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485 lines
16 KiB
C++
485 lines
16 KiB
C++
//===-- hwasan_allocator.cpp ------------------------ ---------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of HWAddressSanitizer.
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//
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// HWAddressSanitizer allocator.
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//===----------------------------------------------------------------------===//
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#include "sanitizer_common/sanitizer_atomic.h"
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#include "sanitizer_common/sanitizer_errno.h"
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#include "sanitizer_common/sanitizer_stackdepot.h"
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#include "hwasan.h"
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#include "hwasan_allocator.h"
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#include "hwasan_checks.h"
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#include "hwasan_mapping.h"
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#include "hwasan_malloc_bisect.h"
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#include "hwasan_thread.h"
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#include "hwasan_report.h"
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namespace __hwasan {
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static Allocator allocator;
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static AllocatorCache fallback_allocator_cache;
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static SpinMutex fallback_mutex;
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static atomic_uint8_t hwasan_allocator_tagging_enabled;
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static constexpr tag_t kFallbackAllocTag = 0xBB & kTagMask;
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static constexpr tag_t kFallbackFreeTag = 0xBC;
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enum RightAlignMode {
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kRightAlignNever,
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kRightAlignSometimes,
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kRightAlignAlways
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};
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// Initialized in HwasanAllocatorInit, an never changed.
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static ALIGNED(16) u8 tail_magic[kShadowAlignment - 1];
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bool HwasanChunkView::IsAllocated() const {
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return metadata_ && metadata_->alloc_context_id &&
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metadata_->get_requested_size();
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}
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// Aligns the 'addr' right to the granule boundary.
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static uptr AlignRight(uptr addr, uptr requested_size) {
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uptr tail_size = requested_size % kShadowAlignment;
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if (!tail_size) return addr;
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return addr + kShadowAlignment - tail_size;
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}
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uptr HwasanChunkView::Beg() const {
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if (metadata_ && metadata_->right_aligned)
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return AlignRight(block_, metadata_->get_requested_size());
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return block_;
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}
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uptr HwasanChunkView::End() const {
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return Beg() + UsedSize();
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}
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uptr HwasanChunkView::UsedSize() const {
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return metadata_->get_requested_size();
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}
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u32 HwasanChunkView::GetAllocStackId() const {
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return metadata_->alloc_context_id;
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}
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uptr HwasanChunkView::ActualSize() const {
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return allocator.GetActuallyAllocatedSize(reinterpret_cast<void *>(block_));
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}
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bool HwasanChunkView::FromSmallHeap() const {
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return allocator.FromPrimary(reinterpret_cast<void *>(block_));
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}
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void GetAllocatorStats(AllocatorStatCounters s) {
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allocator.GetStats(s);
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}
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uptr GetAliasRegionStart() {
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#if defined(HWASAN_ALIASING_MODE)
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constexpr uptr kAliasRegionOffset = 1ULL << (kTaggableRegionCheckShift - 1);
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uptr AliasRegionStart =
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__hwasan_shadow_memory_dynamic_address + kAliasRegionOffset;
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CHECK_EQ(AliasRegionStart >> kTaggableRegionCheckShift,
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__hwasan_shadow_memory_dynamic_address >> kTaggableRegionCheckShift);
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CHECK_EQ(
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(AliasRegionStart + kAliasRegionOffset - 1) >> kTaggableRegionCheckShift,
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__hwasan_shadow_memory_dynamic_address >> kTaggableRegionCheckShift);
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return AliasRegionStart;
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#else
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return 0;
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#endif
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}
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void HwasanAllocatorInit() {
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atomic_store_relaxed(&hwasan_allocator_tagging_enabled,
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!flags()->disable_allocator_tagging);
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SetAllocatorMayReturnNull(common_flags()->allocator_may_return_null);
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allocator.Init(common_flags()->allocator_release_to_os_interval_ms,
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GetAliasRegionStart());
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for (uptr i = 0; i < sizeof(tail_magic); i++)
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tail_magic[i] = GetCurrentThread()->GenerateRandomTag();
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}
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void HwasanAllocatorLock() { allocator.ForceLock(); }
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void HwasanAllocatorUnlock() { allocator.ForceUnlock(); }
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void AllocatorSwallowThreadLocalCache(AllocatorCache *cache) {
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allocator.SwallowCache(cache);
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}
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static uptr TaggedSize(uptr size) {
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if (!size) size = 1;
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uptr new_size = RoundUpTo(size, kShadowAlignment);
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CHECK_GE(new_size, size);
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return new_size;
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}
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static void *HwasanAllocate(StackTrace *stack, uptr orig_size, uptr alignment,
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bool zeroise) {
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if (orig_size > kMaxAllowedMallocSize) {
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if (AllocatorMayReturnNull()) {
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Report("WARNING: HWAddressSanitizer failed to allocate 0x%zx bytes\n",
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orig_size);
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return nullptr;
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}
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ReportAllocationSizeTooBig(orig_size, kMaxAllowedMallocSize, stack);
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}
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if (UNLIKELY(IsRssLimitExceeded())) {
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if (AllocatorMayReturnNull())
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return nullptr;
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ReportRssLimitExceeded(stack);
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}
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alignment = Max(alignment, kShadowAlignment);
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uptr size = TaggedSize(orig_size);
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Thread *t = GetCurrentThread();
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void *allocated;
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if (t) {
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allocated = allocator.Allocate(t->allocator_cache(), size, alignment);
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} else {
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SpinMutexLock l(&fallback_mutex);
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AllocatorCache *cache = &fallback_allocator_cache;
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allocated = allocator.Allocate(cache, size, alignment);
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}
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if (UNLIKELY(!allocated)) {
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SetAllocatorOutOfMemory();
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if (AllocatorMayReturnNull())
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return nullptr;
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ReportOutOfMemory(size, stack);
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}
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Metadata *meta =
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reinterpret_cast<Metadata *>(allocator.GetMetaData(allocated));
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meta->set_requested_size(orig_size);
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meta->alloc_context_id = StackDepotPut(*stack);
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meta->right_aligned = false;
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if (zeroise) {
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internal_memset(allocated, 0, size);
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} else if (flags()->max_malloc_fill_size > 0) {
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uptr fill_size = Min(size, (uptr)flags()->max_malloc_fill_size);
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internal_memset(allocated, flags()->malloc_fill_byte, fill_size);
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}
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if (size != orig_size) {
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u8 *tail = reinterpret_cast<u8 *>(allocated) + orig_size;
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uptr tail_length = size - orig_size;
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internal_memcpy(tail, tail_magic, tail_length - 1);
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// Short granule is excluded from magic tail, so we explicitly untag.
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tail[tail_length - 1] = 0;
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}
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void *user_ptr = allocated;
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// Tagging can only be skipped when both tag_in_malloc and tag_in_free are
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// false. When tag_in_malloc = false and tag_in_free = true malloc needs to
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// retag to 0.
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if (InTaggableRegion(reinterpret_cast<uptr>(user_ptr)) &&
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(flags()->tag_in_malloc || flags()->tag_in_free) &&
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atomic_load_relaxed(&hwasan_allocator_tagging_enabled)) {
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if (flags()->tag_in_malloc && malloc_bisect(stack, orig_size)) {
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tag_t tag = t ? t->GenerateRandomTag() : kFallbackAllocTag;
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uptr tag_size = orig_size ? orig_size : 1;
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uptr full_granule_size = RoundDownTo(tag_size, kShadowAlignment);
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user_ptr =
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(void *)TagMemoryAligned((uptr)user_ptr, full_granule_size, tag);
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if (full_granule_size != tag_size) {
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u8 *short_granule =
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reinterpret_cast<u8 *>(allocated) + full_granule_size;
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TagMemoryAligned((uptr)short_granule, kShadowAlignment,
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tag_size % kShadowAlignment);
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short_granule[kShadowAlignment - 1] = tag;
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}
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} else {
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user_ptr = (void *)TagMemoryAligned((uptr)user_ptr, size, 0);
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}
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}
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RunMallocHooks(user_ptr, size);
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return user_ptr;
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}
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static bool PointerAndMemoryTagsMatch(void *tagged_ptr) {
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CHECK(tagged_ptr);
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uptr tagged_uptr = reinterpret_cast<uptr>(tagged_ptr);
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if (!InTaggableRegion(tagged_uptr))
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return true;
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tag_t mem_tag = *reinterpret_cast<tag_t *>(
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MemToShadow(reinterpret_cast<uptr>(UntagPtr(tagged_ptr))));
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return PossiblyShortTagMatches(mem_tag, tagged_uptr, 1);
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}
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static bool CheckInvalidFree(StackTrace *stack, void *untagged_ptr,
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void *tagged_ptr) {
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// This function can return true if halt_on_error is false.
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if (!MemIsApp(reinterpret_cast<uptr>(untagged_ptr)) ||
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!PointerAndMemoryTagsMatch(tagged_ptr)) {
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ReportInvalidFree(stack, reinterpret_cast<uptr>(tagged_ptr));
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return true;
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}
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return false;
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}
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static void HwasanDeallocate(StackTrace *stack, void *tagged_ptr) {
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CHECK(tagged_ptr);
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RunFreeHooks(tagged_ptr);
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bool in_taggable_region =
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InTaggableRegion(reinterpret_cast<uptr>(tagged_ptr));
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void *untagged_ptr = in_taggable_region ? UntagPtr(tagged_ptr) : tagged_ptr;
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if (CheckInvalidFree(stack, untagged_ptr, tagged_ptr))
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return;
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void *aligned_ptr = reinterpret_cast<void *>(
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RoundDownTo(reinterpret_cast<uptr>(untagged_ptr), kShadowAlignment));
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tag_t pointer_tag = GetTagFromPointer(reinterpret_cast<uptr>(tagged_ptr));
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Metadata *meta =
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reinterpret_cast<Metadata *>(allocator.GetMetaData(aligned_ptr));
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if (!meta) {
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ReportInvalidFree(stack, reinterpret_cast<uptr>(tagged_ptr));
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return;
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}
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uptr orig_size = meta->get_requested_size();
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u32 free_context_id = StackDepotPut(*stack);
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u32 alloc_context_id = meta->alloc_context_id;
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// Check tail magic.
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uptr tagged_size = TaggedSize(orig_size);
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if (flags()->free_checks_tail_magic && orig_size &&
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tagged_size != orig_size) {
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uptr tail_size = tagged_size - orig_size - 1;
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CHECK_LT(tail_size, kShadowAlignment);
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void *tail_beg = reinterpret_cast<void *>(
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reinterpret_cast<uptr>(aligned_ptr) + orig_size);
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tag_t short_granule_memtag = *(reinterpret_cast<tag_t *>(
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reinterpret_cast<uptr>(tail_beg) + tail_size));
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if (tail_size &&
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(internal_memcmp(tail_beg, tail_magic, tail_size) ||
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(in_taggable_region && pointer_tag != short_granule_memtag)))
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ReportTailOverwritten(stack, reinterpret_cast<uptr>(tagged_ptr),
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orig_size, tail_magic);
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}
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meta->set_requested_size(0);
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meta->alloc_context_id = 0;
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// This memory will not be reused by anyone else, so we are free to keep it
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// poisoned.
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Thread *t = GetCurrentThread();
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if (flags()->max_free_fill_size > 0) {
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uptr fill_size =
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Min(TaggedSize(orig_size), (uptr)flags()->max_free_fill_size);
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internal_memset(aligned_ptr, flags()->free_fill_byte, fill_size);
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}
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if (in_taggable_region && flags()->tag_in_free && malloc_bisect(stack, 0) &&
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atomic_load_relaxed(&hwasan_allocator_tagging_enabled)) {
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// Always store full 8-bit tags on free to maximize UAF detection.
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tag_t tag;
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if (t) {
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// Make sure we are not using a short granule tag as a poison tag. This
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// would make us attempt to read the memory on a UaF.
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// The tag can be zero if tagging is disabled on this thread.
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do {
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tag = t->GenerateRandomTag(/*num_bits=*/8);
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} while (
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UNLIKELY((tag < kShadowAlignment || tag == pointer_tag) && tag != 0));
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} else {
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static_assert(kFallbackFreeTag >= kShadowAlignment,
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"fallback tag must not be a short granule tag.");
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tag = kFallbackFreeTag;
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}
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TagMemoryAligned(reinterpret_cast<uptr>(aligned_ptr), TaggedSize(orig_size),
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tag);
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}
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if (t) {
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allocator.Deallocate(t->allocator_cache(), aligned_ptr);
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if (auto *ha = t->heap_allocations())
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ha->push({reinterpret_cast<uptr>(tagged_ptr), alloc_context_id,
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free_context_id, static_cast<u32>(orig_size)});
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} else {
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SpinMutexLock l(&fallback_mutex);
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AllocatorCache *cache = &fallback_allocator_cache;
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allocator.Deallocate(cache, aligned_ptr);
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}
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}
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static void *HwasanReallocate(StackTrace *stack, void *tagged_ptr_old,
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uptr new_size, uptr alignment) {
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void *untagged_ptr_old =
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InTaggableRegion(reinterpret_cast<uptr>(tagged_ptr_old))
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? UntagPtr(tagged_ptr_old)
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: tagged_ptr_old;
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if (CheckInvalidFree(stack, untagged_ptr_old, tagged_ptr_old))
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return nullptr;
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void *tagged_ptr_new =
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HwasanAllocate(stack, new_size, alignment, false /*zeroise*/);
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if (tagged_ptr_old && tagged_ptr_new) {
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Metadata *meta =
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reinterpret_cast<Metadata *>(allocator.GetMetaData(untagged_ptr_old));
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internal_memcpy(
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UntagPtr(tagged_ptr_new), untagged_ptr_old,
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Min(new_size, static_cast<uptr>(meta->get_requested_size())));
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HwasanDeallocate(stack, tagged_ptr_old);
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}
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return tagged_ptr_new;
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}
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static void *HwasanCalloc(StackTrace *stack, uptr nmemb, uptr size) {
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if (UNLIKELY(CheckForCallocOverflow(size, nmemb))) {
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if (AllocatorMayReturnNull())
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return nullptr;
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ReportCallocOverflow(nmemb, size, stack);
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}
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return HwasanAllocate(stack, nmemb * size, sizeof(u64), true);
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}
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HwasanChunkView FindHeapChunkByAddress(uptr address) {
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if (!allocator.PointerIsMine(reinterpret_cast<void *>(address)))
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return HwasanChunkView();
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void *block = allocator.GetBlockBegin(reinterpret_cast<void*>(address));
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if (!block)
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return HwasanChunkView();
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Metadata *metadata =
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reinterpret_cast<Metadata*>(allocator.GetMetaData(block));
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return HwasanChunkView(reinterpret_cast<uptr>(block), metadata);
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}
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static uptr AllocationSize(const void *tagged_ptr) {
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const void *untagged_ptr = UntagPtr(tagged_ptr);
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if (!untagged_ptr) return 0;
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const void *beg = allocator.GetBlockBegin(untagged_ptr);
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Metadata *b = (Metadata *)allocator.GetMetaData(untagged_ptr);
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if (b->right_aligned) {
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if (beg != reinterpret_cast<void *>(RoundDownTo(
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reinterpret_cast<uptr>(untagged_ptr), kShadowAlignment)))
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return 0;
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} else {
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if (beg != untagged_ptr) return 0;
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}
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return b->get_requested_size();
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}
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void *hwasan_malloc(uptr size, StackTrace *stack) {
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return SetErrnoOnNull(HwasanAllocate(stack, size, sizeof(u64), false));
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}
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void *hwasan_calloc(uptr nmemb, uptr size, StackTrace *stack) {
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return SetErrnoOnNull(HwasanCalloc(stack, nmemb, size));
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}
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void *hwasan_realloc(void *ptr, uptr size, StackTrace *stack) {
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if (!ptr)
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return SetErrnoOnNull(HwasanAllocate(stack, size, sizeof(u64), false));
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if (size == 0) {
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HwasanDeallocate(stack, ptr);
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return nullptr;
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}
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return SetErrnoOnNull(HwasanReallocate(stack, ptr, size, sizeof(u64)));
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}
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void *hwasan_reallocarray(void *ptr, uptr nmemb, uptr size, StackTrace *stack) {
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if (UNLIKELY(CheckForCallocOverflow(size, nmemb))) {
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errno = errno_ENOMEM;
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if (AllocatorMayReturnNull())
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return nullptr;
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ReportReallocArrayOverflow(nmemb, size, stack);
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}
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return hwasan_realloc(ptr, nmemb * size, stack);
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}
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void *hwasan_valloc(uptr size, StackTrace *stack) {
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return SetErrnoOnNull(
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HwasanAllocate(stack, size, GetPageSizeCached(), false));
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}
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void *hwasan_pvalloc(uptr size, StackTrace *stack) {
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uptr PageSize = GetPageSizeCached();
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if (UNLIKELY(CheckForPvallocOverflow(size, PageSize))) {
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errno = errno_ENOMEM;
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if (AllocatorMayReturnNull())
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return nullptr;
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ReportPvallocOverflow(size, stack);
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}
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// pvalloc(0) should allocate one page.
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size = size ? RoundUpTo(size, PageSize) : PageSize;
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return SetErrnoOnNull(HwasanAllocate(stack, size, PageSize, false));
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}
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void *hwasan_aligned_alloc(uptr alignment, uptr size, StackTrace *stack) {
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if (UNLIKELY(!CheckAlignedAllocAlignmentAndSize(alignment, size))) {
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errno = errno_EINVAL;
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if (AllocatorMayReturnNull())
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return nullptr;
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ReportInvalidAlignedAllocAlignment(size, alignment, stack);
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}
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return SetErrnoOnNull(HwasanAllocate(stack, size, alignment, false));
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}
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void *hwasan_memalign(uptr alignment, uptr size, StackTrace *stack) {
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if (UNLIKELY(!IsPowerOfTwo(alignment))) {
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errno = errno_EINVAL;
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if (AllocatorMayReturnNull())
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return nullptr;
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ReportInvalidAllocationAlignment(alignment, stack);
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}
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return SetErrnoOnNull(HwasanAllocate(stack, size, alignment, false));
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}
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int hwasan_posix_memalign(void **memptr, uptr alignment, uptr size,
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StackTrace *stack) {
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if (UNLIKELY(!CheckPosixMemalignAlignment(alignment))) {
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if (AllocatorMayReturnNull())
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return errno_EINVAL;
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ReportInvalidPosixMemalignAlignment(alignment, stack);
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}
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void *ptr = HwasanAllocate(stack, size, alignment, false);
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if (UNLIKELY(!ptr))
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// OOM error is already taken care of by HwasanAllocate.
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return errno_ENOMEM;
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CHECK(IsAligned((uptr)ptr, alignment));
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*memptr = ptr;
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return 0;
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}
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void hwasan_free(void *ptr, StackTrace *stack) {
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return HwasanDeallocate(stack, ptr);
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}
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} // namespace __hwasan
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using namespace __hwasan;
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void __hwasan_enable_allocator_tagging() {
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atomic_store_relaxed(&hwasan_allocator_tagging_enabled, 1);
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}
|
|
|
|
void __hwasan_disable_allocator_tagging() {
|
|
atomic_store_relaxed(&hwasan_allocator_tagging_enabled, 0);
|
|
}
|
|
|
|
uptr __sanitizer_get_current_allocated_bytes() {
|
|
uptr stats[AllocatorStatCount];
|
|
allocator.GetStats(stats);
|
|
return stats[AllocatorStatAllocated];
|
|
}
|
|
|
|
uptr __sanitizer_get_heap_size() {
|
|
uptr stats[AllocatorStatCount];
|
|
allocator.GetStats(stats);
|
|
return stats[AllocatorStatMapped];
|
|
}
|
|
|
|
uptr __sanitizer_get_free_bytes() { return 1; }
|
|
|
|
uptr __sanitizer_get_unmapped_bytes() { return 1; }
|
|
|
|
uptr __sanitizer_get_estimated_allocated_size(uptr size) { return size; }
|
|
|
|
int __sanitizer_get_ownership(const void *p) { return AllocationSize(p) != 0; }
|
|
|
|
uptr __sanitizer_get_allocated_size(const void *p) { return AllocationSize(p); }
|