compiler-rt/test/asan/TestCases/Darwin/malloc_set_zone_name-mprotect.cpp

   1 // Regression test for a bug in malloc_create_zone()
   2 // (https://code.google.com/p/address-sanitizer/issues/detail?id=203)
   3 // The old implementation of malloc_create_zone() didn't always return a
   4 // page-aligned address, so we can only test on a best-effort basis.
   5
   6 // RUN: %clangxx_asan %s -o %t
   7 // RUN: %run %t 2>&1
   8
   9 #include <malloc/malloc.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <stdio.h>
  13
  14 const int kNumIter = 4096;
  15 const int kNumZones = 100;
  16 int main() {
  17   char *mem[kNumIter * 2];
  18   // Allocate memory chunks from different size classes up to 1 page.
  19   // (For the case malloc() returns memory chunks in descending order)
  20   for (int i = 0; i < kNumIter; i++) {
  21     mem[i] = (char*)malloc(8 * i);
  22   }
  23   // Try to allocate a page-aligned malloc zone. Otherwise the mprotect() call
  24   // in malloc_set_zone_name() will silently fail.
  25   malloc_zone_t *zone = NULL;
  26   bool aligned = false;
  27   for (int i = 0; i < kNumZones; i++) {
  28     zone = malloc_create_zone(0, 0);
  29     if (((uintptr_t)zone & (~0xfff)) == (uintptr_t)zone) {
  30       aligned = true;
  31       break;
  32     }
  33   }
  34   if (!aligned) {
  35     printf("Warning: couldn't allocate a page-aligned zone.");
  36     return 0;
  37   }
  38   // malloc_set_zone_name() calls mprotect(zone, 4096, PROT_READ | PROT_WRITE),
  39   // modifies the zone contents and then calls mprotect(zone, 4096, PROT_READ).
  40   malloc_set_zone_name(zone, "foobar");
  41   // Allocate memory chunks from different size classes again.
  42   for (int i = 0; i < kNumIter; i++) {
  43     mem[i + kNumIter] = (char*)malloc(8 * i);
  44   }
  45   // Access the allocated memory chunks and free them.
  46   for (int i = 0; i < kNumIter * 2; i++) {
  47     memset(mem[i], 'a', 8 * (i % kNumIter));
  48     free(mem[i]);
  49   }
  50   malloc_destroy_zone(zone);
  51   return 0;
  52 }