USB: microtek: fix info-leak at probe

Add missing bulk-in endpoint sanity check to prevent uninitialised stack
data from being reported to the system log and used as endpoint
addresses.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>
Reported-by: syzbot+5630ca7c3b2be5c9da5e@syzkaller.appspotmail.com
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20191003070931.17009-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/image/microtek.c b/drivers/usb/image/microtek.c
index 0a57c2cc8e5af2ae7dd5e0b3c9a3c0e5191788a3..7a6b122c833fbeaece8a02782ab26581c6480f2f 100644 (file)
--- a/drivers/usb/image/microtek.c
+++ b/drivers/usb/image/microtek.c
@@ -716,6 +716,10 @@ static int mts_usb_probe(struct usb_interface *intf,
 
        }
 
+       if (ep_in_current != &ep_in_set[2]) {
+               MTS_WARNING("couldn't find two input bulk endpoints. Bailing out.\n");
+               return -ENODEV;
+       }
 
        if ( ep_out == -1 ) {
                MTS_WARNING( "couldn't find an output bulk endpoint. Bailing out.\n" );