On Tue, 14 May 2024 16:48:47 -0600 "Theo de Raadt" <dera...@openbsd.org> wrote:
> Matthew Wilcox <wi...@infradead.org> wrote: > > > > Not taking a position on merging, but I have to ask: are we convinced at > > > this point that mseal() isn't a chrome-only system call? Did we ever > > > see the glibc patches that were promised? > > > > I think _this_ version of mseal() is OpenBSD's mimmutable() with a > > basically unused extra 'flags' argument. As such, we have an existance > > proof that it's useful beyond Chrome. > > Yes, it is close enough. > > > I think Liam still had concerns around the > > walk-the-vmas-twice-to-error-out-early part of the implementation? > > Although we can always fix the implementation later; changing the API > > is hard. > > Yes I am a bit worried about the point Liam brings up -- we've discussed > it privately at length. Matthew, to keep it short I have a different > viewpoint: > > Some of the Linux m* system calls have non-conforming, > partial-work-then-return-error > behaviour. I cannot find anything like this in any system call in any other > operating system, and I believe there is a defacto rule against doing this, > and > Linux has an optimization which violating this, and I think it could be fixed > with fairly minor expense, and can't imagine it affecting a single > application. Thanks. > I worry that the non-atomicity will one day be used by an attacker. How might an attacker exploit this?
