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, 4 insertions, 4 deletions

diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c
index 4a53bb58a463..51f077a92fa9 100644
--- a/net/nfc/llcp_sock.c
+++ b/net/nfc/llcp_sock.c
@@ -769,8 +769,8 @@ static int llcp_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
         lock_sock(sk);
 
         if (sk->sk_type == SOCK_DGRAM) {
-                struct sockaddr_nfc_llcp *addr =
-                        (struct sockaddr_nfc_llcp *)msg->msg_name;
+                DECLARE_SOCKADDR(struct sockaddr_nfc_llcp *, addr,
+                                 msg->msg_name);
 
                 if (msg->msg_namelen < sizeof(*addr)) {
                         release_sock(sk);
@@ -842,8 +842,8 @@ static int llcp_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
 
         if (sk->sk_type == SOCK_DGRAM && msg->msg_name) {
                 struct nfc_llcp_ui_cb *ui_cb = nfc_llcp_ui_skb_cb(skb);
-                struct sockaddr_nfc_llcp *sockaddr =
-                        (struct sockaddr_nfc_llcp *) msg->msg_name;
+                DECLARE_SOCKADDR(struct sockaddr_nfc_llcp *, sockaddr,
+                                 msg->msg_name);
 
                 msg->msg_namelen = sizeof(struct sockaddr_nfc_llcp);