Re: False positives in nolibc check

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Wed, Jun 21, 2023 at 05:19:18PM +0700, Ammar Faizi wrote:
> On Wed, Jun 21, 2023 at 12:04:47PM +0200, Stefan Hajnoczi wrote:
> > I don't know which features require the toolchain and libc to cooperate.
> > I guess Thread Local Storage won't work and helper functions that
> > compilers emit (like the memset example that Alviro gave).
> 
> Yeah, thread local storage won't work. But the point of my question is
> about liburing. So I expect the answer that's relevant to liburing.
> 
> I mean, you can still use libc and TLS in your app even though the
> liburing.so and liburing.a are nolibc.
> 
> > Disabling hardening because it requires work to support it in a nolibc
> > world seems dubious to me. I don't think it's a good idea for io_uring
> > to lower security because that hurts its image and reduces adoption.
> > Especially right now, when the security of io_uring is being scrutinized
> > (https://security.googleblog.com/2023/06/learnings-from-kctf-vrps-42-linux.html).
> > 
> > While I'm sharing these opinions with you, I understand that some people
> > want nolibc and are fine with disabling the stack protector. The main
> > thing I would like is for liburing to compile or fail with a clear error
> > message instead of breaking somewhere during the build.
> 
> Right, my mistake. I think it's fixed in upstream by commit:
> 
>    319f4be8bd049055c333185928758d0fb445fc43 ("build: Disable stack protector unconditionally")
> 
> Please give it a whirl. I apologize for breaking the Fedora build.

No need to apologize! Thanks for taking a look.

I ran an rpmbuild with liburing.git/master and it succeeds now.

Stefan

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