Description
The address sanitizer (Asan) is a memory error detector, it finds a number of memory access errors that can occur in C, such as out-of-bounds accesses to heap, stack and global objects, and use-after-free. In general, these issues do not occur in the pure Go code, unless people intentionally use the unsafe package. However, people can use cgo to pass memory back and forth between C and Go, which will cause memory access problems.
Please refer to the following cases.
In this case (case-1) https://play.golang.org/p/eE_8k4poelj, C passes Go an invalid pointer, causing the Go code to have use-after-free errors. In this case (case-2) https://play.golang.org/p/wtHjV-4xuiL, Go passes C a pointer, the C code has out-of-bounds access to heap objects errors. In this case (case-3) https://play.golang.org/p/rOyEo7I7vTY, Go passes C a pointer, the C code has out-of-bounds access to global objects errors.
Integrating Asan with Go would detect the above memory errors. So it is useful. In addition, Asan can help to detect some memory errors that MSan cannot. For example, use-after-free memory error case https://play.golang.org/p/eE_8k4poelj, MSan cannot detect writes on uninitialized memory, while ASan can.
And we can instrument ASan in exactly the same way as MSan. As with the -msan option, if we do not run with -asan option, it has no effect on code execution, if you use it, it may find some memory errors.
Although the above cases are not real world cases. However, on the other hand, when debugging a memory error access in a Go program that calls C code, it is really good to be able to use Asan to ensure that code is correct. Obviously, this will require more code to be maintained in the toolchain, but since almost all of the code is next to the existing MSan code, this is quite limited.
Besides, Arm has a hardware feature MTE (Memory Tagging Extension), it aims to further mitigate these memory safety bugs by enabling us to detect them with low overhead. If ASan will be proven to be useful, we may consider enabling MTE for ASan. In this way, ASan even be enabled in the production environment to help to detect memory errors with low overhead. I saw a blog that introduces enable MTE in Android to detect the most common classes of memory safety bugs. Please refer to the document https://security.googleblog.com/2019/08/adopting-arm-memory-tagging-extension.html.
Thank you.