linux-kernel - [PATCH] tty: Add missing lock in n_tty

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 15 May 2013 12:56:56 +0200
From:	Joerg Roedel <joro@...tes.org>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Jiri Slaby <jslaby@...e.cz>, linux-kernel@...r.kernel.org
Subject: [PATCH] tty: Add missing lock in n_tty_write()

The call of the tty->ops->write callback is protected by
output_lock in all other places I looked at. So it seems the
lock in this code-branch is missing, so take the output_lock
there too.

Cc: stable@...r.kernel.org
Signed-off-by: Joerg Roedel <joro@...tes.org>
---
 drivers/tty/n_tty.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index d655416..ffb94a4 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2058,10 +2058,14 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 			if (tty->ops->flush_chars)
 				tty->ops->flush_chars(tty);
 		} else {
+			struct n_tty_data *l = tty->disc_data;
+
+			mutex_lock(&l->output_lock);
 			while (nr > 0) {
 				c = tty->ops->write(tty, b, nr);
 				if (c < 0) {
 					retval = c;
+					mutex_unlock(&l->output_lock);
 					goto break_out;
 				}
 				if (!c)
@@ -2069,6 +2073,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 				b += c;
 				nr -= c;
 			}
+			mutex_unlock(&l->output_lock);
 		}
 		if (!nr)
 			break;
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/