[PATCH net v4 1/2] sctp: distinguish sequence zero from wildcard in reconf lookup

[Jun Yang <juny24602@gmail.com>]

From: Jun Yang <junvyyang@tencent.com>

Zero is a valid response sequence after strreset_outseq wraps, but
sctp_chunk_lookup_strreset_param() currently treats it as a wildcard.

Add match_seq so response lookups match zero exactly while the one
type-only lookup can still ignore the sequence.

Fixes: 50a41591f110 ("sctp: implement receiver-side procedures for the Add Outgoing Streams Request Parameter")
Cc: stable@kernel.org
Suggested-by: Simon Horman <horms@kernel.org>
Acked-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Jun Yang <junvyyang@tencent.com>
---
 net/sctp/stream.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/net/sctp/stream.c b/net/sctp/stream.c
index 34ffe6c945a4..cfca5aa28c1a 100644
--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -482,7 +482,7 @@ int sctp_send_add_streams(struct sctp_association *asoc,
 
 static struct sctp_paramhdr *sctp_chunk_lookup_strreset_param(
 			struct sctp_association *asoc, __be32 resp_seq,
-			__be16 type)
+			__be16 type, bool match_seq)
 {
 	struct sctp_chunk *chunk = asoc->strreset_chunk;
 	struct sctp_reconf_chunk *hdr;
@@ -499,7 +499,7 @@ static struct sctp_paramhdr *sctp_chunk_lookup_strreset_param(
 		 */
 		struct sctp_strreset_tsnreq *req = param.v;
 
-		if ((!resp_seq || req->request_seq == resp_seq) &&
+		if ((!match_seq || req->request_seq == resp_seq) &&
 		    (!type || type == req->param_hdr.type))
 			return param.v;
 	}
@@ -564,7 +564,7 @@ struct sctp_chunk *sctp_process_strreset_outreq(
 	if (asoc->strreset_chunk) {
 		if (!sctp_chunk_lookup_strreset_param(
 				asoc, outreq->response_seq,
-				SCTP_PARAM_RESET_IN_REQUEST)) {
+				SCTP_PARAM_RESET_IN_REQUEST, true)) {
 			/* same process with outstanding isn't 0 */
 			result = SCTP_STRRESET_ERR_IN_PROGRESS;
 			goto out;
@@ -816,7 +816,7 @@ struct sctp_chunk *sctp_process_strreset_addstrm_out(
 
 	if (asoc->strreset_chunk) {
 		if (!sctp_chunk_lookup_strreset_param(
-			asoc, 0, SCTP_PARAM_RESET_ADD_IN_STREAMS)) {
+			asoc, 0, SCTP_PARAM_RESET_ADD_IN_STREAMS, false)) {
 			/* same process with outstanding isn't 0 */
 			result = SCTP_STRRESET_ERR_IN_PROGRESS;
 			goto out;
@@ -927,7 +927,8 @@ struct sctp_chunk *sctp_process_strreset_resp(
 	struct sctp_paramhdr *req;
 	__u32 result;
 
-	req = sctp_chunk_lookup_strreset_param(asoc, resp->response_seq, 0);
+	req = sctp_chunk_lookup_strreset_param(asoc, resp->response_seq, 0,
+					       true);
 	if (!req)
 		return NULL;
 
-- 
2.55.0