Author: tuexen Date: Thu Oct 3 20:39:17 2019 New Revision: 353069 URL: https://svnweb.freebsd.org/changeset/base/353069
Log: Cleanup sctp_asconf_error_response() and ensure that the parameter is padded as required. This fixes the followig bug reported by OSS-Fuzz for the usersctp stack: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=17790 MFC after: 3 days Modified: head/sys/netinet/sctp_asconf.c Modified: head/sys/netinet/sctp_asconf.c ============================================================================== --- head/sys/netinet/sctp_asconf.c Thu Oct 3 20:22:25 2019 (r353068) +++ head/sys/netinet/sctp_asconf.c Thu Oct 3 20:39:17 2019 (r353069) @@ -105,42 +105,47 @@ sctp_asconf_error_response(uint32_t id, uint16_t cause struct mbuf *m_reply = NULL; struct sctp_asconf_paramhdr *aph; struct sctp_error_cause *error; + size_t buf_len; + uint16_t i, param_length, cause_length, padding_length; uint8_t *tlv; - m_reply = sctp_get_mbuf_for_msg((sizeof(struct sctp_asconf_paramhdr) + - tlv_length + - sizeof(struct sctp_error_cause)), - 0, M_NOWAIT, 1, MT_DATA); + if (error_tlv == NULL) { + tlv_length = 0; + } + cause_length = sizeof(struct sctp_error_cause) + tlv_length; + param_length = sizeof(struct sctp_asconf_paramhdr) + cause_length; + padding_length = tlv_length % 4; + if (padding_length != 0) { + padding_length = 4 - padding_length; + } + buf_len = param_length + padding_length; + if (buf_len > MLEN) { + SCTPDBG(SCTP_DEBUG_ASCONF1, + "asconf_error_response: tlv_length (%xh) too big\n", + tlv_length); + return (NULL); + } + m_reply = sctp_get_mbuf_for_msg(buf_len, 0, M_NOWAIT, 1, MT_DATA); if (m_reply == NULL) { SCTPDBG(SCTP_DEBUG_ASCONF1, "asconf_error_response: couldn't get mbuf!\n"); return (NULL); } aph = mtod(m_reply, struct sctp_asconf_paramhdr *); - error = (struct sctp_error_cause *)(aph + 1); - - aph->correlation_id = id; aph->ph.param_type = htons(SCTP_ERROR_CAUSE_IND); + aph->ph.param_length = htons(param_length); + aph->correlation_id = id; + error = (struct sctp_error_cause *)(aph + 1); error->code = htons(cause); - error->length = tlv_length + sizeof(struct sctp_error_cause); - aph->ph.param_length = error->length + - sizeof(struct sctp_asconf_paramhdr); - - if (aph->ph.param_length > MLEN) { - SCTPDBG(SCTP_DEBUG_ASCONF1, - "asconf_error_response: tlv_length (%xh) too big\n", - tlv_length); - sctp_m_freem(m_reply); /* discard */ - return (NULL); - } + error->length = htons(cause_length); if (error_tlv != NULL) { tlv = (uint8_t *)(error + 1); memcpy(tlv, error_tlv, tlv_length); + for (i = 0; i < padding_length; i++) { + tlv[tlv_length + i] = 0; + } } - SCTP_BUF_LEN(m_reply) = aph->ph.param_length; - error->length = htons(error->length); - aph->ph.param_length = htons(aph->ph.param_length); - + SCTP_BUF_LEN(m_reply) = buf_len; return (m_reply); } @@ -780,8 +785,6 @@ sctp_handle_asconf(struct mbuf *m, unsigned int offset if (m_result != NULL) { SCTP_BUF_NEXT(m_tail) = m_result; m_tail = m_result; - /* update lengths, make sure it's aligned too */ - SCTP_BUF_LEN(m_result) = SCTP_SIZE32(SCTP_BUF_LEN(m_result)); ack_cp->ch.chunk_length += SCTP_BUF_LEN(m_result); /* set flag to force success reports */ error = 1; _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
