| //===-- hwasan_allocator.cpp ------------------------ ---------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file is a part of HWAddressSanitizer. |
| // |
| // HWAddressSanitizer allocator. |
| //===----------------------------------------------------------------------===// |
| |
| #include "sanitizer_common/sanitizer_atomic.h" |
| #include "sanitizer_common/sanitizer_errno.h" |
| #include "sanitizer_common/sanitizer_stackdepot.h" |
| #include "hwasan.h" |
| #include "hwasan_allocator.h" |
| #include "hwasan_mapping.h" |
| #include "hwasan_malloc_bisect.h" |
| #include "hwasan_thread.h" |
| #include "hwasan_report.h" |
| |
| #if HWASAN_WITH_INTERCEPTORS |
| DEFINE_REAL(void *, realloc, void *ptr, uptr size) |
| DEFINE_REAL(void, free, void *ptr) |
| #endif |
| |
| namespace __hwasan { |
| |
| static Allocator allocator; |
| static AllocatorCache fallback_allocator_cache; |
| static SpinMutex fallback_mutex; |
| static atomic_uint8_t hwasan_allocator_tagging_enabled; |
| |
| static const tag_t kFallbackAllocTag = 0xBB; |
| static const tag_t kFallbackFreeTag = 0xBC; |
| |
| enum RightAlignMode { |
| kRightAlignNever, |
| kRightAlignSometimes, |
| kRightAlignAlways |
| }; |
| |
| // These two variables are initialized from flags()->malloc_align_right |
| // in HwasanAllocatorInit and are never changed afterwards. |
| static RightAlignMode right_align_mode = kRightAlignNever; |
| static bool right_align_8 = false; |
| |
| // Initialized in HwasanAllocatorInit, an never changed. |
| static ALIGNED(16) u8 tail_magic[kShadowAlignment]; |
| |
| bool HwasanChunkView::IsAllocated() const { |
| return metadata_ && metadata_->alloc_context_id && metadata_->requested_size; |
| } |
| |
| // Aligns the 'addr' right to the granule boundary. |
| static uptr AlignRight(uptr addr, uptr requested_size) { |
| uptr tail_size = requested_size % kShadowAlignment; |
| if (!tail_size) return addr; |
| if (right_align_8) |
| return tail_size > 8 ? addr : addr + 8; |
| return addr + kShadowAlignment - tail_size; |
| } |
| |
| uptr HwasanChunkView::Beg() const { |
| if (metadata_ && metadata_->right_aligned) |
| return AlignRight(block_, metadata_->requested_size); |
| return block_; |
| } |
| uptr HwasanChunkView::End() const { |
| return Beg() + UsedSize(); |
| } |
| uptr HwasanChunkView::UsedSize() const { |
| return metadata_->requested_size; |
| } |
| u32 HwasanChunkView::GetAllocStackId() const { |
| return metadata_->alloc_context_id; |
| } |
| |
| uptr HwasanChunkView::ActualSize() const { |
| return allocator.GetActuallyAllocatedSize(reinterpret_cast<void *>(block_)); |
| } |
| |
| bool HwasanChunkView::FromSmallHeap() const { |
| return allocator.FromPrimary(reinterpret_cast<void *>(block_)); |
| } |
| |
| void GetAllocatorStats(AllocatorStatCounters s) { |
| allocator.GetStats(s); |
| } |
| |
| void HwasanAllocatorInit() { |
| atomic_store_relaxed(&hwasan_allocator_tagging_enabled, |
| !flags()->disable_allocator_tagging); |
| SetAllocatorMayReturnNull(common_flags()->allocator_may_return_null); |
| allocator.Init(common_flags()->allocator_release_to_os_interval_ms); |
| switch (flags()->malloc_align_right) { |
| case 0: break; |
| case 1: |
| right_align_mode = kRightAlignSometimes; |
| right_align_8 = false; |
| break; |
| case 2: |
| right_align_mode = kRightAlignAlways; |
| right_align_8 = false; |
| break; |
| case 8: |
| right_align_mode = kRightAlignSometimes; |
| right_align_8 = true; |
| break; |
| case 9: |
| right_align_mode = kRightAlignAlways; |
| right_align_8 = true; |
| break; |
| default: |
| Report("ERROR: unsupported value of malloc_align_right flag: %d\n", |
| flags()->malloc_align_right); |
| Die(); |
| } |
| for (uptr i = 0; i < kShadowAlignment; i++) |
| tail_magic[i] = GetCurrentThread()->GenerateRandomTag(); |
| } |
| |
| void AllocatorSwallowThreadLocalCache(AllocatorCache *cache) { |
| allocator.SwallowCache(cache); |
| } |
| |
| static uptr TaggedSize(uptr size) { |
| if (!size) size = 1; |
| uptr new_size = RoundUpTo(size, kShadowAlignment); |
| CHECK_GE(new_size, size); |
| return new_size; |
| } |
| |
| static void *HwasanAllocate(StackTrace *stack, uptr orig_size, uptr alignment, |
| bool zeroise) { |
| if (orig_size > kMaxAllowedMallocSize) { |
| if (AllocatorMayReturnNull()) { |
| Report("WARNING: HWAddressSanitizer failed to allocate 0x%zx bytes\n", |
| orig_size); |
| return nullptr; |
| } |
| ReportAllocationSizeTooBig(orig_size, kMaxAllowedMallocSize, stack); |
| } |
| |
| alignment = Max(alignment, kShadowAlignment); |
| uptr size = TaggedSize(orig_size); |
| Thread *t = GetCurrentThread(); |
| void *allocated; |
| if (t) { |
| allocated = allocator.Allocate(t->allocator_cache(), size, alignment); |
| } else { |
| SpinMutexLock l(&fallback_mutex); |
| AllocatorCache *cache = &fallback_allocator_cache; |
| allocated = allocator.Allocate(cache, size, alignment); |
| } |
| if (UNLIKELY(!allocated)) { |
| SetAllocatorOutOfMemory(); |
| if (AllocatorMayReturnNull()) |
| return nullptr; |
| ReportOutOfMemory(size, stack); |
| } |
| Metadata *meta = |
| reinterpret_cast<Metadata *>(allocator.GetMetaData(allocated)); |
| meta->requested_size = static_cast<u32>(orig_size); |
| meta->alloc_context_id = StackDepotPut(*stack); |
| meta->right_aligned = false; |
| if (zeroise) { |
| internal_memset(allocated, 0, size); |
| } else if (flags()->max_malloc_fill_size > 0) { |
| uptr fill_size = Min(size, (uptr)flags()->max_malloc_fill_size); |
| internal_memset(allocated, flags()->malloc_fill_byte, fill_size); |
| } |
| if (!right_align_mode) |
| internal_memcpy(reinterpret_cast<u8 *>(allocated) + orig_size, tail_magic, |
| size - orig_size); |
| |
| void *user_ptr = allocated; |
| // Tagging can only be skipped when both tag_in_malloc and tag_in_free are |
| // false. When tag_in_malloc = false and tag_in_free = true malloc needs to |
| // retag to 0. |
| if ((flags()->tag_in_malloc || flags()->tag_in_free) && |
| atomic_load_relaxed(&hwasan_allocator_tagging_enabled)) { |
| tag_t tag = flags()->tag_in_malloc && malloc_bisect(stack, orig_size) |
| ? (t ? t->GenerateRandomTag() : kFallbackAllocTag) |
| : 0; |
| user_ptr = (void *)TagMemoryAligned((uptr)user_ptr, size, tag); |
| } |
| |
| if ((orig_size % kShadowAlignment) && (alignment <= kShadowAlignment) && |
| right_align_mode) { |
| uptr as_uptr = reinterpret_cast<uptr>(user_ptr); |
| if (right_align_mode == kRightAlignAlways || |
| GetTagFromPointer(as_uptr) & 1) { // use a tag bit as a random bit. |
| user_ptr = reinterpret_cast<void *>(AlignRight(as_uptr, orig_size)); |
| meta->right_aligned = 1; |
| } |
| } |
| |
| HWASAN_MALLOC_HOOK(user_ptr, size); |
| return user_ptr; |
| } |
| |
| static bool PointerAndMemoryTagsMatch(void *tagged_ptr) { |
| CHECK(tagged_ptr); |
| tag_t ptr_tag = GetTagFromPointer(reinterpret_cast<uptr>(tagged_ptr)); |
| tag_t mem_tag = *reinterpret_cast<tag_t *>( |
| MemToShadow(reinterpret_cast<uptr>(UntagPtr(tagged_ptr)))); |
| return ptr_tag == mem_tag; |
| } |
| |
| static void HwasanDeallocate(StackTrace *stack, void *tagged_ptr) { |
| CHECK(tagged_ptr); |
| HWASAN_FREE_HOOK(tagged_ptr); |
| |
| if (!PointerAndMemoryTagsMatch(tagged_ptr)) |
| ReportInvalidFree(stack, reinterpret_cast<uptr>(tagged_ptr)); |
| |
| void *untagged_ptr = UntagPtr(tagged_ptr); |
| void *aligned_ptr = reinterpret_cast<void *>( |
| RoundDownTo(reinterpret_cast<uptr>(untagged_ptr), kShadowAlignment)); |
| Metadata *meta = |
| reinterpret_cast<Metadata *>(allocator.GetMetaData(aligned_ptr)); |
| uptr orig_size = meta->requested_size; |
| u32 free_context_id = StackDepotPut(*stack); |
| u32 alloc_context_id = meta->alloc_context_id; |
| |
| // Check tail magic. |
| uptr tagged_size = TaggedSize(orig_size); |
| if (flags()->free_checks_tail_magic && !right_align_mode && orig_size) { |
| uptr tail_size = tagged_size - orig_size; |
| CHECK_LT(tail_size, kShadowAlignment); |
| void *tail_beg = reinterpret_cast<void *>( |
| reinterpret_cast<uptr>(aligned_ptr) + orig_size); |
| if (tail_size && internal_memcmp(tail_beg, tail_magic, tail_size)) |
| ReportTailOverwritten(stack, reinterpret_cast<uptr>(tagged_ptr), |
| orig_size, tail_size, tail_magic); |
| } |
| |
| meta->requested_size = 0; |
| meta->alloc_context_id = 0; |
| // This memory will not be reused by anyone else, so we are free to keep it |
| // poisoned. |
| Thread *t = GetCurrentThread(); |
| if (flags()->max_free_fill_size > 0) { |
| uptr fill_size = |
| Min(TaggedSize(orig_size), (uptr)flags()->max_free_fill_size); |
| internal_memset(aligned_ptr, flags()->free_fill_byte, fill_size); |
| } |
| if (flags()->tag_in_free && malloc_bisect(stack, 0) && |
| atomic_load_relaxed(&hwasan_allocator_tagging_enabled)) |
| TagMemoryAligned(reinterpret_cast<uptr>(aligned_ptr), TaggedSize(orig_size), |
| t ? t->GenerateRandomTag() : kFallbackFreeTag); |
| if (t) { |
| allocator.Deallocate(t->allocator_cache(), aligned_ptr); |
| if (auto *ha = t->heap_allocations()) |
| ha->push({reinterpret_cast<uptr>(tagged_ptr), alloc_context_id, |
| free_context_id, static_cast<u32>(orig_size)}); |
| } else { |
| SpinMutexLock l(&fallback_mutex); |
| AllocatorCache *cache = &fallback_allocator_cache; |
| allocator.Deallocate(cache, aligned_ptr); |
| } |
| } |
| |
| static void *HwasanReallocate(StackTrace *stack, void *tagged_ptr_old, |
| uptr new_size, uptr alignment) { |
| if (!PointerAndMemoryTagsMatch(tagged_ptr_old)) |
| ReportInvalidFree(stack, reinterpret_cast<uptr>(tagged_ptr_old)); |
| |
| void *tagged_ptr_new = |
| HwasanAllocate(stack, new_size, alignment, false /*zeroise*/); |
| if (tagged_ptr_old && tagged_ptr_new) { |
| void *untagged_ptr_old = UntagPtr(tagged_ptr_old); |
| Metadata *meta = |
| reinterpret_cast<Metadata *>(allocator.GetMetaData(untagged_ptr_old)); |
| internal_memcpy(UntagPtr(tagged_ptr_new), untagged_ptr_old, |
| Min(new_size, static_cast<uptr>(meta->requested_size))); |
| HwasanDeallocate(stack, tagged_ptr_old); |
| } |
| return tagged_ptr_new; |
| } |
| |
| static void *HwasanCalloc(StackTrace *stack, uptr nmemb, uptr size) { |
| if (UNLIKELY(CheckForCallocOverflow(size, nmemb))) { |
| if (AllocatorMayReturnNull()) |
| return nullptr; |
| ReportCallocOverflow(nmemb, size, stack); |
| } |
| return HwasanAllocate(stack, nmemb * size, sizeof(u64), true); |
| } |
| |
| HwasanChunkView FindHeapChunkByAddress(uptr address) { |
| void *block = allocator.GetBlockBegin(reinterpret_cast<void*>(address)); |
| if (!block) |
| return HwasanChunkView(); |
| Metadata *metadata = |
| reinterpret_cast<Metadata*>(allocator.GetMetaData(block)); |
| return HwasanChunkView(reinterpret_cast<uptr>(block), metadata); |
| } |
| |
| static uptr AllocationSize(const void *tagged_ptr) { |
| const void *untagged_ptr = UntagPtr(tagged_ptr); |
| if (!untagged_ptr) return 0; |
| const void *beg = allocator.GetBlockBegin(untagged_ptr); |
| Metadata *b = (Metadata *)allocator.GetMetaData(untagged_ptr); |
| if (b->right_aligned) { |
| if (beg != reinterpret_cast<void *>(RoundDownTo( |
| reinterpret_cast<uptr>(untagged_ptr), kShadowAlignment))) |
| return 0; |
| } else { |
| if (beg != untagged_ptr) return 0; |
| } |
| return b->requested_size; |
| } |
| |
| void *hwasan_malloc(uptr size, StackTrace *stack) { |
| return SetErrnoOnNull(HwasanAllocate(stack, size, sizeof(u64), false)); |
| } |
| |
| void *hwasan_calloc(uptr nmemb, uptr size, StackTrace *stack) { |
| return SetErrnoOnNull(HwasanCalloc(stack, nmemb, size)); |
| } |
| |
| void *hwasan_realloc(void *ptr, uptr size, StackTrace *stack) { |
| if (!ptr) |
| return SetErrnoOnNull(HwasanAllocate(stack, size, sizeof(u64), false)); |
| |
| #if HWASAN_WITH_INTERCEPTORS |
| // A tag of 0 means that this is a system allocator allocation, so we must use |
| // the system allocator to realloc it. |
| if (!flags()->disable_allocator_tagging && GetTagFromPointer((uptr)ptr) == 0) |
| return REAL(realloc)(ptr, size); |
| #endif |
| |
| if (size == 0) { |
| HwasanDeallocate(stack, ptr); |
| return nullptr; |
| } |
| return SetErrnoOnNull(HwasanReallocate(stack, ptr, size, sizeof(u64))); |
| } |
| |
| void *hwasan_valloc(uptr size, StackTrace *stack) { |
| return SetErrnoOnNull( |
| HwasanAllocate(stack, size, GetPageSizeCached(), false)); |
| } |
| |
| void *hwasan_pvalloc(uptr size, StackTrace *stack) { |
| uptr PageSize = GetPageSizeCached(); |
| if (UNLIKELY(CheckForPvallocOverflow(size, PageSize))) { |
| errno = errno_ENOMEM; |
| if (AllocatorMayReturnNull()) |
| return nullptr; |
| ReportPvallocOverflow(size, stack); |
| } |
| // pvalloc(0) should allocate one page. |
| size = size ? RoundUpTo(size, PageSize) : PageSize; |
| return SetErrnoOnNull(HwasanAllocate(stack, size, PageSize, false)); |
| } |
| |
| void *hwasan_aligned_alloc(uptr alignment, uptr size, StackTrace *stack) { |
| if (UNLIKELY(!CheckAlignedAllocAlignmentAndSize(alignment, size))) { |
| errno = errno_EINVAL; |
| if (AllocatorMayReturnNull()) |
| return nullptr; |
| ReportInvalidAlignedAllocAlignment(size, alignment, stack); |
| } |
| return SetErrnoOnNull(HwasanAllocate(stack, size, alignment, false)); |
| } |
| |
| void *hwasan_memalign(uptr alignment, uptr size, StackTrace *stack) { |
| if (UNLIKELY(!IsPowerOfTwo(alignment))) { |
| errno = errno_EINVAL; |
| if (AllocatorMayReturnNull()) |
| return nullptr; |
| ReportInvalidAllocationAlignment(alignment, stack); |
| } |
| return SetErrnoOnNull(HwasanAllocate(stack, size, alignment, false)); |
| } |
| |
| int hwasan_posix_memalign(void **memptr, uptr alignment, uptr size, |
| StackTrace *stack) { |
| if (UNLIKELY(!CheckPosixMemalignAlignment(alignment))) { |
| if (AllocatorMayReturnNull()) |
| return errno_EINVAL; |
| ReportInvalidPosixMemalignAlignment(alignment, stack); |
| } |
| void *ptr = HwasanAllocate(stack, size, alignment, false); |
| if (UNLIKELY(!ptr)) |
| // OOM error is already taken care of by HwasanAllocate. |
| return errno_ENOMEM; |
| CHECK(IsAligned((uptr)ptr, alignment)); |
| *memptr = ptr; |
| return 0; |
| } |
| |
| void hwasan_free(void *ptr, StackTrace *stack) { |
| #if HWASAN_WITH_INTERCEPTORS |
| // A tag of 0 means that this is a system allocator allocation, so we must use |
| // the system allocator to free it. |
| if (!flags()->disable_allocator_tagging && GetTagFromPointer((uptr)ptr) == 0) |
| return REAL(free)(ptr); |
| #endif |
| |
| return HwasanDeallocate(stack, ptr); |
| } |
| |
| } // namespace __hwasan |
| |
| using namespace __hwasan; |
| |
| void __hwasan_enable_allocator_tagging() { |
| atomic_store_relaxed(&hwasan_allocator_tagging_enabled, 1); |
| } |
| |
| void __hwasan_disable_allocator_tagging() { |
| #if HWASAN_WITH_INTERCEPTORS |
| // Allocator tagging must be enabled for the system allocator fallback to work |
| // correctly. This means that we can't disable it at runtime if it was enabled |
| // at startup since that might result in our deallocations going to the system |
| // allocator. If tagging was disabled at startup we avoid this problem by |
| // disabling the fallback altogether. |
| CHECK(flags()->disable_allocator_tagging); |
| #endif |
| |
| 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); } |