kcm: fix 0-length case for kcm_sendmsg()

[linux-beck.git] / net / kcm / kcmsock.c

diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 7e08a4d3d77d0650e9f0c50cd0ab9a8568147f37..64f0e8531af056b822409f234d8806f463c4d5e5 100644 (file)
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -929,23 +929,25 @@ static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
                        goto out_error;
        }
 
-       /* New message, alloc head skb */
-       head = alloc_skb(0, sk->sk_allocation);
-       while (!head) {
-               kcm_push(kcm);
-               err = sk_stream_wait_memory(sk, &timeo);
-               if (err)
-                       goto out_error;
-
+       if (msg_data_left(msg)) {
+               /* New message, alloc head skb */
                head = alloc_skb(0, sk->sk_allocation);
-       }
+               while (!head) {
+                       kcm_push(kcm);
+                       err = sk_stream_wait_memory(sk, &timeo);
+                       if (err)
+                               goto out_error;
 
-       skb = head;
+                       head = alloc_skb(0, sk->sk_allocation);
+               }
 
-       /* Set ip_summed to CHECKSUM_UNNECESSARY to avoid calling
-        * csum_and_copy_from_iter from skb_do_copy_data_nocache.
-        */
-       skb->ip_summed = CHECKSUM_UNNECESSARY;
+               skb = head;
+
+               /* Set ip_summed to CHECKSUM_UNNECESSARY to avoid calling
+                * csum_and_copy_from_iter from skb_do_copy_data_nocache.
+                */
+               skb->ip_summed = CHECKSUM_UNNECESSARY;
+       }
 
 start:
        while (msg_data_left(msg)) {
@@ -1018,10 +1020,12 @@ wait_for_memory:
        if (eor) {
                bool not_busy = skb_queue_empty(&sk->sk_write_queue);
 
-               /* Message complete, queue it on send buffer */
-               __skb_queue_tail(&sk->sk_write_queue, head);
-               kcm->seq_skb = NULL;
-               KCM_STATS_INCR(kcm->stats.tx_msgs);
+               if (head) {
+                       /* Message complete, queue it on send buffer */
+                       __skb_queue_tail(&sk->sk_write_queue, head);
+                       kcm->seq_skb = NULL;
+                       KCM_STATS_INCR(kcm->stats.tx_msgs);
+               }
 
                if (msg->msg_flags & MSG_BATCH) {
                        kcm->tx_wait_more = true;