fix off-by-one in bounds check

found by "buffer overflow 'ContextVarbind' 3 <= 3" smatch error
ok miod@ stsp@

diff --git a/usr.sbin/tcpdump/print-snmp.c b/usr.sbin/tcpdump/print-snmp.c
index 01c2f99..4458287 100644 (file)
--- a/usr.sbin/tcpdump/print-snmp.c
+++ b/usr.sbin/tcpdump/print-snmp.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: print-snmp.c,v 1.28 2021/10/23 10:47:50 martijn Exp $ */
+/*     $OpenBSD: print-snmp.c,v 1.29 2024/02/03 00:20:21 jsg Exp $     */
 
 /*
  * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996, 1997
@@ -746,7 +746,7 @@ asn1_print(struct be *elem)
                        Class[CONTEXT].Id[elem->id], elem->asnlen);
                break;
        case BE_VB:
-               if (elem->id > sizeof(ContextVarbind)/sizeof(ContextVarbind[0]))
+               if (elem->id >= sizeof(ContextVarbind)/sizeof(ContextVarbind[0]))
                        break;
                printf("%s", ContextVarbind[elem->id]);
                break;