[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20140331113702.GA15459@altlinux.org>
Date: Mon, 31 Mar 2014 15:37:02 +0400
From: "Dmitry V. Levin" <ldv@...linux.org>
To: oss-security@...ts.openwall.com
Subject: Re: pam_timestamp internals
On Mon, Mar 31, 2014 at 12:57:11PM +0200, Sebastian Krahmer wrote:
> On Mon, Mar 31, 2014 at 02:32:09PM +0400, Dmitry V. Levin wrote:
> > On Mon, Mar 24, 2014 at 01:46:43PM +0100, Sebastian Krahmer wrote:
> > > When playing with some PAM modules for my own projects, I came
> > > across some implications of pam_timestamp (which is part of
> > > upstream linux-pam) that should probably be addressed.
> > >
> > > Most importantly, there seems to be a path traversal issue:
> >
> > Thanks, Sebastian! The issue has been fixed in upstream linux-pam by commit
> > https://git.fedorahosted.org/cgit/linux-pam.git/commit/?id=Linux-PAM-1_1_8-32-g9dcead8
>
> Thanks for taking care. I was about to write a patch on my own, but seems
> not necessary anymore.
>
> However, I think that
>
> + if (!strlen(tty) || !strcmp(tty, ".") || !strcmp(tty, "..")) {
>
> could be insufficient.
There is a code in check_tty() that handles '/':
if (strchr(tty, '/') != NULL) {
...
tty = strrchr(tty, '/') + 1;
}
> Any occurence of "." inside tty name should be evil.
Strange - yes, but why evil?
> Above strcmp() matches exactly "." or "..",
> but you also want "../../" etc which should pass above check.
After commit 9dcead8, check_tty() handles all such cases.
> For the ruser check, the strchr(ruser, '/') safes this, but
> ".." occurence may also be treatened appropriately.
Commit 9dcead8 also makes get_ruser() reject "." and ".." as invalid
ruser values.
--
ldv
Content of type "application/pgp-signature" skipped
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
