netdev - [PATCH net 1/6] net: fool proof dev_valid

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Message-Id: <20180405133931.207634-2-edumazet@google.com>
Date:   Thu,  5 Apr 2018 06:39:26 -0700
From:   Eric Dumazet <edumazet@...gle.com>
To:     "David S . Miller" <davem@...emloft.net>
Cc:     netdev <netdev@...r.kernel.org>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: [PATCH net 1/6] net: fool proof dev_valid_name()

We want to use dev_valid_name() to validate tunnel names,
so better use strnlen(name, IFNAMSIZ) than strlen(name) to make
sure to not upset KASAN.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/core/dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 9b04a9fd1dfd0e065a7fe798dd840a07f0e0a4df..969462ebb296250fe5f3b7c4621e9ba9720a2dbe 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1027,7 +1027,7 @@ bool dev_valid_name(const char *name)
 {
 	if (*name == '\0')
 		return false;
-	if (strlen(name) >= IFNAMSIZ)
+	if (strnlen(name, IFNAMSIZ) == IFNAMSIZ)
 		return false;
 	if (!strcmp(name, ".") || !strcmp(name, ".."))
 		return false;
-- 
2.17.0.484.g0c8726318c-goog