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/llc/af_llc.c b/net/llc/af_llc.c
index c71b699eb555..0080d2b0a8ae 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -707,7 +707,7 @@ out:
 static int llc_ui_recvmsg(struct kiocb *iocb, struct socket *sock,
                           struct msghdr *msg, size_t len, int flags)
 {
-        struct sockaddr_llc *uaddr = (struct sockaddr_llc *)msg->msg_name;
+        DECLARE_SOCKADDR(struct sockaddr_llc *, uaddr, msg->msg_name);
         const int nonblock = flags & MSG_DONTWAIT;
         struct sk_buff *skb = NULL;
         struct sock *sk = sock->sk;
@@ -884,7 +884,7 @@ static int llc_ui_sendmsg(struct kiocb *iocb, struct socket *sock,
 {
         struct sock *sk = sock->sk;
         struct llc_sock *llc = llc_sk(sk);
-        struct sockaddr_llc *addr = (struct sockaddr_llc *)msg->msg_name;
+        DECLARE_SOCKADDR(struct sockaddr_llc *, addr, msg->msg_name);
         int flags = msg->msg_flags;
         int noblock = flags & MSG_DONTWAIT;
         struct sk_buff *skb;