netlink: make sure nladdr has correct size in netlink_connect()

KMSAN reports use of uninitialized memory in the case when |alen| is smaller than sizeof(struct sockaddr_nl), and therefore |nladdr| isn't fully copied from the userspace. Signed-off-by: Alexander Potapenko <[email protected]> Fixes: 1da177e ("Linux-2.6.12-rc2") Reviewed-by: Eric Dumazet <[email protected]> Signed-off-by: David S. Miller <[email protected]>
josf · Mar 26, 2018 · 7880287 · 7880287
1 parent e69647a
commit 7880287
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
@@ -1085,6 +1085,9 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr,
 	if (addr->sa_family != AF_NETLINK)
 		return -EINVAL;
 
+	if (alen < sizeof(struct sockaddr_nl))
+		return -EINVAL;
+
 	if ((nladdr->nl_groups || nladdr->nl_pid) &&
 	    !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
 		return -EPERM;