g10/encode.c

   1 /* encode.c - encode data
   2  * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
   3  *               2006 Free Software Foundation, Inc.
   4  *
   5  * This file is part of GnuPG.
   6  *
   7  * GnuPG 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 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * GnuPG 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 this program; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <config.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <errno.h>
  26 #include <assert.h>
  27
  28 #include "gpg.h"
  29 #include "options.h"
  30 #include "packet.h"
  31 #include "status.h"
  32 #include "iobuf.h"
  33 #include "keydb.h"
  34 #include "util.h"
  35 #include "main.h"
  36 #include "filter.h"
  37 #include "trustdb.h"
  38 #include "i18n.h"
  39 #include "status.h"
  40 #include "pkglue.h"
  41
  42
  43 static int encode_simple( const char *filename, int mode, int use_seskey );
  44 static int write_pubkey_enc_from_list( PK_LIST pk_list, DEK *dek, IOBUF out );
  45
  46 /****************
  47  * Encode FILENAME with only the symmetric cipher.  Take input from
  48  * stdin if FILENAME is NULL.
  49  */
  50 int
  51 encode_symmetric( const char *filename )
  52 {
  53     return encode_simple( filename, 1, 0 );
  54 }
  55
  56 /****************
  57  * Encode FILENAME as a literal data packet only. Take input from
  58  * stdin if FILENAME is NULL.
  59  */
  60 int
  61 encode_store( const char *filename )
  62 {
  63     return encode_simple( filename, 0, 0 );
  64 }
  65
  66
  67 static void
  68 encode_seskey( DEK *dek, DEK **seskey, byte *enckey )
  69 {
  70     gcry_cipher_hd_t hd;
  71     byte buf[33];
  72
  73     assert ( dek->keylen <= 32 );
  74     if(!*seskey)
  75       {
  76         *seskey=xmalloc_clear(sizeof(DEK));
  77         (*seskey)->keylen=dek->keylen;
  78         (*seskey)->algo=dek->algo;
  79         make_session_key(*seskey);
  80         /*log_hexdump( "thekey", c->key, c->keylen );*/
  81       }
  82
  83     /* The encrypted session key is prefixed with a one-octet algorithm id.  */
  84     buf[0] = (*seskey)->algo;
  85     memcpy( buf + 1, (*seskey)->key, (*seskey)->keylen );
  86
  87     /* We only pass already checked values to the following fucntion,
  88        thus we consider any failure as fatal.  */
  89     if (gcry_cipher_open (&hd, dek->algo, GCRY_CIPHER_MODE_CFB, 1))
  90       BUG ();
  91     if (gcry_cipher_setkey (hd, dek->key, dek->keylen))
  92       BUG ();
  93     gcry_cipher_setiv (hd, NULL, 0);
  94     gcry_cipher_encrypt (hd, buf, (*seskey)->keylen + 1, NULL, 0);
  95     gcry_cipher_close (hd);
  96
  97     memcpy( enckey, buf, (*seskey)->keylen + 1 );
  98     wipememory( buf, sizeof buf ); /* burn key */
  99 }
 100
 101 /* We try very hard to use a MDC */
 102 static int
 103 use_mdc(PK_LIST pk_list,int algo)
 104 {
 105   /* RFC-1991 and 2440 don't have MDC */
 106   if(RFC1991 || RFC2440)
 107     return 0;
 108
 109   /* --force-mdc overrides --disable-mdc */
 110   if(opt.force_mdc)
 111     return 1;
 112
 113   if(opt.disable_mdc)
 114     return 0;
 115
 116   /* Do the keys really support MDC? */
 117
 118   if(select_mdc_from_pklist(pk_list))
 119     return 1;
 120
 121   /* The keys don't support MDC, so now we do a bit of a hack - if any
 122      of the AESes or TWOFISH are in the prefs, we assume that the user
 123      can handle a MDC.  This is valid for PGP 7, which can handle MDCs
 124      though it will not generate them.  2440bis allows this, by the
 125      way. */
 126
 127   if(select_algo_from_prefs(pk_list,PREFTYPE_SYM,
 128                             CIPHER_ALGO_AES,NULL)==CIPHER_ALGO_AES)
 129     return 1;
 130
 131   if(select_algo_from_prefs(pk_list,PREFTYPE_SYM,
 132                             CIPHER_ALGO_AES192,NULL)==CIPHER_ALGO_AES192)
 133     return 1;
 134
 135   if(select_algo_from_prefs(pk_list,PREFTYPE_SYM,
 136                             CIPHER_ALGO_AES256,NULL)==CIPHER_ALGO_AES256)
 137     return 1;
 138
 139   if(select_algo_from_prefs(pk_list,PREFTYPE_SYM,
 140                             CIPHER_ALGO_TWOFISH,NULL)==CIPHER_ALGO_TWOFISH)
 141     return 1;
 142
 143   /* Last try.  Use MDC for the modern ciphers. */
 144
 145   if (gcry_cipher_get_algo_blklen (algo) != 8)
 146     return 1;
 147
 148   if (opt.verbose)
 149     warn_missing_mdc_from_pklist (pk_list);
 150
 151   return 0; /* No MDC */
 152 }
 153
 154 /* We don't want to use use_seskey yet because older gnupg versions
 155    can't handle it, and there isn't really any point unless we're
 156    making a message that can be decrypted by a public key or
 157    passphrase. */
 158 static int
 159 encode_simple( const char *filename, int mode, int use_seskey )
 160 {
 161     IOBUF inp, out;
 162     PACKET pkt;
 163     PKT_plaintext *pt = NULL;
 164     STRING2KEY *s2k = NULL;
 165     byte enckey[33];
 166     int rc = 0;
 167     int seskeylen = 0;
 168     u32 filesize;
 169     cipher_filter_context_t cfx;
 170     armor_filter_context_t  *afx = NULL;
 171     compress_filter_context_t zfx;
 172     text_filter_context_t tfx;
 173     progress_filter_context_t *pfx;
 174     int do_compress = !RFC1991 && default_compress_algo();
 175
 176     pfx = new_progress_context ();
 177     memset( &cfx, 0, sizeof cfx);
 178     memset( &zfx, 0, sizeof zfx);
 179     memset( &tfx, 0, sizeof tfx);
 180     init_packet(&pkt);
 181
 182     /* prepare iobufs */
 183     inp = iobuf_open(filename);
 184     if (inp)
 185       iobuf_ioctl (inp,3,1,NULL); /* disable fd caching */
 186     if (inp && is_secured_file (iobuf_get_fd (inp)))
 187       {
 188         iobuf_close (inp);
 189         inp = NULL;
 190         errno = EPERM;
 191       }
 192     if( !inp ) {
 193         rc = gpg_error_from_syserror ();
 194         log_error(_("can't open `%s': %s\n"), filename? filename: "[stdin]",
 195                   strerror(errno) );
 196         release_progress_context (pfx);
 197         return rc;
 198     }
 199
 200     handle_progress (pfx, inp, filename);
 201
 202     if( opt.textmode )
 203         iobuf_push_filter( inp, text_filter, &tfx );
 204
 205     /* Due the the fact that we use don't use an IV to encrypt the
 206        session key we can't use the new mode with RFC1991 because
 207        it has no S2K salt. RFC1991 always uses simple S2K. */
 208     if ( RFC1991 && use_seskey )
 209         use_seskey = 0;
 210
 211     cfx.dek = NULL;
 212     if( mode ) {
 213         int canceled;
 214
 215         s2k = xmalloc_clear( sizeof *s2k );
 216         s2k->mode = RFC1991? 0:opt.s2k_mode;
 217         s2k->hash_algo=S2K_DIGEST_ALGO;
 218         cfx.dek = passphrase_to_dek( NULL, 0,
 219                                      default_cipher_algo(), s2k, 2,
 220                                      NULL, &canceled);
 221         if( !cfx.dek || !cfx.dek->keylen ) {
 222             rc = gpg_error (canceled? GPG_ERR_CANCELED:GPG_ERR_INV_PASSPHRASE);
 223             xfree(cfx.dek);
 224             xfree(s2k);
 225             iobuf_close(inp);
 226             log_error(_("error creating passphrase: %s\n"), gpg_strerror (rc));
 227             release_progress_context (pfx);
 228             return rc;
 229         }
 230         if (use_seskey && s2k->mode != 1 && s2k->mode != 3) {
 231             use_seskey = 0;
 232             log_info (_("can't use a symmetric ESK packet "
 233                         "due to the S2K mode\n"));
 234         }
 235
 236         if ( use_seskey )
 237           {
 238             DEK *dek = NULL;
 239
 240             seskeylen = gcry_cipher_get_algo_keylen (default_cipher_algo ());
 241             encode_seskey( cfx.dek, &dek, enckey );
 242             xfree( cfx.dek ); cfx.dek = dek;
 243           }
 244
 245         if(opt.verbose)
 246           log_info(_("using cipher %s\n"),
 247                    openpgp_cipher_algo_name (cfx.dek->algo));
 248
 249         cfx.dek->use_mdc=use_mdc(NULL,cfx.dek->algo);
 250     }
 251
 252     if (do_compress && cfx.dek && cfx.dek->use_mdc
 253         && is_file_compressed(filename, &rc))
 254       {
 255         if (opt.verbose)
 256           log_info(_("`%s' already compressed\n"), filename);
 257         do_compress = 0;
 258       }
 259
 260     if( rc || (rc = open_outfile( filename, opt.armor? 1:0, &out )) ) {
 261         iobuf_cancel(inp);
 262         xfree(cfx.dek);
 263         xfree(s2k);
 264         release_progress_context (pfx);
 265         return rc;
 266     }
 267
 268     if ( opt.armor )
 269       {
 270         afx = new_armor_context ();
 271         push_armor_filter (afx, out);
 272       }
 273
 274     if( s2k && !RFC1991 ) {
 275         PKT_symkey_enc *enc = xmalloc_clear( sizeof *enc + seskeylen + 1 );
 276         enc->version = 4;
 277         enc->cipher_algo = cfx.dek->algo;
 278         enc->s2k = *s2k;
 279         if ( use_seskey && seskeylen ) {
 280             enc->seskeylen = seskeylen + 1; /* algo id */
 281             memcpy( enc->seskey, enckey, seskeylen + 1 );
 282         }
 283         pkt.pkttype = PKT_SYMKEY_ENC;
 284         pkt.pkt.symkey_enc = enc;
 285         if( (rc = build_packet( out, &pkt )) )
 286             log_error("build symkey packet failed: %s\n", g10_errstr(rc) );
 287         xfree(enc);
 288     }
 289
 290     if (!opt.no_literal)
 291       pt=setup_plaintext_name(filename,inp);
 292
 293     /* Note that PGP 5 has problems decrypting symmetrically encrypted
 294        data if the file length is in the inner packet. It works when
 295        only partial length headers are use.  In the past, we always
 296        used partial body length here, but since PGP 2, PGP 6, and PGP
 297        7 need the file length, and nobody should be using PGP 5
 298        nowadays anyway, this is now set to the file length.  Note also
 299        that this only applies to the RFC-1991 style symmetric
 300        messages, and not the RFC-2440 style.  PGP 6 and 7 work with
 301        either partial length or fixed length with the new style
 302        messages. */
 303
 304     if ( !iobuf_is_pipe_filename (filename) && *filename && !opt.textmode )
 305       {
 306         off_t tmpsize;
 307         int overflow;
 308
 309         if ( !(tmpsize = iobuf_get_filelength(inp, &overflow))
 310              && !overflow )
 311           log_info(_("WARNING: `%s' is an empty file\n"), filename );
 312         /* We can't encode the length of very large files because
 313            OpenPGP uses only 32 bit for file sizes.  So if the the
 314            size of a file is larger than 2^32 minus some bytes for
 315            packet headers, we switch to partial length encoding. */
 316         if ( tmpsize < (IOBUF_FILELENGTH_LIMIT - 65536) )
 317           filesize = tmpsize;
 318         else
 319           filesize = 0;
 320       }
 321     else
 322       filesize = opt.set_filesize ? opt.set_filesize : 0; /* stdin */
 323
 324     if (!opt.no_literal) {
 325         pt->timestamp = make_timestamp();
 326         pt->mode = opt.textmode? 't' : 'b';
 327         pt->len = filesize;
 328         pt->new_ctb = !pt->len && !RFC1991;
 329         pt->buf = inp;
 330         pkt.pkttype = PKT_PLAINTEXT;
 331         pkt.pkt.plaintext = pt;
 332         cfx.datalen = filesize && !do_compress ? calc_packet_length( &pkt ) : 0;
 333     }
 334     else
 335       {
 336         cfx.datalen = filesize && !do_compress ? filesize : 0;
 337         pkt.pkttype = 0;
 338         pkt.pkt.generic = NULL;
 339       }
 340
 341     /* register the cipher filter */
 342     if( mode )
 343         iobuf_push_filter( out, cipher_filter, &cfx );
 344     /* register the compress filter */
 345     if( do_compress )
 346       {
 347         if (cfx.dek && cfx.dek->use_mdc)
 348           zfx.new_ctb = 1;
 349         push_compress_filter(out,&zfx,default_compress_algo());
 350       }
 351
 352     /* do the work */
 353     if (!opt.no_literal) {
 354         if( (rc = build_packet( out, &pkt )) )
 355             log_error("build_packet failed: %s\n", g10_errstr(rc) );
 356     }
 357     else {
 358         /* user requested not to create a literal packet,
 359          * so we copy the plain data */
 360         byte copy_buffer[4096];
 361         int  bytes_copied;
 362         while ((bytes_copied = iobuf_read(inp, copy_buffer, 4096)) != -1)
 363             if ( (rc=iobuf_write(out, copy_buffer, bytes_copied)) ) {
 364                 log_error ("copying input to output failed: %s\n",
 365                            gpg_strerror (rc) );
 366                 break;
 367             }
 368         wipememory(copy_buffer, 4096); /* burn buffer */
 369     }
 370
 371     /* finish the stuff */
 372     iobuf_close(inp);
 373     if (rc)
 374         iobuf_cancel(out);
 375     else {
 376         iobuf_close(out); /* fixme: check returncode */
 377         if (mode)
 378             write_status( STATUS_END_ENCRYPTION );
 379     }
 380     if (pt)
 381         pt->buf = NULL;
 382     free_packet(&pkt);
 383     xfree(cfx.dek);
 384     xfree(s2k);
 385     release_armor_context (afx);
 386     release_progress_context (pfx);
 387     return rc;
 388 }
 389
 390 int
 391 setup_symkey(STRING2KEY **symkey_s2k,DEK **symkey_dek)
 392 {
 393   int canceled;
 394
 395   *symkey_s2k=xmalloc_clear(sizeof(STRING2KEY));
 396   (*symkey_s2k)->mode = opt.s2k_mode;
 397   (*symkey_s2k)->hash_algo = S2K_DIGEST_ALGO;
 398
 399   *symkey_dek=passphrase_to_dek(NULL,0,opt.s2k_cipher_algo,
 400                                 *symkey_s2k,2,NULL, &canceled);
 401   if(!*symkey_dek || !(*symkey_dek)->keylen)
 402     {
 403       xfree(*symkey_dek);
 404       xfree(*symkey_s2k);
 405       return gpg_error (canceled?GPG_ERR_CANCELED:GPG_ERR_BAD_PASSPHRASE);
 406     }
 407
 408   return 0;
 409 }
 410
 411 static int
 412 write_symkey_enc(STRING2KEY *symkey_s2k,DEK *symkey_dek,DEK *dek,IOBUF out)
 413 {
 414   int rc, seskeylen = gcry_cipher_get_algo_keylen (dek->algo);
 415
 416   PKT_symkey_enc *enc;
 417   byte enckey[33];
 418   PACKET pkt;
 419
 420   enc=xmalloc_clear(sizeof(PKT_symkey_enc)+seskeylen+1);
 421   encode_seskey(symkey_dek,&dek,enckey);
 422
 423   enc->version = 4;
 424   enc->cipher_algo = opt.s2k_cipher_algo;
 425   enc->s2k = *symkey_s2k;
 426   enc->seskeylen = seskeylen + 1; /* algo id */
 427   memcpy( enc->seskey, enckey, seskeylen + 1 );
 428
 429   pkt.pkttype = PKT_SYMKEY_ENC;
 430   pkt.pkt.symkey_enc = enc;
 431
 432   if((rc=build_packet(out,&pkt)))
 433     log_error("build symkey_enc packet failed: %s\n",g10_errstr(rc));
 434
 435   xfree(enc);
 436   return rc;
 437 }
 438
 439 /****************
 440  * Encrypt the file with the given userids (or ask if none
 441  * is supplied).
 442  */
 443 int
 444 encode_crypt( const char *filename, strlist_t remusr, int use_symkey )
 445 {
 446     IOBUF inp = NULL, out = NULL;
 447     PACKET pkt;
 448     PKT_plaintext *pt = NULL;
 449     DEK *symkey_dek = NULL;
 450     STRING2KEY *symkey_s2k = NULL;
 451     int rc = 0, rc2 = 0;
 452     u32 filesize;
 453     cipher_filter_context_t cfx;
 454     armor_filter_context_t *afx = NULL;
 455     compress_filter_context_t zfx;
 456     text_filter_context_t tfx;
 457     progress_filter_context_t *pfx;
 458     PK_LIST pk_list,work_list;
 459     int do_compress = opt.compress_algo && !RFC1991;
 460
 461     pfx = new_progress_context ();
 462     memset( &cfx, 0, sizeof cfx);
 463     memset( &zfx, 0, sizeof zfx);
 464     memset( &tfx, 0, sizeof tfx);
 465     init_packet(&pkt);
 466
 467     if(use_symkey
 468        && (rc=setup_symkey(&symkey_s2k,&symkey_dek)))
 469       {
 470         release_progress_context (pfx);
 471         return rc;
 472       }
 473
 474     if( (rc=build_pk_list( remusr, &pk_list, PUBKEY_USAGE_ENC)) )
 475       {
 476         release_progress_context (pfx);
 477         return rc;
 478       }
 479
 480     if(PGP2) {
 481       for(work_list=pk_list; work_list; work_list=work_list->next)
 482         if(!(is_RSA(work_list->pk->pubkey_algo) &&
 483              nbits_from_pk(work_list->pk)<=2048))
 484           {
 485             log_info(_("you can only encrypt to RSA keys of 2048 bits or "
 486                        "less in --pgp2 mode\n"));
 487             compliance_failure();
 488             break;
 489           }
 490     }
 491
 492     /* prepare iobufs */
 493     inp = iobuf_open(filename);
 494     if (inp)
 495       iobuf_ioctl (inp,3,1,NULL); /* disable fd caching */
 496     if (inp && is_secured_file (iobuf_get_fd (inp)))
 497       {
 498         iobuf_close (inp);
 499         inp = NULL;
 500         errno = EPERM;
 501       }
 502     if( !inp ) {
 503         rc = gpg_error_from_syserror ();
 504         log_error(_("can't open `%s': %s\n"),
 505                   filename? filename: "[stdin]",
 506                   gpg_strerror (rc) );
 507         goto leave;
 508     }
 509     else if( opt.verbose )
 510         log_info(_("reading from `%s'\n"), filename? filename: "[stdin]");
 511
 512     handle_progress (pfx, inp, filename);
 513
 514     if( opt.textmode )
 515         iobuf_push_filter( inp, text_filter, &tfx );
 516
 517     if( (rc = open_outfile( filename, opt.armor? 1:0, &out )) )
 518         goto leave;
 519
 520     if ( opt.armor )
 521       {
 522         afx = new_armor_context ();
 523         push_armor_filter (afx, out);
 524       }
 525
 526     /* create a session key */
 527     cfx.dek = xmalloc_secure_clear (sizeof *cfx.dek);
 528     if( !opt.def_cipher_algo ) { /* try to get it from the prefs */
 529         cfx.dek->algo = select_algo_from_prefs(pk_list,PREFTYPE_SYM,-1,NULL);
 530         /* The only way select_algo_from_prefs can fail here is when
 531            mixing v3 and v4 keys, as v4 keys have an implicit
 532            preference entry for 3DES, and the pk_list cannot be empty.
 533            In this case, use 3DES anyway as it's the safest choice -
 534            perhaps the v3 key is being used in an OpenPGP
 535            implementation and we know that the implementation behind
 536            any v4 key can handle 3DES. */
 537         if( cfx.dek->algo == -1 ) {
 538             cfx.dek->algo = CIPHER_ALGO_3DES;
 539
 540             if( PGP2 ) {
 541               log_info(_("unable to use the IDEA cipher for all of the keys "
 542                          "you are encrypting to.\n"));
 543               compliance_failure();
 544             }
 545         }
 546
 547         /* In case 3DES has been selected, print a warning if
 548            any key does not have a preference for AES.  This
 549            should help to indentify why encrypting to several
 550            recipients falls back to 3DES. */
 551         if (opt.verbose
 552             && cfx.dek->algo == CIPHER_ALGO_3DES)
 553           warn_missing_aes_from_pklist (pk_list);
 554     }
 555     else {
 556       if(!opt.expert &&
 557          select_algo_from_prefs(pk_list,PREFTYPE_SYM,
 558                                 opt.def_cipher_algo,NULL)!=opt.def_cipher_algo)
 559         log_info(_("WARNING: forcing symmetric cipher %s (%d)"
 560                    " violates recipient preferences\n"),
 561                  openpgp_cipher_algo_name (opt.def_cipher_algo),
 562                  opt.def_cipher_algo);
 563
 564       cfx.dek->algo = opt.def_cipher_algo;
 565     }
 566
 567     cfx.dek->use_mdc=use_mdc(pk_list,cfx.dek->algo);
 568
 569     /* Only do the is-file-already-compressed check if we are using a
 570        MDC.  This forces compressed files to be re-compressed if we do
 571        not have a MDC to give some protection against chosen
 572        ciphertext attacks. */
 573
 574     if (do_compress && cfx.dek->use_mdc && is_file_compressed(filename, &rc2) )
 575       {
 576         if (opt.verbose)
 577           log_info(_("`%s' already compressed\n"), filename);
 578         do_compress = 0;
 579       }
 580     if (rc2)
 581       {
 582         rc = rc2;
 583         goto leave;
 584       }
 585
 586     make_session_key( cfx.dek );
 587     if( DBG_CIPHER )
 588         log_printhex ("DEK is: ", cfx.dek->key, cfx.dek->keylen );
 589
 590     rc = write_pubkey_enc_from_list( pk_list, cfx.dek, out );
 591     if( rc  )
 592         goto leave;
 593
 594     /* We put the passphrase (if any) after any public keys as this
 595        seems to be the most useful on the recipient side - there is no
 596        point in prompting a user for a passphrase if they have the
 597        secret key needed to decrypt. */
 598     if(use_symkey && (rc=write_symkey_enc(symkey_s2k,symkey_dek,cfx.dek,out)))
 599       goto leave;
 600
 601     if (!opt.no_literal)
 602       pt=setup_plaintext_name(filename,inp);
 603
 604     if (!iobuf_is_pipe_filename (filename) && *filename && !opt.textmode )
 605       {
 606         off_t tmpsize;
 607         int overflow;
 608
 609         if ( !(tmpsize = iobuf_get_filelength(inp, &overflow))
 610              && !overflow )
 611           log_info(_("WARNING: `%s' is an empty file\n"), filename );
 612         /* We can't encode the length of very large files because
 613            OpenPGP uses only 32 bit for file sizes.  So if the the
 614            size of a file is larger than 2^32 minus some bytes for
 615            packet headers, we switch to partial length encoding. */
 616         if (tmpsize < (IOBUF_FILELENGTH_LIMIT - 65536) )
 617           filesize = tmpsize;
 618         else
 619           filesize = 0;
 620       }
 621     else
 622       filesize = opt.set_filesize ? opt.set_filesize : 0; /* stdin */
 623
 624     if (!opt.no_literal) {
 625         pt->timestamp = make_timestamp();
 626         pt->mode = opt.textmode ? 't' : 'b';
 627         pt->len = filesize;
 628         pt->new_ctb = !pt->len && !RFC1991;
 629         pt->buf = inp;
 630         pkt.pkttype = PKT_PLAINTEXT;
 631         pkt.pkt.plaintext = pt;
 632         cfx.datalen = filesize && !do_compress? calc_packet_length( &pkt ) : 0;
 633     }
 634     else
 635         cfx.datalen = filesize && !do_compress ? filesize : 0;
 636
 637     /* register the cipher filter */
 638     iobuf_push_filter( out, cipher_filter, &cfx );
 639
 640     /* register the compress filter */
 641     if( do_compress ) {
 642         int compr_algo = opt.compress_algo;
 643
 644         if(compr_algo==-1)
 645           {
 646             if((compr_algo=
 647                 select_algo_from_prefs(pk_list,PREFTYPE_ZIP,-1,NULL))==-1)
 648               compr_algo=DEFAULT_COMPRESS_ALGO;
 649             /* Theoretically impossible to get here since uncompressed
 650                is implicit. */
 651           }
 652         else if(!opt.expert &&
 653                 select_algo_from_prefs(pk_list,PREFTYPE_ZIP,
 654                                        compr_algo,NULL)!=compr_algo)
 655           log_info(_("WARNING: forcing compression algorithm %s (%d)"
 656                      " violates recipient preferences\n"),
 657                    compress_algo_to_string(compr_algo),compr_algo);
 658
 659         /* algo 0 means no compression */
 660         if( compr_algo )
 661           {
 662             if (cfx.dek && cfx.dek->use_mdc)
 663               zfx.new_ctb = 1;
 664             push_compress_filter(out,&zfx,compr_algo);
 665           }
 666     }
 667
 668     /* do the work */
 669     if (!opt.no_literal) {
 670         if( (rc = build_packet( out, &pkt )) )
 671             log_error("build_packet failed: %s\n", g10_errstr(rc) );
 672     }
 673     else {
 674         /* user requested not to create a literal packet, so we copy
 675            the plain data */
 676         byte copy_buffer[4096];
 677         int  bytes_copied;
 678         while ((bytes_copied = iobuf_read(inp, copy_buffer, 4096)) != -1)
 679             if ( (rc=iobuf_write(out, copy_buffer, bytes_copied)) ) {
 680                 log_error ("copying input to output failed: %s\n",
 681                            gpg_strerror (rc));
 682                 break;
 683             }
 684         wipememory(copy_buffer, 4096); /* burn buffer */
 685     }
 686
 687     /* finish the stuff */
 688   leave:
 689     iobuf_close(inp);
 690     if( rc )
 691         iobuf_cancel(out);
 692     else {
 693         iobuf_close(out); /* fixme: check returncode */
 694         write_status( STATUS_END_ENCRYPTION );
 695     }
 696     if( pt )
 697         pt->buf = NULL;
 698     free_packet(&pkt);
 699     xfree(cfx.dek);
 700     xfree(symkey_dek);
 701     xfree(symkey_s2k);
 702     release_pk_list( pk_list );
 703     release_armor_context (afx);
 704     release_progress_context (pfx);
 705     return rc;
 706 }
 707
 708
 709
 710
 711 /****************
 712  * Filter to do a complete public key encryption.
 713  */
 714 int
 715 encrypt_filter( void *opaque, int control,
 716                IOBUF a, byte *buf, size_t *ret_len)
 717 {
 718     size_t size = *ret_len;
 719     encrypt_filter_context_t *efx = opaque;
 720     int rc=0;
 721
 722     if( control == IOBUFCTRL_UNDERFLOW ) { /* decrypt */
 723         BUG(); /* not used */
 724     }
 725     else if( control == IOBUFCTRL_FLUSH ) { /* encrypt */
 726         if( !efx->header_okay ) {
 727             efx->cfx.dek = xmalloc_secure_clear( sizeof *efx->cfx.dek );
 728
 729             if( !opt.def_cipher_algo  ) { /* try to get it from the prefs */
 730                 efx->cfx.dek->algo =
 731                   select_algo_from_prefs(efx->pk_list,PREFTYPE_SYM,-1,NULL);
 732                 if( efx->cfx.dek->algo == -1 ) {
 733                     /* because 3DES is implicitly in the prefs, this can only
 734                      * happen if we do not have any public keys in the list */
 735                     efx->cfx.dek->algo = DEFAULT_CIPHER_ALGO;
 736                 }
 737
 738                 /* In case 3DES has been selected, print a warning if
 739                    any key does not have a preference for AES.  This
 740                    should help to indentify why encrypting to several
 741                    recipients falls back to 3DES. */
 742                 if (opt.verbose
 743                     && efx->cfx.dek->algo == CIPHER_ALGO_3DES)
 744                   warn_missing_aes_from_pklist (efx->pk_list);
 745             }
 746             else {
 747               if(!opt.expert &&
 748                  select_algo_from_prefs(efx->pk_list,PREFTYPE_SYM,
 749                                         opt.def_cipher_algo,
 750                                         NULL)!=opt.def_cipher_algo)
 751                 log_info(_("forcing symmetric cipher %s (%d) "
 752                            "violates recipient preferences\n"),
 753                          openpgp_cipher_algo_name (opt.def_cipher_algo),
 754                          opt.def_cipher_algo);
 755
 756               efx->cfx.dek->algo = opt.def_cipher_algo;
 757             }
 758
 759             efx->cfx.dek->use_mdc = use_mdc(efx->pk_list,efx->cfx.dek->algo);
 760
 761             make_session_key( efx->cfx.dek );
 762             if( DBG_CIPHER )
 763                 log_printhex ("DEK is: ",
 764                               efx->cfx.dek->key, efx->cfx.dek->keylen );
 765
 766             rc = write_pubkey_enc_from_list( efx->pk_list, efx->cfx.dek, a );
 767             if( rc )
 768                 return rc;
 769
 770             if(efx->symkey_s2k && efx->symkey_dek)
 771               {
 772                 rc=write_symkey_enc(efx->symkey_s2k,efx->symkey_dek,
 773                                     efx->cfx.dek,a);
 774                 if(rc)
 775                   return rc;
 776               }
 777
 778             iobuf_push_filter( a, cipher_filter, &efx->cfx );
 779
 780             efx->header_okay = 1;
 781         }
 782         rc = iobuf_write( a, buf, size );
 783
 784     }
 785     else if( control == IOBUFCTRL_FREE )
 786       {
 787         xfree(efx->symkey_dek);
 788         xfree(efx->symkey_s2k);
 789       }
 790     else if( control == IOBUFCTRL_DESC ) {
 791         *(char**)buf = "encrypt_filter";
 792     }
 793     return rc;
 794 }
 795
 796
 797 /****************
 798  * Write pubkey-enc packets from the list of PKs to OUT.
 799  */
 800 static int
 801 write_pubkey_enc_from_list( PK_LIST pk_list, DEK *dek, IOBUF out )
 802 {
 803     PACKET pkt;
 804     PKT_public_key *pk;
 805     PKT_pubkey_enc  *enc;
 806     int rc;
 807
 808     for( ; pk_list; pk_list = pk_list->next ) {
 809         gcry_mpi_t frame;
 810
 811         pk = pk_list->pk;
 812
 813         print_pubkey_algo_note( pk->pubkey_algo );
 814         enc = xmalloc_clear( sizeof *enc );
 815         enc->pubkey_algo = pk->pubkey_algo;
 816         keyid_from_pk( pk, enc->keyid );
 817         enc->throw_keyid = (opt.throw_keyid || (pk_list->flags&1));
 818
 819         if(opt.throw_keyid && (PGP2 || PGP6 || PGP7 || PGP8))
 820           {
 821             log_info(_("you may not use %s while in %s mode\n"),
 822                      "--throw-keyid",compliance_option_string());
 823             compliance_failure();
 824           }
 825
 826         /* Okay, what's going on: We have the session key somewhere in
 827          * the structure DEK and want to encode this session key in
 828          * an integer value of n bits.  pubkey_nbits gives us the
 829          * number of bits we have to use.  We then encode the session
 830          * key in some way and we get it back in the big intger value
 831          * FRAME.  Then we use FRAME, the public key PK->PKEY and the
 832          * algorithm number PK->PUBKEY_ALGO and pass it to pubkey_encrypt
 833          * which returns the encrypted value in the array ENC->DATA.
 834          * This array has a size which depends on the used algorithm
 835          * (e.g. 2 for Elgamal).  We don't need frame anymore because we
 836          * have everything now in enc->data which is the passed to
 837          * build_packet()
 838          */
 839         frame = encode_session_key (dek, pubkey_nbits (pk->pubkey_algo,
 840                                                        pk->pkey) );
 841         rc = pk_encrypt (pk->pubkey_algo, enc->data, frame, pk->pkey);
 842         gcry_mpi_release (frame);
 843         if( rc )
 844             log_error ("pubkey_encrypt failed: %s\n", gpg_strerror (rc) );
 845         else {
 846             if( opt.verbose ) {
 847                 char *ustr = get_user_id_string_native (enc->keyid);
 848                 log_info(_("%s/%s encrypted for: \"%s\"\n"),
 849                          gcry_pk_algo_name (enc->pubkey_algo),
 850                          openpgp_cipher_algo_name (dek->algo),
 851                          ustr );
 852                 xfree(ustr);
 853             }
 854             /* and write it */
 855             init_packet(&pkt);
 856             pkt.pkttype = PKT_PUBKEY_ENC;
 857             pkt.pkt.pubkey_enc = enc;
 858             rc = build_packet( out, &pkt );
 859             if( rc )
 860                log_error("build_packet(pubkey_enc) failed: %s\n", g10_errstr(rc));
 861         }
 862         free_pubkey_enc(enc);
 863         if( rc )
 864             return rc;
 865     }
 866     return 0;
 867 }
 868
 869 void
 870 encode_crypt_files(int nfiles, char **files, strlist_t remusr)
 871 {
 872   int rc = 0;
 873
 874   if (opt.outfile)
 875     {
 876       log_error(_("--output doesn't work for this command\n"));
 877       return;
 878     }
 879
 880   if (!nfiles)
 881     {
 882       char line[2048];
 883       unsigned int lno = 0;
 884       while ( fgets(line, DIM(line), stdin) )
 885         {
 886           lno++;
 887           if (!*line || line[strlen(line)-1] != '\n')
 888             {
 889               log_error("input line %u too long or missing LF\n", lno);
 890               return;
 891             }
 892           line[strlen(line)-1] = '\0';
 893           print_file_status(STATUS_FILE_START, line, 2);
 894           if ( (rc = encode_crypt(line, remusr, 0)) )
 895             log_error("encryption of `%s' failed: %s\n",
 896                       print_fname_stdin(line), g10_errstr(rc) );
 897           write_status( STATUS_FILE_DONE );
 898         }
 899     }
 900   else
 901     {
 902       while (nfiles--)
 903         {
 904           print_file_status(STATUS_FILE_START, *files, 2);
 905           if ( (rc = encode_crypt(*files, remusr, 0)) )
 906             log_error("encryption of `%s' failed: %s\n",
 907                       print_fname_stdin(*files), g10_errstr(rc) );
 908           write_status( STATUS_FILE_DONE );
 909           files++;
 910         }
 911     }
 912 }