source: trunk/server/common/patches/cve-2014-3153-1.patch @ 2581

Last change on this file since 2581 was 2557, checked in by achernya, 10 years ago
Kernel patches against cve-2014-3153 (old, uncommitted changes)
File size: 2.6 KB

  • kernel/futex.c 

    From b58623fb64ff0454ec20bce7a02275a20c23086d Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 3 Jun 2014 12:27:06 +0000
Subject: [PATCH 1/4] futex-prevent-requeue-pi-on-same-futex.patch futex:
 Forbid uaddr == uaddr2 in futex_requeue(...,
 requeue_pi=1)

commit e9c243a5a6de0be8e584c604d353412584b592f8 upstream.

If uaddr == uaddr2, then we have broken the rule of only requeueing from
a non-pi futex to a pi futex with this call.  If we attempt this, then
dangling pointers may be left for rt_waiter resulting in an exploitable
condition.

This change brings futex_requeue() in line with futex_wait_requeue_pi()
which performs the same check as per commit 6f7b0a2a5c0f ("futex: Forbid
uaddr == uaddr2 in futex_wait_requeue_pi()")

[ tglx: Compare the resulting keys as well, as uaddrs might be
  	different depending on the mapping ]

Fixes CVE-2014-3153.

Reported-by: Pinkie Pie
Signed-off-by: Will Drewry <wad@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/futex.c |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/kernel/futex.c b/kernel/futex.c
index 58743c0..93e522f 100644
    a b static int futex_requeue(u32 __user *uaddr1, unsigned int flags, 
    12931293
    12941294        if (requeue_pi) {
    12951295                /*
     1296                 * Requeue PI only works on two distinct uaddrs. This
     1297                 * check is only valid for private futexes. See below.
     1298                 */
     1299                if (uaddr1 == uaddr2)
     1300                        return -EINVAL;
     1301
     1302                /*
    12961303                 * requeue_pi requires a pi_state, try to allocate it now
    12971304                 * without any locks in case it fails.
    12981305                 */
    … … retry: 
    13301337        if (unlikely(ret != 0))
    13311338                goto out_put_key1;
    13321339
     1340        /*
     1341         * The check above which compares uaddrs is not sufficient for
     1342         * shared futexes. We need to compare the keys:
     1343         */
     1344        if (requeue_pi && match_futex(&key1, &key2)) {
     1345                ret = -EINVAL;
     1346                goto out_put_keys;
     1347        }
     1348
    13331349        hb1 = hash_futex(&key1);
    13341350        hb2 = hash_futex(&key2);
    13351351
    … … static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, 
    23602376        if (ret)
    23612377                goto out_key2;
    23622378
     2379        /*
     2380         * The check above which compares uaddrs is not sufficient for
     2381         * shared futexes. We need to compare the keys:
     2382         */
     2383        if (match_futex(&q.key, &key2)) {
     2384                ret = -EINVAL;
     2385                goto out_put_keys;
     2386        }
     2387
    23632388        /* Queue the futex_q, drop the hb lock, wait for wakeup. */
    23642389        futex_wait_queue_me(hb, &q, to);
    23652390
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