[SCTP]: Fix protocol violation when receiving an error lenght INIT-ACK

When receiving an error length INIT-ACK during COOKIE-WAIT,
a 0-vtag ABORT will be responsed. This action violates the
protocol apparently. This patch achieves the following things.
1 If the INIT-ACK contains all the fixed parameters, use init-tag
  recorded from INIT-ACK as vtag.
2 If the INIT-ACK doesn't contain all the fixed parameters,
  just reflect its vtag.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 1bb3c5c35d2a..c0714469233c 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -793,6 +793,9 @@ int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
                         break;
 
                 case SCTP_CID_ABORT:
+                        if (sctp_test_T_bit(chunk)) {
+                                packet->vtag = asoc->c.my_vtag;
+                        }
                 case SCTP_CID_SACK:
                 case SCTP_CID_HEARTBEAT:
                 case SCTP_CID_HEARTBEAT_ACK: