53 lines
1.9 KiB
C++
53 lines
1.9 KiB
C++
//===-- hwasan_poisoning.cpp ------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of HWAddressSanitizer.
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//
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//===----------------------------------------------------------------------===//
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#include "hwasan_poisoning.h"
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#include "hwasan_mapping.h"
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#include "interception/interception.h"
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#include "sanitizer_common/sanitizer_common.h"
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#include "sanitizer_common/sanitizer_linux.h"
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namespace __hwasan {
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uptr TagMemoryAligned(uptr p, uptr size, tag_t tag) {
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CHECK(IsAligned(p, kShadowAlignment));
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CHECK(IsAligned(size, kShadowAlignment));
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uptr shadow_start = MemToShadow(p);
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uptr shadow_size = MemToShadowSize(size);
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uptr page_size = GetPageSizeCached();
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uptr page_start = RoundUpTo(shadow_start, page_size);
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uptr page_end = RoundDownTo(shadow_start + shadow_size, page_size);
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uptr threshold = common_flags()->clear_shadow_mmap_threshold;
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if (SANITIZER_LINUX &&
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UNLIKELY(page_end >= page_start + threshold && tag == 0)) {
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internal_memset((void *)shadow_start, tag, page_start - shadow_start);
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internal_memset((void *)page_end, tag,
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shadow_start + shadow_size - page_end);
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// For an anonymous private mapping MADV_DONTNEED will return a zero page on
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// Linux.
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ReleaseMemoryPagesToOSAndZeroFill(page_start, page_end);
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} else {
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internal_memset((void *)shadow_start, tag, shadow_size);
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}
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return AddTagToPointer(p, tag);
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}
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uptr TagMemory(uptr p, uptr size, tag_t tag) {
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uptr start = RoundDownTo(p, kShadowAlignment);
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uptr end = RoundUpTo(p + size, kShadowAlignment);
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return TagMemoryAligned(start, end - start, tag);
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}
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} // namespace __hwasan
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