Checked in. Thanks.
Yaniv Kaul wrote:
> Attached please find a packet capture that causes crash in SNMP code.
>
> The faulty code is in packet-snmp.c:
> ret = asn1_octet_string_decode (&asn1, &community,
> &community_length, &length);
> if (tree) {
> dissect_snmp2u_parameters(snmp_tree, tvb, offset, length,
> community, community_length);
> }
>
> There's no check on 'ret' value, and so there's a call to
> 'dissect_snmp2u_parameters()' with community as NULL (since the
> asn1_octect_string_decode() fails in this malformed packet).
>
> Attached please find a diff that fixes this problem.
> I went over (briefly) on all packet-snmp.c, and it seems this is the
> ONLY place we don't check the 'ret' value.
>
>
> ------------------------------------------------------------------------
>
> --- packet-snmp.orig.c 2004-06-28 19:22:56.000000000 +0200
> +++ packet-snmp.c 2004-06-28 19:27:54.000000000 +0200
> @@ -1703,6 +1703,11 @@
> case SNMP_VERSION_2u:
> ret = asn1_octet_string_decode (&asn1, &community,
> &community_length, &length);
> + if (ret != ASN1_ERR_NOERROR) {
> + dissect_snmp_parse_error(tvb, offset, pinfo, snmp_tree,
> + "community (2u)", ret);
> + return message_length;
> + }
> if (tree) {
> dissect_snmp2u_parameters(snmp_tree, tvb, offset, length,
> community, community_length);
>
>
> ------------------------------------------------------------------------
>
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