On Fri, 2023-03-10 at 12:00 -0800, H.J. Lu wrote: > > > So it does: > > > 1. Enable shadow stack > > > 2. Call elf libs checking functions > > > 3. If all good, lock shadow stack. Else, disable shadow stack. > > > 4. Return from elf checking functions and if shstk is enabled, > > > don't > > > underflow because it was enabled in step 1 and we have return > > > addresses > > > from 2 on the shadow stack > > > > > > I'm wondering if this can't be improved in glibc to look like: > > > 1. Check elf libs, and record it somewhere > > > 2. Wait until just the right spot > > > 3. If all good, enable and lock shadow stack. > > > > I will try it out. > > > > Currently glibc enables shadow stack as early as possible. There > are only a few places where a function call in glibc never returns. > We can enable shadow stack just before calling main. There are > quite some code paths without shadow stack protection. Is this > an issue? Thanks for checking. Hmm, does the loader get attacked?
