[SCTP]: Follow Add-IP security consideratiosn wrt INIT/INIT-ACK

The Security Considerations section of RFC 5061 has the following
text:

   If an SCTP endpoint that supports this extension receives an INIT
   that indicates that the peer supports the ASCONF extension but does
   NOT support the [RFC4895] extension, the receiver of such an INIT
   MUST send an ABORT in response.  Note that an implementation is
   allowed to silently discard such an INIT as an option as well, but
   under NO circumstance is an implementation allowed to proceed with
   the association setup by sending an INIT-ACK in response.

   An implementation that receives an INIT-ACK that indicates that the
   peer does not support the [RFC4895] extension MUST NOT send the
   COOKIE-ECHO to establish the association.  Instead, the
   implementation MUST discard the INIT-ACK and report to the upper-
   layer user that an association cannot be established destroying the
   Transmission Control Block (TCB).

Follow the recomendations.

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

1 files changed, 3 insertions, 4 deletions

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 0c9f37eb7d8d..511d8c9a171a 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -507,7 +507,9 @@ sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep,
                               &err_chunk)) {
 
                 /* This chunk contains fatal error. It is to be discarded.
-                 * Send an ABORT, with causes if there is any.
+                 * Send an ABORT, with causes.  If there are no causes,
+                 * then there wasn't enough memory.  Just terminate
+                 * the association.
                  */
                 if (err_chunk) {
                         packet = sctp_abort_pkt_new(ep, asoc, arg,
@@ -526,9 +528,6 @@ sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep,
                         } else {
                                 error = SCTP_ERROR_NO_RESOURCE;
                         }
-                } else {
-                        sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands);
-                        error = SCTP_ERROR_INV_PARAM;
                 }
 
                 /* SCTP-AUTH, Section 6.3: