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[asan] Implement max_redzone runtime flag. 

llvm-svn: 198873
This commit is contained in:
Evgeniy Stepanov 2014-01-09 14:41:03 +00:00
parent a24f5cf273
commit 219719a2da
4 changed files with 39 additions and 4 deletions
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3
compiler-rt/lib/asan/asan_allocator2.cc
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@ -133,7 +133,8 @@ static uptr ComputeRZLog(uptr user_requested_size) {
user_requested_size <= (1 << 14) - 256 ? 4 :
user_requested_size <= (1 << 15) - 512 ? 5 :
user_requested_size <= (1 << 16) - 1024 ? 6 : 7;
return Max(rz_log, RZSize2Log(flags()->redzone));
return Min(Max(rz_log, RZSize2Log(flags()->redzone)),
RZSize2Log(flags()->max_redzone));
}
// The memory chunk allocated from the underlying allocator looks like this:

6
compiler-rt/lib/asan/asan_flags.h
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@ -32,9 +32,11 @@ struct Flags {
// Lower value may reduce memory usage but increase the chance of
// false negatives.
int quarantine_size;
// Size (in bytes) of redzones around heap objects.
// Requirement: redzone >= 32, is a power of two.
// Minimal size (in bytes) of redzones around heap objects.
// Requirement: redzone >= 16, is a power of two.
int redzone;
// Maximal size (in bytes) of redzones around heap objects.
int max_redzone;
// If set, prints some debugging information and does additional checks.
bool debug;
// Controls the way to handle globals (0 - don't detect buffer overflow

8
compiler-rt/lib/asan/asan_rtl.cc
View File

@ -96,8 +96,12 @@ static void ParseFlagsFromString(Flags *f, const char *str) {
ParseFlag(str, &f->quarantine_size, "quarantine_size");
ParseFlag(str, &f->redzone, "redzone");
ParseFlag(str, &f->max_redzone, "max_redzone");
CHECK_GE(f->redzone, 16);
CHECK_GE(f->max_redzone, f->redzone);
CHECK_LE(f->max_redzone, 2048);
CHECK(IsPowerOfTwo(f->redzone));
CHECK(IsPowerOfTwo(f->max_redzone));
ParseFlag(str, &f->debug, "debug");
ParseFlag(str, &f->report_globals, "report_globals");
@ -145,6 +149,7 @@ void InitializeFlags(Flags *f, const char *env) {
internal_memset(f, 0, sizeof(*f));
f->quarantine_size = (ASAN_LOW_MEMORY) ? 1UL << 26 : 1UL << 28;
f->redzone = 16;
f->max_redzone = 2048;
f->debug = false;
f->report_globals = 1;
f->check_initialization_order = false;
@ -376,7 +381,8 @@ static void PrintAddressSpaceLayout() {
(void*)MEM_TO_SHADOW(kMidShadowEnd));
}
Printf("\n");
Printf("red_zone=%zu\n", (uptr)flags()->redzone);
Printf("redzone=%zu\n", (uptr)flags()->redzone);
Printf("max_redzone=%zu\n", (uptr)flags()->max_redzone);
Printf("quarantine_size=%zuM\n", (uptr)flags()->quarantine_size >> 20);
Printf("malloc_context_size=%zu\n",
(uptr)common_flags()->malloc_context_size);

26
compiler-rt/lib/asan/lit_tests/TestCases/max_redzone.cc Normal file
View File

@ -0,0 +1,26 @@
// Test max_redzone runtime option.
// RUN: %clangxx_asan -O0 %s -o %t && ASAN_OPTIONS=max_redzone=16 %t 0 2>&1
// RUN: %clangxx_asan -O0 %s -o %t && %t 1 2>&1
// RUN: %clangxx_asan -O3 %s -o %t && ASAN_OPTIONS=max_redzone=16 %t 0 2>&1
// RUN: %clangxx_asan -O3 %s -o %t && %t 1 2>&1
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <sanitizer/asan_interface.h>
int main(int argc, char **argv) {
if (argc < 2)
return 1;
bool large_redzone = atoi(argv[1]);
size_t before = __asan_get_heap_size();
void *pp[10000];
for (int i = 0; i < 10000; ++i)
pp[i] = malloc(4096 - 64);
size_t after = __asan_get_heap_size();
for (int i = 0; i < 10000; ++i)
free(pp[i]);
size_t diff = after - before;
return !(large_redzone ? diff > 46000000 : diff < 46000000);
}