Peter Hurley wrote:
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 <[email protected]>
Cc: Howard Chu <[email protected]>
Cc: One Thousand Gnomes <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: <[email protected]> # 2.6.36+
Signed-off-by: Peter Hurley <[email protected]>
---
drivers/tty/pty.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index a9d256d..46366f0 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;
This patch is clearly wrong, should be && not || in the test.
+
if (tty->link) {
pgrp = tty_get_pgrp(tty->link);
if (pgrp)
--
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/
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