/* packet-mms_asn1.c * * Ronnie Sahlberg 2005 * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include #include #include #include #include #include "packet-ber.h" #include "packet-acse.h" #include "packet-mms.h" #define PNAME "MMS" #define PSNAME "MMS" #define PFNAME "mms" void proto_register_mms(void); void proto_reg_handoff_mms(void); /* Initialize the protocol and registered fields */ static int proto_mms = -1; #include "packet-mms-hf.c" /* Initialize the subtree pointers */ static gint ett_mms = -1; #include "packet-mms-ett.c" static expert_field ei_mms_mal_timeofday_encoding = EI_INIT; static expert_field ei_mms_mal_utctime_encoding = EI_INIT; static expert_field ei_mms_zero_pdu = EI_INIT; /*****************************************************************************/ /* Packet private data */ /* For this dissector, all access to actx->private_data should be made */ /* through this API, which ensures that they will not overwrite each other!! */ /*****************************************************************************/ #define BUFFER_SIZE_PRE 10 #define BUFFER_SIZE_MORE 1024 typedef struct mms_private_data_t { char preCinfo[BUFFER_SIZE_PRE]; char moreCinfo[BUFFER_SIZE_MORE]; } mms_private_data_t; /* Helper function to get or create the private data struct */ static mms_private_data_t* mms_get_private_data(asn1_ctx_t *actx) { packet_info *pinfo = actx->pinfo; mms_private_data_t *private_data = (mms_private_data_t *)p_get_proto_data(pinfo->pool, pinfo, proto_mms, pinfo->curr_layer_num); if(private_data != NULL ) return private_data; else { private_data = wmem_new0(pinfo->pool, mms_private_data_t); p_add_proto_data(pinfo->pool, pinfo, proto_mms, pinfo->curr_layer_num, private_data); return private_data; } } /* Helper function to test presence of private data struct */ static gboolean mms_has_private_data(asn1_ctx_t *actx) { packet_info *pinfo = actx->pinfo; return (p_get_proto_data(pinfo->pool, pinfo, proto_mms, pinfo->curr_layer_num) != NULL); } static void private_data_add_preCinfo(asn1_ctx_t *actx, guint32 val) { mms_private_data_t *private_data = (mms_private_data_t*)mms_get_private_data(actx); g_snprintf(private_data->preCinfo, BUFFER_SIZE_PRE, "%02d ", val); } static char* private_data_get_preCinfo(asn1_ctx_t *actx) { mms_private_data_t *private_data = (mms_private_data_t*)mms_get_private_data(actx); return private_data->preCinfo; } static void private_data_add_moreCinfo_id(asn1_ctx_t *actx, tvbuff_t *tvb) { mms_private_data_t *private_data = (mms_private_data_t*)mms_get_private_data(actx); g_strlcat(private_data->moreCinfo, " ", BUFFER_SIZE_MORE); g_strlcat(private_data->moreCinfo, tvb_get_string_enc(wmem_packet_scope(), tvb, 2, tvb_get_guint8(tvb, 1), ENC_STRING), BUFFER_SIZE_MORE); } static void private_data_add_moreCinfo_float(asn1_ctx_t *actx, tvbuff_t *tvb) { mms_private_data_t *private_data = (mms_private_data_t*)mms_get_private_data(actx); g_snprintf(private_data->moreCinfo, BUFFER_SIZE_MORE, " %f", tvb_get_ieee_float(tvb, 1, ENC_BIG_ENDIAN)); } static char* private_data_get_moreCinfo(asn1_ctx_t *actx) { mms_private_data_t *private_data = (mms_private_data_t*)mms_get_private_data(actx); return private_data->moreCinfo; } /*****************************************************************************/ #include "packet-mms-fn.c" /* * Dissect MMS PDUs inside a PPDU. */ static int dissect_mms(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void* data _U_) { int offset = 0; int old_offset; proto_item *item=NULL; proto_tree *tree=NULL; asn1_ctx_t asn1_ctx; asn1_ctx_init(&asn1_ctx, ASN1_ENC_BER, TRUE, pinfo); if(parent_tree){ item = proto_tree_add_item(parent_tree, proto_mms, tvb, 0, -1, ENC_NA); tree = proto_item_add_subtree(item, ett_mms); } col_set_str(pinfo->cinfo, COL_PROTOCOL, "MMS"); col_clear(pinfo->cinfo, COL_INFO); while (tvb_reported_length_remaining(tvb, offset) > 0){ old_offset=offset; offset=dissect_mms_MMSpdu(FALSE, tvb, offset, &asn1_ctx , tree, -1); if(offset == old_offset){ proto_tree_add_expert(tree, pinfo, &ei_mms_zero_pdu, tvb, offset, -1); break; } } return tvb_captured_length(tvb); } /*--- proto_register_mms -------------------------------------------*/ void proto_register_mms(void) { /* List of fields */ static hf_register_info hf[] = { #include "packet-mms-hfarr.c" }; /* List of subtrees */ static gint *ett[] = { &ett_mms, #include "packet-mms-ettarr.c" }; static ei_register_info ei[] = { { &ei_mms_mal_timeofday_encoding, { "mms.malformed.timeofday_encoding", PI_MALFORMED, PI_WARN, "BER Error: malformed TimeOfDay encoding", EXPFILL }}, { &ei_mms_mal_utctime_encoding, { "mms.malformed.utctime", PI_MALFORMED, PI_WARN, "BER Error: malformed IEC61850 UTCTime encoding", EXPFILL }}, { &ei_mms_zero_pdu, { "mms.zero_pdu", PI_PROTOCOL, PI_ERROR, "Internal error, zero-byte MMS PDU", EXPFILL }}, }; expert_module_t* expert_mms; /* Register protocol */ proto_mms = proto_register_protocol(PNAME, PSNAME, PFNAME); register_dissector("mms", dissect_mms, proto_mms); /* Register fields and subtrees */ proto_register_field_array(proto_mms, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); expert_mms = expert_register_protocol(proto_mms); expert_register_field_array(expert_mms, ei, array_length(ei)); } static gboolean dissect_mms_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_) { /* must check that this really is an mms packet */ int offset = 0; guint32 length = 0 ; guint32 oct; gint idx = 0 ; gint8 tmp_class; gboolean tmp_pc; gint32 tmp_tag; /* first, check do we have at least 2 bytes (pdu) */ if (!tvb_bytes_exist(tvb, 0, 2)) return FALSE; /* no */ /* can we recognize MMS PDU ? Return FALSE if not */ /* get MMS PDU type */ offset = get_ber_identifier(tvb, offset, &tmp_class, &tmp_pc, &tmp_tag); /* check MMS type */ /* Class should be constructed */ if (tmp_class!=BER_CLASS_CON) return FALSE; /* see if the tag is a valid MMS PDU */ try_val_to_str_idx(tmp_tag, mms_MMSpdu_vals, &idx); if (idx == -1) { return FALSE; /* no, it isn't an MMS PDU */ } /* check MMS length */ oct = tvb_get_guint8(tvb, offset)& 0x7F; if (oct==0) /* MMS requires length after tag so not MMS if indefinite length*/ return FALSE; offset = get_ber_length(tvb, offset, &length, NULL); /* do we have enough bytes? */ if (!tvb_bytes_exist(tvb, offset, length)) return FALSE; dissect_mms(tvb, pinfo, parent_tree, data); return TRUE; } /*--- proto_reg_handoff_mms --- */ void proto_reg_handoff_mms(void) { register_ber_oid_dissector("1.0.9506.2.3", dissect_mms, proto_mms,"MMS"); register_ber_oid_dissector("1.0.9506.2.1", dissect_mms, proto_mms,"mms-abstract-syntax-version1(1)"); heur_dissector_add("cotp", dissect_mms_heur, "MMS over COTP", "mms_cotp", proto_mms, HEURISTIC_ENABLE); heur_dissector_add("cotp_is", dissect_mms_heur, "MMS over COTP (inactive subset)", "mms_cotp_is", proto_mms, HEURISTIC_ENABLE); }