//===-- asan_malloc_mac.cc ------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// Mac-specific malloc interception.
//===----------------------------------------------------------------------===//
#ifdef __APPLE__
#include <AvailabilityMacros.h>
#include <CoreFoundation/CFBase.h>
#include <dlfcn.h>
#include <malloc/malloc.h>
#include "asan_allocator.h"
#include "asan_interceptors.h"
#include "asan_internal.h"
#include "asan_mac.h"
#include "asan_report.h"
#include "asan_stack.h"
#include "asan_stats.h"
#include "asan_thread_registry.h"
// Similar code is used in Google Perftools,
// http://code.google.com/p/google-perftools.
// ---------------------- Replacement functions ---------------- {{{1
using namespace __asan; // NOLINT
// TODO(glider): do we need both zones?
static malloc_zone_t *system_malloc_zone = 0;
static malloc_zone_t *system_purgeable_zone = 0;
static malloc_zone_t asan_zone;
CFAllocatorRef cf_asan = 0;
// _CFRuntimeCreateInstance() checks whether the supplied allocator is
// kCFAllocatorSystemDefault and, if it is not, stores the allocator reference
// at the beginning of the allocated memory and returns the pointer to the
// allocated memory plus sizeof(CFAllocatorRef). See
// http://www.opensource.apple.com/source/CF/CF-635.21/CFRuntime.c
// Pointers returned by _CFRuntimeCreateInstance() can then be passed directly
// to free() or CFAllocatorDeallocate(), which leads to false invalid free
// reports.
// The corresponding rdar bug is http://openradar.appspot.com/radar?id=1796404.
void* ALWAYS_INLINE get_saved_cfallocator_ref(void *ptr) {
if (flags()->replace_cfallocator) {
// Make sure we're not hitting the previous page. This may be incorrect
// if ASan's malloc returns an address ending with 0xFF8, which will be
// then padded to a page boundary with a CFAllocatorRef.
uptr arith_ptr = (uptr)ptr;
if ((arith_ptr & 0xFFF) > sizeof(CFAllocatorRef)) {
CFAllocatorRef *saved =
(CFAllocatorRef*)(arith_ptr - sizeof(CFAllocatorRef));
if ((*saved == cf_asan) && asan_mz_size(saved)) ptr = (void*)saved;
}
}
return ptr;
}
// The free() implementation provided by OS X calls malloc_zone_from_ptr()
// to find the owner of |ptr|. If the result is 0, an invalid free() is
// reported. Our implementation falls back to asan_free() in this case
// in order to print an ASan-style report.
//
// For the objects created by _CFRuntimeCreateInstance a CFAllocatorRef is
// placed at the beginning of the allocated chunk and the pointer returned by
// our allocator is off by sizeof(CFAllocatorRef). This pointer can be then
// passed directly to free(), which will lead to errors.
// To overcome this we're checking whether |ptr-sizeof(CFAllocatorRef)|
// contains a pointer to our CFAllocator (assuming no other allocator is used).
// See http://code.google.com/p/address-sanitizer/issues/detail?id=70 for more
// info.
INTERCEPTOR(void, free, void *ptr) {
malloc_zone_t *zone = malloc_zone_from_ptr(ptr);
if (zone) {
#if defined(MAC_OS_X_VERSION_10_6) && \
MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6
if ((zone->version >= 6) && (zone->free_definite_size)) {
zone->free_definite_size(zone, ptr, malloc_size(ptr));
} else {
malloc_zone_free(zone, ptr);
}
#else
malloc_zone_free(zone, ptr);
#endif
} else {
if (!asan_mz_size(ptr)) ptr = get_saved_cfallocator_ref(ptr);
GET_STACK_TRACE_FREE;
asan_free(ptr, &stack, FROM_MALLOC);
}
}
// We can't always replace the default CFAllocator with cf_asan right in
// ReplaceSystemMalloc(), because it is sometimes called before
// __CFInitialize(), when the default allocator is invalid and replacing it may
// crash the program. Instead we wait for the allocator to initialize and jump
// in just after __CFInitialize(). Nobody is going to allocate memory using
// CFAllocators before that, so we won't miss anything.
//
// See http://code.google.com/p/address-sanitizer/issues/detail?id=87
// and http://opensource.apple.com/source/CF/CF-550.43/CFRuntime.c
INTERCEPTOR(void, __CFInitialize, void) {
// If the runtime is built as dynamic library, __CFInitialize wrapper may be
// called before __asan_init.
#if !MAC_INTERPOSE_FUNCTIONS
CHECK(flags()->replace_cfallocator);
CHECK(asan_inited);
#endif
REAL(__CFInitialize)();
if (!cf_asan && asan_inited) MaybeReplaceCFAllocator();
}
namespace {
// TODO(glider): the mz_* functions should be united with the Linux wrappers,
// as they are basically copied from there.
size_t mz_size(malloc_zone_t* zone, const void* ptr) {
return asan_mz_size(ptr);
}
void *mz_malloc(malloc_zone_t *zone, size_t size) {
if (!asan_inited) {
CHECK(system_malloc_zone);
return malloc_zone_malloc(system_malloc_zone, size);
}
GET_STACK_TRACE_MALLOC;
return asan_malloc(size, &stack);
}
void *cf_malloc(CFIndex size, CFOptionFlags hint, void *info) {
if (!asan_inited) {
CHECK(system_malloc_zone);
return malloc_zone_malloc(system_malloc_zone, size);
}
GET_STACK_TRACE_MALLOC;
return asan_malloc(size, &stack);
}
void *mz_calloc(malloc_zone_t *zone, size_t nmemb, size_t size) {
if (!asan_inited) {
// Hack: dlsym calls calloc before REAL(calloc) is retrieved from dlsym.
const size_t kCallocPoolSize = 1024;
static uptr calloc_memory_for_dlsym[kCallocPoolSize];
static size_t allocated;
size_t size_in_words = ((nmemb * size) + kWordSize - 1) / kWordSize;
void *mem = (void*)&calloc_memory_for_dlsym[allocated];
allocated += size_in_words;
CHECK(allocated < kCallocPoolSize);
return mem;
}
GET_STACK_TRACE_MALLOC;
return asan_calloc(nmemb, size, &stack);
}
void *mz_valloc(malloc_zone_t *zone, size_t size) {
if (!asan_inited) {
CHECK(system_malloc_zone);
return malloc_zone_valloc(system_malloc_zone, size);
}
GET_STACK_TRACE_MALLOC;
return asan_memalign(GetPageSizeCached(), size, &stack, FROM_MALLOC);
}
#define GET_ZONE_FOR_PTR(ptr) \
malloc_zone_t *zone_ptr = malloc_zone_from_ptr(ptr); \
const char *zone_name = (zone_ptr == 0) ? 0 : zone_ptr->zone_name
void ALWAYS_INLINE free_common(void *context, void *ptr) {
if (!ptr) return;
if (asan_mz_size(ptr)) {
GET_STACK_TRACE_FREE;
asan_free(ptr, &stack, FROM_MALLOC);
} else {
// If the pointer does not belong to any of the zones, use one of the
// fallback methods to free memory.
malloc_zone_t *zone_ptr = malloc_zone_from_ptr(ptr);
if (zone_ptr == system_purgeable_zone) {
// allocations from malloc_default_purgeable_zone() done before
// __asan_init() may be occasionally freed via free_common().
// see http://code.google.com/p/address-sanitizer/issues/detail?id=99.
malloc_zone_free(zone_ptr, ptr);
} else {
// If the memory chunk pointer was moved to store additional
// CFAllocatorRef, fix it back.
ptr = get_saved_cfallocator_ref(ptr);
GET_STACK_TRACE_FREE;
if (!flags()->mac_ignore_invalid_free) {
asan_free(ptr, &stack, FROM_MALLOC);
} else {
GET_ZONE_FOR_PTR(ptr);
WarnMacFreeUnallocated((uptr)ptr, (uptr)zone_ptr, zone_name, &stack);
return;
}
}
}
}
// TODO(glider): the allocation callbacks need to be refactored.
void mz_free(malloc_zone_t *zone, void *ptr) {
free_common(zone, ptr);
}
void cf_free(void *ptr, void *info) {
free_common(info, ptr);
}
void *mz_realloc(malloc_zone_t *zone, void *ptr, size_t size) {
if (!ptr) {
GET_STACK_TRACE_MALLOC;
return asan_malloc(size, &stack);
} else {
if (asan_mz_size(ptr)) {
GET_STACK_TRACE_MALLOC;
return asan_realloc(ptr, size, &stack);
} else {
// We can't recover from reallocating an unknown address, because
// this would require reading at most |size| bytes from
// potentially unaccessible memory.
GET_STACK_TRACE_FREE;
GET_ZONE_FOR_PTR(ptr);
ReportMacMzReallocUnknown((uptr)ptr, (uptr)zone_ptr, zone_name, &stack);
}
}
}
void *cf_realloc(void *ptr, CFIndex size, CFOptionFlags hint, void *info) {
if (!ptr) {
GET_STACK_TRACE_MALLOC;
return asan_malloc(size, &stack);
} else {
if (asan_mz_size(ptr)) {
GET_STACK_TRACE_MALLOC;
return asan_realloc(ptr, size, &stack);
} else {
// We can't recover from reallocating an unknown address, because
// this would require reading at most |size| bytes from
// potentially unaccessible memory.
GET_STACK_TRACE_FREE;
GET_ZONE_FOR_PTR(ptr);
ReportMacCfReallocUnknown((uptr)ptr, (uptr)zone_ptr, zone_name, &stack);
}
}
}
void mz_destroy(malloc_zone_t* zone) {
// A no-op -- we will not be destroyed!
Printf("mz_destroy() called -- ignoring\n");
}
// from AvailabilityMacros.h
#if defined(MAC_OS_X_VERSION_10_6) && \
MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6
void *mz_memalign(malloc_zone_t *zone, size_t align, size_t size) {
if (!asan_inited) {
CHECK(system_malloc_zone);
return malloc_zone_memalign(system_malloc_zone, align, size);
}
GET_STACK_TRACE_MALLOC;
return asan_memalign(align, size, &stack, FROM_MALLOC);
}
// This function is currently unused, and we build with -Werror.
#if 0
void mz_free_definite_size(malloc_zone_t* zone, void *ptr, size_t size) {
// TODO(glider): check that |size| is valid.
UNIMPLEMENTED();
}
#endif
#endif
kern_return_t mi_enumerator(task_t task, void *,
unsigned type_mask, vm_address_t zone_address,
memory_reader_t reader,
vm_range_recorder_t recorder) {
// Should enumerate all the pointers we have. Seems like a lot of work.
return KERN_FAILURE;
}
size_t mi_good_size(malloc_zone_t *zone, size_t size) {
// I think it's always safe to return size, but we maybe could do better.
return size;
}
boolean_t mi_check(malloc_zone_t *zone) {
UNIMPLEMENTED();
}
void mi_print(malloc_zone_t *zone, boolean_t verbose) {
UNIMPLEMENTED();
}
void mi_log(malloc_zone_t *zone, void *address) {
// I don't think we support anything like this
}
void mi_force_lock(malloc_zone_t *zone) {
asan_mz_force_lock();
}
void mi_force_unlock(malloc_zone_t *zone) {
asan_mz_force_unlock();
}
void mi_statistics(malloc_zone_t *zone, malloc_statistics_t *stats) {
AsanMallocStats malloc_stats;
asanThreadRegistry().FillMallocStatistics(&malloc_stats);
CHECK(sizeof(malloc_statistics_t) == sizeof(AsanMallocStats));
internal_memcpy(stats, &malloc_stats, sizeof(malloc_statistics_t));
}
#if defined(MAC_OS_X_VERSION_10_6) && \
MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6
boolean_t mi_zone_locked(malloc_zone_t *zone) {
// UNIMPLEMENTED();
return false;
}
#endif
} // unnamed namespace
extern int __CFRuntimeClassTableSize;
namespace __asan {
void MaybeReplaceCFAllocator() {
static CFAllocatorContext asan_context = {
/*version*/ 0, /*info*/ &asan_zone,
/*retain*/ 0, /*release*/ 0,
/*copyDescription*/0,
/*allocate*/ &cf_malloc,
/*reallocate*/ &cf_realloc,
/*deallocate*/ &cf_free,
/*preferredSize*/ 0 };
if (!cf_asan)
cf_asan = CFAllocatorCreate(kCFAllocatorUseContext, &asan_context);
if (flags()->replace_cfallocator && CFAllocatorGetDefault() != cf_asan)
CFAllocatorSetDefault(cf_asan);
}
void ReplaceSystemMalloc() {
static malloc_introspection_t asan_introspection;
// Ok to use internal_memset, these places are not performance-critical.
internal_memset(&asan_introspection, 0, sizeof(asan_introspection));
asan_introspection.enumerator = &mi_enumerator;
asan_introspection.good_size = &mi_good_size;
asan_introspection.check = &mi_check;
asan_introspection.print = &mi_print;
asan_introspection.log = &mi_log;
asan_introspection.force_lock = &mi_force_lock;
asan_introspection.force_unlock = &mi_force_unlock;
asan_introspection.statistics = &mi_statistics;
internal_memset(&asan_zone, 0, sizeof(malloc_zone_t));
// Start with a version 4 zone which is used for OS X 10.4 and 10.5.
asan_zone.version = 4;
asan_zone.zone_name = "asan";
asan_zone.size = &mz_size;
asan_zone.malloc = &mz_malloc;
asan_zone.calloc = &mz_calloc;
asan_zone.valloc = &mz_valloc;
asan_zone.free = &mz_free;
asan_zone.realloc = &mz_realloc;
asan_zone.destroy = &mz_destroy;
asan_zone.batch_malloc = 0;
asan_zone.batch_free = 0;
asan_zone.introspect = &asan_introspection;
// from AvailabilityMacros.h
#if defined(MAC_OS_X_VERSION_10_6) && \
MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6
// Switch to version 6 on OSX 10.6 to support memalign.
asan_zone.version = 6;
asan_zone.free_definite_size = 0;
asan_zone.memalign = &mz_memalign;
asan_introspection.zone_locked = &mi_zone_locked;
// Request the default purgable zone to force its creation. The
// current default zone is registered with the purgable zone for
// doing tiny and small allocs. Sadly, it assumes that the default
// zone is the szone implementation from OS X and will crash if it
// isn't. By creating the zone now, this will be true and changing
// the default zone won't cause a problem. (OS X 10.6 and higher.)
system_purgeable_zone = malloc_default_purgeable_zone();
#endif
// Register the ASan zone. At this point, it will not be the
// default zone.
malloc_zone_register(&asan_zone);
// Unregister and reregister the default zone. Unregistering swaps
// the specified zone with the last one registered which for the
// default zone makes the more recently registered zone the default
// zone. The default zone is then re-registered to ensure that
// allocations made from it earlier will be handled correctly.
// Things are not guaranteed to work that way, but it's how they work now.
system_malloc_zone = malloc_default_zone();
malloc_zone_unregister(system_malloc_zone);
malloc_zone_register(system_malloc_zone);
// Make sure the default allocator was replaced.
CHECK(malloc_default_zone() == &asan_zone);
// If __CFInitialize() hasn't been called yet, cf_asan will be created and
// installed as the default allocator after __CFInitialize() finishes (see
// the interceptor for __CFInitialize() above). Otherwise install cf_asan
// right now. On both Snow Leopard and Lion __CFInitialize() calls
// __CFAllocatorInitialize(), which initializes the _base._cfisa field of
// the default allocators we check here.
if (((CFRuntimeBase*)kCFAllocatorSystemDefault)->_cfisa) {
MaybeReplaceCFAllocator();
}
}
} // namespace __asan
#endif // __APPLE__
