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Date:      Sun, 15 Oct 2017 19:33:30 +0000 (UTC)
From:      Michael Tuexen <tuexen@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r324638 - head/sys/netinet
Message-ID:  <201710151933.v9FJXVcA080842@repo.freebsd.org>

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Author: tuexen
Date: Sun Oct 15 19:33:30 2017
New Revision: 324638
URL: https://svnweb.freebsd.org/changeset/base/324638

Log:
  Fix the handling of parital and too short chunks.
  
  Ensure that the current behaviour is consistent: stop processing
  of the chunk, but finish the processing of the previous chunks.
  
  This behaviour might be changed in a later commit to ABORT the
  assoication due to a protocol violation, but changing this
  is a separate issue.
  
  MFC after:	3 days

Modified:
  head/sys/netinet/sctp_input.c

Modified: head/sys/netinet/sctp_input.c
==============================================================================
--- head/sys/netinet/sctp_input.c	Sun Oct 15 19:28:14 2017	(r324637)
+++ head/sys/netinet/sctp_input.c	Sun Oct 15 19:33:30 2017	(r324638)
@@ -4518,7 +4518,6 @@ sctp_process_control(struct mbuf *m, int iphlen, int *
 	 * until we get into jumbo grams and such..
 	 */
 	uint8_t chunk_buf[SCTP_CHUNK_BUFFER_SIZE];
-	struct sctp_tcb *locked_tcb = stcb;
 	int got_auth = 0;
 	uint32_t auth_offset = 0, auth_len = 0;
 	int auth_skipped = 0;
@@ -4530,31 +4529,28 @@ sctp_process_control(struct mbuf *m, int iphlen, int *
 	SCTPDBG(SCTP_DEBUG_INPUT1, "sctp_process_control: iphlen=%u, offset=%u, length=%u stcb:%p\n",
 	    iphlen, *offset, length, (void *)stcb);
 
+	if (stcb) {
+		SCTP_TCB_LOCK_ASSERT(stcb);
+	}
 	/* validate chunk header length... */
 	if (ntohs(ch->chunk_length) < sizeof(*ch)) {
 		SCTPDBG(SCTP_DEBUG_INPUT1, "Invalid header length %d\n",
 		    ntohs(ch->chunk_length));
-		if (locked_tcb) {
-			SCTP_TCB_UNLOCK(locked_tcb);
-		}
-		return (NULL);
+		return (stcb);
 	}
 	/*
 	 * validate the verification tag
 	 */
 	vtag_in = ntohl(sh->v_tag);
 
-	if (locked_tcb) {
-		SCTP_TCB_LOCK_ASSERT(locked_tcb);
-	}
 	if (ch->chunk_type == SCTP_INITIATION) {
 		SCTPDBG(SCTP_DEBUG_INPUT1, "Its an INIT of len:%d vtag:%x\n",
 		    ntohs(ch->chunk_length), vtag_in);
 		if (vtag_in != 0) {
 			/* protocol error- silently discard... */
 			SCTP_STAT_INCR(sctps_badvtag);
-			if (locked_tcb) {
-				SCTP_TCB_UNLOCK(locked_tcb);
+			if (stcb != NULL) {
+				SCTP_TCB_UNLOCK(stcb);
 			}
 			return (NULL);
 		}
@@ -4577,9 +4573,6 @@ sctp_process_control(struct mbuf *m, int iphlen, int *
 			if (*offset >= length) {
 				/* no more data left in the mbuf chain */
 				*offset = length;
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
 				return (NULL);
 			}
 			ch = (struct sctp_chunkhdr *)sctp_m_getptr(m, *offset,
@@ -4588,10 +4581,7 @@ sctp_process_control(struct mbuf *m, int iphlen, int *
 		if (ch == NULL) {
 			/* Help */
 			*offset = length;
-			if (locked_tcb) {
-				SCTP_TCB_UNLOCK(locked_tcb);
-			}
-			return (NULL);
+			return (stcb);
 		}
 		if (ch->chunk_type == SCTP_COOKIE_ECHO) {
 			goto process_control_chunks;
@@ -4628,10 +4618,7 @@ sctp_process_control(struct mbuf *m, int iphlen, int *
 				 * sctp_findassociation_ep_asconf().
 				 */
 				SCTP_INP_DECR_REF(inp);
-			} else {
-				locked_tcb = stcb;
 			}
-
 			/* now go back and verify any auth chunk to be sure */
 			if (auth_skipped && (stcb != NULL)) {
 				struct sctp_auth_chunk *auth;
@@ -4645,10 +4632,7 @@ sctp_process_control(struct mbuf *m, int iphlen, int *
 				    auth_offset)) {
 					/* auth HMAC failed so dump it */
 					*offset = length;
-					if (locked_tcb) {
-						SCTP_TCB_UNLOCK(locked_tcb);
-					}
-					return (NULL);
+					return (stcb);
 				} else {
 					/* remaining chunks are HMAC checked */
 					stcb->asoc.authenticated = 1;
@@ -4664,9 +4648,6 @@ sctp_process_control(struct mbuf *m, int iphlen, int *
 			    mflowtype, mflowid, inp->fibnum,
 			    vrf_id, port);
 			*offset = length;
-			if (locked_tcb) {
-				SCTP_TCB_UNLOCK(locked_tcb);
-			}
 			return (NULL);
 		}
 		asoc = &stcb->asoc;
@@ -4684,8 +4665,8 @@ sctp_process_control(struct mbuf *m, int iphlen, int *
 			} else {
 				/* drop this packet... */
 				SCTP_STAT_INCR(sctps_badvtag);
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
+				if (stcb != NULL) {
+					SCTP_TCB_UNLOCK(stcb);
 				}
 				return (NULL);
 			}
@@ -4698,8 +4679,8 @@ sctp_process_control(struct mbuf *m, int iphlen, int *
 				 * but it won't complete until the shutdown
 				 * is completed
 				 */
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
+				if (stcb != NULL) {
+					SCTP_TCB_UNLOCK(stcb);
 				}
 				snprintf(msg, sizeof(msg), "OOTB, %s:%d at %s", __FILE__, __LINE__, __func__);
 				op_err = sctp_generate_cause(SCTP_BASE_SYSCTL(sctp_diag_info_code),
@@ -4718,8 +4699,8 @@ sctp_process_control(struct mbuf *m, int iphlen, int *
 				    "invalid vtag: %xh, expect %xh\n",
 				    vtag_in, asoc->my_vtag);
 				SCTP_STAT_INCR(sctps_badvtag);
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
+				if (stcb != NULL) {
+					SCTP_TCB_UNLOCK(stcb);
 				}
 				*offset = length;
 				return (NULL);
@@ -4755,10 +4736,7 @@ process_control_chunks:
 		if (chk_length < sizeof(*ch) ||
 		    (*offset + (int)chk_length) > length) {
 			*offset = length;
-			if (locked_tcb) {
-				SCTP_TCB_UNLOCK(locked_tcb);
-			}
-			return (NULL);
+			return (stcb);
 		}
 		SCTP_STAT_INCR_COUNTER64(sctps_incontrolchunks);
 		/*
@@ -4773,8 +4751,8 @@ process_control_chunks:
 			    sizeof(struct sctp_init_ack_chunk), chunk_buf);
 			if (ch == NULL) {
 				*offset = length;
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
+				if (stcb != NULL) {
+					SCTP_TCB_UNLOCK(stcb);
 				}
 				return (NULL);
 			}
@@ -4796,8 +4774,8 @@ process_control_chunks:
 				    chunk_buf);
 				if (ch == NULL) {
 					*offset = length;
-					if (locked_tcb) {
-						SCTP_TCB_UNLOCK(locked_tcb);
+					if (stcb != NULL) {
+						SCTP_TCB_UNLOCK(stcb);
 					}
 					return (NULL);
 				}
@@ -4808,8 +4786,8 @@ process_control_chunks:
 				if (ch == NULL) {
 					SCTP_PRINTF("sctp_process_control: Can't get the all data....\n");
 					*offset = length;
-					if (locked_tcb) {
-						SCTP_TCB_UNLOCK(locked_tcb);
+					if (stcb != NULL) {
+						SCTP_TCB_UNLOCK(stcb);
 					}
 					return (NULL);
 				}
@@ -4849,8 +4827,8 @@ process_control_chunks:
 			    (length - *offset > (int)SCTP_SIZE32(chk_length))) {
 				/* RFC 4960 requires that no ABORT is sent */
 				*offset = length;
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
+				if (stcb != NULL) {
+					SCTP_TCB_UNLOCK(stcb);
 				}
 				return (NULL);
 			}
@@ -4870,8 +4848,8 @@ process_control_chunks:
 			    mflowtype, mflowid,
 			    vrf_id, port);
 			*offset = length;
-			if ((!abort_no_unlock) && (locked_tcb)) {
-				SCTP_TCB_UNLOCK(locked_tcb);
+			if ((!abort_no_unlock) && (stcb != NULL)) {
+				SCTP_TCB_UNLOCK(stcb);
 			}
 			return (NULL);
 			break;
@@ -4881,15 +4859,14 @@ process_control_chunks:
 			SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_INIT-ACK\n");
 			if (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE) {
 				/* We are not interested anymore */
-				if ((stcb) && (stcb->asoc.total_output_queue_size)) {
+				if ((stcb != NULL) && (stcb->asoc.total_output_queue_size)) {
 					;
 				} else {
-					if ((locked_tcb != NULL) && (locked_tcb != stcb)) {
-						/* Very unlikely */
-						SCTP_TCB_UNLOCK(locked_tcb);
+					if (stcb != NULL) {
+						SCTP_TCB_UNLOCK(stcb);
 					}
 					*offset = length;
-					if (stcb) {
+					if (stcb != NULL) {
 #if defined(__APPLE__) || defined(SCTP_SO_LOCK_TESTING)
 						so = SCTP_INP_SO(inp);
 						atomic_add_int(&stcb->asoc.refcnt, 1);
@@ -4911,10 +4888,7 @@ process_control_chunks:
 			if ((num_chunks > 1) ||
 			    (length - *offset > (int)SCTP_SIZE32(chk_length))) {
 				*offset = length;
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
-				return (NULL);
+				return (stcb);
 			}
 			if ((netp) && (*netp)) {
 				ret = sctp_handle_init_ack(m, iphlen, *offset,
@@ -4938,10 +4912,7 @@ process_control_chunks:
 			if ((stcb != NULL) && (ret == 0)) {
 				sctp_chunk_output(stcb->sctp_ep, stcb, SCTP_OUTPUT_FROM_CONTROL_PROC, SCTP_SO_NOT_LOCKED);
 			}
-			if (locked_tcb) {
-				SCTP_TCB_UNLOCK(locked_tcb);
-			}
-			return (NULL);
+			return (stcb);
 			break;
 		case SCTP_SELECTIVE_ACK:
 			{
@@ -5133,10 +5104,7 @@ process_control_chunks:
 			if ((stcb == NULL) || (chk_length != sizeof(struct sctp_heartbeat_chunk))) {
 				/* Its not ours */
 				*offset = length;
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
-				return (NULL);
+				return (stcb);
 			}
 			/* He's alive so give him credit */
 			if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_THRESHOLD_LOGGING) {
@@ -5166,10 +5134,7 @@ process_control_chunks:
 			    (void *)stcb);
 			if ((stcb == NULL) || (chk_length != sizeof(struct sctp_shutdown_chunk))) {
 				*offset = length;
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
-				return (NULL);
+				return (stcb);
 			}
 			if (netp && *netp) {
 				int abort_flag = 0;
@@ -5206,7 +5171,7 @@ process_control_chunks:
 				if (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE) {
 					/* We are not interested anymore */
 			abend:
-					if (stcb) {
+					if (stcb != NULL) {
 						SCTP_TCB_UNLOCK(stcb);
 					}
 					*offset = length;
@@ -5263,6 +5228,9 @@ process_control_chunks:
 					}
 				}
 				if (netp) {
+					struct sctp_tcb *locked_stcb;
+
+					locked_stcb = stcb;
 					ret_buf =
 					    sctp_handle_cookie_echo(m, iphlen,
 					    *offset,
@@ -5273,11 +5241,17 @@ process_control_chunks:
 					    auth_skipped,
 					    auth_offset,
 					    auth_len,
-					    &locked_tcb,
+					    &locked_stcb,
 					    mflowtype,
 					    mflowid,
 					    vrf_id,
 					    port);
+					if ((locked_stcb != NULL) && (locked_stcb != stcb)) {
+						SCTP_TCB_UNLOCK(locked_stcb);
+					}
+					if (stcb != NULL) {
+						SCTP_TCB_LOCK_ASSERT(stcb);
+					}
 				} else {
 					ret_buf = NULL;
 				}
@@ -5285,8 +5259,8 @@ process_control_chunks:
 					SCTP_ASOC_CREATE_UNLOCK(linp);
 				}
 				if (ret_buf == NULL) {
-					if (locked_tcb) {
-						SCTP_TCB_UNLOCK(locked_tcb);
+					if (stcb != NULL) {
+						SCTP_TCB_UNLOCK(stcb);
 					}
 					SCTPDBG(SCTP_DEBUG_INPUT3,
 					    "GAK, null buffer\n");
@@ -5313,10 +5287,7 @@ process_control_chunks:
 		case SCTP_COOKIE_ACK:
 			SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_COOKIE-ACK, stcb %p\n", (void *)stcb);
 			if ((stcb == NULL) || chk_length != sizeof(struct sctp_cookie_ack_chunk)) {
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
-				return (NULL);
+				return (stcb);
 			}
 			if (inp->sctp_flags & SCTP_PCB_FLAGS_SOCKET_GONE) {
 				/* We are not interested anymore */
@@ -5358,11 +5329,8 @@ process_control_chunks:
 			/* He's alive so give him credit */
 			if ((stcb == NULL) || (chk_length != sizeof(struct sctp_ecne_chunk))) {
 				/* Its not ours */
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
 				*offset = length;
-				return (NULL);
+				return (stcb);
 			}
 			if (stcb) {
 				if (stcb->asoc.ecn_supported == 0) {
@@ -5385,12 +5353,8 @@ process_control_chunks:
 			SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_ECN-CWR\n");
 			/* He's alive so give him credit */
 			if ((stcb == NULL) || (chk_length != sizeof(struct sctp_cwr_chunk))) {
-				/* Its not ours */
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
 				*offset = length;
-				return (NULL);
+				return (stcb);
 			}
 			if (stcb) {
 				if (stcb->asoc.ecn_supported == 0) {
@@ -5413,10 +5377,7 @@ process_control_chunks:
 			if ((num_chunks > 1) ||
 			    (length - *offset > (int)SCTP_SIZE32(chk_length))) {
 				*offset = length;
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
-				return (NULL);
+				return (stcb);
 			}
 			if ((stcb) && netp && *netp) {
 				sctp_handle_shutdown_complete((struct sctp_shutdown_complete_chunk *)ch,
@@ -5449,11 +5410,8 @@ process_control_chunks:
 			SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_ASCONF-ACK\n");
 			if (chk_length < sizeof(struct sctp_asconf_ack_chunk)) {
 				/* Its not ours */
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
 				*offset = length;
-				return (NULL);
+				return (stcb);
 			}
 			if ((stcb) && netp && *netp) {
 				if (stcb->asoc.asconf_supported == 0) {
@@ -5479,11 +5437,8 @@ process_control_chunks:
 			SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_FWD-TSN\n");
 			if (chk_length < sizeof(struct sctp_forward_tsn_chunk)) {
 				/* Its not ours */
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
 				*offset = length;
-				return (NULL);
+				return (stcb);
 			}
 			/* He's alive so give him credit */
 			if (stcb) {
@@ -5546,11 +5501,8 @@ process_control_chunks:
 			SCTPDBG(SCTP_DEBUG_INPUT3, "SCTP_STREAM_RESET\n");
 			if (((stcb == NULL) || (ch == NULL) || (chk_length < sizeof(struct sctp_stream_reset_tsn_req)))) {
 				/* Its not ours */
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
 				*offset = length;
-				return (NULL);
+				return (stcb);
 			}
 			if (stcb->asoc.reconfig_supported == 0) {
 				goto unknown_chunk;
@@ -5566,11 +5518,8 @@ process_control_chunks:
 			/* re-get it all please */
 			if (chk_length < sizeof(struct sctp_pktdrop_chunk)) {
 				/* Its not ours */
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
 				*offset = length;
-				return (NULL);
+				return (stcb);
 			}
 			if (ch && (stcb) && netp && (*netp)) {
 				if (stcb->asoc.pktdrop_supported == 0) {
@@ -5579,7 +5528,6 @@ process_control_chunks:
 				sctp_handle_packet_dropped((struct sctp_pktdrop_chunk *)ch,
 				    stcb, *netp,
 				    min(chk_length, (sizeof(chunk_buf) - 4)));
-
 			}
 			break;
 		case SCTP_AUTHENTICATION:
@@ -5601,11 +5549,8 @@ process_control_chunks:
 			    (chk_length > (sizeof(struct sctp_auth_chunk) +
 			    SCTP_AUTH_DIGEST_LEN_MAX))) {
 				/* Its not ours */
-				if (locked_tcb) {
-					SCTP_TCB_UNLOCK(locked_tcb);
-				}
 				*offset = length;
-				return (NULL);
+				return (stcb);
 			}
 			if (got_auth == 1) {
 				/* skip this chunk... it's already auth'd */
@@ -5670,11 +5615,8 @@ next_chunk:
 		ch = (struct sctp_chunkhdr *)sctp_m_getptr(m, *offset,
 		    sizeof(struct sctp_chunkhdr), chunk_buf);
 		if (ch == NULL) {
-			if (locked_tcb) {
-				SCTP_TCB_UNLOCK(locked_tcb);
-			}
 			*offset = length;
-			return (NULL);
+			return (stcb);
 		}
 	}			/* while */
 



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