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author | Kostya Serebryany <kcc@google.com> | 2016-04-22 23:35:00 +0000 |
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committer | Kostya Serebryany <kcc@google.com> | 2016-04-22 23:35:00 +0000 |
commit | dbc8cc0811b459e5155d7cc8872134c4011e0fce (patch) | |
tree | 2547eb7663703a57888227b31af37204aad1996b /lib/sanitizer_common/sanitizer_allocator.h | |
parent | 80fd6de57ba6f262faee90c745d7c90f6007819a (diff) | |
download | compiler-rt-dbc8cc0811b459e5155d7cc8872134c4011e0fce.tar.gz |
[sanitizer] partially un-revert r267094: Allow the sanitizer allocator to use a non-fixed address range. An allocator with a non-fixed address range will be attack-resistan. NFC for the sanitizers at this point.
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@267252 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/sanitizer_common/sanitizer_allocator.h')
-rw-r--r-- | lib/sanitizer_common/sanitizer_allocator.h | 58 |
1 files changed, 39 insertions, 19 deletions
diff --git a/lib/sanitizer_common/sanitizer_allocator.h b/lib/sanitizer_common/sanitizer_allocator.h index 44d6fce3b..344bf69d2 100644 --- a/lib/sanitizer_common/sanitizer_allocator.h +++ b/lib/sanitizer_common/sanitizer_allocator.h @@ -297,9 +297,10 @@ typedef void (*ForEachChunkCallback)(uptr chunk, void *arg); // SizeClassAllocator64 -- allocator for 64-bit address space. // -// Space: a portion of address space of kSpaceSize bytes starting at -// a fixed address (kSpaceBeg). Both constants are powers of two and -// kSpaceBeg is kSpaceSize-aligned. +// Space: a portion of address space of kSpaceSize bytes starting at SpaceBeg. +// If kSpaceBeg is ~0 then SpaceBeg is chosen dynamically my mmap. +// Otherwise SpaceBeg=kSpaceBeg (fixed address). +// kSpaceSize is a power of two. // At the beginning the entire space is mprotect-ed, then small parts of it // are mapped on demand. // @@ -322,9 +323,15 @@ class SizeClassAllocator64 { typedef SizeClassAllocatorLocalCache<ThisT> AllocatorCache; void Init() { - CHECK_EQ(kSpaceBeg, - reinterpret_cast<uptr>(MmapNoAccess(kSpaceBeg, kSpaceSize))); - MapWithCallback(kSpaceEnd, AdditionalSize()); + if (kUsingConstantSpaceBeg) { + CHECK_EQ(kSpaceBeg, + reinterpret_cast<uptr>(MmapNoAccess(kSpaceBeg, kSpaceSize))); + } else { + NonConstSpaceBeg = reinterpret_cast<uptr>( + MmapNoAccess(0, kSpaceSize + AdditionalSize())); + CHECK_NE(NonConstSpaceBeg, ~(uptr)0); + } + MapWithCallback(SpaceEnd(), AdditionalSize()); } void MapWithCallback(uptr beg, uptr size) { @@ -360,12 +367,18 @@ class SizeClassAllocator64 { region->n_freed += b->count; } - static bool PointerIsMine(const void *p) { - return reinterpret_cast<uptr>(p) / kSpaceSize == kSpaceBeg / kSpaceSize; + bool PointerIsMine(const void *p) { + uptr P = reinterpret_cast<uptr>(p); + if (kUsingConstantSpaceBeg && (kSpaceBeg % kSpaceSize) == 0) + return P / kSpaceSize == kSpaceBeg / kSpaceSize; + return P >= SpaceBeg() && P < SpaceEnd(); } - static uptr GetSizeClass(const void *p) { - return (reinterpret_cast<uptr>(p) / kRegionSize) % kNumClassesRounded; + uptr GetSizeClass(const void *p) { + if (kUsingConstantSpaceBeg && (kSpaceBeg % kSpaceSize) == 0) + return ((reinterpret_cast<uptr>(p)) / kRegionSize) % kNumClassesRounded; + return ((reinterpret_cast<uptr>(p) - SpaceBeg()) / kRegionSize) % + kNumClassesRounded; } void *GetBlockBegin(const void *p) { @@ -383,7 +396,7 @@ class SizeClassAllocator64 { return nullptr; } - static uptr GetActuallyAllocatedSize(void *p) { + uptr GetActuallyAllocatedSize(void *p) { CHECK(PointerIsMine(p)); return SizeClassMap::Size(GetSizeClass(p)); } @@ -394,8 +407,9 @@ class SizeClassAllocator64 { uptr class_id = GetSizeClass(p); uptr size = SizeClassMap::Size(class_id); uptr chunk_idx = GetChunkIdx(reinterpret_cast<uptr>(p), size); - return reinterpret_cast<void*>(kSpaceBeg + (kRegionSize * (class_id + 1)) - - (1 + chunk_idx) * kMetadataSize); + return reinterpret_cast<void *>(SpaceBeg() + + (kRegionSize * (class_id + 1)) - + (1 + chunk_idx) * kMetadataSize); } uptr TotalMemoryUsed() { @@ -407,7 +421,7 @@ class SizeClassAllocator64 { // Test-only. void TestOnlyUnmap() { - UnmapWithCallback(kSpaceBeg, kSpaceSize + AdditionalSize()); + UnmapWithCallback(SpaceBeg(), kSpaceSize + AdditionalSize()); } void PrintStats() { @@ -455,7 +469,7 @@ class SizeClassAllocator64 { for (uptr class_id = 1; class_id < kNumClasses; class_id++) { RegionInfo *region = GetRegionInfo(class_id); uptr chunk_size = SizeClassMap::Size(class_id); - uptr region_beg = kSpaceBeg + class_id * kRegionSize; + uptr region_beg = SpaceBeg() + class_id * kRegionSize; for (uptr chunk = region_beg; chunk < region_beg + region->allocated_user; chunk += chunk_size) { @@ -476,8 +490,13 @@ class SizeClassAllocator64 { private: static const uptr kRegionSize = kSpaceSize / kNumClassesRounded; - static const uptr kSpaceEnd = kSpaceBeg + kSpaceSize; - COMPILER_CHECK(kSpaceBeg % kSpaceSize == 0); + + static const bool kUsingConstantSpaceBeg = kSpaceBeg != ~(uptr)0; + uptr NonConstSpaceBeg; + uptr SpaceBeg() const { + return kUsingConstantSpaceBeg ? kSpaceBeg : NonConstSpaceBeg; + } + uptr SpaceEnd() const { return SpaceBeg() + kSpaceSize; } // kRegionSize must be >= 2^32. COMPILER_CHECK((kRegionSize) >= (1ULL << (SANITIZER_WORDSIZE / 2))); // Populate the free list with at most this number of bytes at once @@ -501,7 +520,8 @@ class SizeClassAllocator64 { RegionInfo *GetRegionInfo(uptr class_id) { CHECK_LT(class_id, kNumClasses); - RegionInfo *regions = reinterpret_cast<RegionInfo*>(kSpaceBeg + kSpaceSize); + RegionInfo *regions = + reinterpret_cast<RegionInfo *>(SpaceBeg() + kSpaceSize); return ®ions[class_id]; } @@ -524,7 +544,7 @@ class SizeClassAllocator64 { uptr count = size < kPopulateSize ? SizeClassMap::MaxCached(class_id) : 1; uptr beg_idx = region->allocated_user; uptr end_idx = beg_idx + count * size; - uptr region_beg = kSpaceBeg + kRegionSize * class_id; + uptr region_beg = SpaceBeg() + kRegionSize * class_id; if (end_idx + size > region->mapped_user) { // Do the mmap for the user memory. uptr map_size = kUserMapSize; |