| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.19 113/175] tty: Prevent untrappable signals from malicious program | Date | Tue, 3 Mar 2015 22:14:51 -0800 |
| |
3.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Peter Hurley <peter@hurleysoftware.com>
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@mit.edu> Cc: Howard Chu <hyc@symas.com> Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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 { struct pid *pgrp; + if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP) + return -EINVAL; + if (tty->link) { pgrp = tty_get_pgrp(tty->link); if (pgrp)
|