diff options
Diffstat (limited to 'ui/vnc-ws.c')
| -rw-r--r-- | ui/vnc-ws.c | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/ui/vnc-ws.c b/ui/vnc-ws.c new file mode 100644 index 00000000..b4cb6bde --- /dev/null +++ b/ui/vnc-ws.c @@ -0,0 +1,381 @@ +/* + * 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 <http://www.gnu.org/licenses/>. + */ + +#include "vnc.h" +#include "qemu/main-loop.h" +#include "crypto/hash.h" + +#ifdef CONFIG_VNC_TLS +#include "qemu/sockets.h" + +static int vncws_start_tls_handshake(VncState *vs) +{ + int ret = gnutls_handshake(vs->tls.session); + + if (ret < 0) { + if (!gnutls_error_is_fatal(ret)) { + VNC_DEBUG("Handshake interrupted (blocking)\n"); + if (!gnutls_record_get_direction(vs->tls.session)) { + qemu_set_fd_handler(vs->csock, vncws_tls_handshake_io, + NULL, vs); + } else { + qemu_set_fd_handler(vs->csock, NULL, vncws_tls_handshake_io, + vs); + } + return 0; + } + VNC_DEBUG("Handshake failed %s\n", gnutls_strerror(ret)); + vnc_client_error(vs); + return -1; + } + + if (vs->vd->tls.x509verify) { + if (vnc_tls_validate_certificate(vs) < 0) { + VNC_DEBUG("Client verification failed\n"); + vnc_client_error(vs); + return -1; + } else { + VNC_DEBUG("Client verification passed\n"); + } + } + + VNC_DEBUG("Handshake done, switching to TLS data mode\n"); + qemu_set_fd_handler(vs->csock, vncws_handshake_read, NULL, vs); + + return 0; +} + +void vncws_tls_handshake_io(void *opaque) +{ + VncState *vs = (VncState *)opaque; + + if (!vs->tls.session) { + VNC_DEBUG("TLS Websocket setup\n"); + if (vnc_tls_client_setup(vs, vs->vd->tls.x509cert != NULL) < 0) { + return; + } + } + VNC_DEBUG("Handshake IO continue\n"); + vncws_start_tls_handshake(vs); +} +#endif /* CONFIG_VNC_TLS */ + +void vncws_handshake_read(void *opaque) +{ + VncState *vs = opaque; + uint8_t *handshake_end; + long ret; + /* Typical HTTP headers from novnc are 512 bytes, so limiting + * total header size to 4096 is easily enough. */ + size_t want = 4096 - vs->ws_input.offset; + buffer_reserve(&vs->ws_input, want); + ret = vnc_client_read_buf(vs, buffer_end(&vs->ws_input), want); + + 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_handler(vs->csock, 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)); + } else if (vs->ws_input.offset >= 4096) { + VNC_DEBUG("End of headers not found in first 4096 bytes\n"); + vnc_client_error(vs); + } +} + + +long vnc_client_read_ws(VncState *vs) +{ + int ret, err; + uint8_t *payload; + size_t payload_size, header_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; + + ret = 0; + /* consume as much of ws_input buffer as possible */ + do { + if (vs->ws_payload_remain == 0) { + err = vncws_decode_frame_header(&vs->ws_input, + &header_size, + &vs->ws_payload_remain, + &vs->ws_payload_mask); + if (err <= 0) { + return err; + } + + buffer_advance(&vs->ws_input, header_size); + } + if (vs->ws_payload_remain != 0) { + err = vncws_decode_frame_payload(&vs->ws_input, + &vs->ws_payload_remain, + &vs->ws_payload_mask, + &payload, + &payload_size); + if (err < 0) { + return err; + } + if (err == 0) { + return ret; + } + ret += err; + + buffer_reserve(&vs->input, payload_size); + buffer_append(&vs->input, payload, payload_size); + + buffer_advance(&vs->ws_input, payload_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_handler(vs->csock, 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 *accept = NULL, *response = NULL; + Error *err = NULL; + + 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 */ + if (qcrypto_hash_base64(QCRYPTO_HASH_ALG_SHA1, + combined_key, + WS_CLIENT_KEY_LEN + WS_GUID_LEN, + &accept, + &err) < 0) { + VNC_DEBUG("Hashing Websocket combined key failed %s\n", + error_get_pretty(err)); + error_free(err); + vnc_client_error(vs); + return; + } + + response = g_strdup_printf(WS_HANDSHAKE, accept); + vnc_client_write_buf(vs, (const uint8_t *)response, strlen(response)); + + 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_header(Buffer *input, + size_t *header_size, + size_t *payload_remain, + WsMask *payload_mask) +{ + unsigned char opcode = 0, fin = 0, has_mask = 0; + size_t payload_len; + WsHeader *header = (WsHeader *)input->buffer; + + 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_len = 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_len < 126) { + *payload_remain = payload_len; + *header_size = 6; + *payload_mask = header->u.m; + } else if (payload_len == 126 && input->offset >= 8) { + *payload_remain = be16_to_cpu(header->u.s16.l16); + *header_size = 8; + *payload_mask = header->u.s16.m16; + } else if (payload_len == 127 && input->offset >= 14) { + *payload_remain = be64_to_cpu(header->u.s64.l64); + *header_size = 14; + *payload_mask = header->u.s64.m64; + } else { + /* header not complete */ + return 0; + } + + return 1; +} + +int vncws_decode_frame_payload(Buffer *input, + size_t *payload_remain, WsMask *payload_mask, + uint8_t **payload, size_t *payload_size) +{ + size_t i; + uint32_t *payload32; + + *payload = input->buffer; + /* If we aren't at the end of the payload, then drop + * off the last bytes, so we're always multiple of 4 + * for purpose of unmasking, except at end of payload + */ + if (input->offset < *payload_remain) { + *payload_size = input->offset - (input->offset % 4); + } else { + *payload_size = *payload_remain; + } + if (*payload_size == 0) { + return 0; + } + *payload_remain -= *payload_size; + + /* unmask frame */ + /* process 1 frame (32 bit op) */ + payload32 = (uint32_t *)(*payload); + for (i = 0; i < *payload_size / 4; i++) { + payload32[i] ^= payload_mask->u; + } + /* process the remaining bytes (if any) */ + for (i *= 4; i < *payload_size; i++) { + (*payload)[i] ^= payload_mask->c[i % 4]; + } + + return 1; +} |