aboutsummaryrefslogtreecommitdiff
path: root/src/fs/fs_publish_ublock.c
blob: 83e019b369b047ece509020c6b56f6a60d2798b5 (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
/*
     This file is part of GNUnet.
     Copyright (C) 2009, 2010, 2012, 2013 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.

     GNUnet 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
     Affero General Public License for more details.
*/

/**
 * @file fs/fs_publish_ublock.c
 * @brief publish a UBLOCK in GNUnet
 * @see https://gnunet.org/encoding and #2564
 * @author Krista Bennett
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet_constants.h"
#include "gnunet_signatures.h"
#include "fs_publish_ublock.h"
#include "fs_api.h"
#include "fs_tree.h"


/**
 * Derive the key for symmetric encryption/decryption from
 * the public key and the label.
 *
 * @param skey where to store symmetric key
 * @param iv where to store the IV
 * @param label label to use for key derivation
 * @param pub public key to use for key derivation
 */
static void
derive_ublock_encryption_key (struct GNUNET_CRYPTO_SymmetricSessionKey *skey,
			      struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
			      const char *label,
			      const struct GNUNET_CRYPTO_EcdsaPublicKey *pub)
{
  struct GNUNET_HashCode key;

  /* derive key from 'label' and public key of the namespace */
  GNUNET_assert (GNUNET_YES ==
		 GNUNET_CRYPTO_kdf (&key, sizeof (key),
				    "UBLOCK-ENC", strlen ("UBLOCK-ENC"),
				    label, strlen (label),
				    pub, sizeof (*pub),
				    NULL, 0));
  GNUNET_CRYPTO_hash_to_aes_key (&key, skey, iv);
}


/**
 * Decrypt the given UBlock, storing the result in output.
 *
 * @param input input data
 * @param input_len number of bytes in @a input
 * @param ns public key under which the UBlock was stored
 * @param label label under which the UBlock was stored
 * @param output where to write the result, has input_len bytes
 */
void
GNUNET_FS_ublock_decrypt_ (const void *input,
			   size_t input_len,
			   const struct GNUNET_CRYPTO_EcdsaPublicKey *ns,
			   const char *label,
			   void *output)
{
  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
  struct GNUNET_CRYPTO_SymmetricSessionKey skey;

  derive_ublock_encryption_key (&skey, &iv,
				label, ns);
  GNUNET_CRYPTO_symmetric_decrypt (input, input_len,
			     &skey, &iv,
                             output);
}


/**
 * Context for 'ublock_put_cont'.
 */
struct GNUNET_FS_PublishUblockContext
{

  /**
   * Function to call when done.
   */
  GNUNET_FS_UBlockContinuation cont;

  /**
   * Closure of 'cont'.
   */
  void *cont_cls;

  /**
   * Handle for active datastore operation.
   */
  struct GNUNET_DATASTORE_QueueEntry *qre;

  /**
   * Task to run continuation asynchronously.
   */
  struct GNUNET_SCHEDULER_Task * task;

};


/**
 * Continuation of #GNUNET_FS_publish_ublock_().
 *
 * @param cls closure of type "struct GNUNET_FS_PublishUblockContext*"
 * @param success #GNUNET_SYSERR on failure (including timeout/queue drop)
 *                #GNUNET_NO if content was already there
 *                #GNUNET_YES (or other positive value) on success
 * @param min_expiration minimum expiration time required for 0-priority content to be stored
 *                by the datacache at this time, zero for unknown, forever if we have no
 *                space for 0-priority content
 * @param msg NULL on success, otherwise an error message
 */
static void
ublock_put_cont (void *cls,
		 int32_t success,
		 struct GNUNET_TIME_Absolute min_expiration,
		 const char *msg)
{
  struct GNUNET_FS_PublishUblockContext *uc = cls;

  uc->qre = NULL;
  uc->cont (uc->cont_cls, msg);
  GNUNET_free (uc);
}


/**
 * Run the continuation.
 *
 * @param cls the `struct GNUNET_FS_PublishUblockContext *`
 */
static void
run_cont (void *cls)
{
  struct GNUNET_FS_PublishUblockContext *uc = cls;

  uc->task = NULL;
  uc->cont (uc->cont_cls, NULL);
  GNUNET_free (uc);
}


/**
 * Publish a UBlock.
 *
 * @param h handle to the file sharing subsystem
 * @param dsh datastore handle to use for storage operation
 * @param label identifier to use
 * @param ulabel update label to use, may be an empty string for none
 * @param ns namespace to publish in
 * @param meta metadata to use
 * @param uri URI to refer to in the UBlock
 * @param bo per-block options
 * @param options publication options
 * @param cont continuation
 * @param cont_cls closure for @a cont
 * @return NULL on error (@a cont will still be called)
 */
struct GNUNET_FS_PublishUblockContext *
GNUNET_FS_publish_ublock_ (struct GNUNET_FS_Handle *h,
			   struct GNUNET_DATASTORE_Handle *dsh,
			   const char *label,
			   const char *ulabel,
			   const struct GNUNET_CRYPTO_EcdsaPrivateKey *ns,
			   const struct GNUNET_CONTAINER_MetaData *meta,
			   const struct GNUNET_FS_Uri *uri,
			   const struct GNUNET_FS_BlockOptions *bo,
			   enum GNUNET_FS_PublishOptions options,
			   GNUNET_FS_UBlockContinuation cont, void *cont_cls)
{
  struct GNUNET_FS_PublishUblockContext *uc;
  struct GNUNET_HashCode query;
  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
  struct GNUNET_CRYPTO_SymmetricSessionKey skey;
  struct GNUNET_CRYPTO_EcdsaPrivateKey *nsd;
  struct GNUNET_CRYPTO_EcdsaPublicKey pub;
  char *uris;
  size_t size;
  char *kbe;
  char *sptr;
  ssize_t mdsize;
  size_t slen;
  size_t ulen;
  struct UBlock *ub_plain;
  struct UBlock *ub_enc;

  /* compute ublock to publish */
  if (NULL == meta)
    mdsize = 0;
  else
    mdsize = GNUNET_CONTAINER_meta_data_get_serialized_size (meta);
  GNUNET_assert (mdsize >= 0);
  uris = GNUNET_FS_uri_to_string (uri);
  slen = strlen (uris) + 1;
  if (NULL == ulabel)
    ulen = 1;
  else
    ulen = strlen (ulabel) + 1;
  size = mdsize + sizeof (struct UBlock) + slen + ulen;
  if (size > MAX_UBLOCK_SIZE)
  {
    size = MAX_UBLOCK_SIZE;
    mdsize = size - sizeof (struct UBlock) - (slen + ulen);
  }
  ub_plain = GNUNET_malloc (size);
  kbe = (char *) &ub_plain[1];
  if (NULL != ulabel)
    GNUNET_memcpy (kbe, ulabel, ulen);
  kbe += ulen;
  GNUNET_memcpy (kbe, uris, slen);
  kbe += slen;
  GNUNET_free (uris);
  sptr = kbe;
  if (NULL != meta)
    mdsize =
      GNUNET_CONTAINER_meta_data_serialize (meta, &sptr, mdsize,
					    GNUNET_CONTAINER_META_DATA_SERIALIZE_PART);
  if (-1 == mdsize)
  {
    GNUNET_break (0);
    GNUNET_free (ub_plain);
    cont (cont_cls, _("Internal error."));
    return NULL;
  }
  size = sizeof (struct UBlock) + slen + mdsize + ulen;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
	      "Publishing under identifier `%s'\n",
              label);
  /* get public key of the namespace */
  GNUNET_CRYPTO_ecdsa_key_get_public (ns,
				    &pub);
  derive_ublock_encryption_key (&skey, &iv,
				label, &pub);

  /* encrypt ublock */
  ub_enc = GNUNET_malloc (size);
  GNUNET_CRYPTO_symmetric_encrypt (&ub_plain[1],
			     ulen + slen + mdsize,
			     &skey, &iv,
                             &ub_enc[1]);
  GNUNET_free (ub_plain);
  ub_enc->purpose.size = htonl (ulen + slen + mdsize +
				sizeof (struct UBlock)
				- sizeof (struct GNUNET_CRYPTO_EcdsaSignature));
  ub_enc->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_FS_UBLOCK);

  /* derive signing-key from 'label' and public key of the namespace */
  nsd = GNUNET_CRYPTO_ecdsa_private_key_derive (ns, label, "fs-ublock");
  GNUNET_CRYPTO_ecdsa_key_get_public (nsd,
				    &ub_enc->verification_key);
  GNUNET_assert (GNUNET_OK ==
		 GNUNET_CRYPTO_ecdsa_sign (nsd,
					 &ub_enc->purpose,
					 &ub_enc->signature));
  GNUNET_CRYPTO_hash (&ub_enc->verification_key,
		      sizeof (ub_enc->verification_key),
		      &query);
  GNUNET_free (nsd);

  uc = GNUNET_new (struct GNUNET_FS_PublishUblockContext);
  uc->cont = cont;
  uc->cont_cls = cont_cls;
  if (NULL != dsh)
  {
    uc->qre =
      GNUNET_DATASTORE_put (dsh,
                            0,
                            &query,
                            ulen + slen + mdsize + sizeof (struct UBlock),
                            ub_enc,
                            GNUNET_BLOCK_TYPE_FS_UBLOCK,
                            bo->content_priority,
                            bo->anonymity_level,
                            bo->replication_level,
                            bo->expiration_time,
                            -2, 1,
                            &ublock_put_cont, uc);
  }
  else
  {
    uc->task = GNUNET_SCHEDULER_add_now (&run_cont,
                                         uc);
  }
  GNUNET_free (ub_enc);
  return uc;
}


/**
 * Abort UBlock publishing operation.
 *
 * @param uc operation to abort.
 */
void
GNUNET_FS_publish_ublock_cancel_ (struct GNUNET_FS_PublishUblockContext *uc)
{
  if (NULL != uc->qre)
    GNUNET_DATASTORE_cancel (uc->qre);
  if (NULL != uc->task)
    GNUNET_SCHEDULER_cancel (uc->task);
  GNUNET_free (uc);
}

/* end of fs_publish_ublock.c */