/* packet-websocket.c * Routines for WebSocket dissection * Copyright 2012, Alexis La Goutte * 2015, Peter Wu * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "config.h" #include #include #include #include #include "packet-http.h" #include "packet-tcp.h" /* * The information used comes from: * RFC6455: The WebSocket Protocol * http://www.iana.org/assignments/websocket (last updated 2012-04-12) */ void proto_register_websocket(void); void proto_reg_handoff_websocket(void); static dissector_handle_t data_handle; static dissector_handle_t text_lines_handle; static dissector_handle_t json_handle; static dissector_handle_t sip_handle; #define WEBSOCKET_NONE 0 #define WEBSOCKET_TEXT 1 #define WEBSOCKET_JSON 2 #define WEBSOCKET_SIP 3 static gint pref_text_type = WEBSOCKET_NONE; /* Initialize the protocol and registered fields */ static int proto_websocket = -1; static int proto_http = -1; static int hf_ws_fin = -1; static int hf_ws_reserved = -1; static int hf_ws_opcode = -1; static int hf_ws_mask = -1; static int hf_ws_payload_length = -1; static int hf_ws_payload_length_ext_16 = -1; static int hf_ws_payload_length_ext_64 = -1; static int hf_ws_masking_key = -1; static int hf_ws_payload = -1; static int hf_ws_masked_payload = -1; static int hf_ws_payload_continue = -1; static int hf_ws_payload_close = -1; static int hf_ws_payload_close_status_code = -1; static int hf_ws_payload_close_reason = -1; static int hf_ws_payload_ping = -1; static int hf_ws_payload_pong = -1; static int hf_ws_payload_unknown = -1; static gint ett_ws = -1; static gint ett_ws_pl = -1; static gint ett_ws_mask = -1; static gint ett_ws_control_close = -1; static expert_field ei_ws_payload_unknown = EI_INIT; #define WS_CONTINUE 0x0 #define WS_TEXT 0x1 #define WS_BINARY 0x2 #define WS_CLOSE 0x8 #define WS_PING 0x9 #define WS_PONG 0xA static const value_string ws_opcode_vals[] = { { WS_CONTINUE, "Continuation" }, { WS_TEXT, "Text" }, { WS_BINARY, "Binary" }, { WS_CLOSE, "Connection Close" }, { WS_PING, "Ping" }, { WS_PONG, "Pong" }, { 0, NULL} }; #define MASK_WS_FIN 0x80 #define MASK_WS_RSV 0x70 #define MASK_WS_OPCODE 0x0F #define MASK_WS_MASK 0x80 #define MASK_WS_PAYLOAD_LEN 0x7F static const value_string ws_close_status_code_vals[] = { { 1000, "Normal Closure" }, { 1001, "Going Away" }, { 1002, "Protocol error" }, { 1003, "Unsupported Data" }, { 1004, "---Reserved----" }, { 1005, "No Status Rcvd" }, { 1006, "Abnormal Closure" }, { 1007, "Invalid frame payload data" }, { 1008, "Policy Violation" }, { 1009, "Message Too Big" }, { 1010, "Mandatory Ext." }, { 1011, "Internal Server" }, { 1015, "TLS handshake" }, { 0, NULL} }; static dissector_table_t port_subdissector_table; static heur_dissector_list_t heur_subdissector_list; #define MAX_UNMASKED_LEN (1024 * 256) static tvbuff_t * tvb_unmasked(tvbuff_t *tvb, packet_info *pinfo, const guint offset, guint payload_length, const guint8 *masking_key) { gchar *data_unmask; guint i; const guint8 *data_mask; guint unmasked_length = payload_length > MAX_UNMASKED_LEN ? MAX_UNMASKED_LEN : payload_length; data_unmask = (gchar *)wmem_alloc(pinfo->pool, unmasked_length); data_mask = tvb_get_ptr(tvb, offset, unmasked_length); /* Unmasked(XOR) Data... */ for(i=0; i < unmasked_length; i++) { data_unmask[i] = data_mask[i] ^ masking_key[i%4]; } return tvb_new_real_data(data_unmask, unmasked_length, payload_length); } static void dissect_websocket_control_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint8 opcode) { proto_item *ti; proto_tree *subtree; const guint offset = 0, length = tvb_reported_length(tvb); switch (opcode) { case WS_CLOSE: /* Close */ ti = proto_tree_add_item(tree, hf_ws_payload_close, tvb, offset, length, ENC_NA); subtree = proto_item_add_subtree(ti, ett_ws_control_close); /* Close frame MAY contain a body. */ if (length >= 2) { proto_tree_add_item(subtree, hf_ws_payload_close_status_code, tvb, offset, 2, ENC_BIG_ENDIAN); if (length > 2) proto_tree_add_item(subtree, hf_ws_payload_close_reason, tvb, offset+2, length-2, ENC_UTF_8|ENC_NA); } break; case WS_PING: /* Ping */ proto_tree_add_item(tree, hf_ws_payload_ping, tvb, offset, length, ENC_NA); break; case WS_PONG: /* Pong */ proto_tree_add_item(tree, hf_ws_payload_pong, tvb, offset, length, ENC_NA); break; default: /* Unknown */ ti = proto_tree_add_item(tree, hf_ws_payload_unknown, tvb, offset, length, ENC_NA); expert_add_info_format(pinfo, ti, &ei_ws_payload_unknown, "Dissector for Websocket Opcode (%d)" " code not implemented, Contact Wireshark developers" " if you want this supported", opcode); break; } } static void dissect_websocket_data_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_tree *pl_tree, guint8 opcode) { proto_item *ti; const guint offset = 0, length = tvb_reported_length(tvb); dissector_handle_t handle = NULL; heur_dtbl_entry_t *hdtbl_entry; conversation_t *conv; http_conv_t *http_conv = NULL; /* try to find a dissector which accepts the data. */ conv = find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype, pinfo->srcport, pinfo->destport, 0); if (conv) { http_conv = (http_conv_t *)conversation_get_proto_data(conv, proto_http); if (http_conv) handle = dissector_get_uint_handle(port_subdissector_table, http_conv->server_port); } if (handle) { call_dissector_only(handle, tvb, pinfo, tree, NULL); return; /* handle found, assume dissector took care of it. */ } else if (dissector_try_heuristic(heur_subdissector_list, tvb, pinfo, tree, &hdtbl_entry, NULL)) { return; /* heuristics dissector handled it. */ } /* no dissector wanted it, try to print something appropriate. */ switch (opcode) { case WS_TEXT: /* Text */ { const gchar *saved_match_string = pinfo->match_string; pinfo->match_string = NULL; switch (pref_text_type) { case WEBSOCKET_TEXT: case WEBSOCKET_NONE: default: /* Assume that most text protocols are line-based. */ call_dissector(text_lines_handle, tvb, pinfo, tree); break; case WEBSOCKET_JSON: call_dissector(json_handle, tvb, pinfo, tree); break; case WEBSOCKET_SIP: call_dissector(sip_handle, tvb, pinfo, tree); break; } pinfo->match_string = saved_match_string; } break; case WS_BINARY: /* Binary */ call_dissector(data_handle, tvb, pinfo, tree); break; default: /* Unknown */ ti = proto_tree_add_item(pl_tree, hf_ws_payload_unknown, tvb, offset, length, ENC_NA); expert_add_info_format(pinfo, ti, &ei_ws_payload_unknown, "Dissector for Websocket Opcode (%d)" " code not implemented, Contact Wireshark developers" " if you want this supported", opcode); break; } } static void dissect_websocket_payload(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_tree *ws_tree, guint8 opcode) { const guint offset = 0, length = tvb_reported_length(tvb); proto_item *ti; proto_tree *pl_tree; tvbuff_t *tvb_appdata; /* Payload */ ti = proto_tree_add_item(ws_tree, hf_ws_payload, tvb, offset, length, ENC_NA); pl_tree = proto_item_add_subtree(ti, ett_ws_pl); /* Extension Data */ /* TODO: Add dissector of Extension (not extension available for the moment...) */ /* Application Data */ if (opcode == WS_CONTINUE) { proto_tree_add_item(tree, hf_ws_payload_continue, tvb, offset, length, ENC_NA); /* TODO: Add Fragmentation support (needs FIN bit) * https://tools.ietf.org/html/rfc6455#section-5.4 */ return; } /* Right now this is exactly the same, this may change when exts. are added. tvb_appdata = tvb_new_subset(tvb, offset, length, length); */ tvb_appdata = tvb; if (opcode & 8) { /* Control frames have MSB set. */ dissect_websocket_control_frame(tvb_appdata, pinfo, pl_tree, opcode); } else { dissect_websocket_data_frame(tvb_appdata, pinfo, tree, pl_tree, opcode); } } static int dissect_websocket_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { proto_item *ti, *ti_len; guint8 fin, opcode; gboolean mask; guint short_length, payload_length; guint payload_offset, mask_offset; proto_tree *ws_tree; const guint8 *masking_key = NULL; tvbuff_t *tvb_payload; short_length = tvb_get_guint8(tvb, 1) & MASK_WS_PAYLOAD_LEN; mask_offset = 2; if (short_length == 126) { payload_length = tvb_get_ntohs(tvb, 2); mask_offset += 2; } else if (short_length == 127) { /* warning C4244: '=' : conversion from 'guint64' to 'guint ', possible loss of data */ payload_length = (guint)tvb_get_ntoh64(tvb, 2); mask_offset += 8; } else { payload_length = short_length; } /* Mask */ mask = (tvb_get_guint8(tvb, 1) & MASK_WS_MASK) != 0; payload_offset = mask_offset + (mask ? 4 : 0); col_set_str(pinfo->cinfo, COL_PROTOCOL, "WebSocket"); col_set_str(pinfo->cinfo, COL_INFO, "WebSocket"); ti = proto_tree_add_item(tree, proto_websocket, tvb, 0, payload_offset, ENC_NA); ws_tree = proto_item_add_subtree(ti, ett_ws); /* Flags */ proto_tree_add_item(ws_tree, hf_ws_fin, tvb, 0, 1, ENC_NA); fin = (tvb_get_guint8(tvb, 0) & MASK_WS_FIN) >> 4; proto_tree_add_item(ws_tree, hf_ws_reserved, tvb, 0, 1, ENC_BIG_ENDIAN); /* Opcode */ proto_tree_add_item(ws_tree, hf_ws_opcode, tvb, 0, 1, ENC_BIG_ENDIAN); opcode = tvb_get_guint8(tvb, 0) & MASK_WS_OPCODE; col_append_fstr(pinfo->cinfo, COL_INFO, " %s", val_to_str_const(opcode, ws_opcode_vals, "Unknown Opcode")); col_append_str(pinfo->cinfo, COL_INFO, fin ? " [FIN]" : " "); /* Add Mask bit to the tree */ proto_tree_add_item(ws_tree, hf_ws_mask, tvb, 1, 1, ENC_NA); col_append_str(pinfo->cinfo, COL_INFO, mask ? " [MASKED]" : " "); /* (Extended) Payload Length */ ti_len = proto_tree_add_item(ws_tree, hf_ws_payload_length, tvb, 1, 1, ENC_BIG_ENDIAN); if (short_length == 126) { proto_item_append_text(ti_len, " Extended Payload Length (16 bits)"); proto_tree_add_item(ws_tree, hf_ws_payload_length_ext_16, tvb, 2, 2, ENC_BIG_ENDIAN); } else if (short_length == 127) { proto_item_append_text(ti_len, " Extended Payload Length (64 bits)"); proto_tree_add_item(ws_tree, hf_ws_payload_length_ext_64, tvb, 2, 8, ENC_BIG_ENDIAN); } /* Masking-key */ if (mask) { proto_tree_add_item(ws_tree, hf_ws_masking_key, tvb, mask_offset, 4, ENC_NA); masking_key = tvb_get_ptr(tvb, mask_offset, 4); } if (payload_length > 0) { /* Always unmask payload data before analysing it. */ if (mask) { proto_tree_add_item(ws_tree, hf_ws_masked_payload, tvb, payload_offset, payload_length, ENC_NA); tvb_payload = tvb_unmasked(tvb, pinfo, payload_offset, payload_length, masking_key); tvb_set_child_real_data_tvbuff(tvb, tvb_payload); add_new_data_source(pinfo, tvb_payload, "Unmasked data"); } else { tvb_payload = tvb_new_subset(tvb, payload_offset, payload_length, payload_length); } dissect_websocket_payload(tvb_payload, pinfo, tree, ws_tree, opcode); } return tvb_captured_length(tvb); } static guint get_websocket_frame_length(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_) { guint frame_length, payload_length; gboolean mask; frame_length = 2; /* flags, opcode and Payload length */ mask = tvb_get_guint8(tvb, offset + 1) & MASK_WS_MASK; payload_length = tvb_get_guint8(tvb, offset + 1) & MASK_WS_PAYLOAD_LEN; offset += 2; /* Skip flags, opcode and Payload length */ /* Check for Extended Payload Length. */ if (payload_length == 126) { if (tvb_reported_length_remaining(tvb, offset) < 2) return 0; /* Need more data. */ payload_length = tvb_get_ntohs(tvb, offset); frame_length += 2; /* Extended payload length */ } else if (payload_length == 127) { if (tvb_reported_length_remaining(tvb, offset) < 8) return 0; /* Need more data. */ payload_length = (guint)tvb_get_ntoh64(tvb, offset); frame_length += 8; /* Extended payload length */ } if (mask) frame_length += 4; /* Masking-key */ frame_length += payload_length; /* Payload data */ return frame_length; } static int dissect_websocket(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data) { /* Need at least two bytes for flags, opcode and Payload length. */ tcp_dissect_pdus(tvb, pinfo, tree, TRUE, 2, get_websocket_frame_length, dissect_websocket_frame, data); return tvb_captured_length(tvb); } void proto_register_websocket(void) { static hf_register_info hf[] = { { &hf_ws_fin, { "Fin", "websocket.fin", FT_BOOLEAN, 8, NULL, MASK_WS_FIN, "Indicates that this is the final fragment in a message", HFILL } }, { &hf_ws_reserved, { "Reserved", "websocket.rsv", FT_UINT8, BASE_HEX, NULL, MASK_WS_RSV, "Must be zero", HFILL } }, { &hf_ws_opcode, { "Opcode", "websocket.opcode", FT_UINT8, BASE_DEC, VALS(ws_opcode_vals), MASK_WS_OPCODE, "Defines the interpretation of the Payload data", HFILL } }, { &hf_ws_mask, { "Mask", "websocket.mask", FT_BOOLEAN, 8, NULL, MASK_WS_MASK, "Defines whether the Payload data is masked", HFILL } }, { &hf_ws_payload_length, { "Payload length", "websocket.payload_length", FT_UINT8, BASE_DEC, NULL, MASK_WS_PAYLOAD_LEN, "The length of the Payload data", HFILL } }, { &hf_ws_payload_length_ext_16, { "Extended Payload length (16 bits)", "websocket.payload_length_ext_16", FT_UINT16, BASE_DEC, NULL, 0x0, "The length (16 bits) of the Payload data", HFILL } }, { &hf_ws_payload_length_ext_64, { "Extended Payload length (64 bits)", "websocket.payload_length_ext_64", FT_UINT64, BASE_DEC, NULL, 0x0, "The length (64 bits) of the Payload data", HFILL } }, { &hf_ws_masking_key, { "Masking-Key", "websocket.masking_key", FT_BYTES, BASE_NONE, NULL, 0x0, "All frames sent from the client to the server are masked by a 32-bit value that is contained within the frame", HFILL } }, { &hf_ws_payload, { "Payload", "websocket.payload", FT_NONE, BASE_NONE, NULL, 0x0, "Payload (after unmasking)", HFILL } }, { &hf_ws_masked_payload, { "Masked payload", "websocket.masked_payload", FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_continue, { "Continue", "websocket.payload.continue", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_close, { "Close", "websocket.payload.close", FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_close_status_code, { "Status code", "websocket.payload.close.status_code", FT_UINT16, BASE_DEC, VALS(ws_close_status_code_vals), 0x0, NULL, HFILL } }, { &hf_ws_payload_close_reason, { "Reason", "websocket.payload.close.reason", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_ping, { "Ping", "websocket.payload.ping", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_pong, { "Pong", "websocket.payload.pong", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_unknown, { "Unknown", "websocket.payload.unknown", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, }; static gint *ett[] = { &ett_ws, &ett_ws_pl, &ett_ws_mask, &ett_ws_control_close, }; static ei_register_info ei[] = { { &ei_ws_payload_unknown, { "websocket.payload.unknown.expert", PI_UNDECODED, PI_NOTE, "Dissector for Websocket Opcode", EXPFILL }}, }; static const enum_val_t text_types[] = { {"None", "No subdissection", WEBSOCKET_NONE}, {"Line based text", "Line based text", WEBSOCKET_TEXT}, {"As JSON", "As json", WEBSOCKET_JSON}, {"As SIP", "As SIP", WEBSOCKET_SIP}, {NULL, NULL, -1} }; module_t *websocket_module; expert_module_t* expert_websocket; proto_websocket = proto_register_protocol("WebSocket", "WebSocket", "websocket"); /* * Heuristic dissectors SHOULD register themselves in * this table using the standard heur_dissector_add() * function. */ heur_subdissector_list = register_heur_dissector_list("ws"); port_subdissector_table = register_dissector_table("ws.port", "TCP port for protocols using WebSocket", FT_UINT16, BASE_DEC, DISSECTOR_TABLE_NOT_ALLOW_DUPLICATE); proto_register_field_array(proto_websocket, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); expert_websocket = expert_register_protocol(proto_websocket); expert_register_field_array(expert_websocket, ei, array_length(ei)); register_dissector("websocket", dissect_websocket, proto_websocket); websocket_module = prefs_register_protocol(proto_websocket, proto_reg_handoff_websocket); prefs_register_enum_preference(websocket_module, "text_type", "Dissect websocket text as", "Select dissector for websocket text", &pref_text_type, text_types, WEBSOCKET_NONE); } void proto_reg_handoff_websocket(void) { data_handle = find_dissector("data"); text_lines_handle = find_dissector("data-text-lines"); json_handle = find_dissector("json"); sip_handle = find_dissector("sip"); proto_http = proto_get_id_by_filter_name("http"); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 2 * tab-width: 8 * indent-tabs-mode: nil * End: * * vi: set shiftwidth=2 tabstop=8 expandtab: * :indentSize=2:tabSize=8:noTabs=true: */