/xnu.git] / bsd / kern / kern_core.c
index 70fb531b359c4497125858701368bab1cb21fd7d..a4a3ee6cfef99943e09f736a8fbea47577520755 100644 (file)
@@ -2,7 +2,7 @@
  * Copyright (c) 2000-2006 Apple Computer, 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@
  */
 /* Copyright (c) 1991 NeXT Computer, Inc.  All rights reserved.
  *     This file contains machine independent code for performing core dumps.
  *
  */
+#if CONFIG_COREDUMP
 
 #include <mach/vm_param.h>
 #include <mach/thread_status.h>
-
+#include <sys/content_protection.h>
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/signalvar.h>
 
 #include <vm/vm_kern.h>
 #include <vm/vm_protos.h> /* last */
-#include <vm/vm_map.h>         /* current_map() */
-#include <mach/mach_vm.h>      /* mach_vm_region_recurse() */
-#include <mach/task.h>         /* task_suspend() */
-#include <kern/task.h>         /* get_task_numacts() */
+#include <vm/vm_map.h>          /* current_map() */
+#include <mach/mach_vm.h>       /* mach_vm_region_recurse() */
+#include <mach/task.h>          /* task_suspend() */
+#include <kern/task.h>          /* get_task_numacts() */
+
+#include <security/audit/audit.h>
+
+#if CONFIG_MACF
+#include <security/mac_framework.h>
+#endif /* CONFIG_MACF */
 
 typedef struct {
-       int     flavor;                 /* the number for this flavor */
-       mach_msg_type_number_t  count;  /* count of ints in this flavor */
+       int     flavor;                 /* the number for this flavor */
+       mach_msg_type_number_t  count;  /* count of ints in this flavor */
 } mythread_state_flavor_t;
 
-#if defined (__ppc__)
-/* 64 bit */
-mythread_state_flavor_t thread_flavor_array64[]={
-               {PPC_THREAD_STATE64 , PPC_THREAD_STATE64_COUNT},
-               {PPC_FLOAT_STATE, PPC_FLOAT_STATE_COUNT}, 
-               {PPC_EXCEPTION_STATE64, PPC_EXCEPTION_STATE64_COUNT},
-               {PPC_VECTOR_STATE, PPC_VECTOR_STATE_COUNT}
-               };
-
-/* 32 bit */
-mythread_state_flavor_t thread_flavor_array[]={
-               {PPC_THREAD_STATE , PPC_THREAD_STATE_COUNT},
-               {PPC_FLOAT_STATE, PPC_FLOAT_STATE_COUNT}, 
-               {PPC_EXCEPTION_STATE, PPC_EXCEPTION_STATE_COUNT},
-               {PPC_VECTOR_STATE, PPC_VECTOR_STATE_COUNT}
-               };
-
-#elif defined (__i386__)
-mythread_state_flavor_t thread_flavor_array [] = { 
-               {x86_THREAD_STATE, x86_THREAD_STATE_COUNT},
-               {x86_FLOAT_STATE, x86_FLOAT_STATE_COUNT},
-               {x86_EXCEPTION_STATE, x86_EXCEPTION_STATE_COUNT},
-               };
-int mynum_flavors=3;
+#if defined (__i386__) || defined (__x86_64__)
+mythread_state_flavor_t thread_flavor_array[] = {
+       {x86_THREAD_STATE, x86_THREAD_STATE_COUNT},
+       {x86_FLOAT_STATE, x86_FLOAT_STATE_COUNT},
+       {x86_EXCEPTION_STATE, x86_EXCEPTION_STATE_COUNT},
+};
+int mynum_flavors = 3;
+#elif defined (__arm__)
+mythread_state_flavor_t thread_flavor_array[] = {
+       {ARM_THREAD_STATE, ARM_THREAD_STATE_COUNT},
+       {ARM_VFP_STATE, ARM_VFP_STATE_COUNT},
+       {ARM_EXCEPTION_STATE, ARM_EXCEPTION_STATE_COUNT}
+};
+int mynum_flavors = 3;
+
+#elif defined (__arm64__)
+mythread_state_flavor_t thread_flavor_array[] = {
+       {ARM_THREAD_STATE64, ARM_THREAD_STATE64_COUNT},
+       /* ARM64_TODO: VFP */
+       {ARM_EXCEPTION_STATE64, ARM_EXCEPTION_STATE64_COUNT}
+};
+int mynum_flavors = 2;
 #else
 #error architecture not supported
 #endif
 
 
 typedef struct {
-       vm_offset_t header; 
-       int  hoffset;
+       vm_offset_t header;
+       size_t hoffset;
        mythread_state_flavor_t *flavors;
-       int tstate_size;
-       int flavor_count;
+       size_t tstate_size;
+       size_t flavor_count;
 } tir_t;
 
-/* XXX should be static */
-void collectth_state(thread_t th_act, void *tirp);
+extern int freespace_mb(vnode_t vp);
 
 /* XXX not in a Mach header anywhere */
-kern_return_t thread_getstatus(register thread_t act, int flavor,
-       thread_state_t tstate, mach_msg_type_number_t *count);
-void task_act_iterate_wth_args(task_t, void(*)(thread_t, void *), void *);
-
+kern_return_t thread_getstatus(thread_t act, int flavor,
+    thread_state_t tstate, mach_msg_type_number_t *count);
+void task_act_iterate_wth_args(task_t, void (*)(thread_t, void *), void *);
 
 #ifdef SECURE_KERNEL
-__private_extern__ int do_coredump = 0;        /* default: don't dump cores */
+__XNU_PRIVATE_EXTERN int do_coredump = 0;       /* default: don't dump cores */
 #else
-__private_extern__ int do_coredump = 1;        /* default: dump cores */
+__XNU_PRIVATE_EXTERN int do_coredump = 1;       /* default: dump cores */
 #endif
-__private_extern__ int sugid_coredump = 0; /* default: but not SGUID binaries */
+__XNU_PRIVATE_EXTERN int sugid_coredump = 0; /* default: but not SGUID binaries */
+
 
-void
+/* cpu_type returns only the most generic indication of the current CPU. */
+/* in a core we want to know the kind of process. */
+
+static cpu_type_t
+process_cpu_type(proc_t core_proc)
+{
+       cpu_type_t what_we_think;
+#if defined (__i386__) || defined (__x86_64__)
+       if (IS_64BIT_PROCESS(core_proc)) {
+               what_we_think = CPU_TYPE_X86_64;
+       } else {
+               what_we_think = CPU_TYPE_I386;
+       }
+#elif defined (__arm__) || defined(__arm64__)
+       if (IS_64BIT_PROCESS(core_proc)) {
+               what_we_think = CPU_TYPE_ARM64;
+       } else {
+               what_we_think = CPU_TYPE_ARM;
+       }
+#endif
+
+       return what_we_think;
+}
+
+static cpu_type_t
+process_cpu_subtype(proc_t core_proc)
+{
+       cpu_type_t what_we_think;
+#if defined (__i386__) || defined (__x86_64__)
+       if (IS_64BIT_PROCESS(core_proc)) {
+               what_we_think = CPU_SUBTYPE_X86_64_ALL;
+       } else {
+               what_we_think = CPU_SUBTYPE_I386_ALL;
+       }
+#elif defined (__arm__) || defined(__arm64__)
+       if (IS_64BIT_PROCESS(core_proc)) {
+               what_we_think = CPU_SUBTYPE_ARM64_ALL;
+       } else {
+               what_we_think = CPU_SUBTYPE_ARM_ALL;
+       }
+#endif
+       return what_we_think;
+}
+
+static void
 collectth_state(thread_t th_act, void *tirp)
 {
-       vm_offset_t     header;
-       int  hoffset, i ;
+       vm_offset_t     header;
+       size_t  hoffset, i;
        mythread_state_flavor_t *flavors;
-       struct thread_command   *tc;
+       struct thread_command   *tc;
        tir_t *t = (tir_t *)tirp;
 
-               /*
-                *      Fill in thread command structure.
-                */
-               header = t->header;
-               hoffset = t->hoffset;
-               flavors = t->flavors;
-       
-               tc = (struct thread_command *) (header + hoffset);
-               tc->cmd = LC_THREAD;
-               tc->cmdsize = sizeof(struct thread_command)
-                               + t->tstate_size;
-               hoffset += sizeof(struct thread_command);
-               /*
-                * Follow with a struct thread_state_flavor and
-                * the appropriate thread state struct for each
-                * thread state flavor.
-                */
-               for (i = 0; i < t->flavor_count; i++) {
-                       *(mythread_state_flavor_t *)(header+hoffset) =
-                         flavors[i];
-                       hoffset += sizeof(mythread_state_flavor_t);
-                       thread_getstatus(th_act, flavors[i].flavor,
-                                       (thread_state_t)(header+hoffset),
-                                       &flavors[i].count);
-                       hoffset += flavors[i].count*sizeof(int);
-               }
+       /*
+        *      Fill in thread command structure.
+        */
+       header = t->header;
+       hoffset = t->hoffset;
+       flavors = t->flavors;
+
+       tc = (struct thread_command *) (header + hoffset);
+       tc->cmd = LC_THREAD;
+       tc->cmdsize = (uint32_t)(sizeof(struct thread_command)
+           + t->tstate_size);
+       hoffset += sizeof(struct thread_command);
+       /*
+        * Follow with a struct thread_state_flavor and
+        * the appropriate thread state struct for each
+        * thread state flavor.
+        */
+       for (i = 0; i < t->flavor_count; i++) {
+               *(mythread_state_flavor_t *)(header + hoffset) =
+                   flavors[i];
+               hoffset += sizeof(mythread_state_flavor_t);
+               thread_getstatus(th_act, flavors[i].flavor,
+                   (thread_state_t)(header + hoffset),
+                   &flavors[i].count);
+               hoffset += flavors[i].count * sizeof(int);
+       }
 
-               t->hoffset = hoffset;
+       t->hoffset = hoffset;
 }
 
-
 /*
  * coredump
  *
@@ -168,63 +215,77 @@ collectth_state(thread_t th_act, void *tirp)
  *             indicated
  *
  * Parameters: core_proc                       Process to dump core [*]
+ *                             reserve_mb                      If non-zero, leave filesystem with
+ *                                                                     at least this much free space.
+ *                             coredump_flags  Extra options (ignore rlimit, run fsync)
  *
  * Returns:    0                               Success
- *             EFAULT                          Failed
+ *             !0                              Failure errno
  *
  * IMPORTANT:  This function can only be called on the current process, due
  *             to assumptions below; see variable declaration section for
  *             details.
  */
-#define        MAX_TSTATE_FLAVORS      10
+#define MAX_TSTATE_FLAVORS      10
 int
-coredump(proc_t core_proc)
+coredump(proc_t core_proc, uint32_t reserve_mb, int coredump_flags)
 {
 /* Begin assumptions that limit us to only the current process */
        vfs_context_t ctx = vfs_context_current();
-       vm_map_t        map = current_map();
-       task_t          task = current_task();
+       vm_map_t        map = current_map();
+       task_t          task = current_task();
 /* End assumptions */
        kauth_cred_t cred = vfs_context_ucred(ctx);
        int error = 0;
        struct vnode_attr va;
-       int             thread_count, segment_count;
-       int             command_size, header_size, tstate_size;
-       int             hoffset;
-       off_t           foffset;
-       vm_map_offset_t vmoffset;
-       vm_offset_t     header;
-       vm_map_size_t   vmsize;
-       vm_prot_t       prot;
-       vm_prot_t       maxprot;
-       vm_inherit_t    inherit;
-       int             error1 = 0;
-       char            stack_name[MAXCOMLEN+6];
-       char            *alloced_name = NULL;
-       char            *name;
+       size_t          thread_count, segment_count;
+       size_t          command_size, header_size, tstate_size;
+       size_t          hoffset;
+       off_t           foffset;
+       mach_vm_offset_t vmoffset;
+       vm_offset_t     header;
+       mach_vm_size_t  vmsize;
+       vm_prot_t       prot;
+       vm_prot_t       maxprot;
+       vm_inherit_t    inherit;
+       int             error1 = 0;
+       char            stack_name[MAXCOMLEN + 6];
+       char            *alloced_name = NULL;
+       char            *name = NULL;
        mythread_state_flavor_t flavors[MAX_TSTATE_FLAVORS];
-       vm_size_t       mapsize;
-       int             i;
+       vm_size_t       mapsize;
+       size_t          i;
        uint32_t nesting_depth = 0;
-       kern_return_t   kret;
+       kern_return_t   kret;
        struct vm_region_submap_info_64 vbr;
        mach_msg_type_number_t vbrcount = 0;
        tir_t tir1;
        struct vnode * vp;
-       struct mach_header      *mh = NULL;     /* protected by is_64 */
-       struct mach_header_64   *mh64 = NULL;   /* protected by is_64 */
-       int             is_64 = 0;
-       size_t          mach_header_sz = sizeof(struct mach_header);
-       size_t          segment_command_sz = sizeof(struct segment_command);
-
-       if (do_coredump == 0 ||         /* Not dumping at all */
-           ( (sugid_coredump == 0) &&  /* Not dumping SUID/SGID binaries */
-             ( (cred->cr_svuid != cred->cr_ruid) ||
-               (cred->cr_svgid != cred->cr_rgid)))) {
-           
-               return (EFAULT);
+       struct mach_header      *mh = NULL;     /* protected by is_64 */
+       struct mach_header_64   *mh64 = NULL;   /* protected by is_64 */
+       int             is_64 = 0;
+       size_t          mach_header_sz = sizeof(struct mach_header);
+       size_t          segment_command_sz = sizeof(struct segment_command);
+
+       if (current_proc() != core_proc) {
+               panic("coredump() called against proc that is not current_proc: %p", core_proc);
        }
 
+       if (do_coredump == 0 ||         /* Not dumping at all */
+           ((sugid_coredump == 0) &&   /* Not dumping SUID/SGID binaries */
+           ((kauth_cred_getsvuid(cred) != kauth_cred_getruid(cred)) ||
+           (kauth_cred_getsvgid(cred) != kauth_cred_getrgid(cred))))) {
+               error = EFAULT;
+               goto out2;
+       }
+
+#if CONFIG_MACF
+       error = mac_proc_check_dump_core(core_proc);
+       if (error != 0) {
+               goto out2;
+       }
+#endif
+
        if (IS_64BIT_PROCESS(core_proc)) {
                is_64 = 1;
                mach_header_sz = sizeof(struct mach_header_64);
@@ -233,24 +294,31 @@ coredump(proc_t core_proc)
 
        mapsize = get_vmmap_size(map);
 
-       if (mapsize >=  core_proc->p_rlimit[RLIMIT_CORE].rlim_cur)
-               return (EFAULT);
-       (void) task_suspend(task);
+       if (((coredump_flags & COREDUMP_IGNORE_ULIMIT) == 0) &&
+           (mapsize >= proc_limitgetcur(core_proc, RLIMIT_CORE, FALSE))) {
+               error = EFAULT;
+               goto out2;
+       }
+
+       (void) task_suspend_internal(task);
 
        MALLOC(alloced_name, char *, MAXPATHLEN, M_TEMP, M_NOWAIT | M_ZERO);
 
        /* create name according to sysctl'able format string */
        /* if name creation fails, fall back to historical behaviour... */
-       if (proc_core_name(core_proc->p_comm, kauth_cred_getuid(cred),
-                          core_proc->p_pid, alloced_name, MAXPATHLEN)) {
+       if (alloced_name == NULL ||
+           proc_core_name(core_proc->p_comm, kauth_cred_getuid(cred),
+           core_proc->p_pid, alloced_name, MAXPATHLEN)) {
                snprintf(stack_name, sizeof(stack_name),
-                        "/cores/core.%d", core_proc->p_pid);
+                   "/cores/core.%d", core_proc->p_pid);
                name = stack_name;
-       } else
+       } else {
                name = alloced_name;
+       }
 
-       if ((error = vnode_open(name, (O_CREAT | FWRITE | O_NOFOLLOW), S_IRUSR, VNODE_LOOKUP_NOFOLLOW, &vp, ctx)))
+       if ((error = vnode_open(name, (O_CREAT | FWRITE | O_NOFOLLOW), S_IRUSR, VNODE_LOOKUP_NOFOLLOW, &vp, ctx))) {
                goto out2;
+       }
 
        VATTR_INIT(&va);
        VATTR_WANTED(&va, va_nlink);
@@ -261,11 +329,20 @@ coredump(proc_t core_proc)
                goto out;
        }
 
-       VATTR_INIT(&va);        /* better to do it here than waste more stack in vnode_setsize */
+       VATTR_INIT(&va);        /* better to do it here than waste more stack in vnode_setsize */
        VATTR_SET(&va, va_data_size, 0);
+       if (core_proc == initproc) {
+               VATTR_SET(&va, va_dataprotect_class, PROTECTION_CLASS_D);
+       }
        vnode_setattr(vp, &va, ctx);
        core_proc->p_acflag |= ACORE;
 
+       if ((reserve_mb > 0) &&
+           ((freespace_mb(vp) - (mapsize >> 20)) < reserve_mb)) {
+               error = ENOSPC;
+               goto out;
+       }
+
        /*
         *      If the task is modified while dumping the file
         *      (e.g., changes in threads or VM, the resulting
@@ -273,31 +350,47 @@ coredump(proc_t core_proc)
         */
 
        thread_count = get_task_numacts(task);
-       segment_count = get_vmmap_entries(map); /* XXX */
-#if defined (__ppc__)
-       if (is_64) {
-               tir1.flavor_count = sizeof(thread_flavor_array64)/sizeof(mythread_state_flavor_t);
-               bcopy(thread_flavor_array64, flavors,sizeof(thread_flavor_array64));
-       } else {
-#endif /* __ppc __ */
-               tir1.flavor_count = sizeof(thread_flavor_array)/sizeof(mythread_state_flavor_t);
-               bcopy(thread_flavor_array, flavors,sizeof(thread_flavor_array));
-#if defined (__ppc__)
-       }
-#endif /* __ppc __ */
+       segment_count = get_vmmap_entries(map); /* XXX */
+       tir1.flavor_count = sizeof(thread_flavor_array) / sizeof(mythread_state_flavor_t);
+       bcopy(thread_flavor_array, flavors, sizeof(thread_flavor_array));
        tstate_size = 0;
-       for (i = 0; i < tir1.flavor_count; i++)
+       for (i = 0; i < tir1.flavor_count; i++) {
                tstate_size += sizeof(mythread_state_flavor_t) +
-                 (flavors[i].count * sizeof(int));
-       command_size = segment_count * segment_command_sz +
-         thread_count*sizeof(struct thread_command) +
-         tstate_size*thread_count;
+                   (flavors[i].count * sizeof(int));
+       }
+
+       {
+               size_t lhs;
+               size_t rhs;
+
+               /* lhs = segment_count * segment_command_sz */
+               if (os_mul_overflow(segment_count, segment_command_sz, &lhs)) {
+                       error = ENOMEM;
+                       goto out;
+               }
 
-       header_size = command_size + mach_header_sz;
+               /* rhs = (tstate_size + sizeof(struct thread_command)) * thread_count */
+               if (os_add_and_mul_overflow(tstate_size, sizeof(struct thread_command), thread_count, &rhs)) {
+                       error = ENOMEM;
+                       goto out;
+               }
 
-       (void) kmem_alloc(kernel_map,
-                                   (vm_offset_t *)&header,
-                                   (vm_size_t)header_size);
+               /* command_size = lhs + rhs */
+               if (os_add_overflow(lhs, rhs, &command_size)) {
+                       error = ENOMEM;
+                       goto out;
+               }
+       }
+
+       if (os_add_overflow(command_size, mach_header_sz, &header_size)) {
+               error = ENOMEM;
+               goto out;
+       }
+
+       if (kmem_alloc(kernel_map, &header, (vm_size_t)header_size, VM_KERN_MEMORY_DIAG) != KERN_SUCCESS) {
+               error = ENOMEM;
+               goto out;
+       }
 
        /*
         *      Set up Mach-O header.
@@ -305,44 +398,44 @@ coredump(proc_t core_proc)
        if (is_64) {
                mh64 = (struct mach_header_64 *)header;
                mh64->magic = MH_MAGIC_64;
-               mh64->cputype = cpu_type();
-               mh64->cpusubtype = cpu_subtype();
+               mh64->cputype = process_cpu_type(core_proc);
+               mh64->cpusubtype = process_cpu_subtype(core_proc);
                mh64->filetype = MH_CORE;
-               mh64->ncmds = segment_count + thread_count;
-               mh64->sizeofcmds = command_size;
-               mh64->reserved = 0;             /* 8 byte alignment */
+               mh64->ncmds = (uint32_t)(segment_count + thread_count);
+               mh64->sizeofcmds = (uint32_t)command_size;
+               mh64->reserved = 0;             /* 8 byte alignment */
        } else {
                mh = (struct mach_header *)header;
                mh->magic = MH_MAGIC;
-               mh->cputype = cpu_type();
-               mh->cpusubtype = cpu_subtype();
+               mh->cputype = process_cpu_type(core_proc);
+               mh->cpusubtype = process_cpu_subtype(core_proc);
                mh->filetype = MH_CORE;
-               mh->ncmds = segment_count + thread_count;
-               mh->sizeofcmds = command_size;
+               mh->ncmds = (uint32_t)(segment_count + thread_count);
+               mh->sizeofcmds = (uint32_t)command_size;
        }
 
-       hoffset = mach_header_sz;       /* offset into header */
-       foffset = round_page(header_size);      /* offset into file */
-       vmoffset = MACH_VM_MIN_ADDRESS;         /* offset into VM */
+       hoffset = mach_header_sz;       /* offset into header */
+       foffset = round_page(header_size);      /* offset into file */
+       vmoffset = MACH_VM_MIN_ADDRESS;         /* offset into VM */
 
        /*
-        * We use to check for an error, here, now we try and get 
+        * We use to check for an error, here, now we try and get
         * as much as we can
         */
        while (segment_count > 0) {
-               struct segment_command          *sc;
-               struct segment_command_64       *sc64;
+               struct segment_command          *sc;
+               struct segment_command_64       *sc64;
 
                /*
                 *      Get region information for next region.
                 */
-               
+
                while (1) {
                        vbrcount = VM_REGION_SUBMAP_INFO_COUNT_64;
-                       if((kret = mach_vm_region_recurse(map, 
-                                       &vmoffset, &vmsize, &nesting_depth, 
-                                       (vm_region_recurse_info_t)&vbr,
-                                       &vbrcount)) != KERN_SUCCESS) {
+                       if ((kret = mach_vm_region_recurse(map,
+                           &vmoffset, &vmsize, &nesting_depth,
+                           (vm_region_recurse_info_t)&vbr,
+                           &vbrcount)) != KERN_SUCCESS) {
                                break;
                        }
                        /*
@@ -353,18 +446,19 @@ coredump(proc_t core_proc)
                         */
                        if (!(is_64) &&
                            (vmoffset + vmsize > VM_MAX_ADDRESS)) {
-                               kret = KERN_INVALID_ADDRESS;
+                               kret = KERN_INVALID_ADDRESS;
                                break;
                        }
-                       if(vbr.is_submap) {
+                       if (vbr.is_submap) {
                                nesting_depth++;
                                continue;
                        } else {
                                break;
                        }
                }
-               if(kret != KERN_SUCCESS)
+               if (kret != KERN_SUCCESS) {
                        break;
+               }
 
                prot = vbr.protection;
                maxprot = vbr.max_protection;
@@ -385,19 +479,21 @@ coredump(proc_t core_proc)
                        sc64->maxprot = maxprot;
                        sc64->initprot = prot;
                        sc64->nsects = 0;
-               } else  {
+                       sc64->flags = 0;
+               } else {
                        sc = (struct segment_command *) (header + hoffset);
                        sc->cmd = LC_SEGMENT;
                        sc->cmdsize = sizeof(struct segment_command);
                        /* segment name is zeroed by kmem_alloc */
                        sc->segname[0] = 0;
-                       sc->vmaddr = CAST_DOWN(vm_offset_t,vmoffset);
-                       sc->vmsize = CAST_DOWN(vm_size_t,vmsize);
-                       sc->fileoff = CAST_DOWN(uint32_t,foffset);
-                       sc->filesize = CAST_DOWN(uint32_t,vmsize);
+                       sc->vmaddr = CAST_DOWN_EXPLICIT(uint32_t, vmoffset);
+                       sc->vmsize = CAST_DOWN_EXPLICIT(uint32_t, vmsize);
+                       sc->fileoff = CAST_DOWN_EXPLICIT(uint32_t, foffset); /* will never truncate */
+                       sc->filesize = CAST_DOWN_EXPLICIT(uint32_t, vmsize); /* will never truncate */
                        sc->maxprot = maxprot;
                        sc->initprot = prot;
                        sc->nsects = 0;
+                       sc->flags = 0;
                }
 
                /*
@@ -406,7 +502,7 @@ coredump(proc_t core_proc)
                 */
                if ((prot & VM_PROT_READ) == 0) {
                        mach_vm_protect(map, vmoffset, vmsize, FALSE,
-                                          prot|VM_PROT_READ);
+                           prot | VM_PROT_READ);
                }
                /*
                 *      Only actually perform write if we can read.
@@ -414,23 +510,11 @@ coredump(proc_t core_proc)
                 *      a hole in the file.
                 */
                if ((maxprot & VM_PROT_READ) == VM_PROT_READ
-                       && vbr.user_tag != VM_MEMORY_IOKIT
-                       && coredumpok(map,vmoffset)) {
-                       vm_map_size_t   tmp_vmsize = vmsize;
-                       off_t           xfer_foffset = foffset;
-
-                       //LP64todo - works around vn_rdwr_64() 2G limit
-                       while (tmp_vmsize > 0) {
-                               vm_map_size_t   xfer_vmsize = tmp_vmsize;
-                               if (xfer_vmsize > INT_MAX)
-                                       xfer_vmsize = INT_MAX;
-                               error = vn_rdwr_64(UIO_WRITE, vp,
-                                               vmoffset, xfer_vmsize, xfer_foffset,
-                                       (IS_64BIT_PROCESS(core_proc) ? UIO_USERSPACE64 : UIO_USERSPACE32), 
-                                       IO_NODELOCKED|IO_UNIT, cred, (int *) 0, core_proc);
-                               tmp_vmsize -= xfer_vmsize;
-                               xfer_foffset += xfer_vmsize;
-                       }
+                   && vbr.user_tag != VM_MEMORY_IOKIT
+                   && coredumpok(map, vmoffset)) {
+                       error = vn_rdwr_64(UIO_WRITE, vp, vmoffset, vmsize, foffset,
+                           (IS_64BIT_PROCESS(core_proc) ? UIO_USERSPACE64 : UIO_USERSPACE32),
+                           IO_NOCACHE | IO_NODELOCKED | IO_UNIT, cred, (int64_t *) 0, core_proc);
                }
 
                hoffset += segment_command_sz;
@@ -458,22 +542,39 @@ coredump(proc_t core_proc)
        tir1.hoffset = hoffset;
        tir1.flavors = flavors;
        tir1.tstate_size = tstate_size;
-       task_act_iterate_wth_args(task, collectth_state,&tir1);
+       task_act_iterate_wth_args(task, collectth_state, &tir1);
 
        /*
         *      Write out the Mach header at the beginning of the
         *      file.  OK to use a 32 bit write for this.
         */
-       error = vn_rdwr(UIO_WRITE, vp, (caddr_t)header, header_size, (off_t)0,
-                       UIO_SYSSPACE32, IO_NODELOCKED|IO_UNIT, cred, (int *) 0, core_proc);
+       error = vn_rdwr(UIO_WRITE, vp, (caddr_t)header, (int)MIN(header_size, INT_MAX), (off_t)0,
+           UIO_SYSSPACE, IO_NOCACHE | IO_NODELOCKED | IO_UNIT, cred, (int *) 0, core_proc);
        kmem_free(kernel_map, header, header_size);
+
+       if ((coredump_flags & COREDUMP_FULLFSYNC) && error == 0) {
+               error = VNOP_IOCTL(vp, F_FULLFSYNC, (caddr_t)NULL, 0, ctx);
+       }
 out:
        error1 = vnode_close(vp, FWRITE, ctx);
 out2:
-       if (alloced_name != NULL)
+#if CONFIG_AUDIT
+       audit_proc_coredump(core_proc, name, error);
+#endif
+       if (alloced_name != NULL) {
                FREE(alloced_name, M_TEMP);
-       if (error == 0)
+       }
+       if (error == 0) {
                error = error1;
+       }
 
-       return (error);
+       return error;
 }
+
+#else /* CONFIG_COREDUMP */
+
+/* When core dumps aren't needed, no need to compile this file at all */
+
+#error assertion failed: this section is not compiled
+
+#endif /* CONFIG_COREDUMP */