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From: ebiederm@xmission.com (Eric W. Biederman)
To: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	Eric Biggers <ebiggers3@gmail.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org, linux-api@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/4] Relocate execve() sanity checks
Date: Tue, 19 May 2020 10:06:32 -0500	[thread overview]
Message-ID: <87a724t153.fsf@x220.int.ebiederm.org> (raw)
In-Reply-To: <20200518055457.12302-1-keescook@chromium.org> (Kees Cook's message of "Sun, 17 May 2020 22:54:53 -0700")

Kees Cook <keescook@chromium.org> writes:

> Hi,
>
> While looking at the code paths for the proposed O_MAYEXEC flag, I saw
> some things that looked like they should be fixed up.
>
>   exec: Change uselib(2) IS_SREG() failure to EACCES
> 	This just regularizes the return code on uselib(2).
>
>   exec: Relocate S_ISREG() check
> 	This moves the S_ISREG() check even earlier than it was already.
>
>   exec: Relocate path_noexec() check
> 	This adds the path_noexec() check to the same place as the
> 	S_ISREG() check.
>
>   fs: Include FMODE_EXEC when converting flags to f_mode
> 	This seemed like an oversight, but I suspect there is some
> 	reason I couldn't find for why FMODE_EXEC doesn't get set in
> 	f_mode and just stays in f_flags.

So I took a look at this series.

I think the belt and suspenders approach of adding code in open and then
keeping it in exec and uselib is probably wrong.  My sense of the
situation is a belt and suspenders approach is more likely to be
confusing and result in people making mistakes when maintaining the code
than to actually be helpful.

Eric

  parent reply	other threads:[~2020-05-19 15:10 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-18  5:54 [PATCH 0/4] Relocate execve() sanity checks Kees Cook
2020-05-18  5:54 ` [PATCH 1/4] exec: Change uselib(2) IS_SREG() failure to EACCES Kees Cook
2020-05-18 13:02   ` Christian Brauner
2020-05-18 14:43     ` Jann Horn
2020-05-18 14:46       ` Christian Brauner
2020-05-18 23:57         ` Eric W. Biederman
2020-05-19  8:11           ` Christian Brauner
2020-05-19  8:37           ` Andreas Schwab
2020-05-19 11:56             ` Eric W. Biederman
2020-05-19 12:12               ` Andreas Schwab
2020-05-19 12:28                 ` Eric W. Biederman
2020-05-19 13:29                   ` Christian Brauner
2020-05-19 14:49                     ` Eric W. Biederman
2020-05-19 13:13               ` Christian Brauner
2020-05-19 14:32                 ` Geert Uytterhoeven
2020-05-19 14:47                   ` Christian Brauner
2020-05-18  5:54 ` [PATCH 2/4] exec: Relocate S_ISREG() check Kees Cook
     [not found]   ` <20200525091420.GI12456@shao2-debian>
2020-06-04 22:45     ` [exec] 166d03c9ec: ltp.execveat02.fail Kees Cook
2020-06-05  2:57     ` Kees Cook
2020-05-18  5:54 ` [PATCH 3/4] exec: Relocate path_noexec() check Kees Cook
2020-05-18  5:54 ` [PATCH 4/4] fs: Include FMODE_EXEC when converting flags to f_mode Kees Cook
2020-05-19 15:06 ` Eric W. Biederman [this message]
2020-05-19 16:26   ` [PATCH 0/4] Relocate execve() sanity checks Kees Cook
2020-05-19 17:41     ` Eric W. Biederman
2020-05-19 17:56       ` Kees Cook
2020-05-19 18:42         ` Eric W. Biederman
2020-05-19 21:17           ` Kees Cook
2020-05-19 22:58             ` John Johansen

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