4 files changed, 100 insertions, 0 deletions

diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index cc71f366d1cd..e8e3a64eb322 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -246,6 +246,9 @@ struct sctp_chunk *sctp_make_asconf_update_ip(struct sctp_association *,
                                               int, __be16);
 struct sctp_chunk *sctp_make_asconf_set_prim(struct sctp_association *asoc,
                                              union sctp_addr *addr);
+int sctp_verify_asconf(const struct sctp_association *asoc,
+                       struct sctp_paramhdr *param_hdr, void *chunk_end,
+                       struct sctp_paramhdr **errp);
 struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,
                                        struct sctp_chunk *asconf);
 int sctp_process_asconf_ack(struct sctp_association *asoc,
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index c2fe2dcc9afc..490a2928817c 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -421,6 +421,7 @@ struct sctp_signed_cookie {
  * internally.
  */
 union sctp_addr_param {
+        struct sctp_paramhdr p;
         struct sctp_ipv4addr_param v4;
         struct sctp_ipv6addr_param v6;
 };
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 2e34220d94cd..23ae37ec8711 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -2499,6 +2499,52 @@ static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
         return SCTP_ERROR_NO_ERROR;
 }
 
+/* Verify the ASCONF packet before we process it.  */
+int sctp_verify_asconf(const struct sctp_association *asoc,
+                       struct sctp_paramhdr *param_hdr, void *chunk_end,
+                       struct sctp_paramhdr **errp) {
+        sctp_addip_param_t *asconf_param;
+        union sctp_params param;
+        int length, plen;
+
+        param.v = (sctp_paramhdr_t *) param_hdr;
+        while (param.v <= chunk_end - sizeof(sctp_paramhdr_t)) {
+                length = ntohs(param.p->length);
+                *errp = param.p;
+
+                if (param.v > chunk_end - length ||
+                    length < sizeof(sctp_paramhdr_t))
+                        return 0;
+
+                switch (param.p->type) {
+                case SCTP_PARAM_ADD_IP:
+                case SCTP_PARAM_DEL_IP:
+                case SCTP_PARAM_SET_PRIMARY:
+                        asconf_param = (sctp_addip_param_t *)param.v;
+                        plen = ntohs(asconf_param->param_hdr.length);
+                        if (plen < sizeof(sctp_addip_param_t) +
+                            sizeof(sctp_paramhdr_t))
+                                return 0;
+                        break;
+                case SCTP_PARAM_SUCCESS_REPORT:
+                case SCTP_PARAM_ADAPTATION_LAYER_IND:
+                        if (length != sizeof(sctp_addip_param_t))
+                                return 0;
+
+                        break;
+                default:
+                        break;
+                }
+
+                param.v += WORD_ROUND(length);
+        }
+
+        if (param.v != chunk_end)
+                return 0;
+
+        return 1;
+}
+
 /* Process an incoming ASCONF chunk with the next expected serial no. and
  * return an ASCONF_ACK chunk to be sent in response.
  */
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index caed19d90d06..a583d67cab63 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -117,6 +117,13 @@ static sctp_disposition_t sctp_sf_violation_chunklen(
                                      void *arg,
                                      sctp_cmd_seq_t *commands);
 
+static sctp_disposition_t sctp_sf_violation_paramlen(
+                                     const struct sctp_endpoint *ep,
+                                     const struct sctp_association *asoc,
+                                     const sctp_subtype_t type,
+                                     void *arg,
+                                     sctp_cmd_seq_t *commands);
+
 static sctp_disposition_t sctp_sf_violation_ctsn(
                                      const struct sctp_endpoint *ep,
                                      const struct sctp_association *asoc,
@@ -3296,8 +3303,11 @@ sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
 {
         struct sctp_chunk       *chunk = arg;
         struct sctp_chunk       *asconf_ack = NULL;
+        struct sctp_paramhdr    *err_param = NULL;
         sctp_addiphdr_t         *hdr;
+        union sctp_addr_param   *addr_param;
         __u32                   serial;
+        int                     length;
 
         if (!sctp_vtag_verify(chunk, asoc)) {
                 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
@@ -3313,6 +3323,20 @@ sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
         hdr = (sctp_addiphdr_t *)chunk->skb->data;
         serial = ntohl(hdr->serial);
 
+        addr_param = (union sctp_addr_param *)hdr->params;
+        length = ntohs(addr_param->p.length);
+        if (length < sizeof(sctp_paramhdr_t))
+                return sctp_sf_violation_paramlen(ep, asoc, type,
+                           (void *)addr_param, commands);
+
+        /* Verify the ASCONF chunk before processing it. */
+        if (!sctp_verify_asconf(asoc,
+            (sctp_paramhdr_t *)((void *)addr_param + length),
+            (void *)chunk->chunk_end,
+            &err_param))
+                return sctp_sf_violation_paramlen(ep, asoc, type,
+                           (void *)&err_param, commands);
+
         /* ADDIP 4.2 C1) Compare the value of the serial number to the value
          * the endpoint stored in a new association variable
          * 'Peer-Serial-Number'.
@@ -3367,6 +3391,7 @@ sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep,
         struct sctp_chunk       *asconf_ack = arg;
         struct sctp_chunk       *last_asconf = asoc->addip_last_asconf;
         struct sctp_chunk       *abort;
+        struct sctp_paramhdr    *err_param = NULL;
         sctp_addiphdr_t         *addip_hdr;
         __u32                   sent_serial, rcvd_serial;
 
@@ -3384,6 +3409,14 @@ sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep,
         addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data;
         rcvd_serial = ntohl(addip_hdr->serial);
 
+        /* Verify the ASCONF-ACK chunk before processing it. */
+        if (!sctp_verify_asconf(asoc,
+            (sctp_paramhdr_t *)addip_hdr->params,
+            (void *)asconf_ack->chunk_end,
+            &err_param))
+                return sctp_sf_violation_paramlen(ep, asoc, type,
+                           (void *)&err_param, commands);
+
         if (last_asconf) {
                 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
                 sent_serial = ntohl(addip_hdr->serial);
@@ -3870,6 +3903,23 @@ static sctp_disposition_t sctp_sf_violation_chunklen(
                                         sizeof(err_str));
 }
 
+/*
+ * Handle a protocol violation when the parameter length is invalid.
+ * "Invalid" length is identified as smaller then the minimal length a
+ * given parameter can be.
+ */
+static sctp_disposition_t sctp_sf_violation_paramlen(
+                                     const struct sctp_endpoint *ep,
+                                     const struct sctp_association *asoc,
+                                     const sctp_subtype_t type,
+                                     void *arg,
+                                     sctp_cmd_seq_t *commands) {
+        char err_str[] = "The following parameter had invalid length:";
+
+        return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
+                                        sizeof(err_str));
+}
+
 /* Handle a protocol violation when the peer trying to advance the
  * cumulative tsn ack to a point beyond the max tsn currently sent.
  *