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 <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>
diff --git a/drivers/char/moxa.c b/drivers/char/moxa.c
index 65b6ff2..6799588 100644
--- a/drivers/char/moxa.c
+++ b/drivers/char/moxa.c
@@ -1189,6 +1189,11 @@
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 @@
moxa_close_port(tty);
} else
ch->port.flags |= ASYNC_NORMAL_ACTIVE;
+out_unlock:
mutex_unlock(&moxa_openlock);
-
return retval;
}