On 09/09/19 11:01, Martin Liška wrote: > Hi. > > On 9/6/19 4:46 PM, Matthew Malcomson wrote: >> Ensuring that the shadow stack is cleared on normal function exit will >> be done by adding instrumentation to the function epilogue through the >> compiler. >> longjmp and setjmp are some abnormal methods of exiting the function >> that can't be handled in the compiler since they can be called in >> uninstrumented code to unwind past instrumented function frames. > > I'm curious why you are adding a new code that is not part of libsanitizer > runtime? > Does it mean the current LLVM implementation does not properly handle setjmp > and > longjmp?
Honestly -- I'm not sure. I did a basic test that seemed to show clang not supporting setjmp & longjmp and I made a bit of a foray into how one would approach the problem, but I then left it in a partially done state to focus on other things. It also seems on first blush that C++ exceptions are not handled, but again I haven't yet gone and asked anyone in the know. (it's on the list of things to do, but not yet at the top). > > Note that rule of thumb is that we need to upstream all libsanitizer > changes before we merge libsanitizer. We are doing that in order to not > have a bug difference against upstream libsanitizer. That sounds good to me -- I will remember to go upstream when I look into this. > > Martin >
