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authorPeter Hurley <peter@hurleysoftware.com>2015-01-19 21:05:03 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-02-02 21:09:54 +0300
commit37480a05685ed5b8e1b9bf5e5c53b5810258b149 (patch)
tree9a754bf217c5609849d1a8a43bc28b52471b1bf6
parent19e3ae6b4f07a87822c1c9e7ed99d31860e701af (diff)
downloadlinux-37480a05685ed5b8e1b9bf5e5c53b5810258b149.tar.xz
tty: Prevent untrappable signals from malicious program
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@mit.edu> Cc: Howard Chu <hyc@symas.com> Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> Cc: Jiri Slaby <jslaby@suse.cz> Cc: <stable@vger.kernel.org> # 2.6.36+ Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/tty/pty.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index a9d256d6e909..6e1f1505f04e 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -210,6 +210,9 @@ static int pty_signal(struct tty_struct *tty, int sig)
{
struct pid *pgrp;
+ if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP)
+ return -EINVAL;
+
if (tty->link) {
pgrp = tty_get_pgrp(tty->link);
if (pgrp)