| 1 | //===-- hwasan_malloc_bisect.h ----------------------------------*- C++ -*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // This file is a part of HWAddressSanitizer. |
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| 10 | // |
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| 11 | //===----------------------------------------------------------------------===// |
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| 12 | |
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| 13 | #include "sanitizer_common/sanitizer_hash.h" |
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| 14 | #include "hwasan.h" |
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| 15 | |
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| 16 | namespace __hwasan { |
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| 17 | |
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| 18 | static u32 malloc_hash(StackTrace *stack, uptr orig_size) { |
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| 19 | uptr len = Min(a: stack->size, b: (unsigned)7); |
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| 20 | MurMur2HashBuilder H(len); |
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| 21 | H.add(k: orig_size); |
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| 22 | // Start with frame #1 to skip __sanitizer_malloc frame, which is |
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| 23 | // (a) almost always the same (well, could be operator new or new[]) |
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| 24 | // (b) can change hashes when compiler-rt is rebuilt, invalidating previous |
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| 25 | // bisection results. |
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| 26 | // Because of ASLR, use only offset inside the page. |
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| 27 | for (uptr i = 1; i < len; ++i) H.add(k: ((u32)stack->trace[i]) & 0xFFF); |
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| 28 | return H.get(); |
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| 29 | } |
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| 30 | |
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| 31 | static inline bool malloc_bisect(StackTrace *stack, uptr orig_size) { |
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| 32 | uptr left = flags()->malloc_bisect_left; |
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| 33 | uptr right = flags()->malloc_bisect_right; |
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| 34 | if (LIKELY(left == 0 && right == 0)) |
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| 35 | return true; |
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| 36 | if (!stack) |
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| 37 | return true; |
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| 38 | // Allow malloc_bisect_right > (u32)(-1) to avoid spelling the latter in |
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| 39 | // decimal. |
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| 40 | uptr h = (uptr)malloc_hash(stack, orig_size); |
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| 41 | if (h < left || h > right) |
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| 42 | return false; |
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| 43 | if (flags()->malloc_bisect_dump) { |
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| 44 | Printf(format: "[alloc] %u %zu\n" , h, orig_size); |
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| 45 | stack->Print(); |
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| 46 | } |
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| 47 | return true; |
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| 48 | } |
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| 49 | |
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| 50 | } // namespace __hwasan |
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| 51 | |
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