From 7536ee4bc3da7e9b7fdadba5ba6ade63eaace430 Mon Sep 17 00:00:00 2001 From: Tim Hardeck Date: Mon, 21 Jan 2013 11:04:44 +0100 Subject: vnc: added initial websocket protocol support This patch adds basic Websocket Protocol version 13 - RFC 6455 - support to QEMU VNC. Binary encoding support on the client side is mandatory. Because of the GnuTLS requirement the Websockets implementation is optional (--enable-vnc-ws). To activate Websocket support the VNC option "websocket"is used, for example "-vnc :0,websocket". The listen port for Websocket connections is (5700 + display) so if QEMU VNC is started with :0 the Websocket port would be 5700. As an alternative the Websocket port could be manually specified by using ",websocket=" instead. Parts of the implementation base on Anthony Liguori's QEMU Websocket patch from 2010 and on Joel Martin's LibVNC Websocket implementation. Signed-off-by: Tim Hardeck Signed-off-by: Anthony Liguori --- ui/vnc-ws.c | 284 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 284 insertions(+) create mode 100644 ui/vnc-ws.c (limited to 'ui/vnc-ws.c') diff --git a/ui/vnc-ws.c b/ui/vnc-ws.c new file mode 100644 index 0000000..9ccdc19 --- /dev/null +++ b/ui/vnc-ws.c @@ -0,0 +1,284 @@ +/* + * QEMU VNC display driver: Websockets support + * + * Copyright (C) 2010 Joel Martin + * Copyright (C) 2012 Tim Hardeck + * + * This 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 software 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 software; if not, see . + */ + +#include "vnc.h" + +void vncws_handshake_read(void *opaque) +{ + VncState *vs = opaque; + uint8_t *handshake_end; + long ret; + buffer_reserve(&vs->ws_input, 4096); + ret = vnc_client_read_buf(vs, buffer_end(&vs->ws_input), 4096); + + if (!ret) { + if (vs->csock == -1) { + vnc_disconnect_finish(vs); + } + return; + } + vs->ws_input.offset += ret; + + handshake_end = (uint8_t *)g_strstr_len((char *)vs->ws_input.buffer, + vs->ws_input.offset, WS_HANDSHAKE_END); + if (handshake_end) { + qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs); + vncws_process_handshake(vs, vs->ws_input.buffer, vs->ws_input.offset); + buffer_advance(&vs->ws_input, handshake_end - vs->ws_input.buffer + + strlen(WS_HANDSHAKE_END)); + } +} + + +long vnc_client_read_ws(VncState *vs) +{ + int ret, err; + uint8_t *payload; + size_t payload_size, frame_size; + VNC_DEBUG("Read websocket %p size %zd offset %zd\n", vs->ws_input.buffer, + vs->ws_input.capacity, vs->ws_input.offset); + buffer_reserve(&vs->ws_input, 4096); + ret = vnc_client_read_buf(vs, buffer_end(&vs->ws_input), 4096); + if (!ret) { + return 0; + } + vs->ws_input.offset += ret; + + /* make sure that nothing is left in the ws_input buffer */ + do { + err = vncws_decode_frame(&vs->ws_input, &payload, + &payload_size, &frame_size); + if (err <= 0) { + return err; + } + + buffer_reserve(&vs->input, payload_size); + buffer_append(&vs->input, payload, payload_size); + + buffer_advance(&vs->ws_input, frame_size); + } while (vs->ws_input.offset > 0); + + return ret; +} + +long vnc_client_write_ws(VncState *vs) +{ + long ret; + VNC_DEBUG("Write WS: Pending output %p size %zd offset %zd\n", + vs->output.buffer, vs->output.capacity, vs->output.offset); + vncws_encode_frame(&vs->ws_output, vs->output.buffer, vs->output.offset); + buffer_reset(&vs->output); + ret = vnc_client_write_buf(vs, vs->ws_output.buffer, vs->ws_output.offset); + if (!ret) { + return 0; + } + + buffer_advance(&vs->ws_output, ret); + + if (vs->ws_output.offset == 0) { + qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs); + } + + return ret; +} + +static char *vncws_extract_handshake_entry(const char *handshake, + size_t handshake_len, const char *name) +{ + char *begin, *end, *ret = NULL; + char *line = g_strdup_printf("%s%s: ", WS_HANDSHAKE_DELIM, name); + begin = g_strstr_len(handshake, handshake_len, line); + if (begin != NULL) { + begin += strlen(line); + end = g_strstr_len(begin, handshake_len - (begin - handshake), + WS_HANDSHAKE_DELIM); + if (end != NULL) { + ret = g_strndup(begin, end - begin); + } + } + g_free(line); + return ret; +} + +static void vncws_send_handshake_response(VncState *vs, const char* key) +{ + char combined_key[WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1]; + char hash[SHA1_DIGEST_LEN]; + size_t hash_size = SHA1_DIGEST_LEN; + char *accept = NULL, *response = NULL; + gnutls_datum_t in; + + g_strlcpy(combined_key, key, WS_CLIENT_KEY_LEN + 1); + g_strlcat(combined_key, WS_GUID, WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1); + + /* hash and encode it */ + in.data = (void *)combined_key; + in.size = WS_CLIENT_KEY_LEN + WS_GUID_LEN; + if (gnutls_fingerprint(GNUTLS_DIG_SHA1, &in, hash, &hash_size) + == GNUTLS_E_SUCCESS) { + accept = g_base64_encode((guchar *)hash, SHA1_DIGEST_LEN); + } + if (accept == NULL) { + VNC_DEBUG("Hashing Websocket combined key failed\n"); + vnc_client_error(vs); + return; + } + + response = g_strdup_printf(WS_HANDSHAKE, accept); + vnc_write(vs, response, strlen(response)); + vnc_flush(vs); + + g_free(accept); + g_free(response); + + vs->encode_ws = 1; + vnc_init_state(vs); +} + +void vncws_process_handshake(VncState *vs, uint8_t *line, size_t size) +{ + char *protocols = vncws_extract_handshake_entry((const char *)line, size, + "Sec-WebSocket-Protocol"); + char *version = vncws_extract_handshake_entry((const char *)line, size, + "Sec-WebSocket-Version"); + char *key = vncws_extract_handshake_entry((const char *)line, size, + "Sec-WebSocket-Key"); + + if (protocols && version && key + && g_strrstr(protocols, "binary") + && !strcmp(version, WS_SUPPORTED_VERSION) + && strlen(key) == WS_CLIENT_KEY_LEN) { + vncws_send_handshake_response(vs, key); + } else { + VNC_DEBUG("Defective Websockets header or unsupported protocol\n"); + vnc_client_error(vs); + } + + g_free(protocols); + g_free(version); + g_free(key); +} + +void vncws_encode_frame(Buffer *output, const void *payload, + const size_t payload_size) +{ + size_t header_size = 0; + unsigned char opcode = WS_OPCODE_BINARY_FRAME; + union { + char buf[WS_HEAD_MAX_LEN]; + WsHeader ws; + } header; + + if (!payload_size) { + return; + } + + header.ws.b0 = 0x80 | (opcode & 0x0f); + if (payload_size <= 125) { + header.ws.b1 = (uint8_t)payload_size; + header_size = 2; + } else if (payload_size < 65536) { + header.ws.b1 = 0x7e; + header.ws.u.s16.l16 = cpu_to_be16((uint16_t)payload_size); + header_size = 4; + } else { + header.ws.b1 = 0x7f; + header.ws.u.s64.l64 = cpu_to_be64(payload_size); + header_size = 10; + } + + buffer_reserve(output, header_size + payload_size); + buffer_append(output, header.buf, header_size); + buffer_append(output, payload, payload_size); +} + +int vncws_decode_frame(Buffer *input, uint8_t **payload, + size_t *payload_size, size_t *frame_size) +{ + unsigned char opcode = 0, fin = 0, has_mask = 0; + size_t header_size = 0; + uint32_t *payload32; + WsHeader *header = (WsHeader *)input->buffer; + WsMask mask; + int i; + + if (input->offset < WS_HEAD_MIN_LEN + 4) { + /* header not complete */ + return 0; + } + + fin = (header->b0 & 0x80) >> 7; + opcode = header->b0 & 0x0f; + has_mask = (header->b1 & 0x80) >> 7; + *payload_size = header->b1 & 0x7f; + + if (opcode == WS_OPCODE_CLOSE) { + /* disconnect */ + return -1; + } + + /* Websocket frame sanity check: + * * Websocket fragmentation is not supported. + * * All websockets frames sent by a client have to be masked. + * * Only binary encoding is supported. + */ + if (!fin || !has_mask || opcode != WS_OPCODE_BINARY_FRAME) { + VNC_DEBUG("Received faulty/unsupported Websocket frame\n"); + return -2; + } + + if (*payload_size < 126) { + header_size = 6; + mask = header->u.m; + } else if (*payload_size == 126 && input->offset >= 8) { + *payload_size = be16_to_cpu(header->u.s16.l16); + header_size = 8; + mask = header->u.s16.m16; + } else if (*payload_size == 127 && input->offset >= 14) { + *payload_size = be64_to_cpu(header->u.s64.l64); + header_size = 14; + mask = header->u.s64.m64; + } else { + /* header not complete */ + return 0; + } + + *frame_size = header_size + *payload_size; + + if (input->offset < *frame_size) { + /* frame not complete */ + return 0; + } + + *payload = input->buffer + header_size; + + /* unmask frame */ + /* process 1 frame (32 bit op) */ + payload32 = (uint32_t *)(*payload); + for (i = 0; i < *payload_size / 4; i++) { + payload32[i] ^= mask.u; + } + /* process the remaining bytes (if any) */ + for (i *= 4; i < *payload_size; i++) { + (*payload)[i] ^= mask.c[i % 4]; + } + + return 1; +} -- cgit v1.1