svn commit: r353401 - stable/12/sys/netinet

[Michael Tuexen]

Author: tuexen
Date: Thu Oct 10 14:52:48 2019
New Revision: 353401
URL: https://svnweb.freebsd.org/changeset/base/353401

Log:
  MFC r353145:
  
  Plumb an mbuf leak in a code path that should not be taken. Also avoid
  that this path is taken by setting the tail pointer correctly.
  There is still bug related to handling unordered unfragmented messages
  which were delayed in deferred handling.
  This issue was found by OSS-Fuzz testing the usrsctp stack and reported
  in
  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=17794

Modified:
  stable/12/sys/netinet/sctp_indata.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/netinet/sctp_indata.c
==============================================================================
--- stable/12/sys/netinet/sctp_indata.c	Thu Oct 10 14:51:38 2019	(r353400)
+++ stable/12/sys/netinet/sctp_indata.c	Thu Oct 10 14:52:48 2019	(r353401)
@@ -716,6 +716,7 @@ sctp_add_to_tail_pointer(struct sctp_queued_to_read *c
 	}
 	if (control->tail_mbuf == NULL) {
 		/* TSNH */
+		sctp_m_freem(control->data);
 		control->data = m;
 		sctp_setup_tail_pointer(control);
 		return;
@@ -2119,10 +2120,13 @@ sctp_process_a_data_chunk(struct sctp_tcb *stcb, struc
 			struct mbuf *mm;
 
 			control->data = dmbuf;
+			control->tail_mbuf = NULL;
 			for (mm = control->data; mm; mm = mm->m_next) {
 				control->length += SCTP_BUF_LEN(mm);
+				if (SCTP_BUF_NEXT(mm) == NULL) {
+					control->tail_mbuf = mm;
+				}
 			}
-			control->tail_mbuf = NULL;
 			control->end_added = 1;
 			control->last_frag_seen = 1;
 			control->first_frag_seen = 1;