RFC 9260, Sec 8.5.1 states that for ABORT/SHUTDOWN_COMPLETE, the chunk
MUST be accepted if the vtag of the packet matches its own tag and the
T bit is not set OR if it is set to its peer's vtag and the T bit is set
in chunk flags. Otherwise the packet MUST be silently dropped.
Update vtag verification for ABORT/SHUTDOWN_COMPLETE based on the above
description.
Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.")
Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@xxxxxxxx>
---
net/netfilter/nf_conntrack_proto_sctp.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c
index d88b92a8ffca..2b2c549ba678 100644
--- a/net/netfilter/nf_conntrack_proto_sctp.c
+++ b/net/netfilter/nf_conntrack_proto_sctp.c
@@ -424,22 +424,29 @@ int nf_conntrack_sctp_packet(struct nf_conn *ct,
for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
/* Special cases of Verification tag check (Sec 8.5.1) */
if (sch->type == SCTP_CID_INIT) {
- /* Sec 8.5.1 (A) */
+ /* (A) vtag MUST be zero */
if (sh->vtag != 0)
goto out_unlock;
} else if (sch->type == SCTP_CID_ABORT) {
- /* Sec 8.5.1 (B) */
- if (sh->vtag != ct->proto.sctp.vtag[dir] &&
- sh->vtag != ct->proto.sctp.vtag[!dir])
+ /* (B) vtag MUST match own vtag if T flag is unset OR
+ * MUST match peer's vtag if T flag is set
+ */
+ if ((!(sch->flags & SCTP_CHUNK_FLAG_T) &&
+ sh->vtag != ct->proto.sctp.vtag[dir]) ||
+ ((sch->flags & SCTP_CHUNK_FLAG_T) &&
+ sh->vtag != ct->proto.sctp.vtag[!dir]))
goto out_unlock;
} else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
- /* Sec 8.5.1 (C) */
- if (sh->vtag != ct->proto.sctp.vtag[dir] &&
- sh->vtag != ct->proto.sctp.vtag[!dir] &&
- sch->flags & SCTP_CHUNK_FLAG_T)
+ /* (C) vtag MUST match own vtag if T flag is unset OR
+ * MUST match peer's vtag if T flag is set
+ */
+ if ((!(sch->flags & SCTP_CHUNK_FLAG_T) &&
+ sh->vtag != ct->proto.sctp.vtag[dir]) ||
+ ((sch->flags & SCTP_CHUNK_FLAG_T) &&
+ sh->vtag != ct->proto.sctp.vtag[!dir]))
goto out_unlock;
} else if (sch->type == SCTP_CID_COOKIE_ECHO) {
- /* Sec 8.5.1 (D) */
+ /* (D) vtag must be same as init_vtag as found in INIT_ACK */
if (sh->vtag != ct->proto.sctp.vtag[dir])
goto out_unlock;
} else if (sch->type == SCTP_CID_HEARTBEAT) {
--
2.34.1
