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 cea0934ea7d1ec422323c9d6a881b01e1618f08e..331101e71c283767b9f9a3b4c135f4dd979a567a 100644 (file)
--- 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;