src/convert.c

   1 /*
   2     Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
   3     Ben Kibbey <bjk@luxsci.net>
   4
   5     This file is part of pwmd.
   6
   7     Pwmd is free software: you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation, either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     Pwmd 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
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License
  18     along with Pwmd.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20 #ifdef HAVE_CONFIG_H
  21 #include <config.h>
  22 #endif
  23
  24 #include <fcntl.h>
  25 #include <sys/stat.h>
  26 #include <zlib.h>
  27 #include <errno.h>
  28
  29 #include "pwmd-error.h"
  30 #include <gcrypt.h>
  31 #include "convert.h"
  32 #include "xml.h"
  33 #include "mem.h"
  34 #include "util-misc.h"
  35 #include "cache.h"
  36 #include "crypto.h"
  37 #include "pinentry.h"
  38
  39 #ifndef _
  40 #include "gettext.h"
  41 #define _(msgid) gettext(msgid)
  42 #endif
  43
  44 #define KEYSIZE 32
  45
  46 typedef struct
  47 {
  48   uint8_t magic[5];
  49   uint16_t version;
  50   uint64_t iter;
  51   uint64_t flags;
  52   uint8_t iv[16];
  53   uint8_t salt[8];
  54 } v2_file_header_t;
  55
  56 struct gz_s
  57 {
  58   z_stream z;
  59   void *out;
  60   int done;
  61 };
  62
  63 static unsigned char crypto_magic[5] = "\177PWMD";
  64
  65 static void
  66 gz_cleanup (void *arg)
  67 {
  68   struct gz_s **gz = (struct gz_s **) arg;
  69
  70   if (!gz)
  71     return;
  72
  73   if (!(*gz)->done && (*gz)->out)
  74     gcry_free ((*gz)->out);
  75
  76   if ((*gz)->z.zalloc)
  77     inflateEnd (&(*gz)->z);
  78
  79   xfree (*gz);
  80   *gz = NULL;
  81 }
  82
  83 static void *
  84 z_alloc (void *data, unsigned items, unsigned size)
  85 {
  86   return gcry_calloc (items, size);
  87 }
  88
  89 static void
  90 z_free (void *data, void *p)
  91 {
  92   gcry_free (p);
  93 }
  94
  95 #define ZLIB_BUFSIZE    65536
  96
  97 static gpg_error_t
  98 decompress (void *in, unsigned long insize, void * *out,
  99             unsigned long *outsize)
 100 {
 101   struct gz_s *gz;
 102   gz_header h;
 103   char buf[17];
 104   gpg_error_t rc;
 105   int zrc;
 106
 107   gz = xcalloc (1, sizeof (struct gz_s));
 108   if (!gz)
 109     return GPG_ERR_ENOMEM;
 110
 111   gz->z.zalloc = z_alloc;
 112   gz->z.zfree = z_free;
 113   gz->z.next_in = in;
 114   gz->z.avail_in = (uInt) insize;
 115   gz->z.avail_out = ZLIB_BUFSIZE;
 116   gz->z.next_out = gz->out = gcry_malloc (ZLIB_BUFSIZE);
 117   if (!gz->out)
 118     {
 119       gz_cleanup (&gz);
 120       return GPG_ERR_ENOMEM;
 121     }
 122
 123   zrc = inflateInit2 (&gz->z, 47);
 124   if (zrc != Z_OK)
 125     {
 126       gz_cleanup (&gz);
 127       return zrc == Z_MEM_ERROR ? GPG_ERR_ENOMEM : GPG_ERR_COMPR_ALGO;
 128     }
 129
 130   memset (&h, 0, sizeof (gz_header));
 131   h.comment = (unsigned char *) buf;
 132   h.comm_max = sizeof (buf);
 133   zrc = inflateGetHeader (&gz->z, &h);
 134   if (zrc != Z_OK)
 135     {
 136       gz_cleanup (&gz);
 137       return zrc == Z_MEM_ERROR ? GPG_ERR_ENOMEM : GPG_ERR_COMPR_ALGO;
 138     }
 139
 140   zrc = inflate (&gz->z, Z_BLOCK);
 141   if (zrc != Z_OK)
 142     {
 143       gz_cleanup (&gz);
 144       return zrc == Z_MEM_ERROR ? GPG_ERR_ENOMEM : GPG_ERR_COMPR_ALGO;
 145     }
 146
 147   if (h.comment)
 148     insize = strtoul ((char *) h.comment, NULL, 10);
 149
 150   do
 151     {
 152       void *p;
 153
 154       zrc = inflate (&gz->z, Z_FINISH);
 155       switch (zrc)
 156         {
 157         case Z_OK:
 158           break;
 159         case Z_BUF_ERROR:
 160           if (!gz->z.avail_out)
 161             {
 162               p = gcry_realloc (gz->out, gz->z.total_out + ZLIB_BUFSIZE);
 163               if (!p)
 164                 {
 165                   rc = GPG_ERR_ENOMEM;
 166                   goto fail;
 167                 }
 168
 169               gz->out = p;
 170               gz->z.next_out = (unsigned char *) gz->out + gz->z.total_out;
 171               gz->z.avail_out = ZLIB_BUFSIZE;
 172             }
 173           else
 174             {
 175               rc = GPG_ERR_COMPR_ALGO;
 176               goto fail;
 177             }
 178
 179           break;
 180         case Z_STREAM_END:
 181           break;
 182         default:
 183           rc = GPG_ERR_COMPR_ALGO;
 184           goto fail;
 185           break;
 186         }
 187     }
 188   while (zrc != Z_STREAM_END);
 189
 190   *out = gz->out;
 191   *outsize = gz->z.total_out;
 192   gz->done = 1;
 193   gz_cleanup (&gz);
 194   return 0;
 195
 196 fail:
 197   gz_cleanup (&gz);
 198   return rc;
 199 }
 200
 201 static gpg_error_t
 202 decrypt (v2_file_header_t * fh, unsigned char *key,
 203          unsigned char **ciphertext, size_t datalen, void * *result,
 204          size_t * result_len)
 205 {
 206   gpg_error_t rc;
 207   size_t blocksize, keysize, len;
 208   int algo = cipher_to_gcrypt (fh->flags);
 209   gcry_cipher_hd_t gh = NULL;
 210   uint64_t iter = 0ULL;
 211   unsigned char *data = *ciphertext;
 212
 213   *result = NULL;
 214   *result_len = 0;
 215
 216   /* No encryption iterations. This is a plain (gzipped) file. */
 217   if (!fh->iter)
 218     goto decompress;
 219
 220   if (algo == -1)
 221     return GPG_ERR_CIPHER_ALGO;
 222
 223   rc = gcry_cipher_algo_info (algo, GCRYCTL_TEST_ALGO, NULL, NULL);
 224   if (rc)
 225     return rc;
 226
 227   rc = gcry_cipher_algo_info (algo, GCRYCTL_GET_KEYLEN, NULL, &keysize);
 228   if (rc)
 229     return rc;
 230
 231   rc = gcry_cipher_algo_info (algo, GCRYCTL_GET_BLKLEN, NULL, &blocksize);
 232   if (rc)
 233     return rc;
 234
 235   rc = gcry_cipher_open (&gh, algo, GCRY_CIPHER_MODE_CBC, 0);
 236   if (rc)
 237     return rc;
 238
 239   if ((rc = gcry_cipher_setiv (gh, fh->iv, blocksize)))
 240     goto fail;
 241
 242   if ((rc = gcry_cipher_setkey (gh, key, keysize)))
 243     goto fail;
 244
 245   rc = gcry_cipher_decrypt (gh, data, datalen, NULL, 0);
 246   if (rc)
 247     goto fail;
 248
 249   key[0] ^= 1;
 250   if ((rc = gcry_cipher_setkey (gh, key, keysize)))
 251     goto fail;
 252
 253   while (++iter < fh->iter)
 254     {
 255       if ((rc = gcry_cipher_setiv (gh, fh->iv, blocksize)))
 256         goto fail;
 257
 258       rc = gcry_cipher_decrypt (gh, data, datalen, NULL, 0);
 259       if (rc)
 260         goto fail;
 261     }
 262
 263 decompress:
 264   len = 0;
 265   if (fh->version >= 0x218 && fh->iter > 0ULL)
 266     {
 267       if (memcmp (data, crypto_magic, sizeof (crypto_magic)))
 268         {
 269           rc = GPG_ERR_BAD_PASSPHRASE;
 270           goto fail;
 271         }
 272
 273       len = sizeof (crypto_magic);
 274     }
 275
 276   rc =
 277     decompress (data + len, datalen - len, result,
 278                 (unsigned long *) result_len);
 279   if (rc)
 280     {
 281       if (fh->version < 0x218 && rc == GPG_ERR_COMPR_ALGO)
 282         rc = GPG_ERR_BAD_PASSPHRASE;
 283       goto fail;
 284     }
 285
 286   if (strncasecmp ((char *) *result, "<?xml ", 6) != 0)
 287     {
 288       gcry_free (*result);
 289       *result = NULL;
 290       *result_len = 0;
 291       rc = GPG_ERR_BAD_PASSPHRASE;
 292       goto fail;
 293     }
 294
 295 fail:
 296   if (gh)
 297     gcry_cipher_close (gh);
 298
 299   return rc;
 300 }
 301
 302 gpg_error_t
 303 read_v2_datafile (const char *filename, const char *keyfile,
 304                   void * *result, size_t * result_len, uint16_t * ver,
 305                   int *algo)
 306 {
 307   gpg_error_t rc;
 308   int fd;
 309   v2_file_header_t fh;
 310   size_t len, passphraselen, datalen;
 311 #ifdef WITH_AGENT
 312   struct agent_s *agent = NULL;
 313 #endif
 314   char *passphrase = NULL;
 315   unsigned char *data = NULL;
 316   struct stat st;
 317   unsigned char *key = NULL;
 318   FILE *fp;
 319
 320   if (stat (filename, &st) == -1)
 321     return gpg_error_from_errno (errno);
 322
 323   fd = open (filename, O_RDONLY);
 324   if (fd == -1)
 325     return gpg_error_from_errno (errno);
 326
 327   len = read (fd, &fh, sizeof (fh) - 8);
 328   if (len != sizeof (fh) - 8)
 329     {
 330       rc = GPG_ERR_INV_LENGTH;
 331       goto fail;
 332     }
 333
 334   if (fh.version >= 0x221)
 335     {
 336       len = read (fd, &fh.salt, 8);
 337       if (len != 8)
 338         {
 339           rc = GPG_ERR_INV_LENGTH;
 340           goto fail;
 341         }
 342     }
 343
 344   *ver = fh.version;
 345   *algo = cipher_to_gcrypt (fh.flags);
 346
 347 #ifdef WITH_AGENT
 348   if (use_agent && !keyfile && fh.iter > 0)
 349     {
 350       char *desc;
 351
 352       rc = agent_init (&agent);
 353       if (rc)
 354         goto fail;
 355
 356       desc = plus_escape (_
 357                           ("A passphrase is required to decrypt the file for "
 358                            "converting. Please enter the passphrase below."));
 359       rc = agent_set_pinentry_options (agent);
 360       if (rc)
 361         goto fail;
 362
 363       assuan_begin_confidential (agent->ctx);
 364       rc = send_to_agent (agent, &passphrase, &passphraselen,
 365                           "GET_PASSPHRASE --data pwmd:convert + %s %s",
 366                           _("Passphrase:"), desc);
 367       assuan_end_confidential (agent->ctx);
 368       xfree (desc);
 369       if (rc)
 370         goto fail;
 371
 372       passphraselen--;          // null byte
 373       send_to_agent (agent, NULL, NULL, "CLEAR_PASSPHRASE pwmd:convert");
 374       cleanup_agent (agent);
 375       agent = NULL;
 376     }
 377     else if (keyfile && fh.iter > 0)
 378 #else
 379     if (keyfile && fh.iter > 0)
 380 #endif
 381     {
 382       struct stat pst;
 383       int pfd = open (keyfile, O_RDONLY);
 384
 385       if (pfd == -1)
 386         {
 387           rc = gpg_error_from_errno (errno);
 388           goto fail;
 389         }
 390
 391       if (stat (keyfile, &pst) == -1)
 392         {
 393           rc = gpg_error_from_errno (errno);
 394           close (pfd);
 395           goto fail;
 396         }
 397
 398       passphrase = xmalloc (pst.st_size);
 399       if (!passphrase)
 400         {
 401           rc = GPG_ERR_ENOMEM;
 402           close (pfd);
 403           goto fail;
 404         }
 405
 406       passphraselen = read (pfd, passphrase, pst.st_size);
 407       close (pfd);
 408       if (passphraselen != pst.st_size)
 409         {
 410           rc = GPG_ERR_INV_LENGTH;
 411           goto fail;
 412         }
 413     }
 414     else if (fh.iter > 0)
 415       {
 416         rc = getpin_common (NULL, filename, PINENTRY_OPEN, &passphrase,
 417                             &passphraselen);
 418         if (rc)
 419           goto fail;
 420       }
 421
 422   key = gcry_malloc (KEYSIZE);
 423   if (!key)
 424     {
 425       rc = GPG_ERR_ENOMEM;
 426       goto fail;
 427     }
 428
 429   fp = fdopen (fd, "r");
 430   len = st.st_size - ftell (fp);
 431
 432   if (fh.version >= 0x221 && fh.version < 0x0300)
 433     {
 434       rc = gcry_kdf_derive (passphrase, passphraselen, GCRY_KDF_ITERSALTED_S2K,
 435                             GCRY_MD_SHA1, fh.salt, 8, 1000, KEYSIZE, key);
 436       if (rc)
 437         goto fail;
 438     }
 439   else
 440     gcry_md_hash_buffer (GCRY_MD_SHA256, key, passphrase, passphraselen);
 441
 442   data = gcry_malloc (len);
 443   if (!data)
 444     {
 445       rc = GPG_ERR_ENOMEM;
 446       goto fail;
 447     }
 448
 449   datalen = read (fd, data, len);
 450   if (datalen != len)
 451     {
 452       rc = GPG_ERR_INV_LENGTH;
 453       goto fail;
 454     }
 455
 456   fprintf (stderr, _("Decrypting ...\n"));
 457   rc = decrypt (&fh, key, &data, datalen, result, result_len);
 458
 459 fail:
 460   gcry_free (key);
 461   gcry_free (data);
 462   xfree (passphrase);
 463
 464 #ifdef WITH_AGENT
 465   if (agent)
 466     cleanup_agent (agent);
 467 #endif
 468
 469   if (fd != -1)
 470     close (fd);
 471   return rc;
 472 }