From f99bcff7a290768e035f3d4726e103c6ebe858bf Mon Sep 17 00:00:00 2001 From: Bernard Pidoux Date: Sat, 21 Mar 2009 13:33:55 -0700 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/ax25/af_ax25.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c index fd9d06f291d..7da5ebb84e9 100644 --- a/net/ax25/af_ax25.c +++ b/net/ax25/af_ax25.c @@ -1435,6 +1435,11 @@ static int ax25_sendmsg(struct kiocb *iocb, struct socket *sock, 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 @@ static int ax25_recvmsg(struct kiocb *iocb, struct socket *sock, 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; -- 2.41.1