On Wed, Jun 03, 2020 at 02:03:22AM +0200, Kamil Rytarowski wrote: > On 03.06.2020 01:49, Andrew Doran wrote: > > On the assembly thing recall that recently you expressed a desire to remove > > all of the amd64 assembly string functions from libc because of sanitizers - > > I invested my time to do up a little demo to try and show you why that's not > > a good idea: > > > > http://mail-index.netbsd.org/port-amd64/2020/04/19/msg003226.html > > Please note that interceptors for string functions are not just some > extra burden, but also very useful approach to feedback a fuzzer through > additional coverage. > > At least libFuzzer and honggfuzz wrap many kinds of string functions and > use it for fuzzing. We should add a special mode in KCOV to feedback > userland (syzkaller) with traces from string functions. > > https://github.com/google/honggfuzz/blob/bbb476eec95ad927d6d7d3d367d2b3e38eed3569/libhfuzz/memorycmp.c#L24
No argument from me there at all. I think that's a great idea and was looking at the interceptors in TSAN recently to see how they work. Andrew