linux-kernel - [05/29] tty: fix race in tty

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: <20100123001110.875409458@mini.kroah.org>
Date:	Fri, 22 Jan 2010 16:09:49 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Al Viro <viro@...IV.linux.org.uk>,
	Tavis Ormandy <taviso@...gle.com>,
	Jeff Dike <jdike@...toit.com>, Julien Tinnes <jln@...gle.com>,
	Matt Mackall <mpm@...enic.com>
Subject: [05/29] tty: fix race in tty_fasync

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Greg Kroah-Hartman <gregkh@...e.de>

commit 703625118069f9f8960d356676662d3db5a9d116 upstream.

We need to keep the lock held over the call to __f_setown() to
prevent a PID race.

Thanks to Al Viro for pointing out the problem, and to Travis for
making us look here in the first place.

Cc: Eric W. Biederman <ebiederm@...ssion.com>
Cc: Al Viro <viro@...IV.linux.org.uk>
Cc: Alan Cox <alan@...rguk.ukuu.org.uk>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Tavis Ormandy <taviso@...gle.com>
Cc: Jeff Dike <jdike@...toit.com>
Cc: Julien Tinnes <jln@...gle.com>
Cc: Matt Mackall <mpm@...enic.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/char/tty_io.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1930,8 +1930,8 @@ static int tty_fasync(int fd, struct fil
 			pid = task_pid(current);
 			type = PIDTYPE_PID;
 		}
-		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 		retval = __f_setown(filp, pid, type, 0);
+		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 		if (retval)
 			goto out;
 	} else {

--
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/