svn commit: r360662 - head/sys/netinet

[Michael Tuexen]

Author: tuexen
Date: Tue May  5 17:52:44 2020
New Revision: 360662
URL: https://svnweb.freebsd.org/changeset/base/360662

Log:
  Fix the computation of the numbers of entries of the mapping array to
  look at when generating a SACK. This was wrong in case of sequence
  numbers wrap arounds.
  
  Thanks to Gwenael FOURRE for reporting the issue for the userland stack:
  https://github.com/sctplab/usrsctp/issues/462
  MFC after:		3 days

Modified:
  head/sys/netinet/sctp_output.c

Modified: head/sys/netinet/sctp_output.c
==============================================================================
--- head/sys/netinet/sctp_output.c	Tue May  5 17:50:27 2020	(r360661)
+++ head/sys/netinet/sctp_output.c	Tue May  5 17:52:44 2020	(r360662)
@@ -10713,7 +10713,7 @@ sctp_send_sack(struct sctp_tcb *stcb, int so_locked
 		if (highest_tsn > asoc->mapping_array_base_tsn) {
 			siz = (((highest_tsn - asoc->mapping_array_base_tsn) + 1) + 7) / 8;
 		} else {
-			siz = (((MAX_TSN - highest_tsn) + 1) + highest_tsn + 7) / 8;
+			siz = (((MAX_TSN - asoc->mapping_array_base_tsn) + 1) + highest_tsn + 7) / 8;
 		}
 	} else {
 		sack = NULL;