From: Andrew Morton <akpm@linux-foundation.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: oleg@redhat.com, viro@zeniv.linux.org.uk, rostedt@goodmis.org,
fweisbec@gmail.com, mingo@redhat.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kmod: Check for NULL at call_usermodehelper_exec().
Date: Mon, 23 Sep 2013 14:30:57 -0700 [thread overview]
Message-ID: <20130923143057.a6a7ac7d524f890bfef92b72@linux-foundation.org> (raw)
In-Reply-To: <201309240612.ADE82877.MSFHVtOOFLFOQJ@I-love.SAKURA.ne.jp>
On Tue, 24 Sep 2013 06:12:34 +0900 Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> wrote:
> Andrew, would you pick up this patch?
>
> Regards.
> ----------
> >From d6ff218545060c5f8b75b15d5b34bffcf625508f Mon Sep 17 00:00:00 2001
> From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Date: Mon, 16 Sep 2013 02:19:10 +0900
> Subject: [PATCH] kmod: Check for NULL at call_usermodehelper_exec().
>
> If /proc/sys/kernel/core_pattern contains only "|", NULL pointer dereference
> happens upon core dump because argv_split("") returns argv[0] == NULL.
>
> This bug was once fixed by commit 264b83c0 "usermodehelper: check
> subprocess_info->path != NULL" but was by error reintroduced by commit
> 7f57cfa4 "usermodehelper: kill the sub_info->path[0] check".
>
> This bug seems to exist since 2.6.19 (the version which core dump to pipe was
> added). Depending on kernel version and config, some side effect might happen
> immediately after this oops (e.g. kernel panic with 2.6.32-358.18.1.el6).
>
> ...
>
> --- a/kernel/kmod.c
> +++ b/kernel/kmod.c
> @@ -571,6 +571,10 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
> DECLARE_COMPLETION_ONSTACK(done);
> int retval = 0;
>
> + if (!sub_info->path) {
> + call_usermodehelper_freeinfo(sub_info);
> + return -ENOENT;
> + }
> helper_lock();
> if (!khelper_wq || usermodehelper_disabled) {
> retval = -EBUSY;
The error is that the user put a bare "|" into
/proc/sys/kernel/core_pattern. Is ENOENT ("No such file or directory")
the most appropriate error code here? I think EINVAL ("Invalid
argument")?
next prev parent reply other threads:[~2013-09-23 21:30 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-14 7:32 [PATCH] argv_split: Return NULL if argument contains no non-whitespace Tetsuo Handa
2013-09-14 15:41 ` Oleg Nesterov
2013-09-15 0:10 ` [PATCH] argv_split: Return NULL if argument contains nonon-whitespace Tetsuo Handa
2013-09-15 14:23 ` [PATCH] kmod: Check for NULL at call_usermodehelper_exec() Tetsuo Handa
2013-09-15 16:31 ` Oleg Nesterov
2013-09-15 17:02 ` Tetsuo Handa
2013-09-15 17:15 ` Oleg Nesterov
2013-09-15 17:26 ` Tetsuo Handa
2013-09-15 17:34 ` Oleg Nesterov
2013-09-23 21:12 ` Tetsuo Handa
2013-09-23 21:30 ` Andrew Morton [this message]
2013-09-24 14:58 ` Tetsuo Handa
2013-09-15 16:26 ` [PATCH] argv_split: Return NULL if argument contains nonon-whitespace Oleg Nesterov
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