Function sctp_validate_init_auth_params

freebsd/netinet/sctp_auth.c:1771–1912

- * validates the AUTHentication related parameters in an INIT/INIT-ACK * Note: currently only used for INIT as INIT-ACK is handled inline * with sctp_load_addresses_from_init() */

 * with sctp_load_addresses_from_init()
 */
int
sctp_validate_init_auth_params(struct mbuf *m, int offset, int limit)
{
	struct sctp_paramhdr *phdr, param_buf;
	uint16_t ptype, plen;
	int peer_supports_asconf = 0;
	int peer_supports_auth = 0;
	int got_random = 0, got_hmacs = 0, got_chklist = 0;
	uint8_t saw_asconf = 0;
	uint8_t saw_asconf_ack = 0;

	/* go through each of the params. */
	phdr = sctp_get_next_param(m, offset, &param_buf, sizeof(param_buf));
	while (phdr) {
		ptype = ntohs(phdr->param_type);
		plen = ntohs(phdr->param_length);

		if (offset + plen > limit) {
			break;
		}
		if (plen < sizeof(struct sctp_paramhdr)) {
			break;
		}
		if (ptype == SCTP_SUPPORTED_CHUNK_EXT) {
			/* A supported extension chunk */
			struct sctp_supported_chunk_types_param *pr_supported;
			uint8_t local_store[SCTP_SMALL_CHUNK_STORE];
			int num_ent, i;

			if (plen > sizeof(local_store)) {
				break;
			}
			phdr = sctp_get_next_param(m, offset,
			    (struct sctp_paramhdr *)&local_store,
			    plen);
			if (phdr == NULL) {
				return (-1);
			}
			pr_supported = (struct sctp_supported_chunk_types_param *)phdr;
			num_ent = plen - sizeof(struct sctp_paramhdr);
			for (i = 0; i < num_ent; i++) {
				switch (pr_supported->chunk_types[i]) {
				case SCTP_ASCONF:
				case SCTP_ASCONF_ACK:
					peer_supports_asconf = 1;
					break;
				default:
					/* one we don't care about */
					break;
				}
			}
		} else if (ptype == SCTP_RANDOM) {
			/* enforce the random length */
			if (plen != (sizeof(struct sctp_auth_random) +
			    SCTP_AUTH_RANDOM_SIZE_REQUIRED)) {
				SCTPDBG(SCTP_DEBUG_AUTH1,
				    "SCTP: invalid RANDOM len\n");
				return (-1);