summaryrefslogtreecommitdiff
path: root/modules/libmar/src/mar_read.c
blob: 378eaea882b4c5b00cc97a0ddace0367ce5c7768 (plain)
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
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <sys/types.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include "mar_private.h"
#include "mar.h"

#ifdef XP_WIN
#include <winsock2.h>
#else
#include <netinet/in.h>
#endif


/* this is the same hash algorithm used by nsZipArchive.cpp */
static uint32_t mar_hash_name(const char *name) {
  uint32_t val = 0;
  unsigned char* c;

  for (c = (unsigned char *) name; *c; ++c)
    val = val*37 + *c;

  return val % TABLESIZE;
}

static int mar_insert_item(MarFile *mar, const char *name, int namelen,
                           uint32_t offset, uint32_t length, uint32_t flags) {
  MarItem *item, *root;
  uint32_t hash;
  
  item = (MarItem *) malloc(sizeof(MarItem) + namelen);
  if (!item)
    return -1;
  item->next = NULL;
  item->offset = offset;
  item->length = length;
  item->flags = flags;
  memcpy(item->name, name, namelen + 1);

  hash = mar_hash_name(name);

  root = mar->item_table[hash];
  if (!root) {
    mar->item_table[hash] = item;
  } else {
    /* append item */
    while (root->next)
      root = root->next;
    root->next = item;
  }
  return 0;
}

static int mar_consume_index(MarFile *mar, char **buf, const char *buf_end) {
  /*
   * Each item has the following structure:
   *   uint32_t offset      (network byte order)
   *   uint32_t length      (network byte order)
   *   uint32_t flags       (network byte order)
   *   char     name[N]     (where N >= 1)
   *   char     null_byte;
   */
  uint32_t offset;
  uint32_t length;
  uint32_t flags;
  const char *name;
  int namelen;

  if ((buf_end - *buf) < (int)(3*sizeof(uint32_t) + 2))
    return -1;

  memcpy(&offset, *buf, sizeof(offset));
  *buf += sizeof(offset);

  memcpy(&length, *buf, sizeof(length));
  *buf += sizeof(length);

  memcpy(&flags, *buf, sizeof(flags));
  *buf += sizeof(flags);

  offset = ntohl(offset);
  length = ntohl(length);
  flags = ntohl(flags);

  name = *buf;
  /* find namelen; must take care not to read beyond buf_end */
  while (**buf) {
    /* buf_end points one byte past the end of buf's allocation */
    if (*buf == (buf_end - 1))
      return -1;
    ++(*buf);
  }
  namelen = (*buf - name);
  /* must ensure that namelen is valid */
  if (namelen < 0) {
    return -1;
  }
  /* consume null byte */
  if (*buf == buf_end)
    return -1;
  ++(*buf);

  return mar_insert_item(mar, name, namelen, offset, length, flags);
}

static int mar_read_index(MarFile *mar) {
  char id[MAR_ID_SIZE], *buf, *bufptr, *bufend;
  uint32_t offset_to_index, size_of_index;

  /* verify MAR ID */
  fseek(mar->fp, 0, SEEK_SET);
  if (fread(id, MAR_ID_SIZE, 1, mar->fp) != 1)
    return -1;
  if (memcmp(id, MAR_ID, MAR_ID_SIZE) != 0)
    return -1;

  if (fread(&offset_to_index, sizeof(uint32_t), 1, mar->fp) != 1)
    return -1;
  offset_to_index = ntohl(offset_to_index);

  if (fseek(mar->fp, offset_to_index, SEEK_SET))
    return -1;
  if (fread(&size_of_index, sizeof(uint32_t), 1, mar->fp) != 1)
    return -1;
  size_of_index = ntohl(size_of_index);

  buf = (char *) malloc(size_of_index);
  if (!buf)
    return -1;
  if (fread(buf, size_of_index, 1, mar->fp) != 1) {
    free(buf);
    return -1;
  }

  bufptr = buf;
  bufend = buf + size_of_index;
  while (bufptr < bufend && mar_consume_index(mar, &bufptr, bufend) == 0);

  free(buf);
  return (bufptr == bufend) ? 0 : -1;
}

/**
 * Internal shared code for mar_open and mar_wopen.
 * On failure, will fclose(fp).
 */
static MarFile *mar_fpopen(FILE *fp)
{
  MarFile *mar;

  mar = (MarFile *) malloc(sizeof(*mar));
  if (!mar) {
    fclose(fp);
    return NULL;
  }

  mar->fp = fp;
  mar->item_table_is_valid = 0;
  memset(mar->item_table, 0, sizeof(mar->item_table));

  return mar;
}

MarFile *mar_open(const char *path) {
  FILE *fp;

  fp = fopen(path, "rb");
  if (!fp) {
    fprintf(stderr, "ERROR: could not open file in mar_open()\n");
    perror(path);
    return NULL;
  }

  return mar_fpopen(fp);
}

#ifdef XP_WIN
MarFile *mar_wopen(const wchar_t *path) {
  FILE *fp;

  _wfopen_s(&fp, path, L"rb");
  if (!fp) {
    fprintf(stderr, "ERROR: could not open file in mar_wopen()\n");
    _wperror(path);
    return NULL;
  }

  return mar_fpopen(fp);
}
#endif

void mar_close(MarFile *mar) {
  MarItem *item;
  int i;

  fclose(mar->fp);

  for (i = 0; i < TABLESIZE; ++i) {
    item = mar->item_table[i];
    while (item) {
      MarItem *temp = item;
      item = item->next;
      free(temp);
    }
  }

  free(mar);
}

/**
 * Determines the MAR file information.
 *
 * @param fp                     An opened MAR file in read mode.
 * @param hasSignatureBlock      Optional out parameter specifying if the MAR
 *                               file has a signature block or not.
 * @param numSignatures          Optional out parameter for storing the number
 *                               of signatures in the MAR file.
 * @param hasAdditionalBlocks    Optional out parameter specifying if the MAR
 *                               file has additional blocks or not.
 * @param offsetAdditionalBlocks Optional out parameter for the offset to the 
 *                               first additional block. Value is only valid if
 *                               hasAdditionalBlocks is not equal to 0.
 * @param numAdditionalBlocks    Optional out parameter for the number of
 *                               additional blocks.  Value is only valid if
 *                               hasAdditionalBlocks is not equal to 0.
 * @return 0 on success and non-zero on failure.
 */
int get_mar_file_info_fp(FILE *fp, 
                         int *hasSignatureBlock,
                         uint32_t *numSignatures,
                         int *hasAdditionalBlocks,
                         uint32_t *offsetAdditionalBlocks,
                         uint32_t *numAdditionalBlocks)
{
  uint32_t offsetToIndex, offsetToContent, signatureCount, signatureLen, i;
  
  /* One of hasSignatureBlock or hasAdditionalBlocks must be non NULL */
  if (!hasSignatureBlock && !hasAdditionalBlocks) {
    return -1;
  }


  /* Skip to the start of the offset index */
  if (fseek(fp, MAR_ID_SIZE, SEEK_SET)) {
    return -1;
  }

  /* Read the offset to the index. */
  if (fread(&offsetToIndex, sizeof(offsetToIndex), 1, fp) != 1) {
    return -1;
  }
  offsetToIndex = ntohl(offsetToIndex);

  if (numSignatures) {
     /* Skip past the MAR file size field */
    if (fseek(fp, sizeof(uint64_t), SEEK_CUR)) {
      return -1;
    }

    /* Read the number of signatures field */
    if (fread(numSignatures, sizeof(*numSignatures), 1, fp) != 1) {
      return -1;
    }
    *numSignatures = ntohl(*numSignatures);
  }

  /* Skip to the first index entry past the index size field 
     We do it in 2 calls because offsetToIndex + sizeof(uint32_t) 
     could oerflow in theory. */
  if (fseek(fp, offsetToIndex, SEEK_SET)) {
    return -1;
  }

  if (fseek(fp, sizeof(uint32_t), SEEK_CUR)) {
    return -1;
  }

  /* Read the first offset to content field. */
  if (fread(&offsetToContent, sizeof(offsetToContent), 1, fp) != 1) {
    return -1;
  }
  offsetToContent = ntohl(offsetToContent);

  /* Check if we have a new or old MAR file */
  if (hasSignatureBlock) {
    if (offsetToContent == MAR_ID_SIZE + sizeof(uint32_t)) {
      *hasSignatureBlock = 0;
    } else {
      *hasSignatureBlock = 1;
    }
  }

  /* If the caller doesn't care about the product info block 
     value, then just return */
  if (!hasAdditionalBlocks) {
    return 0;
  }

   /* Skip to the start of the signature block */
  if (fseeko(fp, SIGNATURE_BLOCK_OFFSET, SEEK_SET)) {
    return -1;
  }

  /* Get the number of signatures */
  if (fread(&signatureCount, sizeof(signatureCount), 1, fp) != 1) {
    return -1;
  }
  signatureCount = ntohl(signatureCount);

  /* Check that we have less than the max amount of signatures so we don't
     waste too much of either updater's or signmar's time. */
  if (signatureCount > MAX_SIGNATURES) {
    return -1;
  }

  /* Skip past the whole signature block */
  for (i = 0; i < signatureCount; i++) {
    /* Skip past the signature algorithm ID */
    if (fseek(fp, sizeof(uint32_t), SEEK_CUR)) {
      return -1;
    }

    /* Read the signature length and skip past the signature */
    if (fread(&signatureLen, sizeof(uint32_t), 1, fp) != 1) {
      return -1;
    }
    signatureLen = ntohl(signatureLen);
    if (fseek(fp, signatureLen, SEEK_CUR)) {
      return -1;
    }
  }

  if ((int64_t)ftell(fp) == (int64_t)offsetToContent) {
    *hasAdditionalBlocks = 0;
  } else {
    if (numAdditionalBlocks) {
      /* We have an additional block, so read in the number of additional blocks
         and set the offset. */
      *hasAdditionalBlocks = 1;
      if (fread(numAdditionalBlocks, sizeof(uint32_t), 1, fp) != 1) {
        return -1;
      }
      *numAdditionalBlocks = ntohl(*numAdditionalBlocks);
      if (offsetAdditionalBlocks) {
        *offsetAdditionalBlocks = ftell(fp);
      }
    } else if (offsetAdditionalBlocks) {
      /* numAdditionalBlocks is not specified but offsetAdditionalBlocks 
         is, so fill it! */
      *offsetAdditionalBlocks = ftell(fp) + sizeof(uint32_t);
    }
  }

  return 0;
}

/** 
 * Reads the product info block from the MAR file's additional block section.
 * The caller is responsible for freeing the fields in infoBlock
 * if the return is successful.
 *
 * @param infoBlock Out parameter for where to store the result to
 * @return 0 on success, -1 on failure
*/
int
read_product_info_block(char *path, 
                        struct ProductInformationBlock *infoBlock)
{
  int rv;
  MarFile mar;
  mar.fp = fopen(path, "rb");
  if (!mar.fp) {
    fprintf(stderr, "ERROR: could not open file in read_product_info_block()\n");
    perror(path);
    return -1;
  }
  rv = mar_read_product_info_block(&mar, infoBlock);
  fclose(mar.fp);
  return rv;
}

/** 
 * Reads the product info block from the MAR file's additional block section.
 * The caller is responsible for freeing the fields in infoBlock
 * if the return is successful.
 *
 * @param infoBlock Out parameter for where to store the result to
 * @return 0 on success, -1 on failure
*/
int
mar_read_product_info_block(MarFile *mar, 
                            struct ProductInformationBlock *infoBlock)
{
  uint32_t i, offsetAdditionalBlocks, numAdditionalBlocks,
    additionalBlockSize, additionalBlockID;
  int hasAdditionalBlocks;

  /* The buffer size is 97 bytes because the MAR channel name < 64 bytes, and 
     product version < 32 bytes + 3 NULL terminator bytes. */
  char buf[97] = { '\0' };
  if (get_mar_file_info_fp(mar->fp, NULL, NULL,
                           &hasAdditionalBlocks,
                           &offsetAdditionalBlocks,
                           &numAdditionalBlocks) != 0) {
    return -1;
  }
  for (i = 0; i < numAdditionalBlocks; ++i) {
    /* Read the additional block size */
    if (fread(&additionalBlockSize, 
              sizeof(additionalBlockSize), 
              1, mar->fp) != 1) {
      return -1;
    }
    additionalBlockSize = ntohl(additionalBlockSize) - 
                          sizeof(additionalBlockSize) - 
                          sizeof(additionalBlockID);

    /* Read the additional block ID */
    if (fread(&additionalBlockID, 
              sizeof(additionalBlockID), 
              1, mar->fp) != 1) {
      return -1;
    }
    additionalBlockID = ntohl(additionalBlockID);

    if (PRODUCT_INFO_BLOCK_ID == additionalBlockID) {
      const char *location;
      int len;

      /* This block must be at most 104 bytes.
         MAR channel name < 64 bytes, and product version < 32 bytes + 3 NULL 
         terminator bytes. We only check for 96 though because we remove 8 
         bytes above from the additionalBlockSize: We subtract 
         sizeof(additionalBlockSize) and sizeof(additionalBlockID) */
      if (additionalBlockSize > 96) {
        return -1;
      }

    if (fread(buf, additionalBlockSize, 1, mar->fp) != 1) {
        return -1;
      }

      /* Extract the MAR channel name from the buffer.  For now we
         point to the stack allocated buffer but we strdup this
         if we are within bounds of each field's max length. */
      location = buf;
      len = strlen(location);
      infoBlock->MARChannelID = location;
      location += len + 1;
      if (len >= 64) {
        infoBlock->MARChannelID = NULL;
        return -1;
      }

      /* Extract the version from the buffer */
      len = strlen(location);
      infoBlock->productVersion = location;
      location += len + 1;
      if (len >= 32) {
        infoBlock->MARChannelID = NULL;
        infoBlock->productVersion = NULL;
        return -1;
      }
      infoBlock->MARChannelID = 
        strdup(infoBlock->MARChannelID);
      infoBlock->productVersion = 
        strdup(infoBlock->productVersion);
      return 0;
    } else {
      /* This is not the additional block you're looking for. Move along. */
      if (fseek(mar->fp, additionalBlockSize, SEEK_CUR)) {
        return -1;
      }
    }
  }

  /* If we had a product info block we would have already returned */
  return -1;
}

const MarItem *mar_find_item(MarFile *mar, const char *name) {
  uint32_t hash;
  const MarItem *item;

  if (!mar->item_table_is_valid) {
    if (mar_read_index(mar)) {
      return NULL;
    } else {
      mar->item_table_is_valid = 1;
    }
  }

  hash = mar_hash_name(name);

  item = mar->item_table[hash];
  while (item && strcmp(item->name, name) != 0)
    item = item->next;

  return item;
}

int mar_enum_items(MarFile *mar, MarItemCallback callback, void *closure) {
  MarItem *item;
  int i;

  if (!mar->item_table_is_valid) {
    if (mar_read_index(mar)) {
      return -1;
    } else {
      mar->item_table_is_valid = 1;
    }
  }

  for (i = 0; i < TABLESIZE; ++i) {
    item = mar->item_table[i];
    while (item) {
      int rv = callback(mar, item, closure);
      if (rv)
        return rv;
      item = item->next;
    }
  }

  return 0;
}

int mar_read(MarFile *mar, const MarItem *item, int offset, char *buf,
             int bufsize) {
  int nr;

  if (offset == (int) item->length)
    return 0;
  if (offset > (int) item->length)
    return -1;

  nr = item->length - offset;
  if (nr > bufsize)
    nr = bufsize;

  if (fseek(mar->fp, item->offset + offset, SEEK_SET))
    return -1;

  return fread(buf, 1, nr, mar->fp);
}

/**
 * Determines the MAR file information.
 *
 * @param path                   The path of the MAR file to check.
 * @param hasSignatureBlock      Optional out parameter specifying if the MAR
 *                               file has a signature block or not.
 * @param numSignatures          Optional out parameter for storing the number
 *                               of signatures in the MAR file.
 * @param hasAdditionalBlocks    Optional out parameter specifying if the MAR
 *                               file has additional blocks or not.
 * @param offsetAdditionalBlocks Optional out parameter for the offset to the 
 *                               first additional block. Value is only valid if
 *                               hasAdditionalBlocks is not equal to 0.
 * @param numAdditionalBlocks    Optional out parameter for the number of
 *                               additional blocks.  Value is only valid if
 *                               has_additional_blocks is not equal to 0.
 * @return 0 on success and non-zero on failure.
 */
int get_mar_file_info(const char *path, 
                      int *hasSignatureBlock,
                      uint32_t *numSignatures,
                      int *hasAdditionalBlocks,
                      uint32_t *offsetAdditionalBlocks,
                      uint32_t *numAdditionalBlocks)
{
  int rv;
  FILE *fp = fopen(path, "rb");
  if (!fp) {
    fprintf(stderr, "ERROR: could not open file in get_mar_file_info()\n");
    perror(path);
    return -1;
  }

  rv = get_mar_file_info_fp(fp, hasSignatureBlock, 
                            numSignatures, hasAdditionalBlocks,
                            offsetAdditionalBlocks, numAdditionalBlocks);

  fclose(fp);
  return rv;
}