linux-kernel - Re: [PATCH] set*uid() must not fail-and-return on OOM/rlimits

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1156089203.23756.46.camel@laptopd505.fenrus.org>
Date:	Sun, 20 Aug 2006 17:53:22 +0200
From:	Arjan van de Ven <arjan@...radead.org>
To:	Solar Designer <solar@...nwall.com>
Cc:	Alex Riesen <fork0@...rs.sourceforge.net>,
	Willy Tarreau <wtarreau@...a.kernel.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] set*uid() must not fail-and-return on OOM/rlimits

On Sun, 2006-08-20 at 19:30 +0400, Solar Designer wrote:
> On Sun, Aug 20, 2006 at 12:07:06PM +0200, Alex Riesen wrote:
> > Solar Designer, Sun, Aug 20, 2006 02:38:40 +0200:
> > > Attached is a trivial patch (extracted from 2.4.33-ow1) that makes
> > > set*uid() kill the current process rather than proceed with -EAGAIN when
> > > the kernel is running out of memory.  Apparently, alloc_uid() can't fail
> > > and return anyway due to properties of the allocator, in which case the
> > > patch does not change a thing.  But better safe than sorry.
> > 
> > Why not ENOMEM?
> 
> ENOMEM would not be any better than EAGAIN from the security standpoint.
> 
> The problem is that there are lots of privileged userspace programs that
> do not bother to check the return value from set*uid() calls (or
> otherwise check that the calls succeeded) before proceeding with work
> that is only safe to do with the *uid switched as intended.

sounds like a good argument to get the setuid functions marked
__must_check in glibc...

-- 
if you want to mail me at work (you don't), use arjan (at) linux.intel.com

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/