net: core: inet[46]_pton strlen len types

inet[46]_pton check the input length against
a sane length limit (INET[6]_ADDRSTRLEN), but
the strlen value gets truncated due to being stored in an int,
so there's a theoretical potential for a >4G string to pass
the limit test.
Use size_t since that's what strlen actually returns.

I've had a hunt for callers that could hit this, but
I've not managed to find anything that doesn't get checked with
some other limit first; but it's possible that I've missed
something in the depth of the storage target paths.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20221029014604.114024-1-linux@treblig.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/utils.c

@@ -302,7 +302,7 @@ static int inet4_pton(const char *src, u16 port_num,
 		struct sockaddr_storage *addr)
 {
 	struct sockaddr_in *addr4 = (struct sockaddr_in *)addr;
-	int srclen = strlen(src);
+	size_t srclen = strlen(src);
 
 	if (srclen > INET_ADDRSTRLEN)
 		return -EINVAL;
@@ -322,7 +322,7 @@ static int inet6_pton(struct net *net, const char *src, u16 port_num,
 {
 	struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)addr;
 	const char *scope_delim;
-	int srclen = strlen(src);
+	size_t srclen = strlen(src);
 
 	if (srclen > INET6_ADDRSTRLEN)
 		return -EINVAL;