[PATCH] net: dccp: delete redundant ackvec record in dccp_insert_options()

[Hangyu Hua <hbh25y@gmail.com>]

A useless record can be insert into av_records when dccp_insert_options()
fails after dccp_insert_option_ackvec(). Repeated triggering may cause
av_records to have a lot of useless record with the same avr_ack_seqno.

Fixes: 8b7b6c75c638 ("dccp: Integrate feature-negotiation insertion code")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
---
 net/dccp/options.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/net/dccp/options.c b/net/dccp/options.c
index d24cad05001e..8aa4abeb15ea 100644
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -549,6 +549,8 @@ static void dccp_insert_option_padding(struct sk_buff *skb)
 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
+	struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
+	struct dccp_ackvec_record *avr;
 
 	DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
 
@@ -577,16 +579,22 @@ int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
 
 	if (dp->dccps_hc_rx_insert_options) {
 		if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
-			return -1;
+			goto delete_ackvec;
 		dp->dccps_hc_rx_insert_options = 0;
 	}
 
 	if (dp->dccps_timestamp_echo != 0 &&
 	    dccp_insert_option_timestamp_echo(dp, NULL, skb))
-		return -1;
+		goto delete_ackvec;
 
 	dccp_insert_option_padding(skb);
 	return 0;
+
+delete_ackvec:
+	avr = dccp_ackvec_lookup(&av->av_records, DCCP_SKB_CB(skb)->dccpd_seq);
+	list_del(&avr->avr_node);
+	kmem_cache_free(dccp_ackvec_record_slab, avr);
+	return -1;
 }
 
 int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
-- 
2.34.1