From: Oleg Nesterov <oleg@redhat.com>
To: Leon Yu <chianglungyu@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Kees Cook <keescook@chromium.org>, Michal Hocko <mhocko@suse.com>,
John Stultz <john.stultz@linaro.org>,
Mateusz Guzik <mguzik@redhat.com>,
Janis Danisevskis <jdanis@google.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] proc: fix NULL dereference when reading /proc/<pid>/auxv
Date: Thu, 20 Oct 2016 19:04:39 +0200 [thread overview]
Message-ID: <20161020170438.GA13724@redhat.com> (raw)
In-Reply-To: <1476966200-14457-1-git-send-email-chianglungyu@gmail.com>
On 10/20, Leon Yu wrote:
>
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -1014,6 +1014,9 @@ static ssize_t auxv_read(struct file *file, char __user *buf,
> {
> struct mm_struct *mm = file->private_data;
> unsigned int nwords = 0;
> +
> + if (!mm)
> + return 0;
> do {
> nwords += 2;
> } while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
Michal disagrees and I won't argue with his patch which makes __mem_open()
fail if ->mm == NULL. Even if I don't really understand why should we change
the old behaviour, this _can_ break or at least confuse something/someone.
However, even if we do the change above, personally I do think we should
fix the trivial bug first, then surprise the user-space.
Acked-by: Oleg Nesterov <oleg@redhat.com>
next prev parent reply other threads:[~2016-10-20 17:06 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-19 13:59 [PATCH] proc: fix NULL dereference when reading /proc/<pid>/auxv Leon Yu
2016-10-19 14:13 ` Michal Hocko
2016-10-19 16:12 ` Oleg Nesterov
2016-10-19 16:17 ` Michal Hocko
2016-10-19 16:44 ` Oleg Nesterov
2016-10-19 17:00 ` Michal Hocko
2016-10-19 14:20 ` Al Viro
2016-10-19 14:51 ` Michal Hocko
2016-10-19 14:51 ` Leon Yu
2016-10-19 17:17 ` Michal Hocko
2016-10-20 12:32 ` Leon Yu
2016-10-20 12:44 ` Michal Hocko
2016-10-20 12:23 ` [PATCH v2] " Leon Yu
2016-10-20 17:04 ` Oleg Nesterov [this message]
2016-10-20 19:21 ` Michal Hocko
2016-10-21 12:47 ` Leon Yu
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