net: add build-time checks for msg->msg_name size

This is a follow-up patch to f3d3342602f8bc ("net: rework recvmsg
handler msg_name and msg_namelen logic").

DECLARE_SOCKADDR validates that the structure we use for writing the
name information to is not larger than the buffer which is reserved
for msg->msg_name (which is 128 bytes). Also use DECLARE_SOCKADDR
consistently in sendmsg code paths.

Signed-off-by: Steffen Hurrle <steffen@hurrle.net>
Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/can/raw.c b/net/can/raw.c
index 641e1c895123..07d72d852324 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -675,8 +675,7 @@ static int raw_sendmsg(struct kiocb *iocb, struct socket *sock,
         int err;
 
         if (msg->msg_name) {
-                struct sockaddr_can *addr =
-                        (struct sockaddr_can *)msg->msg_name;
+                DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
 
                 if (msg->msg_namelen < sizeof(*addr))
                         return -EINVAL;
@@ -775,6 +774,7 @@ static int raw_recvmsg(struct kiocb *iocb, struct socket *sock,
         sock_recv_ts_and_drops(msg, sk, skb);
 
         if (msg->msg_name) {
+                __sockaddr_check_size(sizeof(struct sockaddr_can));
                 msg->msg_namelen = sizeof(struct sockaddr_can);
                 memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
         }