diff --git a/rules/decoder-events.rules b/rules/decoder-events.rules index 965c9c137f75..19ae61d6c4ab 100644 --- a/rules/decoder-events.rules +++ b/rules/decoder-events.rules @@ -106,6 +106,7 @@ alert pkthdr any any -> any any (msg:"SURICATA FRAG IPv4 Packet size too large"; alert pkthdr any any -> any any (msg:"SURICATA FRAG IPv4 Fragmentation overlap"; decode-event:ipv4.frag_overlap; classtype:protocol-command-decode; sid:2200070; rev:2;) alert pkthdr any any -> any any (msg:"SURICATA FRAG IPv6 Packet size too large"; decode-event:ipv6.frag_pkt_too_large; classtype:protocol-command-decode; sid:2200071; rev:3;) alert pkthdr any any -> any any (msg:"SURICATA FRAG IPv6 Fragmentation overlap"; decode-event:ipv6.frag_overlap; classtype:protocol-command-decode; sid:2200072; rev:2;) +alert pkthdr any any -> any any (msg:"SURICATA FRAG IPv6 Fragment invalid length"; decode-event:ipv6.frag_invalid_length; classtype:protocol-command-decode; sid:2200119; rev:1;) # checksum rules alert ip any any -> any any (msg:"SURICATA IPv4 invalid checksum"; ipv4-csum:invalid; classtype:protocol-command-decode; sid:2200073; rev:2;) @@ -149,5 +150,5 @@ alert pkthdr any any -> any any (msg:"SURICATA CHDLC packet too small"; decode-e alert pkthdr any any -> any any (msg:"SURICATA packet with too many layers"; decode-event:too_many_layers; classtype:protocol-command-decode; sid:2200116; rev:1;) -# next sid is 2200119 +# next sid is 2200120 diff --git a/src/decode-events.c b/src/decode-events.c index 4c1d3d03aad7..8023d107508a 100644 --- a/src/decode-events.c +++ b/src/decode-events.c @@ -458,6 +458,10 @@ const struct DecodeEvents_ DEvents[] = { "decoder.ipv6.frag_overlap", IPV6_FRAG_OVERLAP, }, + { + "decoder.ipv6.frag_invalid_length", + IPV6_FRAG_INVALID_LENGTH, + }, /* Fragment ignored due to internal error */ { "decoder.ipv4.frag_ignored", diff --git a/src/decode-events.h b/src/decode-events.h index 86e64a7c0fab..6fad62e27846 100644 --- a/src/decode-events.h +++ b/src/decode-events.h @@ -169,6 +169,7 @@ enum { IPV6_FRAG_PKT_TOO_LARGE, IPV4_FRAG_OVERLAP, IPV6_FRAG_OVERLAP, + IPV6_FRAG_INVALID_LENGTH, /* Fragment ignored due to internal error */ IPV4_FRAG_IGNORED, diff --git a/src/decode-ipv6.c b/src/decode-ipv6.c index e2fecf31bea6..5c9b739ac015 100644 --- a/src/decode-ipv6.c +++ b/src/decode-ipv6.c @@ -453,6 +453,12 @@ DecodeIPV6ExtHdrs(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, plen -= hdrextlen; break; } + if (p->ip6eh.fh_more_frags_set != 0 && plen % 8 != 0) { + // cf https://datatracker.ietf.org/doc/html/rfc2460#section-4.5 + // each, except possibly the last ("rightmost") one, + // being an integer multiple of 8 octets long. + ENGINE_SET_EVENT(p, IPV6_FRAG_INVALID_LENGTH); + } /* the rest is parsed upon reassembly */ p->flags |= PKT_IS_FRAGMENT;