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From: Kees Cook <keescook@chromium.org>
To: Ariadne Conill <ariadne@dereferenced.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Eric Biederman <ebiederm@xmission.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH v2] fs/exec: require argv[0] presence in do_execveat_common()
Date: Wed, 26 Jan 2022 13:25:27 -0800	[thread overview]
Message-ID: <202201261323.9499FA51@keescook> (raw)
In-Reply-To: <5e963fab-88d4-2039-1cf4-6661e9bd16b@dereferenced.org>

On Wed, Jan 26, 2022 at 03:13:10PM -0600, Ariadne Conill wrote:
> Looks good to me, but I wonder if we shouldn't set an argv of
> {bprm->filename, NULL} instead of {"", NULL}.  Discussion in IRC led to the
> realization that multicall programs will try to use argv[0] and might crash
> in this scenario.  If we're going to fake an argv, I guess we should try to
> do it right.

They're crashing currently, though, yes? I think the goal is to move
toward making execve(..., NULL, NULL) just not work at all. Using the
{"", NULL} injection just gets us closer to protecting a bad userspace
program. I think things _should_ crash if they try to start depending
on this work-around.

-- 
Kees Cook

  reply	other threads:[~2022-01-26 21:25 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-26 11:44 [PATCH v2] fs/exec: require argv[0] presence in do_execveat_common() Ariadne Conill
2022-01-26 14:40 ` Matthew Wilcox
2022-01-26 17:41   ` Ariadne Conill
2022-01-26 14:59 ` Matthew Wilcox
2022-01-26 16:40   ` Kees Cook
2022-01-26 16:57   ` Eric W. Biederman
2022-01-26 17:32     ` Ariadne Conill
2022-01-26 18:03     ` Matthew Wilcox
2022-01-26 18:38       ` Ariadne Conill
2022-01-26 20:09 ` Kees Cook
2022-01-26 20:23   ` Ariadne Conill
2022-01-26 20:56     ` Kees Cook
2022-01-26 21:13       ` Ariadne Conill
2022-01-26 21:25         ` Kees Cook [this message]
2022-01-26 21:30           ` Ariadne Conill
2022-01-26 22:49             ` Kees Cook
2022-01-26 23:07               ` Ariadne Conill

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