caif: Add sockaddr length check before accessing sa_family in connect handler

j00ru · davem330 · commit 20a3d5bf5e5b · 2017-06-13T16:16:11.000-04:00
Verify that the caller-provided sockaddr structure is large enough to
contain the sa_family field, before accessing it in the connect()
handler of the AF_CAIF socket. Since the syscall doesn't enforce a minimum
size of the corresponding memory region, very short sockaddrs (zero or one
byte long) result in operating on uninitialized memory while referencing
sa_family.

Signed-off-by: Mateusz Jurczyk &lt;mjurczyk@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
@@ -754,6 +754,10 @@ static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
 
 	lock_sock(sk);
 
+	err = -EINVAL;
+	if (addr_len < offsetofend(struct sockaddr, sa_family))
+		goto out;
+
 	err = -EAFNOSUPPORT;
 	if (uaddr->sa_family != AF_CAIF)
 		goto out;
