af_iucv: cleanup and refactor recvmsg() EFAULT handling

If the skb cannot be copied to user iovec, always return -EFAULT.
The skb is enqueued again, except MSG_PEEK flag is set, to allow user space
applications to correct its iovec pointer.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 7 deletions

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index 95e38d3d2d74..f0dea1b8ed4b 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -965,7 +965,6 @@ static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
         int noblock = flags & MSG_DONTWAIT;
         struct sock *sk = sock->sk;
         struct iucv_sock *iucv = iucv_sk(sk);
-        int target;
         unsigned int copied, rlen;
         struct sk_buff *skb, *rskb, *cskb;
         int err = 0;
@@ -979,8 +978,6 @@ static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
         if (flags & (MSG_OOB))
                 return -EOPNOTSUPP;
 
-        target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
-
         skb = skb_recv_datagram(sk, flags, noblock, &err);
         if (!skb) {
                 if (sk->sk_shutdown & RCV_SHUTDOWN)
@@ -993,10 +990,9 @@ static int iucv_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
 
         cskb = skb;
         if (memcpy_toiovec(msg->msg_iov, cskb->data, copied)) {
-                skb_queue_head(&sk->sk_receive_queue, skb);
-                if (copied == 0)
-                        return -EFAULT;
-                goto done;
+                if (!(flags & MSG_PEEK))
+                        skb_queue_head(&sk->sk_receive_queue, skb);
+                return -EFAULT;
         }
 
         /* SOCK_SEQPACKET: set MSG_TRUNC if recv buf size is too small */