SCTP: Allow ADD_IP to work with AUTH for backward compatibility.

This patch adds a tunable that will allow ADD_IP to work without
AUTH for backward compatibility.  The default value is off since
the default value for ADD_IP is off as well.  People who need
to use ADD-IP with older implementations take risks of connection
hijacking and should consider upgrading or turning this tunable on.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 2ff3a3df049d..43e8de1228f9 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -2137,8 +2137,10 @@ int sctp_process_init(struct sctp_association *asoc, sctp_cid_t cid,
 
         /* If the peer claims support for ADD-IP without support
          * for AUTH, disable support for ADD-IP.
+         * Do this only if backward compatible mode is turned off.
          */
-        if (asoc->peer.asconf_capable && !asoc->peer.auth_capable) {
+        if (!sctp_addip_noauth &&
+             (asoc->peer.asconf_capable && !asoc->peer.auth_capable)) {
                 asoc->peer.addip_disabled_mask |= (SCTP_PARAM_ADD_IP |
                                                   SCTP_PARAM_DEL_IP |
                                                   SCTP_PARAM_SET_PRIMARY);