| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| #include "config.h" |
| #include "guac_recording.h" |
| #include "telnet.h" |
| #include "terminal.h" |
| |
| #include <guacamole/client.h> |
| #include <guacamole/protocol.h> |
| #include <libtelnet.h> |
| |
| #include <errno.h> |
| #include <netdb.h> |
| #include <netinet/in.h> |
| #include <poll.h> |
| #include <pthread.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/socket.h> |
| #include <sys/time.h> |
| #include <unistd.h> |
| |
| /** |
| * Support levels for various telnet options, required for connection |
| * negotiation by telnet_init(), part of libtelnet. |
| */ |
| static const telnet_telopt_t __telnet_options[] = { |
| { TELNET_TELOPT_ECHO, TELNET_WONT, TELNET_DO }, |
| { TELNET_TELOPT_TTYPE, TELNET_WILL, TELNET_DONT }, |
| { TELNET_TELOPT_COMPRESS2, TELNET_WONT, TELNET_DO }, |
| { TELNET_TELOPT_MSSP, TELNET_WONT, TELNET_DO }, |
| { TELNET_TELOPT_NAWS, TELNET_WILL, TELNET_DONT }, |
| { TELNET_TELOPT_NEW_ENVIRON, TELNET_WILL, TELNET_DONT }, |
| { -1, 0, 0 } |
| }; |
| |
| /** |
| * Write the entire buffer given to the specified file descriptor, retrying |
| * the write automatically if necessary. This function will return a value |
| * not equal to the buffer's size iff an error occurs which prevents all |
| * future writes. |
| * |
| * @param fd The file descriptor to write to. |
| * @param buffer The buffer to write. |
| * @param size The number of bytes from the buffer to write. |
| */ |
| static int __guac_telnet_write_all(int fd, const char* buffer, int size) { |
| |
| int remaining = size; |
| while (remaining > 0) { |
| |
| /* Attempt to write data */ |
| int ret_val = write(fd, buffer, remaining); |
| if (ret_val <= 0) |
| return -1; |
| |
| /* If successful, contine with what data remains (if any) */ |
| remaining -= ret_val; |
| buffer += ret_val; |
| |
| } |
| |
| return size; |
| |
| } |
| |
| /** |
| * Searches for a line matching the stored password regex, appending the given |
| * buffer to the internal pattern matching buffer. The internal pattern match |
| * buffer is cleared whenever a newline is read. Returns TRUE if a match is found and the |
| * value is sent. |
| */ |
| static bool __guac_telnet_regex_search(guac_client* client, regex_t* regex, char* value, const char* buffer, int size) { |
| |
| static char line_buffer[1024] = {0}; |
| static int length = 0; |
| |
| guac_telnet_client* telnet_client = (guac_telnet_client*) client->data; |
| |
| int i; |
| const char* current; |
| |
| /* Ensure line buffer contains only the most recent line */ |
| current = buffer; |
| for (i = 0; i < size; i++) { |
| |
| /* Reset line buffer and shift input buffer for each newline */ |
| if (*(current++) == '\n') { |
| length = 0; |
| buffer += i; |
| size -= i; |
| i = 0; |
| } |
| } |
| |
| /* Truncate if necessary */ |
| if (size + length + 1 > sizeof(line_buffer)) |
| size = sizeof(line_buffer) - length - 1; |
| |
| /* Append to line */ |
| memcpy(&(line_buffer[length]), buffer, size); |
| length += size; |
| line_buffer[length] = '\0'; |
| |
| /* Send value upon match */ |
| if (regexec(regex, line_buffer, 0, NULL, 0) == 0) { |
| |
| /* Send value */ |
| guac_terminal_send_string(telnet_client->term, value); |
| guac_terminal_send_key(telnet_client->term, 0xFF0D, 1); |
| guac_terminal_send_key(telnet_client->term, 0xFF0D, 0); |
| |
| /* Stop searching for prompt */ |
| return TRUE; |
| |
| } |
| |
| return FALSE; |
| } |
| |
| /** |
| * Event handler, as defined by libtelnet. This function is passed to |
| * telnet_init() and will be called for every event fired by libtelnet, |
| * including feature enable/disable and receipt/transmission of data. |
| */ |
| static void __guac_telnet_event_handler(telnet_t* telnet, telnet_event_t* event, void* data) { |
| |
| guac_client* client = (guac_client*) data; |
| guac_telnet_client* telnet_client = (guac_telnet_client*) client->data; |
| guac_telnet_settings* settings = telnet_client->settings; |
| |
| switch (event->type) { |
| |
| /* Terminal output received */ |
| case TELNET_EV_DATA: |
| guac_terminal_write(telnet_client->term, event->data.buffer, event->data.size); |
| |
| /* Continue search for username prompt */ |
| if (settings->username_regex != NULL) { |
| if (__guac_telnet_regex_search(client, |
| settings->username_regex, settings->username, |
| event->data.buffer, event->data.size)) { |
| guac_client_log(client, GUAC_LOG_DEBUG, "Username sent"); |
| regfree(settings->username_regex); |
| free(settings->username_regex); |
| settings->username_regex = NULL; |
| } |
| } |
| |
| /* Continue search for password prompt */ |
| if (settings->password_regex != NULL) { |
| if (__guac_telnet_regex_search(client, |
| settings->password_regex, settings->password, |
| event->data.buffer, event->data.size)) { |
| |
| guac_client_log(client, GUAC_LOG_DEBUG, "Password sent"); |
| |
| /* Do not continue searching for username once password is sent */ |
| if (settings->username_regex != NULL) { |
| regfree(settings->username_regex); |
| free(settings->username_regex); |
| settings->username_regex = NULL; |
| } |
| |
| regfree(settings->password_regex); |
| free(settings->password_regex); |
| settings->password_regex = NULL; |
| } |
| } |
| break; |
| |
| /* Data destined for remote end */ |
| case TELNET_EV_SEND: |
| if (__guac_telnet_write_all(telnet_client->socket_fd, event->data.buffer, event->data.size) |
| != event->data.size) |
| guac_client_stop(client); |
| break; |
| |
| /* Remote feature enabled */ |
| case TELNET_EV_WILL: |
| if (event->neg.telopt == TELNET_TELOPT_ECHO) |
| telnet_client->echo_enabled = 0; /* Disable local echo, as remote will echo */ |
| break; |
| |
| /* Remote feature disabled */ |
| case TELNET_EV_WONT: |
| if (event->neg.telopt == TELNET_TELOPT_ECHO) |
| telnet_client->echo_enabled = 1; /* Enable local echo, as remote won't echo */ |
| break; |
| |
| /* Local feature enable */ |
| case TELNET_EV_DO: |
| if (event->neg.telopt == TELNET_TELOPT_NAWS) { |
| telnet_client->naws_enabled = 1; |
| guac_telnet_send_naws(telnet, telnet_client->term->term_width, telnet_client->term->term_height); |
| } |
| break; |
| |
| /* Terminal type request */ |
| case TELNET_EV_TTYPE: |
| if (event->ttype.cmd == TELNET_TTYPE_SEND) |
| telnet_ttype_is(telnet_client->telnet, "linux"); |
| break; |
| |
| /* Environment request */ |
| case TELNET_EV_ENVIRON: |
| |
| /* Only send USER if entire environment was requested */ |
| if (event->environ.size == 0) |
| guac_telnet_send_user(telnet, settings->username); |
| |
| break; |
| |
| /* Connection warnings */ |
| case TELNET_EV_WARNING: |
| guac_client_log(client, GUAC_LOG_WARNING, "%s", event->error.msg); |
| break; |
| |
| /* Connection errors */ |
| case TELNET_EV_ERROR: |
| guac_client_abort(client, GUAC_PROTOCOL_STATUS_UPSTREAM_ERROR, |
| "Telnet connection closing with error: %s", event->error.msg); |
| break; |
| |
| /* Ignore other events */ |
| default: |
| break; |
| |
| } |
| |
| } |
| |
| /** |
| * Input thread, started by the main telnet client thread. This thread |
| * continuously reads from the terminal's STDIN and transfers all read |
| * data to the telnet connection. |
| * |
| * @param data The current guac_client instance. |
| * @return Always NULL. |
| */ |
| static void* __guac_telnet_input_thread(void* data) { |
| |
| guac_client* client = (guac_client*) data; |
| guac_telnet_client* telnet_client = (guac_telnet_client*) client->data; |
| |
| char buffer[8192]; |
| int bytes_read; |
| |
| /* Write all data read */ |
| while ((bytes_read = guac_terminal_read_stdin(telnet_client->term, buffer, sizeof(buffer))) > 0) { |
| telnet_send(telnet_client->telnet, buffer, bytes_read); |
| if (telnet_client->echo_enabled) |
| guac_terminal_write(telnet_client->term, buffer, bytes_read); |
| } |
| |
| return NULL; |
| |
| } |
| |
| /** |
| * Connects to the telnet server specified within the data associated |
| * with the given guac_client, which will have been populated by |
| * guac_client_init. |
| * |
| * @return The connected telnet instance, if successful, or NULL if the |
| * connection fails for any reason. |
| */ |
| static telnet_t* __guac_telnet_create_session(guac_client* client) { |
| |
| int retval; |
| |
| int fd; |
| struct addrinfo* addresses; |
| struct addrinfo* current_address; |
| |
| char connected_address[1024]; |
| char connected_port[64]; |
| |
| guac_telnet_client* telnet_client = (guac_telnet_client*) client->data; |
| guac_telnet_settings* settings = telnet_client->settings; |
| |
| struct addrinfo hints = { |
| .ai_family = AF_UNSPEC, |
| .ai_socktype = SOCK_STREAM, |
| .ai_protocol = IPPROTO_TCP |
| }; |
| |
| /* Get socket */ |
| fd = socket(AF_INET, SOCK_STREAM, 0); |
| |
| /* Get addresses connection */ |
| if ((retval = getaddrinfo(settings->hostname, settings->port, |
| &hints, &addresses))) { |
| guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR, "Error parsing given address or port: %s", |
| gai_strerror(retval)); |
| return NULL; |
| |
| } |
| |
| /* Attempt connection to each address until success */ |
| current_address = addresses; |
| while (current_address != NULL) { |
| |
| int retval; |
| |
| /* Resolve hostname */ |
| if ((retval = getnameinfo(current_address->ai_addr, |
| current_address->ai_addrlen, |
| connected_address, sizeof(connected_address), |
| connected_port, sizeof(connected_port), |
| NI_NUMERICHOST | NI_NUMERICSERV))) |
| guac_client_log(client, GUAC_LOG_DEBUG, "Unable to resolve host: %s", gai_strerror(retval)); |
| |
| /* Connect */ |
| if (connect(fd, current_address->ai_addr, |
| current_address->ai_addrlen) == 0) { |
| |
| guac_client_log(client, GUAC_LOG_DEBUG, "Successfully connected to " |
| "host %s, port %s", connected_address, connected_port); |
| |
| /* Done if successful connect */ |
| break; |
| |
| } |
| |
| /* Otherwise log information regarding bind failure */ |
| else |
| guac_client_log(client, GUAC_LOG_DEBUG, "Unable to connect to " |
| "host %s, port %s: %s", |
| connected_address, connected_port, strerror(errno)); |
| |
| current_address = current_address->ai_next; |
| |
| } |
| |
| /* If unable to connect to anything, fail */ |
| if (current_address == NULL) { |
| guac_client_abort(client, GUAC_PROTOCOL_STATUS_UPSTREAM_ERROR, "Unable to connect to any addresses."); |
| return NULL; |
| } |
| |
| /* Free addrinfo */ |
| freeaddrinfo(addresses); |
| |
| /* Open telnet session */ |
| telnet_t* telnet = telnet_init(__telnet_options, __guac_telnet_event_handler, 0, client); |
| if (telnet == NULL) { |
| guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR, "Telnet client allocation failed."); |
| return NULL; |
| } |
| |
| /* Save file descriptor */ |
| telnet_client->socket_fd = fd; |
| |
| return telnet; |
| |
| } |
| |
| /** |
| * Sends a 16-bit value over the given telnet connection with the byte order |
| * required by the telnet protocol. |
| * |
| * @param telnet The telnet connection to use. |
| * @param value The value to send. |
| */ |
| static void __guac_telnet_send_uint16(telnet_t* telnet, uint16_t value) { |
| |
| unsigned char buffer[2]; |
| buffer[0] = (value >> 8) & 0xFF; |
| buffer[1] = value & 0xFF; |
| |
| telnet_send(telnet, (char*) buffer, 2); |
| |
| } |
| |
| /** |
| * Sends an 8-bit value over the given telnet connection. |
| * |
| * @param telnet The telnet connection to use. |
| * @param value The value to send. |
| */ |
| static void __guac_telnet_send_uint8(telnet_t* telnet, uint8_t value) { |
| telnet_send(telnet, (char*) (&value), 1); |
| } |
| |
| void guac_telnet_send_naws(telnet_t* telnet, uint16_t width, uint16_t height) { |
| telnet_begin_sb(telnet, TELNET_TELOPT_NAWS); |
| __guac_telnet_send_uint16(telnet, width); |
| __guac_telnet_send_uint16(telnet, height); |
| telnet_finish_sb(telnet); |
| } |
| |
| void guac_telnet_send_user(telnet_t* telnet, const char* username) { |
| |
| /* IAC SB NEW-ENVIRON IS */ |
| telnet_begin_sb(telnet, TELNET_TELOPT_NEW_ENVIRON); |
| __guac_telnet_send_uint8(telnet, TELNET_ENVIRON_IS); |
| |
| /* Only send username if defined */ |
| if (username != NULL) { |
| |
| /* VAR "USER" */ |
| __guac_telnet_send_uint8(telnet, TELNET_ENVIRON_VAR); |
| telnet_send(telnet, "USER", 4); |
| |
| /* VALUE username */ |
| __guac_telnet_send_uint8(telnet, TELNET_ENVIRON_VALUE); |
| telnet_send(telnet, username, strlen(username)); |
| |
| } |
| |
| /* IAC SE */ |
| telnet_finish_sb(telnet); |
| |
| } |
| |
| /** |
| * Waits for data on the given file descriptor for up to one second. The |
| * return value is identical to that of select(): 0 on timeout, < 0 on |
| * error, and > 0 on success. |
| * |
| * @param socket_fd The file descriptor to wait for. |
| * @return A value greater than zero on success, zero on timeout, and |
| * less than zero on error. |
| */ |
| static int __guac_telnet_wait(int socket_fd) { |
| |
| /* Build array of file descriptors */ |
| struct pollfd fds[] = {{ |
| .fd = socket_fd, |
| .events = POLLIN, |
| .revents = 0, |
| }}; |
| |
| /* Wait for one second */ |
| return poll(fds, 1, 1000); |
| |
| } |
| |
| void* guac_telnet_client_thread(void* data) { |
| |
| guac_client* client = (guac_client*) data; |
| guac_telnet_client* telnet_client = (guac_telnet_client*) client->data; |
| guac_telnet_settings* settings = telnet_client->settings; |
| |
| pthread_t input_thread; |
| char buffer[8192]; |
| int wait_result; |
| |
| /* Set up screen recording, if requested */ |
| if (settings->recording_path != NULL) { |
| guac_common_recording_create(client, |
| settings->recording_path, |
| settings->recording_name, |
| settings->create_recording_path); |
| } |
| |
| /* Create terminal */ |
| telnet_client->term = guac_terminal_create(client, |
| settings->font_name, settings->font_size, |
| settings->resolution, settings->width, settings->height, |
| settings->color_scheme); |
| |
| /* Fail if terminal init failed */ |
| if (telnet_client->term == NULL) { |
| guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR, |
| "Terminal initialization failed"); |
| return NULL; |
| } |
| |
| /* Set up typescript, if requested */ |
| if (settings->typescript_path != NULL) { |
| guac_terminal_create_typescript(telnet_client->term, |
| settings->typescript_path, |
| settings->typescript_name, |
| settings->create_typescript_path); |
| } |
| |
| /* Open telnet session */ |
| telnet_client->telnet = __guac_telnet_create_session(client); |
| if (telnet_client->telnet == NULL) { |
| /* Already aborted within __guac_telnet_create_session() */ |
| return NULL; |
| } |
| |
| /* Logged in */ |
| guac_client_log(client, GUAC_LOG_INFO, "Telnet connection successful."); |
| |
| /* Start input thread */ |
| if (pthread_create(&(input_thread), NULL, __guac_telnet_input_thread, (void*) client)) { |
| guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR, "Unable to start input thread"); |
| return NULL; |
| } |
| |
| /* While data available, write to terminal */ |
| while ((wait_result = __guac_telnet_wait(telnet_client->socket_fd)) >= 0) { |
| |
| /* Resume waiting of no data available */ |
| if (wait_result == 0) |
| continue; |
| |
| int bytes_read = read(telnet_client->socket_fd, buffer, sizeof(buffer)); |
| if (bytes_read <= 0) |
| break; |
| |
| telnet_recv(telnet_client->telnet, buffer, bytes_read); |
| |
| } |
| |
| /* Kill client and Wait for input thread to die */ |
| guac_client_stop(client); |
| pthread_join(input_thread, NULL); |
| |
| guac_client_log(client, GUAC_LOG_INFO, "Telnet connection ended."); |
| return NULL; |
| |
| } |
| |
