[patch 026/108] char: moxa, prevent opening unavailable ports

Greg KH
2009-07-01T00:53:55Z

[-- Attachment #1: char-moxa-prevent-opening-unavailable-ports.patch --]
[-- Type: text/plain, Size: 1532 bytes --]

2.6.30-stable review patch. If anyone has any objections, please let us know.

------------------

From: Dirk Eibach <eibach@gdsys.de>

commit a90b037583d5f1ae3e54e9c687c79df82d1d34a4 upstream.

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 <eibach@gdsys.de>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/char/moxa.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/char/moxa.c
+++ b/drivers/char/moxa.c
@@ -1184,6 +1184,11 @@ static int moxa_open(struct tty_struct *
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;
@@ -1208,8 +1213,8 @@ static int moxa_open(struct tty_struct *
moxa_close_port(tty);
} else
ch->port.flags |= ASYNC_NORMAL_ACTIVE;
+out_unlock:
mutex_unlock(&moxa_openlock);
-
return retval;
}