xref: /freebsd/contrib/llvm-project/compiler-rt/lib/hwasan/hwasan_malloc_bisect.h (revision 6966ac055c3b7a39266fb982493330df7a097997)
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 
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 
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