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/ipv4/raw.c b/net/ipv4/raw.c
index 81e6cfd5a365..c04518f4850a 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -493,7 +493,7 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
          */
 
         if (msg->msg_namelen) {
-                struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
+                DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
                 err = -EINVAL;
                 if (msg->msg_namelen < sizeof(*usin))
                         goto out;
@@ -690,7 +690,7 @@ static int raw_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
         struct inet_sock *inet = inet_sk(sk);
         size_t copied = 0;
         int err = -EOPNOTSUPP;
-        struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
+        DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
         struct sk_buff *skb;
 
         if (flags & MSG_OOB)