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>

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 41f1039..44f2672 100644 (file)
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -212,6 +212,7 @@ extern struct sctp_globals {
        
        /* Flag to indicate if addip is enabled. */
        int addip_enable;
+       int addip_noauth_enable;
 
        /* Flag to indicate if PR-SCTP is enabled. */
        int prsctp_enable;
@@ -249,6 +250,7 @@ extern struct sctp_globals {
 #define sctp_local_addr_list           (sctp_globals.local_addr_list)
 #define sctp_local_addr_lock           (sctp_globals.addr_list_lock)
 #define sctp_addip_enable              (sctp_globals.addip_enable)
+#define sctp_addip_noauth              (sctp_globals.addip_noauth_enable)
 #define sctp_prsctp_enable             (sctp_globals.prsctp_enable)
 #define sctp_auth_enable               (sctp_globals.auth_enable)
 

diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index eaad5c5..013e3d3 100644 (file)
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -262,10 +262,14 @@ static struct sctp_association *sctp_association_init(struct sctp_association *a
         */
        asoc->peer.sack_needed = 1;
 
-       /* Assume that the peer recongizes ASCONF until reported otherwise
-        * via an ERROR chunk.
+       /* Assume that the peer will tell us if he recognizes ASCONF
+        * as part of INIT exchange.
+        * The sctp_addip_noauth option is there for backward compatibilty
+        * and will revert old behavior.
         */
        asoc->peer.asconf_capable = 0;
+       if (sctp_addip_noauth)
+               asoc->peer.asconf_capable = 1;
 
        /* Create an input queue.  */
        sctp_inq_init(&asoc->base.inqueue);

diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 40c1a47..ecfab03 100644 (file)
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1179,6 +1179,7 @@ SCTP_STATIC __init int sctp_init(void)
 
        /* Disable ADDIP by default. */
        sctp_addip_enable = 0;
+       sctp_addip_noauth = 0;
 
        /* Enable PR-SCTP by default. */
        sctp_prsctp_enable = 1;

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 2ff3a3d..43e8de1 100644 (file)
--- 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);

diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 0669778..da4f157 100644 (file)
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -263,6 +263,15 @@ static ctl_table sctp_table[] = {
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec
        },
+       {
+               .ctl_name       = CTL_UNNUMBERED,
+               .procname       = "addip_noauth_enable",
+               .data           = &sctp_addip_noauth,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = &proc_dointvec,
+               .strategy       = &sysctl_intvec
+       },
        { .ctl_name = 0 }
 };