aboutsummaryrefslogtreecommitdiffstats
path: root/libempathy/empathy-tls-verifier.c
blob: 265f34843f4451e70e469d64bd03d7009b871b97 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
/*
 * empathy-tls-verifier.c - Source for EmpathyTLSVerifier
 * Copyright (C) 2010 Collabora Ltd.
 * @author Cosimo Cecchi <cosimo.cecchi@collabora.co.uk>
 * @author Stef Walter <stefw@collabora.co.uk>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <config.h>

#include <gnutls/gnutls.h>
#include <gnutls/x509.h>

#include <telepathy-glib/util.h>

#include "empathy-tls-verifier.h"

#include <gcr/gcr.h>

#define DEBUG_FLAG EMPATHY_DEBUG_TLS
#include "empathy-debug.h"
#include "empathy-utils.h"

G_DEFINE_TYPE (EmpathyTLSVerifier, empathy_tls_verifier,
    G_TYPE_OBJECT)

#define GET_PRIV(obj) EMPATHY_GET_PRIV (obj, EmpathyTLSVerifier);

enum {
  PROP_TLS_CERTIFICATE = 1,
  PROP_HOSTNAME,
  PROP_REFERENCE_IDENTITIES,

  LAST_PROPERTY,
};

typedef struct {
  EmpathyTLSCertificate *certificate;
  gchar *hostname;
  gchar **reference_identities;

  GSimpleAsyncResult *verify_result;
  GHashTable *details;

  gboolean dispose_run;
} EmpathyTLSVerifierPriv;

static gboolean
verification_output_to_reason (gint res,
    guint verify_output,
    EmpTLSCertificateRejectReason *reason)
{
  gboolean retval = TRUE;

  g_assert (reason != NULL);

  if (res != GNUTLS_E_SUCCESS)
    {
      retval = FALSE;

      /* the certificate is not structurally valid */
      switch (res)
        {
        case GNUTLS_E_INSUFFICIENT_CREDENTIALS:
          *reason = EMP_TLS_CERTIFICATE_REJECT_REASON_UNTRUSTED;
          break;
        case GNUTLS_E_CONSTRAINT_ERROR:
          *reason = EMP_TLS_CERTIFICATE_REJECT_REASON_LIMIT_EXCEEDED;
          break;
        default:
          *reason = EMP_TLS_CERTIFICATE_REJECT_REASON_UNKNOWN;
          break;
        }

      goto out;
    }

  /* the certificate is structurally valid, check for other errors. */
  if (verify_output & GNUTLS_CERT_INVALID)
    {
      retval = FALSE;

      if (verify_output & GNUTLS_CERT_SIGNER_NOT_FOUND)
        *reason = EMP_TLS_CERTIFICATE_REJECT_REASON_SELF_SIGNED;
      else if (verify_output & GNUTLS_CERT_SIGNER_NOT_CA)
        *reason = EMP_TLS_CERTIFICATE_REJECT_REASON_UNTRUSTED;
      else if (verify_output & GNUTLS_CERT_INSECURE_ALGORITHM)
        *reason = EMP_TLS_CERTIFICATE_REJECT_REASON_INSECURE;
      else if (verify_output & GNUTLS_CERT_NOT_ACTIVATED)
        *reason = EMP_TLS_CERTIFICATE_REJECT_REASON_NOT_ACTIVATED;
      else if (verify_output & GNUTLS_CERT_EXPIRED)
        *reason = EMP_TLS_CERTIFICATE_REJECT_REASON_EXPIRED;
      else
        *reason = EMP_TLS_CERTIFICATE_REJECT_REASON_UNKNOWN;

      goto out;
    }

 out:
  return retval;
}

static void
build_certificate_list_for_gnutls (GcrCertificateChain *chain,
        gnutls_x509_crt_t **list,
        guint *n_list,
        gnutls_x509_crt_t **anchors,
        guint *n_anchors)
{
  GcrCertificate *cert;
  guint idx, length;
  gnutls_x509_crt_t *retval;
  gnutls_x509_crt_t gcert;
  gnutls_datum_t datum;
  gsize n_data;

  g_assert (list);
  g_assert (n_list);
  g_assert (anchors);
  g_assert (n_anchors);

  *list = *anchors = NULL;
  *n_list = *n_anchors = 0;

  length = gcr_certificate_chain_get_length (chain);
  retval = g_malloc0 (sizeof (gnutls_x509_crt_t) * length);

  /* Convert the main body of the chain to gnutls */
  for (idx = 0; idx < length; ++idx)
    {
      cert = gcr_certificate_chain_get_certificate (chain, idx);
      datum.data = (gpointer)gcr_certificate_get_der_data (cert, &n_data);
      datum.size = n_data;

      gnutls_x509_crt_init (&gcert);
      if (gnutls_x509_crt_import (gcert, &datum, GNUTLS_X509_FMT_DER) < 0)
        g_return_if_reached ();

      retval[idx] = gcert;
    }

  *list = retval;
  *n_list = length;

  /* See if we have an anchor */
  if (gcr_certificate_chain_get_status (chain) ==
          GCR_CERTIFICATE_CHAIN_ANCHORED)
    {
      cert = gcr_certificate_chain_get_anchor (chain);
      g_return_if_fail (cert);

      datum.data = (gpointer)gcr_certificate_get_der_data (cert, &n_data);
      datum.size = n_data;

      gnutls_x509_crt_init (&gcert);
      if (gnutls_x509_crt_import (gcert, &datum, GNUTLS_X509_FMT_DER) < 0)
        g_return_if_reached ();

      retval = g_malloc0 (sizeof (gnutls_x509_crt_t) * 1);
      retval[0] = gcert;
      *anchors = retval;
      *n_anchors = 1;
    }
}

static void
free_certificate_list_for_gnutls (gnutls_x509_crt_t *list,
        guint n_list)
{
  guint idx;

  for (idx = 0; idx < n_list; idx++)
    gnutls_x509_crt_deinit (list[idx]);
  g_free (list);
}

static void
complete_verification (EmpathyTLSVerifier *self)
{
  EmpathyTLSVerifierPriv *priv = GET_PRIV (self);

  DEBUG ("Verification successful, completing...");

  g_simple_async_result_complete_in_idle (priv->verify_result);

  tp_clear_object (&priv->verify_result);
}

static void
abort_verification (EmpathyTLSVerifier *self,
    EmpTLSCertificateRejectReason reason)
{
  EmpathyTLSVerifierPriv *priv = GET_PRIV (self);

  DEBUG ("Verification error %u, aborting...", reason);

  g_simple_async_result_set_error (priv->verify_result,
      G_IO_ERROR, reason, "TLS verification failed with reason %u",
      reason);
  g_simple_async_result_complete_in_idle (priv->verify_result);

  tp_clear_object (&priv->verify_result);
}

static void
debug_certificate (GcrCertificate *cert)
{
    gchar *subject = gcr_certificate_get_subject_dn (cert);
    DEBUG ("Certificate: %s", subject);
    g_free (subject);
}

static void
debug_certificate_chain (GcrCertificateChain *chain)
{
    GEnumClass *enum_class;
    GEnumValue *enum_value;
    gint idx, length;
    GcrCertificate *cert;

    enum_class = G_ENUM_CLASS
            (g_type_class_peek (GCR_TYPE_CERTIFICATE_CHAIN_STATUS));
    enum_value = g_enum_get_value (enum_class,
            gcr_certificate_chain_get_status (chain));
    length = gcr_certificate_chain_get_length (chain);
    DEBUG ("Certificate chain: length %u status %s",
            length, enum_value ? enum_value->value_nick : "XXX");

    for (idx = 0; idx < length; ++idx)
      {
        cert = gcr_certificate_chain_get_certificate (chain, idx);
        debug_certificate (cert);
      }
}

static void
perform_verification (EmpathyTLSVerifier *self,
        GcrCertificateChain *chain)
{
  gboolean ret = FALSE;
  EmpTLSCertificateRejectReason reason =
    EMP_TLS_CERTIFICATE_REJECT_REASON_UNKNOWN;
  gnutls_x509_crt_t *list, *anchors;
  guint n_list, n_anchors;
  guint verify_output;
  gint res;
  gint i;
  gboolean matched = FALSE;
  EmpathyTLSVerifierPriv *priv = GET_PRIV (self);

  DEBUG ("Performing verification");
  debug_certificate_chain (chain);

  list = anchors = NULL;
  n_list = n_anchors = 0;

  /*
   * If the first certificate is an pinned certificate then we completely
   * ignore the rest of the verification process.
   */
  if (gcr_certificate_chain_get_status (chain) == GCR_CERTIFICATE_CHAIN_PINNED)
    {
      DEBUG ("Found pinned certificate for %s", priv->hostname);
      complete_verification (self);
      goto out;
  }

  build_certificate_list_for_gnutls (chain, &list, &n_list,
          &anchors, &n_anchors);
  if (list == NULL || n_list == 0) {
      g_warn_if_reached ();
      abort_verification (self, EMP_TLS_CERTIFICATE_REJECT_REASON_UNKNOWN);
      goto out;
  }

  verify_output = 0;
  res = gnutls_x509_crt_list_verify (list, n_list, anchors, n_anchors,
           NULL, 0, 0, &verify_output);
  ret = verification_output_to_reason (res, verify_output, &reason);

  DEBUG ("Certificate verification gave result %d with reason %u", ret,
          reason);

  if (!ret) {
      abort_verification (self, reason);
      goto out;
  }

  /* now check if the certificate matches one of the reference identities. */
  if (priv->reference_identities != NULL)
    {
      for (i = 0, matched = FALSE; priv->reference_identities[i] != NULL; ++i)
        {
          if (gnutls_x509_crt_check_hostname (list[0],
                  priv->reference_identities[i]) == 1)
            {
              matched = TRUE;
              break;
            }
        }
    }

  if (!matched)
    {
      gchar *certified_hostname;

      certified_hostname = empathy_get_x509_certificate_hostname (list[0]);
      tp_asv_set_string (priv->details,
          "expected-hostname", priv->hostname);
      tp_asv_set_string (priv->details,
          "certificate-hostname", certified_hostname);

      DEBUG ("Hostname mismatch: got %s but expected %s",
          certified_hostname, priv->hostname);

      g_free (certified_hostname);
      abort_verification (self,
              EMP_TLS_CERTIFICATE_REJECT_REASON_HOSTNAME_MISMATCH);
      goto out;
    }

  DEBUG ("Hostname matched");
  complete_verification (self);

 out:
  free_certificate_list_for_gnutls (list, n_list);
  free_certificate_list_for_gnutls (anchors, n_anchors);
}

static void
perform_verification_cb (GObject *object,
        GAsyncResult *res,
        gpointer user_data)
{
  GError *error = NULL;

  GcrCertificateChain *chain = GCR_CERTIFICATE_CHAIN (object);
  EmpathyTLSVerifier *self = EMPATHY_TLS_VERIFIER (user_data);

  /* Even if building the chain fails, try verifying what we have */
  if (!gcr_certificate_chain_build_finish (chain, res, &error))
    {
      DEBUG ("Building of certificate chain failed: %s", error->message);
      g_clear_error (&error);
    }

  perform_verification (self, chain);

  /* Matches ref when staring chain build */
  g_object_unref (self);
}

static void
empathy_tls_verifier_get_property (GObject *object,
    guint property_id,
    GValue *value,
    GParamSpec *pspec)
{
  EmpathyTLSVerifierPriv *priv = GET_PRIV (object);

  switch (property_id)
    {
    case PROP_TLS_CERTIFICATE:
      g_value_set_object (value, priv->certificate);
      break;
    case PROP_HOSTNAME:
      g_value_set_string (value, priv->hostname);
      break;
    case PROP_REFERENCE_IDENTITIES:
      g_value_set_boxed (value, priv->reference_identities);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
      break;
    }
}

static void
empathy_tls_verifier_set_property (GObject *object,
    guint property_id,
    const GValue *value,
    GParamSpec *pspec)
{
  EmpathyTLSVerifierPriv *priv = GET_PRIV (object);

  switch (property_id)
    {
    case PROP_TLS_CERTIFICATE:
      priv->certificate = g_value_dup_object (value);
      break;
    case PROP_HOSTNAME:
      priv->hostname = g_value_dup_string (value);
      break;
    case PROP_REFERENCE_IDENTITIES:
      priv->reference_identities = g_value_dup_boxed (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
      break;
    }
}

static void
empathy_tls_verifier_dispose (GObject *object)
{
  EmpathyTLSVerifierPriv *priv = GET_PRIV (object);

  if (priv->dispose_run)
    return;

  priv->dispose_run = TRUE;

  tp_clear_object (&priv->certificate);

  G_OBJECT_CLASS (empathy_tls_verifier_parent_class)->dispose (object);
}

static void
empathy_tls_verifier_finalize (GObject *object)
{
  EmpathyTLSVerifierPriv *priv = GET_PRIV (object);

  DEBUG ("%p", object);

  tp_clear_boxed (G_TYPE_HASH_TABLE, &priv->details);
  g_free (priv->hostname);
  g_strfreev (priv->reference_identities);

  G_OBJECT_CLASS (empathy_tls_verifier_parent_class)->finalize (object);
}

static void
empathy_tls_verifier_init (EmpathyTLSVerifier *self)
{
  EmpathyTLSVerifierPriv *priv;

  priv = self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self,
      EMPATHY_TYPE_TLS_VERIFIER, EmpathyTLSVerifierPriv);
  priv->details = tp_asv_new (NULL, NULL);
}

static void
empathy_tls_verifier_class_init (EmpathyTLSVerifierClass *klass)
{
  GParamSpec *pspec;
  GObjectClass *oclass = G_OBJECT_CLASS (klass);

  g_type_class_add_private (klass, sizeof (EmpathyTLSVerifierPriv));

  oclass->set_property = empathy_tls_verifier_set_property;
  oclass->get_property = empathy_tls_verifier_get_property;
  oclass->finalize = empathy_tls_verifier_finalize;
  oclass->dispose = empathy_tls_verifier_dispose;

  pspec = g_param_spec_object ("certificate", "The EmpathyTLSCertificate",
      "The EmpathyTLSCertificate to be verified.",
      EMPATHY_TYPE_TLS_CERTIFICATE,
      G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
  g_object_class_install_property (oclass, PROP_TLS_CERTIFICATE, pspec);

  pspec = g_param_spec_string ("hostname", "The hostname",
      "The hostname which is certified by the certificate.",
      NULL,
      G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
  g_object_class_install_property (oclass, PROP_HOSTNAME, pspec);

  pspec = g_param_spec_boxed ("reference-identities",
      "The reference identities",
      "The certificate should certify one of these identities.",
      G_TYPE_STRV,
      G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
  g_object_class_install_property (oclass, PROP_REFERENCE_IDENTITIES, pspec);
}

EmpathyTLSVerifier *
empathy_tls_verifier_new (EmpathyTLSCertificate *certificate,
    const gchar *hostname, const gchar **reference_identities)
{
  g_assert (EMPATHY_IS_TLS_CERTIFICATE (certificate));
  g_assert (hostname != NULL);
  g_assert (reference_identities != NULL);

  return g_object_new (EMPATHY_TYPE_TLS_VERIFIER,
      "certificate", certificate,
      "hostname", hostname,
      "reference-identities", reference_identities,
      NULL);
}

void
empathy_tls_verifier_verify_async (EmpathyTLSVerifier *self,
    GAsyncReadyCallback callback,
    gpointer user_data)
{
  GcrCertificateChain *chain;
  GcrCertificate *cert;
  GPtrArray *cert_data = NULL;
  GArray *data;
  guint idx;
  EmpathyTLSVerifierPriv *priv = GET_PRIV (self);

  DEBUG ("Starting verification");

  g_return_if_fail (priv->verify_result == NULL);

  g_object_get (priv->certificate, "cert-data", &cert_data, NULL);
  g_return_if_fail (cert_data);

  priv->verify_result = g_simple_async_result_new (G_OBJECT (self),
      callback, user_data, NULL);

  /* Create a certificate chain */
  chain = gcr_certificate_chain_new ();
  for (idx = 0; idx < cert_data->len; ++idx) {
    data = g_ptr_array_index (cert_data, idx);
    cert = gcr_simple_certificate_new (data->data, data->len);
    gcr_certificate_chain_add (chain, cert);
    g_object_unref (cert);
  }

  gcr_certificate_chain_build_async (chain, GCR_PURPOSE_CLIENT_AUTH, priv->hostname, 0,
          NULL, perform_verification_cb, g_object_ref (self));

  g_object_unref (chain);
  g_boxed_free (TP_ARRAY_TYPE_UCHAR_ARRAY_LIST, cert_data);
}

gboolean
empathy_tls_verifier_verify_finish (EmpathyTLSVerifier *self,
    GAsyncResult *res,
    EmpTLSCertificateRejectReason *reason,
    GHashTable **details,
    GError **error)
{
  EmpathyTLSVerifierPriv *priv = GET_PRIV (self);

  if (g_simple_async_result_propagate_error (G_SIMPLE_ASYNC_RESULT (res),
          error))
    {
      if (reason != NULL)
        *reason = (*error)->code;

      if (details != NULL)
        {
          *details = tp_asv_new (NULL, NULL);
          tp_g_hash_table_update (*details, priv->details,
              (GBoxedCopyFunc) g_strdup,
              (GBoxedCopyFunc) tp_g_value_slice_dup);
        }

      return FALSE;
    }

  if (reason != NULL)
    *reason = EMP_TLS_CERTIFICATE_REJECT_REASON_UNKNOWN;

  return TRUE;
}

void
empathy_tls_verifier_store_exception (EmpathyTLSVerifier *self)
{
  GArray *data;
  GcrCertificate *cert;
  GPtrArray *cert_data = NULL;
  GError *error = NULL;
  EmpathyTLSVerifierPriv *priv = GET_PRIV (self);

  g_object_get (priv->certificate, "cert-data", &cert_data, NULL);
  g_return_if_fail (cert_data);

  if (!cert_data->len)
    {
      DEBUG ("No certificate to pin.");
      return;
    }

  /* The first certificate in the chain is for the host */
  data = g_ptr_array_index (cert_data, 0);
  cert = gcr_simple_certificate_new ((gpointer)data->data, data->len);

  DEBUG ("Storing pinned certificate:");
  debug_certificate (cert);

  if (!gcr_trust_add_pinned_certificate (cert, GCR_PURPOSE_CLIENT_AUTH,
          priv->hostname, NULL, &error))
      DEBUG ("Can't store the pinned certificate: %s", error->message);

  g_object_unref (cert);
  g_boxed_free (TP_ARRAY_TYPE_UCHAR_ARRAY_LIST, cert_data);
}