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| author | Peter Hurley <peter@hurleysoftware.com> | 2015-01-19 13:05:03 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-03-06 14:40:51 -0800 |
| commit | 4324af6a14ad1c0553a35d82a17d2a6066e98b79 (patch) | |
| tree | 39bd777527127c59a5b792e13c6e1ceee2fa3337 | |
| parent | 9d8039b13aea028b16676c28fcac358ec24e7b3b (diff) | |
| download | lwn-4324af6a14ad1c0553a35d82a17d2a6066e98b79.tar.gz lwn-4324af6a14ad1c0553a35d82a17d2a6066e98b79.zip | |
tty: Prevent untrappable signals from malicious program
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>
| -rw-r--r-- | drivers/tty/pty.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index abfd99089781..7cb36813aac2 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -215,6 +215,9 @@ static int pty_signal(struct tty_struct *tty, int sig) 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); |