net: sunrpc: Fix an off by one in rpc_sockaddr2uaddr()

[ Upstream commit d6f4de70 ]

The intent is to check if the strings' are truncated or not. So, >= should
be used instead of >, because strlcat() and snprintf() return the length of
the output, excluding the trailing NULL.

Fixes: a02d6926 ("SUNRPC: Provide functions for managing universal addresses")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

net/sunrpc/addr.c

@@ -284,10 +284,10 @@ char *rpc_sockaddr2uaddr(const struct sockaddr *sap, gfp_t gfp_flags)
 	}
 
 	if (snprintf(portbuf, sizeof(portbuf),
-		     ".%u.%u", port >> 8, port & 0xff) > (int)sizeof(portbuf))
+		     ".%u.%u", port >> 8, port & 0xff) >= (int)sizeof(portbuf))
 		return NULL;
 
-	if (strlcat(addrbuf, portbuf, sizeof(addrbuf)) > sizeof(addrbuf))
+	if (strlcat(addrbuf, portbuf, sizeof(addrbuf)) >= sizeof(addrbuf))
 		return NULL;
 
 	return kstrdup(addrbuf, gfp_flags);