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/netrom/af_netrom.c b/net/netrom/af_netrom.c
index 53c19a35fc6d..b74aa0755521 100644
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -1028,7 +1028,7 @@ static int nr_sendmsg(struct kiocb *iocb, struct socket *sock,
 {
         struct sock *sk = sock->sk;
         struct nr_sock *nr = nr_sk(sk);
-        struct sockaddr_ax25 *usax = (struct sockaddr_ax25 *)msg->msg_name;
+        DECLARE_SOCKADDR(struct sockaddr_ax25 *, usax, msg->msg_name);
         int err;
         struct sockaddr_ax25 sax;
         struct sk_buff *skb;
@@ -1137,7 +1137,7 @@ static int nr_recvmsg(struct kiocb *iocb, struct socket *sock,
                       struct msghdr *msg, size_t size, int flags)
 {
         struct sock *sk = sock->sk;
-        struct sockaddr_ax25 *sax = (struct sockaddr_ax25 *)msg->msg_name;
+        DECLARE_SOCKADDR(struct sockaddr_ax25 *, sax, msg->msg_name);
         size_t copied;
         struct sk_buff *skb;
         int er;