This is a note to let you know that I've just added the patch titled
tty: Prevent untrappable signals from malicious program
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tty-prevent-untrappable-signals-from-malicious-program.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 37480a05685ed5b8e1b9bf5e5c53b5810258b149 Mon Sep 17 00:00:00 2001
From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Date: Mon, 19 Jan 2015 13:05:03 -0500
Subject: tty: Prevent untrappable signals from malicious program
From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
commit 37480a05685ed5b8e1b9bf5e5c53b5810258b149 upstream.
Commit 26df6d13406d1a5 ("tty: Add EXTPROC support for LINEMODE")
allows a process which has opened a pty master to send _any_ signal
to the process group of the pty slave. Although potentially
exploitable by a malicious program running a setuid program on
a pty slave, it's unknown if this exploit currently exists.
Limit to signals actually used.
Cc: Theodore Ts'o <tytso@xxxxxxx>
Cc: Howard Chu <hyc@xxxxxxxxx>
Cc: One Thousand Gnomes <gnomes@xxxxxxxxxxxxxxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxx>
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/pty.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -210,6 +210,9 @@ static int pty_signal(struct tty_struct
unsigned long flags;
struct pid *pgrp;
+ if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP)
+ return -EINVAL;
+
if (tty->link) {
spin_lock_irqsave(&tty->link->ctrl_lock, flags);
pgrp = get_pid(tty->link->pgrp);
Patches currently in stable-queue which might be from peter@xxxxxxxxxxxxxxxxxx are
queue-3.18/tty-prevent-untrappable-signals-from-malicious-program.patch
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