Subject: [PATCH AUTOSEL 4.14 26/28] sxgbe: Fix off by one in samsung driver strncpy size arg

From: Sasha Levin <[email-masked]>
Date: Wed, 18 Mar 2020 16:55:53 -0400

From: Dominik Czarnota <[email-masked]>

[ Upstream commit f3cc008bf6d59b8d93b4190e01d3e557b0040e15 ]

This patch fixes an off-by-one error in strncpy size argument in
drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c. The issue is that in:

        strncmp(opt, "eee_timer:", 6)

the passed string literal: "eee_timer:" has 10 bytes (without the NULL
byte) and the passed size argument is 6. As a result, the logic will
also accept other, malformed strings, e.g. "eee_tiXXX:".

This bug doesn't seem to have any security impact since its present in
module's cmdline parsing code.

Signed-off-by: Dominik Czarnota <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c b/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c
index 89831adb8eb75..6d27eec85fcef 100644
--- a/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c
+++ b/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c
@@ -2284,7 +2284,7 @@ static int __init sxgbe_cmdline_opt(char *str)
 	if (!str || !*str)
 		return -EINVAL;
 	while ((opt = strsep(&str, ",")) != NULL) {
-		if (!strncmp(opt, "eee_timer:", 6)) {
+		if (!strncmp(opt, "eee_timer:", 10)) {
 			if (kstrtoint(opt + 10, 0, &eee_timer))
 				goto err;
 		}
-- 
2.20.1