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>

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index 95e38d3..f0dea1b 100644 (file)
--- 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 */