FFmpeg  4.4.5
tls_mbedtls.c
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1 /*
2  * TLS/SSL Protocol
3  * Copyright (c) 2018 Thomas Volkert
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <mbedtls/version.h>
23 #include <mbedtls/ctr_drbg.h>
24 #include <mbedtls/entropy.h>
25 #include <mbedtls/net_sockets.h>
26 #include <mbedtls/platform.h>
27 #include <mbedtls/ssl.h>
28 #include <mbedtls/x509_crt.h>
29 
30 #include "avformat.h"
31 #include "internal.h"
32 #include "url.h"
33 #include "tls.h"
34 #include "libavutil/parseutils.h"
35 
36 typedef struct TLSContext {
37  const AVClass *class;
39  mbedtls_ssl_context ssl_context;
40  mbedtls_ssl_config ssl_config;
41  mbedtls_entropy_context entropy_context;
42  mbedtls_ctr_drbg_context ctr_drbg_context;
43  mbedtls_x509_crt ca_cert;
44  mbedtls_x509_crt own_cert;
45  mbedtls_pk_context priv_key;
46  char *priv_key_pw;
47 } TLSContext;
48 
49 #define OFFSET(x) offsetof(TLSContext, x)
50 
51 static int tls_close(URLContext *h)
52 {
53  TLSContext *tls_ctx = h->priv_data;
54 
55  mbedtls_ssl_close_notify(&tls_ctx->ssl_context);
56  mbedtls_pk_free(&tls_ctx->priv_key);
57  mbedtls_x509_crt_free(&tls_ctx->ca_cert);
58  mbedtls_x509_crt_free(&tls_ctx->own_cert);
59  mbedtls_ssl_free(&tls_ctx->ssl_context);
60  mbedtls_ssl_config_free(&tls_ctx->ssl_config);
61  mbedtls_ctr_drbg_free(&tls_ctx->ctr_drbg_context);
62  mbedtls_entropy_free(&tls_ctx->entropy_context);
63 
64  ffurl_closep(&tls_ctx->tls_shared.tcp);
65  return 0;
66 }
67 
68 static int handle_transport_error(URLContext *h, const char* func_name, int react_on_eagain, int ret)
69 {
70  switch (ret) {
71  case AVERROR(EAGAIN):
72  return react_on_eagain;
73  case AVERROR_EXIT:
74  return 0;
75  case AVERROR(EPIPE):
76  case AVERROR(ECONNRESET):
77  return MBEDTLS_ERR_NET_CONN_RESET;
78  default:
79  av_log(h, AV_LOG_ERROR, "%s returned 0x%x\n", func_name, ret);
80  errno = EIO;
81  return MBEDTLS_ERR_NET_SEND_FAILED;
82  }
83 }
84 
85 static int mbedtls_send(void *ctx, const unsigned char *buf, size_t len)
86 {
87  URLContext *h = (URLContext*) ctx;
88  int ret = ffurl_write(h, buf, len);
89  if (ret >= 0)
90  return ret;
91 
92  if (h->max_packet_size && len > h->max_packet_size)
93  return MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL;
94 
95  return handle_transport_error(h, "ffurl_write", MBEDTLS_ERR_SSL_WANT_WRITE, ret);
96 }
97 
98 static int mbedtls_recv(void *ctx, unsigned char *buf, size_t len)
99 {
100  URLContext *h = (URLContext*) ctx;
101  int ret = ffurl_read(h, buf, len);
102  if (ret >= 0)
103  return ret;
104 
105  if (h->max_packet_size && len > h->max_packet_size)
106  return MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL;
107 
108  return handle_transport_error(h, "ffurl_read", MBEDTLS_ERR_SSL_WANT_READ, ret);
109 }
110 
111 static void handle_pk_parse_error(URLContext *h, int ret)
112 {
113  switch (ret) {
114  case MBEDTLS_ERR_PK_FILE_IO_ERROR:
115  av_log(h, AV_LOG_ERROR, "Read of key file failed. Is it actually there, are the access permissions correct?\n");
116  break;
117  case MBEDTLS_ERR_PK_PASSWORD_REQUIRED:
118  av_log(h, AV_LOG_ERROR, "A password for the private key is missing.\n");
119  break;
120  case MBEDTLS_ERR_PK_PASSWORD_MISMATCH:
121  av_log(h, AV_LOG_ERROR, "The given password for the private key is wrong.\n");
122  break;
123  default:
124  av_log(h, AV_LOG_ERROR, "mbedtls_pk_parse_key returned -0x%x\n", -ret);
125  break;
126  }
127 }
128 
129 static void handle_handshake_error(URLContext *h, int ret)
130 {
131  switch (ret) {
132 #if MBEDTLS_VERSION_MAJOR < 3
133  case MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE:
134  av_log(h, AV_LOG_ERROR, "None of the common ciphersuites is usable. Was the local certificate correctly set?\n");
135  break;
136 #else
137  case MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE:
138  av_log(h, AV_LOG_ERROR, "TLS handshake failed.\n");
139  break;
140 #endif
141  case MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE:
142  av_log(h, AV_LOG_ERROR, "A fatal alert message was received from the peer, has the peer a correct certificate?\n");
143  break;
144  case MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED:
145  av_log(h, AV_LOG_ERROR, "No CA chain is set, but required to operate. Was the CA correctly set?\n");
146  break;
147  case MBEDTLS_ERR_NET_CONN_RESET:
148  av_log(h, AV_LOG_ERROR, "TLS handshake was aborted by peer.\n");
149  break;
150  default:
151  av_log(h, AV_LOG_ERROR, "mbedtls_ssl_handshake returned -0x%x\n", -ret);
152  break;
153  }
154 }
155 
156 static void parse_options(TLSContext *tls_ctxc, const char *uri)
157 {
158  char buf[1024];
159  const char *p = strchr(uri, '?');
160  if (!p)
161  return;
162 
163  if (!tls_ctxc->priv_key_pw && av_find_info_tag(buf, sizeof(buf), "key_password", p))
164  tls_ctxc->priv_key_pw = av_strdup(buf);
165 }
166 
167 static int tls_open(URLContext *h, const char *uri, int flags, AVDictionary **options)
168 {
169  TLSContext *tls_ctx = h->priv_data;
170  TLSShared *shr = &tls_ctx->tls_shared;
171  uint32_t verify_res_flags;
172  int ret;
173 
174  // parse additional options
175  parse_options(tls_ctx, uri);
176 
177  if ((ret = ff_tls_open_underlying(shr, h, uri, options)) < 0)
178  goto fail;
179 
180  mbedtls_ssl_init(&tls_ctx->ssl_context);
181  mbedtls_ssl_config_init(&tls_ctx->ssl_config);
182  mbedtls_entropy_init(&tls_ctx->entropy_context);
183  mbedtls_ctr_drbg_init(&tls_ctx->ctr_drbg_context);
184  mbedtls_x509_crt_init(&tls_ctx->ca_cert);
185  mbedtls_pk_init(&tls_ctx->priv_key);
186 
187  // load trusted CA
188  if (shr->ca_file) {
189  if ((ret = mbedtls_x509_crt_parse_file(&tls_ctx->ca_cert, shr->ca_file)) != 0) {
190  av_log(h, AV_LOG_ERROR, "mbedtls_x509_crt_parse_file for CA cert returned %d\n", ret);
191  goto fail;
192  }
193  }
194 
195  // load own certificate
196  if (shr->cert_file) {
197  if ((ret = mbedtls_x509_crt_parse_file(&tls_ctx->own_cert, shr->cert_file)) != 0) {
198  av_log(h, AV_LOG_ERROR, "mbedtls_x509_crt_parse_file for own cert returned %d\n", ret);
199  goto fail;
200  }
201  }
202 
203  // seed the random number generator
204  if ((ret = mbedtls_ctr_drbg_seed(&tls_ctx->ctr_drbg_context,
205  mbedtls_entropy_func,
206  &tls_ctx->entropy_context,
207  NULL, 0)) != 0) {
208  av_log(h, AV_LOG_ERROR, "mbedtls_ctr_drbg_seed returned %d\n", ret);
209  goto fail;
210  }
211 
212  // load key file
213  if (shr->key_file) {
214  if ((ret = mbedtls_pk_parse_keyfile(&tls_ctx->priv_key,
215  shr->key_file,
216  tls_ctx->priv_key_pw
217 #if MBEDTLS_VERSION_MAJOR >= 3
218  , mbedtls_ctr_drbg_random,
219  &tls_ctx->ctr_drbg_context
220 #endif
221  )) != 0) {
222  handle_pk_parse_error(h, ret);
223  goto fail;
224  }
225  }
226 
227  if ((ret = mbedtls_ssl_config_defaults(&tls_ctx->ssl_config,
228  shr->listen ? MBEDTLS_SSL_IS_SERVER : MBEDTLS_SSL_IS_CLIENT,
229  MBEDTLS_SSL_TRANSPORT_STREAM,
230  MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
231  av_log(h, AV_LOG_ERROR, "mbedtls_ssl_config_defaults returned %d\n", ret);
232  goto fail;
233  }
234 
235  mbedtls_ssl_conf_authmode(&tls_ctx->ssl_config,
236  shr->ca_file ? MBEDTLS_SSL_VERIFY_REQUIRED : MBEDTLS_SSL_VERIFY_NONE);
237  mbedtls_ssl_conf_rng(&tls_ctx->ssl_config, mbedtls_ctr_drbg_random, &tls_ctx->ctr_drbg_context);
238  mbedtls_ssl_conf_ca_chain(&tls_ctx->ssl_config, &tls_ctx->ca_cert, NULL);
239 
240  // set own certificate and private key
241  if ((ret = mbedtls_ssl_conf_own_cert(&tls_ctx->ssl_config, &tls_ctx->own_cert, &tls_ctx->priv_key)) != 0) {
242  av_log(h, AV_LOG_ERROR, "mbedtls_ssl_conf_own_cert returned %d\n", ret);
243  goto fail;
244  }
245 
246  if ((ret = mbedtls_ssl_setup(&tls_ctx->ssl_context, &tls_ctx->ssl_config)) != 0) {
247  av_log(h, AV_LOG_ERROR, "mbedtls_ssl_setup returned %d\n", ret);
248  goto fail;
249  }
250 
251  if (!shr->listen && !shr->numerichost) {
252  if ((ret = mbedtls_ssl_set_hostname(&tls_ctx->ssl_context, shr->host)) != 0) {
253  av_log(h, AV_LOG_ERROR, "mbedtls_ssl_set_hostname returned %d\n", ret);
254  goto fail;
255  }
256  }
257 
258  // set I/O functions to use FFmpeg internal code for transport layer
259  mbedtls_ssl_set_bio(&tls_ctx->ssl_context, shr->tcp, mbedtls_send, mbedtls_recv, NULL);
260 
261  // ssl handshake
262  while ((ret = mbedtls_ssl_handshake(&tls_ctx->ssl_context)) != 0) {
263  if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
265  goto fail;
266  }
267  }
268 
269  if (shr->verify) {
270  // check the result of the certificate verification
271  if ((verify_res_flags = mbedtls_ssl_get_verify_result(&tls_ctx->ssl_context)) != 0) {
272  av_log(h, AV_LOG_ERROR, "mbedtls_ssl_get_verify_result reported problems "\
273  "with the certificate verification, returned flags: %u\n",
274  verify_res_flags);
275  if (verify_res_flags & MBEDTLS_X509_BADCERT_NOT_TRUSTED)
276  av_log(h, AV_LOG_ERROR, "The certificate is not correctly signed by the trusted CA.\n");
277  goto fail;
278  }
279  }
280 
281  return 0;
282 
283 fail:
284  tls_close(h);
285  return AVERROR(EIO);
286 }
287 
288 static int handle_tls_error(URLContext *h, const char* func_name, int ret)
289 {
290  switch (ret) {
291  case MBEDTLS_ERR_SSL_WANT_READ:
292  case MBEDTLS_ERR_SSL_WANT_WRITE:
293  return AVERROR(EAGAIN);
294  case MBEDTLS_ERR_NET_SEND_FAILED:
295  case MBEDTLS_ERR_NET_RECV_FAILED:
296  return AVERROR(EIO);
297  case MBEDTLS_ERR_NET_CONN_RESET:
298  case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
299  av_log(h, AV_LOG_WARNING, "%s reported connection reset by peer\n", func_name);
300  return AVERROR_EOF;
301  default:
302  av_log(h, AV_LOG_ERROR, "%s returned -0x%x\n", func_name, -ret);
303  return AVERROR(EIO);
304  }
305 }
306 
307 static int tls_read(URLContext *h, uint8_t *buf, int size)
308 {
309  TLSContext *tls_ctx = h->priv_data;
310  int ret;
311 
312  if ((ret = mbedtls_ssl_read(&tls_ctx->ssl_context, buf, size)) > 0) {
313  // return read length
314  return ret;
315  }
316 
317  return handle_tls_error(h, "mbedtls_ssl_read", ret);
318 }
319 
320 static int tls_write(URLContext *h, const uint8_t *buf, int size)
321 {
322  TLSContext *tls_ctx = h->priv_data;
323  int ret;
324 
325  if ((ret = mbedtls_ssl_write(&tls_ctx->ssl_context, buf, size)) > 0) {
326  // return written length
327  return ret;
328  }
329 
330  return handle_tls_error(h, "mbedtls_ssl_write", ret);
331 }
332 
334 {
335  TLSContext *c = h->priv_data;
336  return ffurl_get_file_handle(c->tls_shared.tcp);
337 }
338 
340 {
341  TLSContext *s = h->priv_data;
342  return ffurl_get_short_seek(s->tls_shared.tcp);
343 }
344 
345 static const AVOption options[] = {
346  TLS_COMMON_OPTIONS(TLSContext, tls_shared), \
347  {"key_password", "Password for the private key file", OFFSET(priv_key_pw), AV_OPT_TYPE_STRING, .flags = TLS_OPTFL }, \
348  { NULL }
349 };
350 
351 static const AVClass tls_class = {
352  .class_name = "tls",
353  .item_name = av_default_item_name,
354  .option = options,
355  .version = LIBAVUTIL_VERSION_INT,
356 };
357 
359  .name = "tls",
360  .url_open2 = tls_open,
361  .url_read = tls_read,
362  .url_write = tls_write,
363  .url_close = tls_close,
364  .url_get_file_handle = tls_get_file_handle,
365  .url_get_short_seek = tls_get_short_seek,
366  .priv_data_size = sizeof(TLSContext),
368  .priv_data_class = &tls_class,
369 };
uint8_t
Main libavformat public API header.
int ffurl_read(URLContext *h, unsigned char *buf, int size)
Read up to size bytes from the resource accessed by h, and store the read bytes in buf.
Definition: avio.c:404
int ffurl_get_short_seek(URLContext *h)
Return the current short seek threshold value for this URL.
Definition: avio.c:647
int ffurl_closep(URLContext **hh)
Close the resource accessed by the URLContext h, and free the memory used by it.
Definition: avio.c:441
int ffurl_write(URLContext *h, const unsigned char *buf, int size)
Write size bytes from buf to the resource accessed by h.
Definition: avio.c:418
int ffurl_get_file_handle(URLContext *h)
Return the file descriptor associated with this URL.
Definition: avio.c:623
#define flags(name, subs,...)
Definition: cbs_av1.c:572
#define s(width, name)
Definition: cbs_vp9.c:257
#define fail()
Definition: checkasm.h:133
#define NULL
Definition: coverity.c:32
@ AV_OPT_TYPE_STRING
Definition: opt.h:229
#define AVERROR_EXIT
Immediate exit was requested; the called function should not be restarted.
Definition: error.h:56
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define AVERROR(e)
Definition: error.h:43
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:200
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:253
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
common internal API header
int av_find_info_tag(char *arg, int arg_size, const char *tag1, const char *info)
Attempt to find a specific tag in a URL.
Definition: parseutils.c:751
misc parsing utilities
Describe the class of an AVClass context structure.
Definition: log.h:67
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
AVOption.
Definition: opt.h:248
char * priv_key_pw
Definition: tls_mbedtls.c:46
mbedtls_ctr_drbg_context ctr_drbg_context
Definition: tls_mbedtls.c:42
mbedtls_ssl_context ssl_context
Definition: tls_mbedtls.c:39
mbedtls_ssl_config ssl_config
Definition: tls_mbedtls.c:40
mbedtls_x509_crt ca_cert
Definition: tls_mbedtls.c:43
mbedtls_pk_context priv_key
Definition: tls_mbedtls.c:45
mbedtls_x509_crt own_cert
Definition: tls_mbedtls.c:44
mbedtls_entropy_context entropy_context
Definition: tls_mbedtls.c:41
TLSShared tls_shared
Definition: tls_gnutls.c:50
Definition: tls.h:29
int listen
Definition: tls.h:34
int numerichost
Definition: tls.h:40
int verify
Definition: tls.h:31
char * ca_file
Definition: tls.h:30
URLContext * tcp
Definition: tls.h:42
char * key_file
Definition: tls.h:33
char * host
Definition: tls.h:36
char * cert_file
Definition: tls.h:32
Definition: url.h:38
const char * name
Definition: url.h:55
#define av_log(a,...)
AVFormatContext * ctx
Definition: movenc.c:48
int ff_tls_open_underlying(TLSShared *c, URLContext *parent, const char *uri, AVDictionary **options)
Definition: tls.c:56
#define TLS_COMMON_OPTIONS(pstruct, options_field)
Definition: tls.h:46
#define TLS_OPTFL
Definition: tls.h:45
static int tls_close(URLContext *h)
Definition: tls_mbedtls.c:51
static const AVClass tls_class
Definition: tls_mbedtls.c:351
static void handle_pk_parse_error(URLContext *h, int ret)
Definition: tls_mbedtls.c:111
const URLProtocol ff_tls_protocol
Definition: tls_mbedtls.c:358
static const AVOption options[]
Definition: tls_mbedtls.c:345
static void handle_handshake_error(URLContext *h, int ret)
Definition: tls_mbedtls.c:129
static int tls_read(URLContext *h, uint8_t *buf, int size)
Definition: tls_mbedtls.c:307
static int handle_tls_error(URLContext *h, const char *func_name, int ret)
Definition: tls_mbedtls.c:288
static int handle_transport_error(URLContext *h, const char *func_name, int react_on_eagain, int ret)
Definition: tls_mbedtls.c:68
static int tls_open(URLContext *h, const char *uri, int flags, AVDictionary **options)
Definition: tls_mbedtls.c:167
static int tls_get_short_seek(URLContext *h)
Definition: tls_mbedtls.c:339
static int tls_write(URLContext *h, const uint8_t *buf, int size)
Definition: tls_mbedtls.c:320
static int mbedtls_send(void *ctx, const unsigned char *buf, size_t len)
Definition: tls_mbedtls.c:85
static int mbedtls_recv(void *ctx, unsigned char *buf, size_t len)
Definition: tls_mbedtls.c:98
static void parse_options(TLSContext *tls_ctxc, const char *uri)
Definition: tls_mbedtls.c:156
#define OFFSET(x)
Definition: tls_mbedtls.c:49
static int tls_get_file_handle(URLContext *h)
Definition: tls_mbedtls.c:333
int size
unbuffered private I/O API
#define URL_PROTOCOL_FLAG_NETWORK
Definition: url.h:34
int len
static double c[64]