linux-kernel - [tip:core/urgent] futexes: Fix infinite loop in get_futex

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: <tip-7c8fa4f04ab956076605422d5ed37410893a8a73@git.kernel.org>
Date:	Sat, 11 Jul 2009 08:22:00 GMT
From:	tip-bot for Sonny Rao <sonnyrao@...ibm.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
	sonnyrao@...ibm.com, tglx@...utronix.de, mingo@...e.hu
Subject: [tip:core/urgent] futexes: Fix infinite loop in get_futex_key() on huge page

Commit-ID:  7c8fa4f04ab956076605422d5ed37410893a8a73
Gitweb:     http://git.kernel.org/tip/7c8fa4f04ab956076605422d5ed37410893a8a73
Author:     Sonny Rao <sonnyrao@...ibm.com>
AuthorDate: Fri, 10 Jul 2009 18:13:13 -0500
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Sat, 11 Jul 2009 10:18:45 +0200

futexes: Fix infinite loop in get_futex_key() on huge page

get_futex_key() can infinitely loop if it is called on a
virtual address that is within a huge page but not aligned to
the beginning of that page.  The call to get_user_pages_fast
will return the struct page for a sub-page within the huge page
and the check for page->mapping will always fail.

The fix is to call compound_head on the page before checking
that it's mapped.

Signed-off-by: Sonny Rao <sonnyrao@...ibm.com>
Cc: stable@...nel.org
Cc: anton@...ba.org
Cc: rajamony@...ibm.com
Cc: speight@...ibm.com
Cc: mstephen@...ibm.com
Cc: grimm@...ibm.com
Cc: mikey@...abs.au.ibm.com
LKML-Reference: <20090710231313.GA23572@...ibm.com>
Signed-off-by: Ingo Molnar <mingo@...e.hu>


---
 kernel/futex.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index 794c862..0672ff8 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -247,6 +247,7 @@ again:
 	if (err < 0)
 		return err;
 
+	page = compound_head(page);
 	lock_page(page);
 	if (!page->mapping) {
 		unlock_page(page);
--
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/