commit 3e21f4af170bebf47c187c1ff8bf155583c9f3b1 upstream.

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 <[email protected]>
Cc: Ben Hutchings <[email protected]>
Signed-off-by: Willy Tarreau <[email protected]>
---
 drivers/char/lp.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/char/lp.c b/drivers/char/lp.c
index 0913d79..6b61910 100644
--- a/drivers/char/lp.c
+++ b/drivers/char/lp.c
@@ -857,7 +857,11 @@ 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;
        }
-- 
2.8.0.rc2.1.gbe9624a

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