[PATCH AUTOSEL for 4.4 033/162] caif: Add sockaddr length check before accessing sa_family in connect handler

[Sasha Levin <Alexander.Levin@microsoft.com>]

From: Mateusz Jurczyk <mjurczyk@google.com>

[ Upstream commit 20a3d5bf5e5b13c02450ab6178ec374abd830686 ]

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 <mjurczyk@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 net/caif/caif_socket.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
index aa209b1066c9..bbc80e4e08f5 100644
--- 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;
-- 
2.15.1