From 9ccb645683ef46e3c52c12c088a368baa58447d4 Mon Sep 17 00:00:00 2001

From: Colin Ian King <colin.king@canonical.com>

Date: Sat, 24 Nov 2018 12:34:10 +0000

Subject: [PATCH] altera-stapl: check for a null key before strcasecmp'ing it

Git-commit: 9ccb645683ef46e3c52c12c088a368baa58447d4

Patch-mainline: v5.0-rc1

References: bsc#1051510

Currently the null check on key is occurring after the strcasecmp on

the key, hence there is a potential null pointer dereference on key.

Fix this by checking if key is null first. Also replace the == 0

check on strcasecmp with just the ! operator.

Detected by CoverityScan, CID#1248787 ("Dereference before null check")

Fixes: fa766c9be58b ("[media] Altera FPGA firmware download module")

Signed-off-by: Colin Ian King <colin.king@canonical.com>

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/misc/altera-stapl/altera.c | 3 +--

 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/misc/altera-stapl/altera.c b/drivers/misc/altera-stapl/altera.c

index ef83a9078646..d2ed3b9728b7 100644

--- a/drivers/misc/altera-stapl/altera.c

+++ b/drivers/misc/altera-stapl/altera.c

@@ -2176,8 +2176,7 @@ static int altera_get_note(u8 *p, s32 program_size,

 			key_ptr = &p[note_strings +

 					get_unaligned_be32(

 					&p[note_table + (8 * i)])];

-			if ((strncasecmp(key, key_ptr, strlen(key_ptr)) == 0) &&

-						(key != NULL)) {

+			if (key && !strncasecmp(key, key_ptr, strlen(key_ptr))) {

 				status = 0;

 				value_ptr = &p[note_strings +

-- 

2.16.4