From 5b332abd66c3d6e7ef84326989ab17eb99ae24d4 Mon Sep 17 00:00:00 2001 From: Evgeniy Stepanov Date: Fri, 7 Sep 2018 00:27:11 +0000 Subject: [PATCH] [hwasan] Fix malloc overflow detection. Check size limit before rounding up, otherwise malloc((size_t)-1) would happily allocate 0 bytes. Steal a nice test case from scudo. llvm-svn: 341612 --- compiler-rt/lib/hwasan/hwasan_allocator.cc | 16 +++--- compiler-rt/test/hwasan/TestCases/sizes.cpp | 80 +++++++++++++++++++++++++++++ 2 files changed, 89 insertions(+), 7 deletions(-) create mode 100644 compiler-rt/test/hwasan/TestCases/sizes.cpp diff --git a/compiler-rt/lib/hwasan/hwasan_allocator.cc b/compiler-rt/lib/hwasan/hwasan_allocator.cc index c9783b7..b9c379e 100644 --- a/compiler-rt/lib/hwasan/hwasan_allocator.cc +++ b/compiler-rt/lib/hwasan/hwasan_allocator.cc @@ -65,22 +65,24 @@ void AllocatorSwallowThreadLocalCache(AllocatorCache *cache) { static uptr TaggedSize(uptr size) { if (!size) size = 1; - return RoundUpTo(size, kShadowAlignment); + 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) { - alignment = Max(alignment, kShadowAlignment); - uptr size = TaggedSize(orig_size); - - if (size > kMaxAllowedMallocSize) { + if (orig_size > kMaxAllowedMallocSize) { if (AllocatorMayReturnNull()) { Report("WARNING: HWAddressSanitizer failed to allocate 0x%zx bytes\n", - size); + orig_size); return nullptr; } - ReportAllocationSizeTooBig(size, kMaxAllowedMallocSize, stack); + ReportAllocationSizeTooBig(orig_size, kMaxAllowedMallocSize, stack); } + + alignment = Max(alignment, kShadowAlignment); + uptr size = TaggedSize(orig_size); Thread *t = GetCurrentThread(); void *allocated; if (t) { diff --git a/compiler-rt/test/hwasan/TestCases/sizes.cpp b/compiler-rt/test/hwasan/TestCases/sizes.cpp new file mode 100644 index 0000000..52217de --- /dev/null +++ b/compiler-rt/test/hwasan/TestCases/sizes.cpp @@ -0,0 +1,80 @@ +// RUN: %clangxx_hwasan %s -lstdc++ -o %t +// RUN: %env_hwasan_opts=allocator_may_return_null=0 not %run %t malloc 2>&1 | FileCheck %s --check-prefix=CHECK-max +// RUN: %env_hwasan_opts=allocator_may_return_null=1 %run %t malloc 2>&1 +// RUN: %env_hwasan_opts=allocator_may_return_null=0 not %run %t malloc max 2>&1 | FileCheck %s --check-prefix=CHECK-max +// RUN: %env_hwasan_opts=allocator_may_return_null=1 %run %t malloc max 2>&1 +// RUN: %env_hwasan_opts=allocator_may_return_null=0 not %run %t calloc 2>&1 | FileCheck %s --check-prefix=CHECK-calloc +// RUN: %env_hwasan_opts=allocator_may_return_null=1 %run %t calloc 2>&1 +// RUN: %env_hwasan_opts=allocator_may_return_null=0 not %run %t new 2>&1 | FileCheck %s --check-prefix=CHECK-max +// RUN: %env_hwasan_opts=allocator_may_return_null=1 not %run %t new 2>&1 | FileCheck %s --check-prefix=CHECK-oom +// RUN: %env_hwasan_opts=allocator_may_return_null=0 not %run %t new max 2>&1 | FileCheck %s --check-prefix=CHECK-max +// RUN: %env_hwasan_opts=allocator_may_return_null=1 not %run %t new max 2>&1 | FileCheck %s --check-prefix=CHECK-oom +// RUN: %env_hwasan_opts=allocator_may_return_null=0 not %run %t new-nothrow 2>&1 | FileCheck %s --check-prefix=CHECK-max +// RUN: %env_hwasan_opts=allocator_may_return_null=1 %run %t new-nothrow 2>&1 +// RUN: %env_hwasan_opts=allocator_may_return_null=0 not %run %t new-nothrow max 2>&1 | FileCheck %s --check-prefix=CHECK-max +// RUN: %env_hwasan_opts=allocator_may_return_null=1 %run %t new-nothrow max 2>&1 +// RUN: %run %t usable 2>&1 + +// Tests for various edge cases related to sizes, notably the maximum size the +// allocator can allocate. Tests that an integer overflow in the parameters of +// calloc is caught. + +#include +#include +#include +#include + +#include +#include + +#include + +int main(int argc, char **argv) { + assert(argc <= 3); + bool test_size_max = argc == 3 && !strcmp(argv[2], "max"); + + static const size_t kMaxAllowedMallocSize = 1ULL << 40; + static const size_t kChunkHeaderSize = 16; + + size_t MallocSize = test_size_max ? std::numeric_limits::max() + : kMaxAllowedMallocSize; + + if (!strcmp(argv[1], "malloc")) { + void *p = malloc(MallocSize); + assert(!p); + p = malloc(kMaxAllowedMallocSize - kChunkHeaderSize); + assert(!p); + } else if (!strcmp(argv[1], "calloc")) { + // Trigger an overflow in calloc. + size_t size = std::numeric_limits::max(); + void *p = calloc((size / 0x1000) + 1, 0x1000); + assert(!p); + } else if (!strcmp(argv[1], "new")) { + void *p = operator new(MallocSize); + assert(!p); + } else if (!strcmp(argv[1], "new-nothrow")) { + void *p = operator new(MallocSize, std::nothrow); + assert(!p); + } else if (!strcmp(argv[1], "usable")) { + // Playing with the actual usable size of a chunk. + void *p = malloc(1007); + assert(p); + size_t size = __sanitizer_get_allocated_size(p); + assert(size >= 1007); + memset(p, 'A', size); + p = realloc(p, 2014); + assert(p); + size = __sanitizer_get_allocated_size(p); + assert(size >= 2014); + memset(p, 'B', size); + free(p); + } else { + assert(0); + } + + return 0; +} + +// CHECK-max: {{ERROR: HWAddressSanitizer: requested allocation size .* exceeds maximum supported size}} +// CHECK-oom: ERROR: HWAddressSanitizer: allocator is out of memory +// CHECK-calloc: ERROR: HWAddressSanitizer: calloc parameters overflow -- 2.7.4