From a90b037583d5f1ae3e54e9c687c79df82d1d34a4 Mon Sep 17 00:00:00 2001 From: Dirk Eibach Date: Thu, 18 Jun 2009 16:49:15 -0700 Subject: [PATCH] char: moxa, prevent opening unavailable ports In moxa.c there are 32 minor numbers reserved for each device. The number of ports actually available per device is stored in moxa_board_conf->numPorts. This number is not considered in moxa_open(). Opening a port that is not available results in a kernel oops. This patch adds a test to moxa_open() that prevents opening unavailable ports. [akpm@linux-foundation.org: avoid multiple returns] Signed-off-by: Dirk Eibach Signed-off-by: Jiri Slaby Cc: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/moxa.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/char/moxa.c b/drivers/char/moxa.c index 65b6ff2442c6..6799588b0099 100644 --- a/drivers/char/moxa.c +++ b/drivers/char/moxa.c @@ -1189,6 +1189,11 @@ static int moxa_open(struct tty_struct *tty, struct file *filp) return -ENODEV; } + if (port % MAX_PORTS_PER_BOARD >= brd->numPorts) { + retval = -ENODEV; + goto out_unlock; + } + ch = &brd->ports[port % MAX_PORTS_PER_BOARD]; ch->port.count++; tty->driver_data = ch; @@ -1213,8 +1218,8 @@ static int moxa_open(struct tty_struct *tty, struct file *filp) moxa_close_port(tty); } else ch->port.flags |= ASYNC_NORMAL_ACTIVE; +out_unlock: mutex_unlock(&moxa_openlock); - return retval; } -- 2.20.1