guacamole-spice-protocol/src/protocols/ssh/sftp.c

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/*
* Copyright (C) 2013 Glyptodon LLC
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
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#include "config.h"
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#include "client.h"
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#include "sftp.h"
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#include <fcntl.h>
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#include <libgen.h>
#include <stdbool.h>
#include <string.h>
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#include <libssh2_sftp.h>
#include <guacamole/client.h>
#include <guacamole/protocol.h>
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#include <guacamole/socket.h>
#include <guacamole/stream.h>
static bool __ssh_guac_valid_filename(char* filename) {
/* Disallow "." as a filename */
if (strcmp(filename, ".") == 0)
return false;
/* Disallow ".." as a filename */
if (strcmp(filename, "..") == 0)
return false;
/* Search for path separator characters */
for (;;) {
char c = *(filename++);
if (c == '\0')
break;
/* Replace slashes with underscores */
if (c == '\\' || c == '/')
return false;
}
/* If filename does not contain a path, it's ok */
return true;
}
int guac_sftp_file_handler(guac_client* client, guac_stream* stream,
char* mimetype, char* filename) {
ssh_guac_client_data* client_data = (ssh_guac_client_data*) client->data;
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char fullpath[GUAC_SFTP_MAX_PATH];
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LIBSSH2_SFTP_HANDLE* file;
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int i;
/* Ensure filename is a valid filename and not a path */
if (!__ssh_guac_valid_filename(filename)) {
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guac_protocol_send_ack(client->socket, stream, "SFTP: Illegal filename",
GUAC_PROTOCOL_STATUS_CLIENT_BAD_REQUEST);
guac_socket_flush(client->socket);
return 0;
}
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/* Copy upload path, append trailing slash */
for (i=0; i<GUAC_SFTP_MAX_PATH; i++) {
char c = client_data->sftp_upload_path[i];
if (c == '\0') {
fullpath[i++] = '/';
break;
}
fullpath[i] = c;
}
/* Append filename */
for (; i<GUAC_SFTP_MAX_PATH; i++) {
char c = *(filename++);
if (c == '\0')
break;
fullpath[i] = c;
}
/* If path + filename exceeds max length, abort */
if (i == GUAC_SFTP_MAX_PATH) {
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guac_protocol_send_ack(client->socket, stream, "SFTP: Name too long", GUAC_PROTOCOL_STATUS_CLIENT_OVERRUN);
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guac_socket_flush(client->socket);
return 0;
}
/* Terminate path string */
fullpath[i] = '\0';
/* Open file via SFTP */
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file = libssh2_sftp_open(client_data->sftp_session, fullpath,
LIBSSH2_FXF_WRITE | LIBSSH2_FXF_CREAT | LIBSSH2_FXF_TRUNC,
S_IRUSR | S_IWUSR);
/* Inform of status */
if (file != NULL) {
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guac_protocol_send_ack(client->socket, stream, "SFTP: File opened", GUAC_PROTOCOL_STATUS_SUCCESS);
guac_socket_flush(client->socket);
}
else {
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guac_client_log_error(client, "Unable to open file \"%s\": %s",
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fullpath, libssh2_sftp_last_error(client_data->sftp_session));
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guac_protocol_send_ack(client->socket, stream, "SFTP: Open failed", GUAC_PROTOCOL_STATUS_RESOURCE_NOT_FOUND);
guac_socket_flush(client->socket);
}
/* Set handlers for file stream */
stream->blob_handler = guac_sftp_blob_handler;
stream->end_handler = guac_sftp_end_handler;
/* Store file within stream */
stream->data = file;
return 0;
}
int guac_sftp_blob_handler(guac_client* client, guac_stream* stream,
void* data, int length) {
/* Pull file from stream */
ssh_guac_client_data* client_data = (ssh_guac_client_data*) client->data;
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LIBSSH2_SFTP_HANDLE* file = (LIBSSH2_SFTP_HANDLE*) stream->data;
/* Attempt write */
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if (libssh2_sftp_write(file, data, length) == length) {
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guac_protocol_send_ack(client->socket, stream, "SFTP: OK", GUAC_PROTOCOL_STATUS_SUCCESS);
guac_socket_flush(client->socket);
}
/* Inform of any errors */
else {
guac_client_log_error(client, "Unable to write to file: %s",
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libssh2_sftp_last_error(client_data->sftp_session));
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guac_protocol_send_ack(client->socket, stream, "SFTP: Write failed", GUAC_PROTOCOL_STATUS_SERVER_ERROR);
guac_socket_flush(client->socket);
}
return 0;
}
int guac_sftp_end_handler(guac_client* client, guac_stream* stream) {
/* Pull file from stream */
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LIBSSH2_SFTP_HANDLE* file = (LIBSSH2_SFTP_HANDLE*) stream->data;
/* Attempt to close file */
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if (libssh2_sftp_close(file) == 0) {
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guac_protocol_send_ack(client->socket, stream, "SFTP: OK", GUAC_PROTOCOL_STATUS_SUCCESS);
guac_socket_flush(client->socket);
}
else {
guac_client_log_error(client, "Unable to close file");
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guac_protocol_send_ack(client->socket, stream, "SFTP: Close failed", GUAC_PROTOCOL_STATUS_SERVER_ERROR);
guac_socket_flush(client->socket);
}
return 0;
}
int guac_sftp_ack_handler(guac_client* client, guac_stream* stream,
char* message, guac_protocol_status status) {
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ssh_guac_client_data* client_data = (ssh_guac_client_data*) client->data;
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LIBSSH2_SFTP_HANDLE* file = (LIBSSH2_SFTP_HANDLE*) stream->data;
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/* If successful, read data */
if (status == GUAC_PROTOCOL_STATUS_SUCCESS) {
/* Attempt read into buffer */
char buffer[4096];
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int bytes_read = libssh2_sftp_read(file, buffer, sizeof(buffer));
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/* If bytes read, send as blob */
if (bytes_read > 0)
guac_protocol_send_blob(client->socket, stream,
buffer, bytes_read);
/* If EOF, send end */
else if (bytes_read == 0) {
guac_protocol_send_end(client->socket, stream);
guac_client_free_stream(client, stream);
}
/* Otherwise, fail stream */
else {
guac_client_log_error(client, "Error reading file: %s",
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libssh2_sftp_last_error(client_data->sftp_session));
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guac_protocol_send_end(client->socket, stream);
guac_client_free_stream(client, stream);
}
guac_socket_flush(client->socket);
}
/* Otherwise, return stream to client */
else
guac_client_free_stream(client, stream);
return 0;
}
guac_stream* guac_sftp_download_file(guac_client* client,
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char* filename) {
ssh_guac_client_data* client_data = (ssh_guac_client_data*) client->data;
guac_stream* stream;
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LIBSSH2_SFTP_HANDLE* file;
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/* Attempt to open file for reading */
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file = libssh2_sftp_open(client_data->sftp_session, filename,
LIBSSH2_FXF_READ, 0);
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if (file == NULL) {
guac_client_log_error(client, "Unable to read file \"%s\": %s",
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filename,
libssh2_sftp_last_error(client_data->sftp_session));
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return NULL;
}
/* Allocate stream */
stream = guac_client_alloc_stream(client);
stream->ack_handler = guac_sftp_ack_handler;
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stream->data = file;
/* Send stream start, strip name */
filename = basename(filename);
guac_protocol_send_file(client->socket, stream,
"application/octet-stream", filename);
guac_socket_flush(client->socket);
return stream;
}
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void guac_sftp_set_upload_path(guac_client* client, char* path) {
ssh_guac_client_data* client_data = (ssh_guac_client_data*) client->data;
int length = strnlen(path, GUAC_SFTP_MAX_PATH);
/* Ignore requests which exceed maximum-allowed path */
if (length > GUAC_SFTP_MAX_PATH) {
guac_client_log_error(client,
"Submitted path exceeds limit of %i bytes",
GUAC_SFTP_MAX_PATH);
return;
}
/* Copy path */
memcpy(client_data->sftp_upload_path, path, length);
}