git: 0f63c2d187c4 - stable/13 - sctp: check that the computed frag point is a multiple of 4

The branch stable/13 has been updated by tuexen:

URL: https://cgit.FreeBSD.org/src/commit/?id=0f63c2d187c4b67cdeaa0d4cfdae88db48106bcb

commit 0f63c2d187c4b67cdeaa0d4cfdae88db48106bcb
Author:     Michael Tuexen <tuexen@FreeBSD.org>
AuthorDate: 2021-12-28 08:40:52 +0000
Commit:     Michael Tuexen <tuexen@FreeBSD.org>
CommitDate: 2022-02-22 23:56:17 +0000

    sctp: check that the computed frag point is a multiple of 4
    
    Reported by:    syzbot+5da189fc1fe80b31f5bd@syzkaller.appspotmail.com
    
    (cherry picked from commit ca0dd19f09335496390829851862c894f89a87f9)
---
 sys/netinet/sctp_output.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/sys/netinet/sctp_output.c b/sys/netinet/sctp_output.c
index 598831220033..8b4a891c23aa 100644
--- a/sys/netinet/sctp_output.c
+++ b/sys/netinet/sctp_output.c
@@ -6246,13 +6246,12 @@ sctp_get_frag_point(struct sctp_tcb *stcb)
 	if (asoc->smallest_mtu % 4) {
 		overhead += (asoc->smallest_mtu % 4);
 	}
-	KASSERT(overhead % 4 == 0,
-	    ("overhead (%u) not a multiple of 4", overhead));
 	KASSERT(asoc->smallest_mtu > overhead,
 	    ("Association MTU (%u) too small for overhead (%u)",
 	    asoc->smallest_mtu, overhead));
-
 	frag_point = asoc->smallest_mtu - overhead;
+	KASSERT(frag_point % 4 == 0,
+	    ("frag_point (%u) not a multiple of 4", frag_point));
 	/* Honor MAXSEG socket option. */
 	if ((asoc->sctp_frag_point > 0) &&
 	    (asoc->sctp_frag_point < frag_point)) {