From: Kees Cook <keescook@chromium.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Al Viro <viro@zeniv.linux.org.uk>,
Luis Chamberlain <mcgrof@kernel.org>,
linux-fsdevel@vger.kernel.org,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
linux-security-module@vger.kernel.org,
"Serge E. Hallyn" <serge@hallyn.com>,
James Morris <jmorris@namei.org>,
Kentaro Takeda <takedakn@nttdata.co.jp>,
Casey Schaufler <casey@schaufler-ca.com>,
John Johansen <john.johansen@canonical.com>,
Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 2/7] exec: Factor out alloc_bprm
Date: Tue, 14 Jul 2020 14:38:22 -0700 [thread overview]
Message-ID: <202007141438.C4E2A2A9@keescook> (raw)
In-Reply-To: <87pn8y6x9a.fsf@x220.int.ebiederm.org>
On Tue, Jul 14, 2020 at 08:29:05AM -0500, Eric W. Biederman wrote:
>
> Currently it is necessary for the usermode helper code and the code
> that launches init to use set_fs so that pages coming from the kernel
> look like they are coming from userspace.
>
> To allow that usage of set_fs to be removed cleanly the argument
> copying from userspace needs to happen earlier. Move the allocation
> of the bprm into it's own function (alloc_bprm) and move the call of
> alloc_bprm before unshare_files so that bprm can ultimately be
> allocated, the arguments can be placed on the new stack, and then the
> bprm can be passed into the core of exec.
>
> Neither the allocation of struct binprm nor the unsharing depend upon each
> other so swapping the order in which they are called is trivially safe.
>
> To keep things consistent the order of cleanup at the end of
> do_execve_common swapped to match the order of initialization.
>
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2020-07-14 21:38 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-14 13:27 [PATCH 0/7] Implementing kernel_execve Eric W. Biederman
2020-07-14 13:28 ` [PATCH 1/7] exec: Remove unnecessary spaces from binfmts.h Eric W. Biederman
2020-07-14 21:38 ` Kees Cook
2020-07-15 6:28 ` Christoph Hellwig
2020-07-14 13:29 ` [PATCH 2/7] exec: Factor out alloc_bprm Eric W. Biederman
2020-07-14 21:38 ` Kees Cook [this message]
2020-07-15 6:30 ` Christoph Hellwig
2020-07-14 13:29 ` [PATCH 3/7] exec: Move initialization of bprm->filename into alloc_bprm Eric W. Biederman
2020-07-14 21:38 ` Kees Cook
2020-07-15 6:34 ` Christoph Hellwig
2020-07-14 13:30 ` [PATCH 4/7] exec: Move bprm_mm_init " Eric W. Biederman
2020-07-14 21:37 ` Kees Cook
2020-07-15 6:35 ` Christoph Hellwig
2020-07-14 13:30 ` [PATCH 5/7] exec: Factor bprm_execve out of do_execve_common Eric W. Biederman
2020-07-14 21:38 ` Kees Cook
2020-07-15 6:36 ` Christoph Hellwig
2020-07-14 13:31 ` [PATCH 6/7] exec: Factor bprm_stack_limits out of prepare_arg_pages Eric W. Biederman
2020-07-14 21:41 ` Kees Cook
2020-07-15 6:38 ` Christoph Hellwig
2020-07-14 13:31 ` [PATCH 7/7] exec: Implement kernel_execve Eric W. Biederman
2020-07-14 21:49 ` Kees Cook
2020-07-15 6:42 ` Christoph Hellwig
2020-07-15 14:55 ` David Laight
2020-07-15 15:09 ` Kees Cook
2020-07-15 16:46 ` David Laight
2020-07-15 15:00 ` Kees Cook
2020-07-15 18:20 ` Christoph Hellwig
2020-07-15 6:42 ` Christoph Hellwig
2020-07-15 18:23 ` Eric W. Biederman
2020-07-14 15:32 ` [PATCH 0/7] Implementing kernel_execve Linus Torvalds
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