Re: [PATCH] exec: drop a racy path_noexec check

From: Kees Cook
Date: Wed Aug 07 2024 - 17:06:21 EST


On Tue, Aug 06, 2024 at 09:06:17AM +0200, Christian Brauner wrote:
> On Mon, 05 Aug 2024 15:17:21 +0200, Mateusz Guzik wrote:
> > Both i_mode and noexec checks wrapped in WARN_ON stem from an artifact
> > of the previous implementation. They used to legitimately check for the
> > condition, but that got moved up in two commits:
> > 633fb6ac3980 ("exec: move S_ISREG() check earlier")
> > 0fd338b2d2cd ("exec: move path_noexec() check earlier")
> >
> > Instead of being removed said checks are WARN_ON'ed instead, which
> > has some debug value
> >
> > [...]
>
> Applied to the vfs.misc branch of the vfs/vfs.git tree.

NAK, please drop this patch. I want to keep the "redundant"
path_noexec(), since it still provides meaningful signal. We can remove
it from the WARN_ON_ONCE(), but I don't want to drop it.

--
Kees Cook