Compare commits
2 Commits
main
..
591956471e
| Author | SHA1 | Date | |
|---|---|---|---|
 doylet
|
591956471e | ||
|
doylet
|
7d0aa69421 |
+19
-98
@@ -1,9 +1,10 @@
|
||||
|
||||
#include <sanitizer/asan_interface.h>
|
||||
#define WIN32_MEAN_AND_LEAN
|
||||
#include <Windows.h>
|
||||
#include <stdint.h>
|
||||
#include <stdio.h>
|
||||
#include <assert.h>
|
||||
#include <string.h>
|
||||
#include <sanitizer/asan_interface.h>
|
||||
|
||||
#define IsPowerOfTwo(value, pot) ((((size_t)value) & (((size_t)pot) - 1)) == 0)
|
||||
#define AsanAlignment 8
|
||||
@@ -56,95 +57,15 @@ static void PrintPoisonMemoryRegion(int step, char const *array, size_t array_si
|
||||
|
||||
int main()
|
||||
{
|
||||
printf(
|
||||
"# ASAN Manual Poisoning\n"
|
||||
"\n"
|
||||
"## TLDR\n"
|
||||
"\n"
|
||||
"`__asan_poison_memory_region(ptr, size)`\n"
|
||||
"\n"
|
||||
"Poisons the byte region `[ptr, AlignDown(ptr+size, 8))`\n"
|
||||
"\n"
|
||||
"`__asan_unpoison_memory_region(ptr, size)`\n"
|
||||
"\n"
|
||||
"Unpoisons the byte region `[AlignDown(ptr, 8), ptr+size)`\n"
|
||||
"\n"
|
||||
"Use the provided macros that are conditionally enabled if ASAN is\n"
|
||||
"defined from `<sanitizer/asan_interface.h>`.\n"
|
||||
"\n"
|
||||
"```\n"
|
||||
"ASAN_POISON_MEMORY_REGION(addr, size)\n"
|
||||
"ASAN_UNPOISON_MEMORY_REGION(addr, size)\n"
|
||||
"```\n"
|
||||
"\n"
|
||||
"If in doubt, use `__asan_address_is_poisoned` to sanity check the\n"
|
||||
"ranges requested to be un/poisoned to avoid potential gaps in\n"
|
||||
"marked-up memory that may lead to undetected read/writes.\n"
|
||||
"\n"
|
||||
"## Overview\n"
|
||||
"\n"
|
||||
"ASAN provides a way to manually markup ranges of bytes to\n"
|
||||
"prohibit or permit reads to those addresses. In\n"
|
||||
"`<sanitizer/asan_interface.h>` there's a vague brief mention to\n"
|
||||
"alignment requirements for the poison API:\n"
|
||||
"\n"
|
||||
"```cpp\n"
|
||||
"/// ... This function is not guaranteed to poison the entire region -\n"
|
||||
"/// it could poison only a subregion of <c>[addr, addr+size)</c> due to ASan\n"
|
||||
"/// alignment restrictions.\n"
|
||||
"void __asan_poison_memory_region(void const volatile *addr, size_t size);\n"
|
||||
"\n"
|
||||
"/// ... This function could unpoison a super-region of <c>[addr, addr+size)</c> due\n"
|
||||
"/// to ASan alignment restrictions.\n"
|
||||
"void __asan_unpoison_memory_region(void const volatile *addr, size_t size);\n"
|
||||
"```\n"
|
||||
"\n"
|
||||
"There's another small foot-note in Google's "
|
||||
"[AddressSanitizerManualPoisoning](https://github.com/google/"
|
||||
"sanitizers/wiki/AddressSanitizerManualPoisoning)\n"
|
||||
"documentation that states:\n"
|
||||
"\n"
|
||||
"```\n"
|
||||
"If you have a custom allocation arena, the typical workflow would be\n"
|
||||
"to poison the entire arena first, and then unpoison allocated chunks\n"
|
||||
"of memory leaving poisoned redzones between them. The allocated\n"
|
||||
"chunks should start with 8-aligned addresses.\n"
|
||||
"```\n"
|
||||
"\n"
|
||||
"So then this repository runs some simple tests to clarify the behaviour\n"
|
||||
"of the API on un/aligned addresses at various sizes without having\n"
|
||||
"to dig into source code or read the [ASAN paper](https://static."
|
||||
"googleusercontent.com/media/research.google.com/en/pubs/archive/"
|
||||
"37752.pdf).\n"
|
||||
"\n"
|
||||
"We use a stack-allocated 16 byte array and test un/poisoning\n"
|
||||
"various ranges of bytes from different alignments to clarify the\n"
|
||||
"poisoning behaviour of the API. This reveals that calling the API\n"
|
||||
"haphazardly, unaligned or straddling boundaries can lead to gaps in\n"
|
||||
"poisoned memory and hide potential leaks (as also demonstrated in\n"
|
||||
"[Manual ASAN poisoning and alignment]"
|
||||
"(https://github.com/mcgov/asan_alignment_example)).\n"
|
||||
"\n"
|
||||
"## References\n"
|
||||
"\n"
|
||||
"- [Manual ASAN poisoning and alignment](https://github.com/mcgov/asan_alignment_example) example by `mcgov`\n"
|
||||
"- [Address Sanitizer: A Fast Address Sanity Checker](https://static.googleusercontent.com/media/research.google.com/en//pubs/archive/37752.pdf)\n"
|
||||
"- [sanitizer/asan_interface.h](https://github.com/llvm-mirror/compiler-rt/blob/master/include/sanitizer/asan_interface.h)\n"
|
||||
"\n"
|
||||
"## Raw Test Results\n"
|
||||
"\n"
|
||||
"Here we poison a sliding window of 7 bytes to demonstrate that ASAN\n"
|
||||
"poisoning will only poison the byte region if the region meets an 8\n"
|
||||
"byte aligned address. It will only poison bytes up to the boundary,\n"
|
||||
"any bytes that straddle the boundary that do not hit the next 8 byte\n"
|
||||
"boundary are not poisoned.\n"
|
||||
"\n");
|
||||
printf("Here we demonstrate that ASAN poison-ing will only poison the\n"
|
||||
"byte region if the region meets an 8 byte boundary. It will only\n"
|
||||
"poison bytes upto the 8 byte boundary, any bytes that straddle\n"
|
||||
"the boundary that do not hit the next 8 byte boundary are not\n"
|
||||
"poison-ed.\n\n");
|
||||
|
||||
uint32_t const ASAN_ALIGNMENT = 8;
|
||||
uint32_t const REGION_WINDOW = 7;
|
||||
char array[16] = {};
|
||||
|
||||
printf("```\n");
|
||||
for (size_t poison_index = 0; poison_index < sizeof(array) - (REGION_WINDOW - 1); poison_index++) {
|
||||
assert(IsPowerOfTwo(array, ASAN_ALIGNMENT));
|
||||
|
||||
@@ -166,15 +87,12 @@ int main()
|
||||
__asan_unpoison_memory_region(array, sizeof(array));
|
||||
printf("\n");
|
||||
}
|
||||
printf("```\n");
|
||||
|
||||
printf(
|
||||
"Now we demonstrate that unpoisoning 1 byte in the 8 byte window\n"
|
||||
"will unpoison all bytes prior to it up until the previous 8 byte \n"
|
||||
"boundary.\n"
|
||||
"\n");
|
||||
"Now we demonstrate that unpoison-ing 1 byte in the 8 byte window\n"
|
||||
"will unpoison all bytes prior to it up until the start of the window\n"
|
||||
"until the previous 8 byte boundary.\n\n");
|
||||
|
||||
printf("```\n");
|
||||
for (size_t unpoison_index = 0; unpoison_index < sizeof(array); unpoison_index++) {
|
||||
assert(IsPowerOfTwo(array, ASAN_ALIGNMENT));
|
||||
|
||||
@@ -215,14 +133,11 @@ int main()
|
||||
|
||||
__asan_unpoison_memory_region(array, sizeof(array));
|
||||
}
|
||||
printf("```\n");
|
||||
|
||||
printf(
|
||||
"Unpoisoning across 8 byte boundaries may lead to undesired\n"
|
||||
"Unpoison-ing across 8 byte boundaries may lead to undesired\n"
|
||||
"behaviour, with all bytes on the left side of the boundary being\n"
|
||||
"unpoisoned\n\n");
|
||||
|
||||
printf("```\n");
|
||||
{
|
||||
// NOTE: Print byte array ==================================================================
|
||||
|
||||
@@ -256,6 +171,12 @@ int main()
|
||||
|
||||
PrintPoisonedBytes(4 /*step*/, array, sizeof(array));
|
||||
}
|
||||
printf("```\n");
|
||||
|
||||
printf("\n\nTLDR:\n"
|
||||
" __asan_poison_memory_region(ptr, size)\n"
|
||||
" Poisons the byte region [ptr, AlignDown(ptr+size, 8))\n\n"
|
||||
" __asan_unpoison_memory_region(ptr, size)\n"
|
||||
" Unpoisons the byte region [AlignDown(ptr, 8), ptr+size)\n\n"
|
||||
);
|
||||
return 0;
|
||||
}
|
||||
|
||||
@@ -2,7 +2,7 @@
|
||||
set script_dir_backslash=%~dp0
|
||||
set script_dir=%script_dir_backslash:~0,-1%
|
||||
|
||||
if not exist %script_dir%\Build mkdir %script_dir%\Build
|
||||
pushd %script_dir%\Build
|
||||
cl %script_dir%\asan_example.cpp -Zi -fsanitize=address -nologo -link || exit /b 1
|
||||
if not exist Build mkdir Build
|
||||
pushd Build
|
||||
cl %script_dir%\asan_example.cpp -Zi -O2 -fsanitize=address -nologo -link || exit /b 1
|
||||
popd
|
||||
|
||||
@@ -1,9 +0,0 @@
|
||||
#!/bin/bash
|
||||
script_dir=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
|
||||
|
||||
mkdir -p ${script_dir}/Build
|
||||
pushd ${script_dir}/Build
|
||||
gcc ${script_dir}/asan_example.cpp -g -fsanitize=address -o asan_example
|
||||
popd
|
||||
|
||||
|
||||
@@ -1,232 +0,0 @@
|
||||
# ASAN Manual Poisoning
|
||||
|
||||
## TLDR
|
||||
|
||||
`__asan_poison_memory_region(ptr, size)`
|
||||
|
||||
Poisons the byte region `[ptr, AlignDown(ptr+size, 8))`
|
||||
|
||||
`__asan_unpoison_memory_region(ptr, size)`
|
||||
|
||||
Unpoisons the byte region `[AlignDown(ptr, 8), ptr+size)`
|
||||
|
||||
Use the provided macros that are conditionally enabled if ASAN is
|
||||
defined from `<sanitizer/asan_interface.h>`.
|
||||
|
||||
```
|
||||
ASAN_POISON_MEMORY_REGION(addr, size)
|
||||
ASAN_UNPOISON_MEMORY_REGION(addr, size)
|
||||
```
|
||||
|
||||
If in doubt, use `__asan_address_is_poisoned` to sanity check the
|
||||
ranges requested to be un/poisoned to avoid potential gaps in
|
||||
marked-up memory that may lead to undetected read/writes.
|
||||
|
||||
## Overview
|
||||
|
||||
ASAN provides a way to manually markup ranges of bytes to
|
||||
prohibit or permit reads to those addresses. In
|
||||
`<sanitizer/asan_interface.h>` there's a vague brief mention to
|
||||
alignment requirements for the poison API:
|
||||
|
||||
```cpp
|
||||
/// ... This function is not guaranteed to poison the entire region -
|
||||
/// it could poison only a subregion of <c>[addr, addr+size)</c> due to ASan
|
||||
/// alignment restrictions.
|
||||
void __asan_poison_memory_region(void const volatile *addr, size_t size);
|
||||
|
||||
/// ... This function could unpoison a super-region of <c>[addr, addr+size)</c> due
|
||||
/// to ASan alignment restrictions.
|
||||
void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
|
||||
```
|
||||
|
||||
There's another small foot-note in Google's [AddressSanitizerManualPoisoning](https://github.com/google/sanitizers/wiki/AddressSanitizerManualPoisoning)
|
||||
documentation that states:
|
||||
|
||||
```
|
||||
If you have a custom allocation arena, the typical workflow would be
|
||||
to poison the entire arena first, and then unpoison allocated chunks
|
||||
of memory leaving poisoned redzones between them. The allocated
|
||||
chunks should start with 8-aligned addresses.
|
||||
```
|
||||
|
||||
So then this repository runs some simple tests to clarify the behaviour
|
||||
of the API on un/aligned addresses at various sizes without having
|
||||
to dig into source code or read the [ASAN paper](https://static.googleusercontent.com/media/research.google.com/en/pubs/archive/37752.pdf).
|
||||
|
||||
We use a stack-allocated 16 byte array and test un/poisoning
|
||||
various ranges of bytes from different alignments to clarify the
|
||||
poisoning behaviour of the API. This reveals that calling the API
|
||||
haphazardly, unaligned or straddling boundaries can lead to gaps in
|
||||
poisoned memory and hide potential leaks (as also demonstrated in
|
||||
[Manual ASAN poisoning and alignment](https://github.com/mcgov/asan_alignment_example)).
|
||||
|
||||
## References
|
||||
|
||||
- [Manual ASAN poisoning and alignment](https://github.com/mcgov/asan_alignment_example) example by `mcgov`
|
||||
- [Address Sanitizer: A Fast Address Sanity Checker](https://static.googleusercontent.com/media/research.google.com/en//pubs/archive/37752.pdf)
|
||||
- [sanitizer/asan_interface.h](https://github.com/llvm-mirror/compiler-rt/blob/master/include/sanitizer/asan_interface.h)
|
||||
|
||||
## Raw Test Results
|
||||
|
||||
Here we poison a sliding window of 7 bytes to demonstrate that ASAN
|
||||
poisoning will only poison the byte region if the region meets an 8
|
||||
byte aligned address. It will only poison bytes up to the boundary,
|
||||
any bytes that straddle the boundary that do not hit the next 8 byte
|
||||
boundary are not poisoned.
|
||||
|
||||
```
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x |
|
||||
2. __asan_address_is_poisoned |
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x |
|
||||
2. __asan_address_is_poisoned x x x x x x x |
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x | x
|
||||
2. __asan_address_is_poisoned x x x x x x |
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x | x x
|
||||
2. __asan_address_is_poisoned x x x x x |
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x | x x x
|
||||
2. __asan_address_is_poisoned x x x x |
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x | x x x x
|
||||
2. __asan_address_is_poisoned x x x |
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x | x x x x x
|
||||
2. __asan_address_is_poisoned x x |
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x | x x x x x x
|
||||
2. __asan_address_is_poisoned x |
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region | x x x x x x x
|
||||
2. __asan_address_is_poisoned |
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region | x x x x x x x
|
||||
2. __asan_address_is_poisoned | x x x x x x x
|
||||
|
||||
```
|
||||
Now we demonstrate that unpoisoning 1 byte in the 8 byte window
|
||||
will unpoison all bytes prior to it up until the previous 8 byte
|
||||
boundary.
|
||||
|
||||
```
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region x |
|
||||
4. __asan_address_is_poisoned x x x x x x x | x x x x x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region x |
|
||||
4. __asan_address_is_poisoned x x x x x x | x x x x x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region x |
|
||||
4. __asan_address_is_poisoned x x x x x | x x x x x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region x |
|
||||
4. __asan_address_is_poisoned x x x x | x x x x x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region x |
|
||||
4. __asan_address_is_poisoned x x x | x x x x x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region x |
|
||||
4. __asan_address_is_poisoned x x | x x x x x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region x |
|
||||
4. __asan_address_is_poisoned x | x x x x x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region x |
|
||||
4. __asan_address_is_poisoned | x x x x x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region | x
|
||||
4. __asan_address_is_poisoned x x x x x x x x | x x x x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region | x
|
||||
4. __asan_address_is_poisoned x x x x x x x x | x x x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region | x
|
||||
4. __asan_address_is_poisoned x x x x x x x x | x x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region | x
|
||||
4. __asan_address_is_poisoned x x x x x x x x | x x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region | x
|
||||
4. __asan_address_is_poisoned x x x x x x x x | x x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region | x
|
||||
4. __asan_address_is_poisoned x x x x x x x x | x x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region | x
|
||||
4. __asan_address_is_poisoned x x x x x x x x | x
|
||||
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region | x
|
||||
4. __asan_address_is_poisoned x x x x x x x x |
|
||||
|
||||
```
|
||||
Unpoisoning across 8 byte boundaries may lead to undesired
|
||||
behaviour, with all bytes on the left side of the boundary being
|
||||
unpoisoned
|
||||
|
||||
```
|
||||
Byte Array 00 01 02 03 04 05 06 07 | 08 09 10 11 12 13 14 15
|
||||
1. __asan_poison_memory_region x x x x x x x x | x x x x x x x x
|
||||
2. __asan_address_is_poisoned x x x x x x x x | x x x x x x x x
|
||||
3. __asan_unpoison_memory_region x | x
|
||||
4. __asan_address_is_poisoned | x x x x x x x
|
||||
```
|
||||
Reference in New Issue
Block a user