libsanitizer/hwasan/hwasan_malloc_bisect.h

   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