From: Oleg Nesterov <oleg@tv-sign.ru>
Date: Fri, 1 Jun 2007 07:46:53 +0000 (-0700)
Subject: [PATCH] tty: fix leakage of -ERESTARTSYS to userland
X-Git-Tag: v2.6.21.5~28
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=36323d56d52a634758f1288b8a92653b5e6bc1fa;p=thirdparty%2Fkernel%2Fstable.git

[PATCH] tty: fix leakage of -ERESTARTSYS to userland

Spotted by Satoru Takeuchi.

kill_pgrp(task_pgrp(current)) sends the signal to the current's thread
group, but can choose any sub-thread as a target for signal_wake_up().
This means that job_control() and tty_check_change() may return
-ERESTARTSYS without signal_pending().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index 6ac3ca4c723c2..5a6c649bc9933 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -1191,6 +1191,7 @@ static int job_control(struct tty_struct *tty, struct file *file)
 			    is_current_pgrp_orphaned())
 				return -EIO;
 			kill_pgrp(task_pgrp(current), SIGTTIN, 1);
+			set_thread_flag(TIF_SIGPENDING);
 			return -ERESTARTSYS;
 		}
 	}
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 7a32df5949075..2000120f9ecc8 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1121,7 +1121,8 @@ int tty_check_change(struct tty_struct * tty)
 		return 0;
 	if (is_current_pgrp_orphaned())
 		return -EIO;
-	(void) kill_pgrp(task_pgrp(current), SIGTTOU, 1);
+	kill_pgrp(task_pgrp(current), SIGTTOU, 1);
+	set_thread_flag(TIF_SIGPENDING);
 	return -ERESTARTSYS;
 }