svn commit: r353145 - head/sys/netinet

[Michael Tuexen]

Author: tuexen
Date: Sun Oct  6 08:47:10 2019
New Revision: 353145
URL: https://svnweb.freebsd.org/changeset/base/353145

Log:
  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
  
  MFC after:		3 days

Modified:
  head/sys/netinet/sctp_indata.c

Modified: head/sys/netinet/sctp_indata.c
==============================================================================
--- head/sys/netinet/sctp_indata.c	Sun Oct  6 04:36:53 2019	(r353144)
+++ head/sys/netinet/sctp_indata.c	Sun Oct  6 08:47:10 2019	(r353145)
@@ -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;