char: lp: fix possible integer overflow in lp_setup()
The lp_setup() code doesn't apply any bounds checking when passing
"lp=none", and only in this case, resulting in an overflow of the
parport_nr[] array. All versions in Git history are affected.
Reported-By: Roee Hay <roee.hay@hcl.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/char/lp.c b/drivers/char/lp.c
index 565e4cf..8249762 100644
--- a/drivers/char/lp.c
+++ b/drivers/char/lp.c
@@ -859,7 +859,11 @@ static int __init lp_setup (char *str)
} else if (!strcmp(str, "auto")) {
parport_nr[0] = LP_PARPORT_AUTO;
} else if (!strcmp(str, "none")) {
- parport_nr[parport_ptr++] = LP_PARPORT_NONE;
+ if (parport_ptr < LP_NO)
+ parport_nr[parport_ptr++] = LP_PARPORT_NONE;
+ else
+ printk(KERN_INFO "lp: too many ports, %s ignored.\n",
+ str);
} else if (!strcmp(str, "reset")) {
reset = 1;
}