From 9389810c0e731d22f77704368bc8e44eb2ca6ab3 Mon Sep 17 00:00:00 2001 From: doyle Date: Mon, 28 Aug 2023 23:41:57 +1000 Subject: [PATCH] Add comments from --- asan_example.cpp | 26 ++++++++++++++++++++++---- readme.md | 28 +++++++++++++++++++++++----- 2 files changed, 45 insertions(+), 9 deletions(-) diff --git a/asan_example.cpp b/asan_example.cpp index 7014980..0a9822d 100644 --- a/asan_example.cpp +++ b/asan_example.cpp @@ -84,8 +84,26 @@ int main() "## Overview\n" "\n" "ASAN provides a way to manually markup ranges of bytes to\n" - "prohibit or permit reads to those addresses. There's a short\n" - "foot-note in Google's " + "prohibit or permit reads to those addresses. In\n" + "` there's a brief mention for the poison\n" + "and unpoison API respectively:`\n" + "\n" + "```cpp\n" + "/// ... This function is not guaranteed to poison the entire region -\n" + "/// it could poison only a subregion of [addr, addr+size) due to ASan\n" + "/// alignment restrictions.\n" + "void __asan_poison_memory_region(void const volatile *addr, size_t size);\n" + "```\n" + "\n" + "and:\n" + "\n" + "```cpp\n" + "/// This function could unpoison a super-region of [addr, addr+size) 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 brief foot-note in Google's " "[AddressSanitizerManualPoisoning](https://github.com/google/" "sanitizers/wiki/AddressSanitizerManualPoisoning)\n" "documentation that states:\n" @@ -97,8 +115,8 @@ int main() "chunks should start with 8-aligned addresses.\n" "```\n" "\n" - "This repository runs some simple tests to clarify the behaviour of\n" - "the API on un/aligned addresses at various sizes without having\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" diff --git a/readme.md b/readme.md index 27cee04..92cd084 100644 --- a/readme.md +++ b/readme.md @@ -25,8 +25,26 @@ 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. There's a short -foot-note in Google's [AddressSanitizerManualPoisoning](https://github.com/google/sanitizers/wiki/AddressSanitizerManualPoisoning) +prohibit or permit reads to those addresses. In +` there's a brief mention for the poison +and unpoison API respectively:` + +```cpp +/// ... This function is not guaranteed to poison the entire region - +/// it could poison only a subregion of [addr, addr+size) due to ASan +/// alignment restrictions. +void __asan_poison_memory_region(void const volatile *addr, size_t size); +``` + +and: + +```cpp +/// This function could unpoison a super-region of [addr, addr+size) due +/// to ASan alignment restrictions. +void __asan_unpoison_memory_region(void const volatile *addr, size_t size); +``` + +There's another brief foot-note in Google's [AddressSanitizerManualPoisoning](https://github.com/google/sanitizers/wiki/AddressSanitizerManualPoisoning) documentation that states: ``` @@ -36,8 +54,8 @@ of memory leaving poisoned redzones between them. The allocated chunks should start with 8-aligned addresses. ``` -This repository runs some simple tests to clarify the behaviour of -the API on un/aligned addresses at various sizes without having +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 @@ -50,7 +68,7 @@ poisoned memory and hide potential leaks (as also demonstrated in ## 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) +- [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