From: Francois-Xavier Le Bail <devel.fx.lebail@orange.fr>
Date: Sat, 11 Apr 2020 14:02:13 +0000 (+0200)
Subject: IPv4/IPv6 demux: ICMPv4 in IPv6 is invalid
X-Git-Tag: tcpdump-4.99-bp~456
X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/ab22c228c885fd8eee863b1d47eecbf19f96bfb3

IPv4/IPv6 demux: ICMPv4 in IPv6 is invalid

"  ICMP messages are sent using the basic IP header.
   ...
   Version

      4"
(RFC 792)
---

diff --git a/print-ip-demux.c b/print-ip-demux.c
index d3f03b66..9d562d77 100644
--- a/print-ip-demux.c
+++ b/print-ip-demux.c
@@ -105,7 +105,13 @@ again:
 		break;
 
 	case IPPROTO_ICMP:
-		icmp_print(ndo, bp, length, iph, fragmented);
+		if (ver == 4)
+			icmp_print(ndo, bp, length, iph, fragmented);
+		else {
+			ND_PRINT("[%s requires IPv4]",
+				 tok2str(ipproto_values,"unknown",nh));
+			nd_print_invalid(ndo);
+		}
 		break;
 
 	case IPPROTO_ICMPV6: