[src/trunk]: src/sys/netipsec Fix inverted logic, otherwise the kernel crashe...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/05f28157ca72
branches:  trunk
changeset: 829888:05f28157ca72
user:      maxv <maxv%NetBSD.org@localhost>
date:      Fri Feb 16 11:25:16 2018 +0000

description:
Fix inverted logic, otherwise the kernel crashes when receiving a 1-byte
AH packet. Triggerable before authentication when IPsec and forwarding
are both enabled.

diffstat:

 sys/netipsec/ipsec.c |  6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diffs (27 lines):

diff -r 2f930d3b6285 -r 05f28157ca72 sys/netipsec/ipsec.c
--- a/sys/netipsec/ipsec.c      Fri Feb 16 11:07:44 2018 +0000
+++ b/sys/netipsec/ipsec.c      Fri Feb 16 11:25:16 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: ipsec.c,v 1.129 2018/02/16 11:07:44 maxv Exp $ */
+/* $NetBSD: ipsec.c,v 1.130 2018/02/16 11:25:16 maxv Exp $ */
 /* $FreeBSD: src/sys/netipsec/ipsec.c,v 1.2.2.2 2003/07/01 01:38:13 sam Exp $ */
 /* $KAME: ipsec.c,v 1.103 2001/05/24 07:14:18 sakane Exp $ */
 
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ipsec.c,v 1.129 2018/02/16 11:07:44 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ipsec.c,v 1.130 2018/02/16 11:25:16 maxv Exp $");
 
 /*
  * IPsec controller part.
@@ -1038,7 +1038,7 @@
                        spidx->dst.sin.sin_port = uh.uh_dport;
                        return;
                case IPPROTO_AH:
-                       if (m->m_pkthdr.len > off + sizeof(ip6e))
+                       if (off + sizeof(ip6e) > m->m_pkthdr.len)
                                goto done;
                        /* XXX sigh, this works but is totally bogus */
                        m_copydata(m, off, sizeof(ip6e), &ip6e);