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, 1 insertions, 3 deletions

diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index 687360da62d9..9bb63ffec4f2 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -1779,10 +1779,8 @@ static int vmci_transport_dgram_dequeue(struct kiocb *kiocb,
                 goto out;
 
         if (msg->msg_name) {
-                struct sockaddr_vm *vm_addr;
-
                 /* Provide the address of the sender. */
-                vm_addr = (struct sockaddr_vm *)msg->msg_name;
+                DECLARE_SOCKADDR(struct sockaddr_vm *, vm_addr, msg->msg_name);
                 vsock_addr_init(vm_addr, dg->src.context, dg->src.resource);
                 msg->msg_namelen = sizeof(*vm_addr);
         }