diff options
-rw-r--r-- | include/sanitizer/asan_interface.h | 9 | ||||
-rw-r--r-- | lib/asan/asan_internal.h | 1 | ||||
-rw-r--r-- | lib/asan/asan_poisoning.cc | 37 | ||||
-rw-r--r-- | lib/asan/asan_report.cc | 3 | ||||
-rw-r--r-- | lib/asan/asan_rtl.cc | 2 | ||||
-rw-r--r-- | lib/asan/lit_tests/use-after-scope-inlined.cc | 29 | ||||
-rw-r--r-- | lib/asan/tests/asan_test_utils.h | 2 |
7 files changed, 82 insertions, 1 deletions
diff --git a/include/sanitizer/asan_interface.h b/include/sanitizer/asan_interface.h index 788e90f4c..a09c6b2af 100644 --- a/include/sanitizer/asan_interface.h +++ b/include/sanitizer/asan_interface.h @@ -66,6 +66,15 @@ extern "C" { void __asan_stack_free(uptr ptr, uptr size, uptr real_stack) SANITIZER_INTERFACE_ATTRIBUTE; + // These two functions are used by instrumented code in the + // use-after-scope mode. They mark memory for local variables as + // unaddressable when they leave scope and addressable before the + // function exits. + void __asan_poison_stack_memory(uptr addr, uptr size) + SANITIZER_INTERFACE_ATTRIBUTE; + void __asan_unpoison_stack_memory(uptr addr, uptr size) + SANITIZER_INTERFACE_ATTRIBUTE; + // Marks memory region [addr, addr+size) as unaddressable. // This memory must be previously allocated by the user program. Accessing // addresses in this region from instrumented code is forbidden until diff --git a/lib/asan/asan_internal.h b/lib/asan/asan_internal.h index 201822c62..1a50e6033 100644 --- a/lib/asan/asan_internal.h +++ b/lib/asan/asan_internal.h @@ -161,6 +161,7 @@ const int kAsanStackPartialRedzoneMagic = 0xf4; const int kAsanStackAfterReturnMagic = 0xf5; const int kAsanInitializationOrderMagic = 0xf6; const int kAsanUserPoisonedMemoryMagic = 0xf7; +const int kAsanStackUseAfterScopeMagic = 0xf8; const int kAsanGlobalRedzoneMagic = 0xf9; const int kAsanInternalHeapMagic = 0xfe; diff --git a/lib/asan/asan_poisoning.cc b/lib/asan/asan_poisoning.cc index ce9de9278..dcdc7f8ac 100644 --- a/lib/asan/asan_poisoning.cc +++ b/lib/asan/asan_poisoning.cc @@ -151,3 +151,40 @@ void __asan_unpoison_memory_region(void const volatile *addr, uptr size) { bool __asan_address_is_poisoned(void const volatile *addr) { return __asan::AddressIsPoisoned((uptr)addr); } + +// This is a simplified version of __asan_(un)poison_memory_region, which +// assumes that left border of region to be poisoned is properly aligned. +static void PoisonAlignedStackMemory(uptr addr, uptr size, bool do_poison) { + if (size == 0) return; + uptr aligned_size = size & ~(SHADOW_GRANULARITY - 1); + PoisonShadow(addr, aligned_size, + do_poison ? kAsanStackUseAfterScopeMagic : 0); + if (size == aligned_size) + return; + s8 end_offset = (s8)(size - aligned_size); + s8* shadow_end = (s8*)MemToShadow(addr + aligned_size); + s8 end_value = *shadow_end; + if (do_poison) { + // If possible, mark all the bytes mapping to last shadow byte as + // unaddressable. + if (end_value > 0 && end_value <= end_offset) + *shadow_end = kAsanStackUseAfterScopeMagic; + } else { + // If necessary, mark few first bytes mapping to last shadow byte + // as addressable + if (end_value != 0) + *shadow_end = Max(end_value, end_offset); + } +} + +void __asan_poison_stack_memory(uptr addr, uptr size) { + if (flags()->verbosity > 0) + Report("poisoning: %p %zx\n", (void*)addr, size); + PoisonAlignedStackMemory(addr, size, true); +} + +void __asan_unpoison_stack_memory(uptr addr, uptr size) { + if (flags()->verbosity > 0) + Report("unpoisoning: %p %zx\n", (void*)addr, size); + PoisonAlignedStackMemory(addr, size, false); +} diff --git a/lib/asan/asan_report.cc b/lib/asan/asan_report.cc index 51b081e15..262791989 100644 --- a/lib/asan/asan_report.cc +++ b/lib/asan/asan_report.cc @@ -457,6 +457,9 @@ void __asan_report_error(uptr pc, uptr bp, uptr sp, case kAsanUserPoisonedMemoryMagic: bug_descr = "use-after-poison"; break; + case kAsanStackUseAfterScopeMagic: + bug_descr = "stack-use-after-scope"; + break; case kAsanGlobalRedzoneMagic: bug_descr = "global-buffer-overflow"; break; diff --git a/lib/asan/asan_rtl.cc b/lib/asan/asan_rtl.cc index bd5c0fe8d..d205f26d6 100644 --- a/lib/asan/asan_rtl.cc +++ b/lib/asan/asan_rtl.cc @@ -248,6 +248,8 @@ static NOINLINE void force_interface_symbols() { case 34: __asan_malloc_hook(0, 0); break; case 35: __asan_free_hook(0); break; case 36: __asan_symbolize(0, 0, 0); break; + case 37: __asan_poison_stack_memory(0, 0); break; + case 38: __asan_unpoison_stack_memory(0, 0); break; } } diff --git a/lib/asan/lit_tests/use-after-scope-inlined.cc b/lib/asan/lit_tests/use-after-scope-inlined.cc new file mode 100644 index 000000000..c192bc2fe --- /dev/null +++ b/lib/asan/lit_tests/use-after-scope-inlined.cc @@ -0,0 +1,29 @@ +// Test with "-O2" only to make sure inlining (leading to use-after-scope) +// happens. "always_inline" is not enough, as Clang doesn't emit +// llvm.lifetime intrinsics at -O0. +// +// RUN: %clangxx_asan -m64 -O2 -fsanitize=use-after-scope %s -o %t && \ +// RUN: %t 2>&1 | %symbolize | FileCheck %s +// RUN: %clangxx_asan -m32 -O2 -fsanitize=use-after-scope %s -o %t && \ +// RUN: %t 2>&1 | %symbolize | FileCheck %s + +int *arr; + +__attribute__((always_inline)) +void inlined(int arg) { + int x[5]; + for (int i = 0; i < arg; i++) x[i] = i; + arr = x; +} + +int main(int argc, char *argv[]) { + inlined(argc); + return arr[argc - 1]; // BOOM + // CHECK: ERROR: AddressSanitizer: stack-use-after-scope + // CHECK: READ of size 4 at 0x{{.*}} thread T0 + // CHECK: #0 0x{{.*}} in {{_?}}main + // CHECK: {{.*}}use-after-scope-inlined.cc:[[@LINE-4]] + // CHECK: Address 0x{{.*}} is located at offset + // CHECK: [[OFFSET:[^ ]*]] in frame <main> of T0's stack: + // CHECK: {{\[}}[[OFFSET]], {{.*}}) 'x.i' +} diff --git a/lib/asan/tests/asan_test_utils.h b/lib/asan/tests/asan_test_utils.h index be7820efc..f810438fc 100644 --- a/lib/asan/tests/asan_test_utils.h +++ b/lib/asan/tests/asan_test_utils.h @@ -55,7 +55,7 @@ typedef __int64 int64_t; // Make the compiler thinks that something is going on there. inline void break_optimization(void *arg) { - __asm__ __volatile__ ("" : : "r" (arg) : "memory"); + __asm__ __volatile__("" : : "r" (arg) : "memory"); } // This function returns its parameter but in such a way that compiler |