From: Matthew Wilcox <willy@infradead.org>
To: Christian Brauner <brauner@kernel.org>
Cc: kernel test robot <oliver.sang@intel.com>,
Kees Cook <keescook@chromium.org>,
Ariadne Conill <ariadne@dereferenced.org>,
0day robot <lkp@intel.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Rich Felker <dalias@libc.org>,
Eric Biederman <ebiederm@xmission.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
LKML <linux-kernel@vger.kernel.org>,
lkp@lists.01.org, Andrew Morton <akpm@linux-foundation.org>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
stable@vger.kernel.org
Subject: Re: [fs/exec] 80bd5afdd8: xfstests.generic.633.fail
Date: Mon, 31 Jan 2022 15:51:21 +0000 [thread overview]
Message-ID: <YfgFeWbZPl+gAUYE@casper.infradead.org> (raw)
In-Reply-To: <20220131153707.oe45h7tuci2cbfuv@wittgenstein>
On Mon, Jan 31, 2022 at 04:37:07PM +0100, Christian Brauner wrote:
> On Mon, Jan 31, 2022 at 03:19:22PM +0000, Matthew Wilcox wrote:
> > On Mon, Jan 31, 2022 at 04:08:19PM +0100, Christian Brauner wrote:
> > > On Mon, Jan 31, 2022 at 10:43:52PM +0800, kernel test robot wrote:
> > > I can fix this rather simply in our upstream fstests with:
> > >
> > > static char *argv[] = {
> > > "",
> > > };
> > >
> > > I guess.
> > >
> > > But doesn't
> > >
> > > static char *argv[] = {
> > > NULL,
> > > };
> > >
> > > seem something that should work especially with execveat()?
> >
> > The problem is that the exec'ed program sees an argc of 0, which is the
> > problem we're trying to work around in the kernel (instead of leaving
> > it to ld.so to fix for suid programs).
>
> Ok, just seems a bit more intuitive for path-based exec than for
> fd-based execveat().
>
> What's argv[0] supposed to contain in these cases?
>
> 1. execveat(fd, NULL, ..., AT_EMPTY_PATH)
> 2. execveat(fd, "my-file", ..., )
>
> "" in both 1. and 2.?
> "" in 1. and "my-file" in 2.?
You didn't specify argv for either of those, so I have no idea.
Programs shouldn't be assuming anything about argv[0]; it's purely
advisory. Unfortunately, some of them do. And some of them are suid.
next prev parent reply other threads:[~2022-01-31 15:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-27 0:07 [PATCH v3] fs/exec: require argv[0] presence in do_execveat_common() Ariadne Conill
2022-01-27 5:29 ` Kees Cook
2022-01-27 16:51 ` Eric W. Biederman
2022-01-31 14:43 ` [fs/exec] 80bd5afdd8: xfstests.generic.633.fail kernel test robot
2022-01-31 15:08 ` Christian Brauner
2022-01-31 15:19 ` Matthew Wilcox
2022-01-31 15:37 ` Christian Brauner
2022-01-31 15:51 ` Matthew Wilcox [this message]
2022-01-31 16:14 ` Christian Brauner
2022-01-31 17:13 ` Christian Brauner
2022-01-31 21:59 ` Andrew Morton
2022-01-31 22:49 ` Kees Cook
2022-02-01 13:28 ` Christian Brauner
2022-02-01 13:28 ` Christian Brauner
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