oss-sec mailing list archives
Re: Linux kernel futex local privilege escalation (CVE-2014-3153)
From: Phil Turnbull <phil.turnbull () oracle com>
Date: Thu, 05 Jun 2014 19:25:24 -0400
On 05/06/14 10:45, Solar Designer wrote:
I've attached patches by Thomas Gleixner (four e-mails, in mbox format), as well as back-ports of those by John Johansen of Canonical, who wrote: --- For anyone who is interested I've attached back ports of the patches to 3.13 - minor conflicts in patch 4. It has applied cleanly back to 3.2 and 2.6.32 - conflict is in patches 3, and 4 ---
Hi, We are currently preparing Ksplice updates for our supported kernels and spotted something odd in the 2.6.32 backport. In patches-2.6.32.tgz:patches/0003-futex-Always-cleanup-owner-tid-in-unlock_pi.patch there is this change (ignoring whitespace changes): curval = cmpxchg_futex_value_locked(uaddr, uval, newval); - - if (curval == -EFAULT) + if (curval) ret = -EFAULT; which seems to change the behaviour of the function. The purpose of the return value of cmpxchg_futex_value_locked changed in 37a9d912b24f96a0591 "futex: Sanitize cmpxchg_futex_value_locked API" which is not included in 2.6.32. This patch changes the return value to a status code, but in 2.6.32 the return value is the value of the futex or -EFAULT. With this backported patch, any futex with a non-zero value will return -EFAULT. Can you please clarify whether this change was intentional or is an error introduced in the backport? Thanks, Phil
Current thread:
- Linux kernel futex local privilege escalation (CVE-2014-3153) Solar Designer (Jun 05)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Solar Designer (Jun 05)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Greg KH (Jun 05)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Kees Cook (Jun 05)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Phil Turnbull (Jun 05)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) John Johansen (Jun 05)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Rich Felker (Jun 05)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Solar Designer (Jun 05)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Rich Felker (Jun 05)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Thomas Gleixner (Jun 05)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) rf (Jun 06)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Greg KH (Jun 06)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) rf (Jun 06)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Greg KH (Jun 06)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) rf (Jun 06)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Solar Designer (Jun 05)
- Re: Linux kernel futex local privilege escalation (CVE-2014-3153) Solar Designer (Jun 05)