/* packet-websocket.c * Routines for WebSocket dissection * Copyright 2012, Alexis La Goutte * * $Id$ * * 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. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include #include /* * The information used comes from: * RFC6455: The WebSocket Protocol * http://www.iana.org/assignments/websocket (last updated 2012-04-12) */ /* Initialize the protocol and registered fields */ static int proto_websocket = -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_payload_unmask = -1; static int hf_ws_payload_continue = -1; static int hf_ws_payload_text = -1; static int hf_ws_payload_text_mask = -1; static int hf_ws_payload_text_unmask = -1; static int hf_ws_payload_binary = -1; static int hf_ws_payload_binary_mask = -1; static int hf_ws_payload_binary_unmask = -1; static int hf_ws_payload_close = -1; static int hf_ws_payload_close_mask = -1; static int hf_ws_payload_close_unmask = -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_ping_mask = -1; static int hf_ws_payload_ping_unmask = -1; static int hf_ws_payload_pong = -1; static int hf_ws_payload_pong_mask = -1; static int hf_ws_payload_pong_unmask = -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; #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} }; #define MAX_UNMASKED_LEN (1024 * 64) tvbuff_t * tvb_unmasked(tvbuff_t *tvb, const int offset, int payload_length, const guint8 *masking_key) { gchar *data_unmask; tvbuff_t *tvb_unmask = NULL; int i; const guint8 *data_mask; int unmasked_length = payload_length > MAX_UNMASKED_LEN ? MAX_UNMASKED_LEN : payload_length; data_unmask = g_malloc(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]; } tvb_unmask = tvb_new_real_data(data_unmask, unmasked_length, unmasked_length); tvb_set_free_cb(tvb_unmask, g_free); return tvb_unmask; } static int dissect_websocket_payload(tvbuff_t *tvb, packet_info *pinfo, proto_tree *ws_tree, guint8 opcode, guint64 payload_length, guint8 mask, const guint8* masking_key) { int offset = 0; int payload_length_32bit; proto_item *ti_unmask, *ti; proto_tree *pl_tree, *mask_tree = NULL; tvbuff_t *unmask_tvb = NULL; /* Wireshark does not handle packets larger than 2^31-1 bytes. */ payload_length_32bit = (int)payload_length; if (payload_length != (guint64)payload_length_32bit) { proto_tree_add_text(ws_tree, tvb, offset, -1, "Payload length %" G_GINT64_MODIFIER "u is too large to dissect", payload_length); return tvb_length(tvb); } /* Payload */ ti = proto_tree_add_item(ws_tree, hf_ws_payload, tvb, offset, payload_length_32bit, ENC_NA); pl_tree = proto_item_add_subtree(ti, ett_ws_pl); if(mask){ unmask_tvb = tvb_unmasked(tvb, offset, payload_length_32bit, masking_key); tvb_set_child_real_data_tvbuff(tvb, unmask_tvb); add_new_data_source(pinfo, unmask_tvb, payload_length_32bit > (int) tvb_length(unmask_tvb) ? "Unmasked Data (truncated)" : "Unmasked Data"); ti = proto_tree_add_item(ws_tree, hf_ws_payload_unmask, unmask_tvb, offset, payload_length_32bit, ENC_NA); mask_tree = proto_item_add_subtree(ti, ett_ws_mask); } /* Extension Data */ /* TODO: Add dissector of Extension (not extension available for the moment...) */ /* Application Data */ switch(opcode){ case WS_CONTINUE: /* Continue */ proto_tree_add_item(pl_tree, hf_ws_payload_continue, tvb, offset, payload_length_32bit, ENC_NA); /* TODO: Add Fragmentation support... */ break; case WS_TEXT: /* Text */ if(mask){ proto_tree_add_item(pl_tree, hf_ws_payload_text_mask, tvb, offset, payload_length_32bit, ENC_NA); ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_text_unmask, unmask_tvb, offset, payload_length_32bit, ENC_UTF_8|ENC_NA); PROTO_ITEM_SET_GENERATED(ti_unmask); ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_text, unmask_tvb, offset, payload_length_32bit, ENC_UTF_8|ENC_NA); PROTO_ITEM_SET_HIDDEN(ti_unmask); }else{ proto_tree_add_item(pl_tree, hf_ws_payload_text, tvb, offset, payload_length_32bit, ENC_UTF_8|ENC_NA); } offset += payload_length_32bit; break; case WS_BINARY: /* Binary */ if(mask){ proto_tree_add_item(pl_tree, hf_ws_payload_binary_mask, tvb, offset, payload_length_32bit, ENC_NA); ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_binary_unmask, unmask_tvb, offset, payload_length_32bit, ENC_NA); PROTO_ITEM_SET_GENERATED(ti_unmask); ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_binary, unmask_tvb, offset, payload_length_32bit, ENC_NA); PROTO_ITEM_SET_HIDDEN(ti_unmask); }else{ proto_tree_add_item(pl_tree, hf_ws_payload_binary, tvb, offset, payload_length_32bit, ENC_NA); } offset += payload_length_32bit; break; case WS_CLOSE: /* Close */ if(mask){ proto_tree_add_item(pl_tree, hf_ws_payload_close_mask, tvb, offset, payload_length_32bit, ENC_NA); ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_close_unmask, unmask_tvb, offset, payload_length_32bit, ENC_NA); PROTO_ITEM_SET_GENERATED(ti_unmask); ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_close, unmask_tvb, offset, payload_length_32bit, ENC_NA); PROTO_ITEM_SET_HIDDEN(ti_unmask); ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_close_status_code, unmask_tvb, offset, 2, ENC_BIG_ENDIAN); PROTO_ITEM_SET_GENERATED(ti_unmask); if(payload_length_32bit > 2){ ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_close_reason, unmask_tvb, offset+2, payload_length_32bit-2, ENC_ASCII|ENC_NA); PROTO_ITEM_SET_GENERATED(ti_unmask); } }else{ proto_tree_add_item(pl_tree, hf_ws_payload_close, tvb, offset, payload_length_32bit, ENC_NA); proto_tree_add_item(pl_tree, hf_ws_payload_close_status_code, tvb, offset, 2, ENC_BIG_ENDIAN); if(payload_length_32bit > 2){ proto_tree_add_item(pl_tree, hf_ws_payload_close_reason, tvb, offset+2, payload_length_32bit-2, ENC_ASCII|ENC_NA); } } offset += payload_length_32bit; break; case WS_PING: /* Ping */ if(mask){ proto_tree_add_item(pl_tree, hf_ws_payload_ping_mask, tvb, offset, payload_length_32bit, ENC_NA); ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_ping_unmask, unmask_tvb, offset, payload_length_32bit, ENC_NA); PROTO_ITEM_SET_GENERATED(ti_unmask); ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_ping, unmask_tvb, offset, payload_length_32bit, ENC_NA); PROTO_ITEM_SET_HIDDEN(ti_unmask); }else{ proto_tree_add_item(pl_tree, hf_ws_payload_ping, tvb, offset, payload_length_32bit, ENC_NA); } offset += payload_length_32bit; break; case WS_PONG: /* Pong */ if(mask){ proto_tree_add_item(pl_tree, hf_ws_payload_pong_mask, tvb, offset, payload_length_32bit, ENC_NA); ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_pong_unmask, unmask_tvb, offset, payload_length_32bit, ENC_NA); PROTO_ITEM_SET_GENERATED(ti_unmask); ti_unmask = proto_tree_add_item(mask_tree, hf_ws_payload_pong, unmask_tvb, offset, payload_length_32bit, ENC_NA); PROTO_ITEM_SET_HIDDEN(ti_unmask); }else{ proto_tree_add_item(pl_tree, hf_ws_payload_pong, tvb, offset, payload_length_32bit, ENC_NA); } offset += payload_length_32bit; break; default: /* Unknown */ ti = proto_tree_add_item(pl_tree, hf_ws_payload_unknown, tvb, offset, payload_length_32bit, ENC_NA); expert_add_info_format(pinfo, ti, PI_UNDECODED, PI_NOTE, "Dissector for Websocket Opcode (%d)" " code not implemented, Contact Wireshark developers" " if you want this supported", opcode); break; } return offset; } static int dissect_websocket(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_item *ti, *ti_len; proto_tree *ws_tree = NULL; int offset = 0; guint8 fin, opcode, mask; const guint8 *masking_key = NULL; guint64 payload_length; tvbuff_t *tvb_payload = NULL; col_set_str(pinfo->cinfo, COL_PROTOCOL, "WebSocket"); col_set_str(pinfo->cinfo, COL_INFO, "WebSocket"); if (tree) { ti = proto_tree_add_item(tree, proto_websocket, tvb, 0, -1, ENC_NA); ws_tree = proto_item_add_subtree(ti, ett_ws); } /* Flags */ proto_tree_add_item(ws_tree, hf_ws_fin, tvb, offset, 1, ENC_NA); fin = (tvb_get_guint8(tvb, offset) & MASK_WS_FIN) >> 4; proto_tree_add_item(ws_tree, hf_ws_reserved, tvb, offset, 1, ENC_NA); /* Opcode */ proto_tree_add_item(ws_tree, hf_ws_opcode, tvb, offset, 1, ENC_NA); opcode = tvb_get_guint8(tvb, offset) & MASK_WS_OPCODE; col_append_fstr(pinfo->cinfo, COL_INFO, " %s", val_to_str_const(opcode, ws_opcode_vals, "Unknown Opcode")); col_append_fstr(pinfo->cinfo, COL_INFO, " %s", fin ? "[FIN]" : ""); offset +=1; /* Mask */ proto_tree_add_item(ws_tree, hf_ws_mask, tvb, offset, 1, ENC_NA); mask = (tvb_get_guint8(tvb, offset) & MASK_WS_MASK) >> 4; col_append_fstr(pinfo->cinfo, COL_INFO, " %s", mask ? "[MASKED]" : ""); /* (Extended) Payload Length */ ti_len = proto_tree_add_item(ws_tree, hf_ws_payload_length, tvb, offset, 1, ENC_NA); payload_length = (guint64)tvb_get_guint8(tvb, offset) & MASK_WS_PAYLOAD_LEN; offset +=1; switch(payload_length){ case 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, offset, 2, ENC_BIG_ENDIAN); payload_length = (guint64)tvb_get_ntohs(tvb, offset); offset += 2; break; case 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, offset, 8, ENC_BIG_ENDIAN); payload_length = tvb_get_ntoh64(tvb, offset); offset += 8; break; default: break; } /* Masking-key */ if(mask){ proto_tree_add_item(ws_tree, hf_ws_masking_key, tvb, offset, 4, ENC_NA); masking_key = tvb_get_ptr(tvb, offset, 4); offset += 4; } tvb_payload = tvb_new_subset_remaining(tvb, offset); offset += dissect_websocket_payload(tvb_payload, pinfo, ws_tree, opcode, payload_length, mask, masking_key); return offset; } 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 (16 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, NULL, HFILL } }, { &hf_ws_payload_unmask, { "Unmask Payload", "websocket.payload.unmask", 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_text, { "Text", "websocket.payload.text", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_text_mask, { "Text", "websocket.payload.text_mask", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_text_unmask, { "Text unmask", "websocket.payload.text_unmask", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_binary, { "Binary", "websocket.payload.binary", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_binary_mask, { "Binary", "websocket.payload.binary_mask", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_binary_unmask, { "Binary", "websocket.payload.binary_unmask", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_close, { "Close", "websocket.payload.close", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_close_mask, { "Close", "websocket.payload.close_mask", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_close_unmask, { "Unmask Close", "websocket.payload.close_unmask", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_close_status_code, { "Close", "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_ping_mask, { "Ping", "websocket.payload.ping_mask", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_ping_unmask, { "Ping", "websocket.payload.ping_unmask", 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_pong_mask, { "Pong", "websocket.payload.pong_mask", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_ws_payload_pong_unmask, { "Pong", "websocket.payload.pong_unmask", 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 }; proto_websocket = proto_register_protocol("WebSocket", "WebSocket", "websocket"); proto_register_field_array(proto_websocket, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); new_register_dissector("websocket", dissect_websocket, proto_websocket); } /* * Editor modelines - http://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: */