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libssh.c
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1 /*
2  * Copyright (c) 2013 Lukasz Marek <lukasz.m.luki@gmail.com>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <fcntl.h>
22 #define LIBSSH_STATIC
23 #include <libssh/sftp.h>
24 #include "libavutil/avstring.h"
25 #include "libavutil/opt.h"
26 #include "libavutil/attributes.h"
27 #include "avformat.h"
28 #include "internal.h"
29 #include "url.h"
30 
31 typedef struct {
32  const AVClass *class;
33  ssh_session session;
34  sftp_session sftp;
35  sftp_file file;
36  int64_t filesize;
38  int trunc;
39  char *priv_key;
41 
42 static av_cold int libssh_create_ssh_session(LIBSSHContext *libssh, const char* hostname, unsigned int port)
43 {
44  static const int verbosity = SSH_LOG_NOLOG;
45 
46  if (!(libssh->session = ssh_new())) {
47  av_log(libssh, AV_LOG_ERROR, "SSH session creation failed: %s\n", ssh_get_error(libssh->session));
48  return AVERROR(ENOMEM);
49  }
50  ssh_options_set(libssh->session, SSH_OPTIONS_HOST, hostname);
51  ssh_options_set(libssh->session, SSH_OPTIONS_PORT, &port);
52  ssh_options_set(libssh->session, SSH_OPTIONS_LOG_VERBOSITY, &verbosity);
53  if (libssh->rw_timeout > 0) {
54  long timeout = libssh->rw_timeout * 1000;
55  ssh_options_set(libssh->session, SSH_OPTIONS_TIMEOUT_USEC, &timeout);
56  }
57 
58  if (ssh_connect(libssh->session) != SSH_OK) {
59  av_log(libssh, AV_LOG_ERROR, "Connection failed: %s\n", ssh_get_error(libssh->session));
60  return AVERROR(EIO);
61  }
62 
63  return 0;
64 }
65 
66 static av_cold int libssh_authentication(LIBSSHContext *libssh, const char *user, const char *password)
67 {
68  int authorized = 0;
69  int auth_methods;
70 
71  if (user)
72  ssh_options_set(libssh->session, SSH_OPTIONS_USER, user);
73 
74  if (ssh_userauth_none(libssh->session, NULL) == SSH_AUTH_SUCCESS)
75  return 0;
76 
77  auth_methods = ssh_userauth_list(libssh->session, NULL);
78 
79  if (auth_methods & SSH_AUTH_METHOD_PUBLICKEY) {
80  if (libssh->priv_key) {
81  ssh_string pub_key;
82  ssh_private_key priv_key;
83  int type;
84  if (!ssh_try_publickey_from_file(libssh->session, libssh->priv_key, &pub_key, &type)) {
85  priv_key = privatekey_from_file(libssh->session, libssh->priv_key, type, password);
86  if (ssh_userauth_pubkey(libssh->session, NULL, pub_key, priv_key) == SSH_AUTH_SUCCESS) {
87  av_log(libssh, AV_LOG_DEBUG, "Authentication successful with selected private key.\n");
88  authorized = 1;
89  }
90  } else {
91  av_log(libssh, AV_LOG_DEBUG, "Invalid key is provided.\n");
92  return AVERROR(EACCES);
93  }
94  } else if (ssh_userauth_autopubkey(libssh->session, password) == SSH_AUTH_SUCCESS) {
95  av_log(libssh, AV_LOG_DEBUG, "Authentication successful with auto selected key.\n");
96  authorized = 1;
97  }
98  }
99 
100  if (!authorized && (auth_methods & SSH_AUTH_METHOD_PASSWORD)) {
101  if (ssh_userauth_password(libssh->session, NULL, password) == SSH_AUTH_SUCCESS) {
102  av_log(libssh, AV_LOG_DEBUG, "Authentication successful with password.\n");
103  authorized = 1;
104  }
105  }
106 
107  if (!authorized) {
108  av_log(libssh, AV_LOG_ERROR, "Authentication failed.\n");
109  return AVERROR(EACCES);
110  }
111 
112  return 0;
113 }
114 
116 {
117  if (!(libssh->sftp = sftp_new(libssh->session))) {
118  av_log(libssh, AV_LOG_ERROR, "SFTP session creation failed: %s\n", ssh_get_error(libssh->session));
119  return AVERROR(ENOMEM);
120  }
121 
122  if (sftp_init(libssh->sftp) != SSH_OK) {
123  av_log(libssh, AV_LOG_ERROR, "Error initializing sftp session: %s\n", ssh_get_error(libssh->session));
124  return AVERROR(EIO);
125  }
126 
127  return 0;
128 }
129 
130 static av_cold int libssh_open_file(LIBSSHContext *libssh, int flags, const char *file)
131 {
132  int access;
133 
134  if ((flags & AVIO_FLAG_WRITE) && (flags & AVIO_FLAG_READ)) {
135  access = O_CREAT | O_RDWR;
136  if (libssh->trunc)
137  access |= O_TRUNC;
138  } else if (flags & AVIO_FLAG_WRITE) {
139  access = O_CREAT | O_WRONLY;
140  if (libssh->trunc)
141  access |= O_TRUNC;
142  } else
143  access = O_RDONLY;
144 
145  /* 0666 = -rw-rw-rw- = read+write for everyone, minus umask */
146  if (!(libssh->file = sftp_open(libssh->sftp, file, access, 0666))) {
147  av_log(libssh, AV_LOG_ERROR, "Error opening sftp file: %s\n", ssh_get_error(libssh->session));
148  return AVERROR(EIO);
149  }
150 
151  return 0;
152 }
153 
155 {
156  sftp_attributes stat;
157 
158  if (!(stat = sftp_fstat(libssh->file))) {
159  av_log(libssh, AV_LOG_WARNING, "Cannot stat remote file.\n");
160  libssh->filesize = -1;
161  } else {
162  libssh->filesize = stat->size;
163  sftp_attributes_free(stat);
164  }
165 }
166 
168 {
169  LIBSSHContext *libssh = h->priv_data;
170  if (libssh->file) {
171  sftp_close(libssh->file);
172  libssh->file = NULL;
173  }
174  if (libssh->sftp) {
175  sftp_free(libssh->sftp);
176  libssh->sftp = NULL;
177  }
178  if (libssh->session) {
179  ssh_disconnect(libssh->session);
180  ssh_free(libssh->session);
181  libssh->session = NULL;
182  }
183  return 0;
184 }
185 
186 static av_cold int libssh_open(URLContext *h, const char *url, int flags)
187 {
188  LIBSSHContext *libssh = h->priv_data;
189  char proto[10], path[MAX_URL_SIZE], hostname[1024], credencials[1024];
190  int port = 22, ret;
191  const char *user = NULL, *pass = NULL;
192  char *end = NULL;
193 
194  av_url_split(proto, sizeof(proto),
195  credencials, sizeof(credencials),
196  hostname, sizeof(hostname),
197  &port,
198  path, sizeof(path),
199  url);
200 
201  if (port <= 0 || port > 65535)
202  port = 22;
203 
204  if ((ret = libssh_create_ssh_session(libssh, hostname, port)) < 0)
205  goto fail;
206 
207  user = av_strtok(credencials, ":", &end);
208  pass = av_strtok(end, ":", &end);
209 
210  if ((ret = libssh_authentication(libssh, user, pass)) < 0)
211  goto fail;
212 
213  if ((ret = libssh_create_sftp_session(libssh)) < 0)
214  goto fail;
215 
216  if ((ret = libssh_open_file(libssh, flags, path)) < 0)
217  goto fail;
218 
219  libssh_stat_file(libssh);
220 
221  return 0;
222 
223  fail:
224  libssh_close(h);
225  return ret;
226 }
227 
228 static int64_t libssh_seek(URLContext *h, int64_t pos, int whence)
229 {
230  LIBSSHContext *libssh = h->priv_data;
231  int64_t newpos;
232 
233  if (libssh->filesize == -1 && (whence == AVSEEK_SIZE || whence == SEEK_END)) {
234  av_log(h, AV_LOG_ERROR, "Error during seeking.\n");
235  return AVERROR(EIO);
236  }
237 
238  switch(whence) {
239  case AVSEEK_SIZE:
240  return libssh->filesize;
241  case SEEK_SET:
242  newpos = pos;
243  break;
244  case SEEK_CUR:
245  newpos = sftp_tell64(libssh->file) + pos;
246  break;
247  case SEEK_END:
248  newpos = libssh->filesize + pos;
249  break;
250  default:
251  return AVERROR(EINVAL);
252  }
253 
254  if (newpos < 0) {
255  av_log(h, AV_LOG_ERROR, "Seeking to nagative position.\n");
256  return AVERROR(EINVAL);
257  }
258 
259  if (sftp_seek64(libssh->file, newpos)) {
260  av_log(h, AV_LOG_ERROR, "Error during seeking.\n");
261  return AVERROR(EIO);
262  }
263 
264  return newpos;
265 }
266 
267 static int libssh_read(URLContext *h, unsigned char *buf, int size)
268 {
269  LIBSSHContext *libssh = h->priv_data;
270  int bytes_read;
271 
272  if ((bytes_read = sftp_read(libssh->file, buf, size)) < 0) {
273  av_log(libssh, AV_LOG_ERROR, "Read error.\n");
274  return AVERROR(EIO);
275  }
276  return bytes_read;
277 }
278 
279 static int libssh_write(URLContext *h, const unsigned char *buf, int size)
280 {
281  LIBSSHContext *libssh = h->priv_data;
282  int bytes_written;
283 
284  if ((bytes_written = sftp_write(libssh->file, buf, size)) < 0) {
285  av_log(libssh, AV_LOG_ERROR, "Write error.\n");
286  return AVERROR(EIO);
287  }
288  return bytes_written;
289 }
290 
291 #define OFFSET(x) offsetof(LIBSSHContext, x)
292 #define D AV_OPT_FLAG_DECODING_PARAM
293 #define E AV_OPT_FLAG_ENCODING_PARAM
294 static const AVOption options[] = {
295  {"timeout", "set timeout of socket I/O operations", OFFSET(rw_timeout), AV_OPT_TYPE_INT, {.i64 = -1}, -1, INT_MAX, D|E },
296  {"truncate", "Truncate existing files on write", OFFSET(trunc), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, E },
297  {"private_key", "set path to private key", OFFSET(priv_key), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D|E },
298  {NULL}
299 };
300 
302  .class_name = "libssh",
303  .item_name = av_default_item_name,
304  .option = options,
305  .version = LIBAVUTIL_VERSION_INT,
306 };
307 
309  .name = "sftp",
310  .url_open = libssh_open,
311  .url_read = libssh_read,
312  .url_write = libssh_write,
313  .url_seek = libssh_seek,
314  .url_close = libssh_close,
315  .priv_data_size = sizeof(LIBSSHContext),
316  .priv_data_class = &libssh_context_class,
318 };