From: Eric Dumazet <edumazet@google.com>
Date: Thu, 5 Apr 2018 13:39:26 +0000 (-0700)
Subject: net: fool proof dev_valid_name()
X-Git-Tag: v4.1.52~158
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1b4c07610f2a870a2e75623fef2caba39ee5b47d;p=thirdparty%2Fkernel%2Fstable.git

net: fool proof dev_valid_name()

[ Upstream commit a9d48205d0aedda021fc3728972a9e9934c2b9de ]

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@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---

diff --git a/net/core/dev.c b/net/core/dev.c
index cea0934ea7d1e..331101e71c283 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -957,7 +957,7 @@ 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;