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