From: Shuah Khan <shuah@kernel.org>
To: marcel@holtmann.org, johan.hedberg@gmail.com, johan@kernel.org,
viro@zeniv.linux.org.uk
Cc: Shuah Khan <shuah@kernel.org>,
linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v4] bluetooth: Fix WARNING in tty_set_termios()
Date: Sun, 3 Feb 2019 12:38:48 -0700 [thread overview]
Message-ID: <20190203193848.12959-1-shuah@kernel.org> (raw)
tty_set_termios() has the following WARN_ON which can be triggered with a
syscall to invoke TIOCSETD __NR_ioctl.
WARN_ON(tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_MASTER);
Reference: https://syzkaller.appspot.com/bug?id=2410d22f1d8e5984217329dd0884b01d99e3e48d
"The problem started with commit 7721383f4199 ("Bluetooth: hci_uart: Support
operational speed during setup") which introduced a new way for how
tty_set_termios() could end up being called for a master pty."
Fix it by by preventing setting the HCI line discipline for PTYs in
hci_uart_tty_open().
Reported-by: syzbot+a950165cbb86bdd023a4@syzkaller.appspotmail.com
Cc: Johan Hovold <johan@kernel.org>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Shuah Khan <shuah@kernel.org>
---
drivers/bluetooth/hci_ldisc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index fbf7b4df23ab..c8faa4759cb7 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -475,9 +475,9 @@ static int hci_uart_tty_open(struct tty_struct *tty)
BT_DBG("tty %p", tty);
/* Error if the tty has no write op instead of leaving an exploitable
- * hole
+ * hole. In addition check if setting HCI line discipline is allowed.
*/
- if (tty->ops->write == NULL)
+ if (tty->ops->write == NULL || tty->ops->set_termios == NULL)
return -EOPNOTSUPP;
hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL);
--
2.17.1
next reply other threads:[~2019-02-03 19:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-03 19:38 Shuah Khan [this message]
2019-02-04 5:39 ` [PATCH v4] bluetooth: Fix WARNING in tty_set_termios() Marcel Holtmann
2019-02-04 18:44 ` shuah
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190203193848.12959-1-shuah@kernel.org \
--to=shuah@kernel.org \
--cc=johan.hedberg@gmail.com \
--cc=johan@kernel.org \
--cc=linux-bluetooth@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=marcel@holtmann.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).