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
16 namespace __hwasan {
17
malloc_hash(StackTrace * stack,uptr orig_size)18 static 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
malloc_bisect(StackTrace * stack,uptr orig_size)31 static 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