From: Pavel Machek <pavel@ucw.cz>
To: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>, Rik van Riel <riel@redhat.com>,
David Rientjes <rientjes@google.com>,
Aaron Tomlin <atomlin@redhat.com>,
Dario Faggioli <raistlin@linux.it>,
Andi Kleen <ak@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>, Jens Axboe <axboe@fb.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Paul Wise <pabs3@bonedaddy.net>
Subject: Re: [PATCH] sysctl: terminate strings also on \r
Date: Mon, 27 Oct 2014 10:56:26 +0100 [thread overview]
Message-ID: <20141027095626.GD9807@amd> (raw)
In-Reply-To: <CAGXu5j+sW89tZDA5GQnkL4E9wHTScftyxUhyAjbWnEfxGocBjg@mail.gmail.com>
On Wed 2014-10-22 16:43:10, Kees Cook wrote:
> On Wed, Oct 22, 2014 at 4:26 PM, Andrew Morton
> <akpm@linux-foundation.org> wrote:
> > On Tue, 21 Oct 2014 13:21:37 -0700 Kees Cook <keescook@chromium.org> wrote:
> >
> >> From: Paul Wise <pabs3@bonedaddy.net>
> >>
> >> This partially mitigates a common strategy used by attackers for hiding
> >> the full contents of strings in procfs from naive sysadmins who use cat,
> >> more or sysctl to inspect the contents of strings in procfs.
> >>
> >> ...
> >>
> >> --- a/kernel/sysctl.c
> >> +++ b/kernel/sysctl.c
> >> @@ -1739,7 +1739,7 @@ static int _proc_do_string(char *data, int maxlen, int write,
> >> while ((p - buffer) < *lenp && len < maxlen - 1) {
> >> if (get_user(c, p++))
> >> return -EFAULT;
> >> - if (c == 0 || c == '\n')
> >> + if (c == 0 || c == '\n' || c == '\r')
> >> break;
> >> data[len++] = c;
> >> }
> >
> > There are no valid uses of \r in a procfs write?
>
> I struggle to imagine one; everything I found that uses proc_dostring
> seems to be names, paths, and commands.
Well, filename can contain \r, right?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2014-10-27 9:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-21 20:21 [PATCH] sysctl: terminate strings also on \r Kees Cook
2014-10-22 10:03 ` Aaron Tomlin
2014-10-22 13:39 ` Paul E. McKenney
2014-10-22 22:49 ` David Rientjes
2014-10-22 23:26 ` Andrew Morton
2014-10-22 23:43 ` Kees Cook
2014-10-23 2:00 ` Andrew Morton
2014-10-23 16:39 ` Kees Cook
2014-10-23 18:23 ` Andrew Morton
2014-10-23 18:50 ` Kees Cook
2014-10-27 9:56 ` Pavel Machek [this message]
2014-10-27 10:11 ` Geert Uytterhoeven
2014-10-27 12:01 ` Pavel Machek
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