On Tue, Jun 20, 2023 at 10:49:08PM +0700, Ammar Faizi wrote: > On Tue, Jun 20, 2023 at 03:31:52PM +0200, Stefan Hajnoczi wrote: > > This is caused by the stack protector compiler options, which depend on > > the libc __stack_chk_fail_local symbol. > > Guillem fixed it last week. Does this commit fix the stack protector > problem? https://github.com/axboe/liburing/commit/319f4be8bd049055c333185928758d0fb445fc43 > > > In general, I'm concerned that nolibc is fragile because the toolchain > > and libc sometimes have dependencies that are activated by certain > > compiler options. Some users will want libc and others will not. Maybe > > make it an explicit option instead of probing? > > I made nolibc always enabled because I don't see the need of using libc > in liburing. If we have a real reason of using libc, maybe adding > '--use-libc' is better than bringing back '--nolibc'. > > I agree with what Alviro said that using stack protector in liburing is > too overkill. That's why I see no reason for the upstream to support it. > > Can you mention other dependencies that do need libc? That information > would be useful to consider bringing back libc to liburing. 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). 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. Stefan
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