[SCTP]: Add check for hmac_algo parameter in sctp_verify_param()
Wei Yongjun [Sun, 13 Apr 2008 01:39:19 +0000 (18:39 -0700)]
RFC 4890 has the following text:

  The HMAC algorithm based on SHA-1 MUST be supported and
  included in the HMAC-ALGO parameter.

As a result, we need to check in sctp_verify_param() that HMAC_SHA1 is
present in the list.  If not, we should probably treat this as a
protocol violation.

It should also be a protocol violation if the HMAC parameter is empty.

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

net/sctp/sm_make_chunk.c

index 578630e..36ebb39 100644 (file)
@@ -1982,7 +1982,10 @@ static sctp_ierror_t sctp_verify_param(const struct sctp_association *asoc,
                                        struct sctp_chunk *chunk,
                                        struct sctp_chunk **err_chunk)
 {
+       struct sctp_hmac_algo_param *hmacs;
        int retval = SCTP_IERROR_NO_ERROR;
+       __u16 n_elt, id = 0;
+       int i;
 
        /* FIXME - This routine is not looking at each parameter per the
         * chunk type, i.e., unrecognized parameters should be further
@@ -2056,9 +2059,29 @@ static sctp_ierror_t sctp_verify_param(const struct sctp_association *asoc,
                break;
 
        case SCTP_PARAM_HMAC_ALGO:
-               if (sctp_auth_enable)
-                       break;
-               /* Fall Through */
+               if (!sctp_auth_enable)
+                       goto fallthrough;
+
+               hmacs = (struct sctp_hmac_algo_param *)param.p;
+               n_elt = (ntohs(param.p->length) - sizeof(sctp_paramhdr_t)) >> 1;
+
+               /* SCTP-AUTH: Section 6.1
+                * The HMAC algorithm based on SHA-1 MUST be supported and
+                * included in the HMAC-ALGO parameter.
+                */
+               for (i = 0; i < n_elt; i++) {
+                       id = ntohs(hmacs->hmac_ids[i]);
+
+                       if (id == SCTP_AUTH_HMAC_ID_SHA1)
+                               break;
+               }
+
+               if (id != SCTP_AUTH_HMAC_ID_SHA1) {
+                       sctp_process_inv_paramlength(asoc, param.p, chunk,
+                                                    err_chunk);
+                       retval = SCTP_IERROR_ABORT;
+               }
+               break;
 fallthrough:
        default:
                SCTP_DEBUG_PRINTK("Unrecognized param: %d for chunk %d.\n",