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Diffstat (limited to 'compiler-rt/lib/asan/asan_poisoning.h')
-rw-r--r-- | compiler-rt/lib/asan/asan_poisoning.h | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/compiler-rt/lib/asan/asan_poisoning.h b/compiler-rt/lib/asan/asan_poisoning.h new file mode 100644 index 000000000000..62dd9bd0edd3 --- /dev/null +++ b/compiler-rt/lib/asan/asan_poisoning.h @@ -0,0 +1,100 @@ +//===-- asan_poisoning.h ----------------------------------------*- C++ -*-===// +// +// 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 AddressSanitizer, an address sanity checker. +// +// Shadow memory poisoning by ASan RTL and by user application. +//===----------------------------------------------------------------------===// + +#include "asan_interceptors.h" +#include "asan_internal.h" +#include "asan_mapping.h" +#include "sanitizer_common/sanitizer_flags.h" +#include "sanitizer_common/sanitizer_platform.h" + +namespace __asan { + +// Enable/disable memory poisoning. +void SetCanPoisonMemory(bool value); +bool CanPoisonMemory(); + +// Poisons the shadow memory for "size" bytes starting from "addr". +void PoisonShadow(uptr addr, uptr size, u8 value); + +// Poisons the shadow memory for "redzone_size" bytes starting from +// "addr + size". +void PoisonShadowPartialRightRedzone(uptr addr, + uptr size, + uptr redzone_size, + u8 value); + +// Fast versions of PoisonShadow and PoisonShadowPartialRightRedzone that +// assume that memory addresses are properly aligned. Use in +// performance-critical code with care. +ALWAYS_INLINE void FastPoisonShadow(uptr aligned_beg, uptr aligned_size, + u8 value) { + DCHECK(!value || CanPoisonMemory()); +#if SANITIZER_FUCHSIA + __sanitizer_fill_shadow(aligned_beg, aligned_size, value, + common_flags()->clear_shadow_mmap_threshold); +#else + uptr shadow_beg = MEM_TO_SHADOW(aligned_beg); + uptr shadow_end = MEM_TO_SHADOW( + aligned_beg + aligned_size - SHADOW_GRANULARITY) + 1; + // FIXME: Page states are different on Windows, so using the same interface + // for mapping shadow and zeroing out pages doesn't "just work", so we should + // probably provide higher-level interface for these operations. + // For now, just memset on Windows. + if (value || SANITIZER_WINDOWS == 1 || + // RTEMS doesn't have have pages, let alone a fast way to zero + // them, so default to memset. + SANITIZER_RTEMS == 1 || + shadow_end - shadow_beg < common_flags()->clear_shadow_mmap_threshold) { + REAL(memset)((void*)shadow_beg, value, shadow_end - shadow_beg); + } else { + uptr page_size = GetPageSizeCached(); + uptr page_beg = RoundUpTo(shadow_beg, page_size); + uptr page_end = RoundDownTo(shadow_end, page_size); + + if (page_beg >= page_end) { + REAL(memset)((void *)shadow_beg, 0, shadow_end - shadow_beg); + } else { + if (page_beg != shadow_beg) { + REAL(memset)((void *)shadow_beg, 0, page_beg - shadow_beg); + } + if (page_end != shadow_end) { + REAL(memset)((void *)page_end, 0, shadow_end - page_end); + } + ReserveShadowMemoryRange(page_beg, page_end - 1, nullptr); + } + } +#endif // SANITIZER_FUCHSIA +} + +ALWAYS_INLINE void FastPoisonShadowPartialRightRedzone( + uptr aligned_addr, uptr size, uptr redzone_size, u8 value) { + DCHECK(CanPoisonMemory()); + bool poison_partial = flags()->poison_partial; + u8 *shadow = (u8*)MEM_TO_SHADOW(aligned_addr); + for (uptr i = 0; i < redzone_size; i += SHADOW_GRANULARITY, shadow++) { + if (i + SHADOW_GRANULARITY <= size) { + *shadow = 0; // fully addressable + } else if (i >= size) { + *shadow = (SHADOW_GRANULARITY == 128) ? 0xff : value; // unaddressable + } else { + // first size-i bytes are addressable + *shadow = poison_partial ? static_cast<u8>(size - i) : 0; + } + } +} + +// Calls __sanitizer::ReleaseMemoryPagesToOS() on +// [MemToShadow(p), MemToShadow(p+size)]. +void FlushUnneededASanShadowMemory(uptr p, uptr size); + +} // namespace __asan |