ax25: zero length frame filtering in AX25
In previous commit 244f46ae6e9e18f6fc0be7d1f49febde4762c34b
was introduced a zero length frame filter for ROSE protocole.
This patch has the same purpose at AX25 frame level for the same
reason. Empty frames have no meaning in AX25 protocole.
Signed-off-by: Bernard Pidoux <f6bvp@amsat.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index fd9d06f..7da5ebb 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -1435,6 +1435,11 @@
size_t size;
int lv, err, addr_len = msg->msg_namelen;
+ /* AX.25 empty data frame has no meaning : don't send */
+ if (len == 0) {
+ return (0);
+ }
+
if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_CMSG_COMPAT))
return -EINVAL;
@@ -1634,6 +1639,13 @@
skb_reset_transport_header(skb);
copied = skb->len;
+ /* AX.25 empty data frame has no meaning : ignore it */
+ if (copied == 0) {
+ err = copied;
+ skb_free_datagram(sk, skb);
+ goto out;
+ }
+
if (copied > size) {
copied = size;
msg->msg_flags |= MSG_TRUNC;