g10/build-packet.c

   1 /* build-packet.c - assemble packets and write them
   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 <assert.h>
  26 #include <ctype.h>
  27
  28 #include "gpg.h"
  29 #include "packet.h"
  30 #include "status.h"
  31 #include "iobuf.h"
  32 #include "util.h"
  33 #include "cipher.h"
  34 #include "i18n.h"
  35 #include "options.h"
  36
  37 static int do_user_id( IOBUF out, int ctb, PKT_user_id *uid );
  38 static int do_public_key( IOBUF out, int ctb, PKT_public_key *pk );
  39 static int do_secret_key( IOBUF out, int ctb, PKT_secret_key *pk );
  40 static int do_symkey_enc( IOBUF out, int ctb, PKT_symkey_enc *enc );
  41 static int do_pubkey_enc( IOBUF out, int ctb, PKT_pubkey_enc *enc );
  42 static u32 calc_plaintext( PKT_plaintext *pt );
  43 static int do_plaintext( IOBUF out, int ctb, PKT_plaintext *pt );
  44 static int do_encrypted( IOBUF out, int ctb, PKT_encrypted *ed );
  45 static int do_encrypted_mdc( IOBUF out, int ctb, PKT_encrypted *ed );
  46 static int do_compressed( IOBUF out, int ctb, PKT_compressed *cd );
  47 static int do_signature( IOBUF out, int ctb, PKT_signature *sig );
  48 static int do_onepass_sig( IOBUF out, int ctb, PKT_onepass_sig *ops );
  49
  50 static int calc_header_length( u32 len, int new_ctb );
  51 static int write_16(IOBUF inp, u16 a);
  52 static int write_32(IOBUF inp, u32 a);
  53 static int write_header( IOBUF out, int ctb, u32 len );
  54 static int write_sign_packet_header( IOBUF out, int ctb, u32 len );
  55 static int write_header2( IOBUF out, int ctb, u32 len, int hdrlen );
  56 static int write_new_header( IOBUF out, int ctb, u32 len, int hdrlen );
  57 static int write_version( IOBUF out, int ctb );
  58
  59 /****************
  60  * Build a packet and write it to INP
  61  * Returns: 0 := okay
  62  *         >0 := error
  63  * Note: Caller must free the packet
  64  */
  65 int
  66 build_packet( IOBUF out, PACKET *pkt )
  67 {
  68     int new_ctb=0, rc=0, ctb;
  69     int pkttype;
  70
  71     if( DBG_PACKET )
  72         log_debug("build_packet() type=%d\n", pkt->pkttype );
  73     assert( pkt->pkt.generic );
  74
  75     switch( (pkttype = pkt->pkttype) )
  76       {
  77       case PKT_PLAINTEXT: new_ctb = pkt->pkt.plaintext->new_ctb; break;
  78       case PKT_ENCRYPTED:
  79       case PKT_ENCRYPTED_MDC: new_ctb = pkt->pkt.encrypted->new_ctb; break;
  80       case PKT_COMPRESSED:new_ctb = pkt->pkt.compressed->new_ctb; break;
  81       case PKT_USER_ID:
  82         if( pkt->pkt.user_id->attrib_data )
  83           pkttype = PKT_ATTRIBUTE;
  84         break;
  85       default: break;
  86       }
  87
  88     if( new_ctb || pkttype > 15 ) /* new format */
  89         ctb = 0xc0 | (pkttype & 0x3f);
  90     else
  91         ctb = 0x80 | ((pkttype & 15)<<2);
  92     switch( pkttype )
  93       {
  94       case PKT_ATTRIBUTE:
  95       case PKT_USER_ID:
  96         rc = do_user_id( out, ctb, pkt->pkt.user_id );
  97         break;
  98       case PKT_OLD_COMMENT:
  99       case PKT_COMMENT:
 100         /*
 101           Ignore these.  Theoretically, this will never be called as
 102           we have no way to output comment packets any longer, but
 103           just in case there is some code path that would end up
 104           outputting a comment that was written before comments were
 105           dropped (in the public key?) this is a no-op.
 106         */
 107         break;
 108       case PKT_PUBLIC_SUBKEY:
 109       case PKT_PUBLIC_KEY:
 110         rc = do_public_key( out, ctb, pkt->pkt.public_key );
 111         break;
 112       case PKT_SECRET_SUBKEY:
 113       case PKT_SECRET_KEY:
 114         rc = do_secret_key( out, ctb, pkt->pkt.secret_key );
 115         break;
 116       case PKT_SYMKEY_ENC:
 117         rc = do_symkey_enc( out, ctb, pkt->pkt.symkey_enc );
 118         break;
 119       case PKT_PUBKEY_ENC:
 120         rc = do_pubkey_enc( out, ctb, pkt->pkt.pubkey_enc );
 121         break;
 122       case PKT_PLAINTEXT:
 123         rc = do_plaintext( out, ctb, pkt->pkt.plaintext );
 124         break;
 125       case PKT_ENCRYPTED:
 126         rc = do_encrypted( out, ctb, pkt->pkt.encrypted );
 127         break;
 128       case PKT_ENCRYPTED_MDC:
 129         rc = do_encrypted_mdc( out, ctb, pkt->pkt.encrypted );
 130         break;
 131       case PKT_COMPRESSED:
 132         rc = do_compressed( out, ctb, pkt->pkt.compressed );
 133         break;
 134       case PKT_SIGNATURE:
 135         rc = do_signature( out, ctb, pkt->pkt.signature );
 136         break;
 137       case PKT_ONEPASS_SIG:
 138         rc = do_onepass_sig( out, ctb, pkt->pkt.onepass_sig );
 139         break;
 140       case PKT_RING_TRUST:
 141         break; /* ignore it (keyring.c does write it directly)*/
 142       case PKT_MDC: /* we write it directly, so we should never see it here. */
 143       default:
 144         log_bug("invalid packet type in build_packet()\n");
 145         break;
 146       }
 147
 148     return rc;
 149 }
 150
 151
 152 /*
 153  * Write the mpi A to OUT.
 154  */
 155 static int
 156 mpi_write (iobuf_t out, gcry_mpi_t a)
 157 {
 158   char buffer[(MAX_EXTERN_MPI_BITS+7)/8+2]; /* 2 is for the mpi length. */
 159   size_t nbytes;
 160   int rc;
 161
 162   nbytes = DIM(buffer);
 163   rc = gcry_mpi_print (GCRYMPI_FMT_PGP, buffer, nbytes, &nbytes, a );
 164   if( !rc )
 165     rc = iobuf_write( out, buffer, nbytes );
 166   else if (gpg_err_code(rc) == GPG_ERR_TOO_SHORT )
 167     {
 168       log_info ("mpi too large (%u bits)\n", gcry_mpi_get_nbits (a));
 169       /* The buffer was too small. We better tell the user about the MPI. */
 170       rc = gpg_error (GPG_ERR_TOO_LARGE);
 171     }
 172
 173   return rc;
 174 }
 175
 176
 177
 178 /****************
 179  * calculate the length of a packet described by PKT
 180  */
 181 u32
 182 calc_packet_length( PACKET *pkt )
 183 {
 184     u32 n=0;
 185     int new_ctb = 0;
 186
 187     assert( pkt->pkt.generic );
 188     switch( pkt->pkttype ) {
 189       case PKT_PLAINTEXT:
 190         n = calc_plaintext( pkt->pkt.plaintext );
 191         new_ctb = pkt->pkt.plaintext->new_ctb;
 192         break;
 193       case PKT_ATTRIBUTE:
 194       case PKT_USER_ID:
 195       case PKT_COMMENT:
 196       case PKT_PUBLIC_KEY:
 197       case PKT_SECRET_KEY:
 198       case PKT_SYMKEY_ENC:
 199       case PKT_PUBKEY_ENC:
 200       case PKT_ENCRYPTED:
 201       case PKT_SIGNATURE:
 202       case PKT_ONEPASS_SIG:
 203       case PKT_RING_TRUST:
 204       case PKT_COMPRESSED:
 205       default:
 206         log_bug("invalid packet type in calc_packet_length()");
 207         break;
 208     }
 209
 210     n += calc_header_length(n, new_ctb);
 211     return n;
 212 }
 213
 214 static void
 215 write_fake_data (IOBUF out, gcry_mpi_t a)
 216 {
 217   if (a)
 218     {
 219       unsigned int n;
 220       void *p;
 221
 222       p = gcry_mpi_get_opaque ( a, &n );
 223       iobuf_write (out, p, (n+7)/8 );
 224     }
 225 }
 226
 227 static int
 228 do_user_id( IOBUF out, int ctb, PKT_user_id *uid )
 229 {
 230     int rc;
 231
 232     if( uid->attrib_data )
 233       {
 234         write_header(out, ctb, uid->attrib_len);
 235         rc = iobuf_write( out, uid->attrib_data, uid->attrib_len );
 236       }
 237     else
 238       {
 239         write_header2( out, ctb, uid->len, 2 );
 240         rc = iobuf_write( out, uid->name, uid->len );
 241       }
 242     return 0;
 243 }
 244
 245 static int
 246 do_public_key( IOBUF out, int ctb, PKT_public_key *pk )
 247 {
 248   int rc = 0;
 249   int n, i;
 250   IOBUF a = iobuf_temp();
 251
 252   if ( !pk->version )
 253     iobuf_put( a, 3 );
 254   else
 255     iobuf_put( a, pk->version );
 256   write_32(a, pk->timestamp );
 257   if ( pk->version < 4 )
 258     {
 259       u16 ndays;
 260       if ( pk->expiredate )
 261         ndays = (u16)((pk->expiredate - pk->timestamp) / 86400L);
 262       else
 263         ndays = 0;
 264       write_16(a, ndays );
 265     }
 266   iobuf_put (a, pk->pubkey_algo );
 267   n = pubkey_get_npkey ( pk->pubkey_algo );
 268   if ( !n )
 269     write_fake_data( a, pk->pkey[0] );
 270   for (i=0; i < n && !rc ; i++ )
 271     rc = mpi_write(a, pk->pkey[i] );
 272
 273   if (!rc)
 274     {
 275       write_header2 (out, ctb, iobuf_get_temp_length(a), pk->hdrbytes);
 276       rc = iobuf_write_temp ( out, a );
 277     }
 278
 279   iobuf_close(a);
 280   return rc;
 281 }
 282
 283
 284 static int
 285 do_secret_key( IOBUF out, int ctb, PKT_secret_key *sk )
 286 {
 287   int rc = 0;
 288   int i, nskey, npkey;
 289   IOBUF a = iobuf_temp(); /* Build in a self-enlarging buffer.  */
 290
 291   /* Write the version number - if none is specified, use 3 */
 292   if ( !sk->version )
 293     iobuf_put ( a, 3 );
 294   else
 295     iobuf_put ( a, sk->version );
 296   write_32 (a, sk->timestamp );
 297
 298   /* v3 needs the expiration time. */
 299   if ( sk->version < 4 )
 300     {
 301       u16 ndays;
 302       if ( sk->expiredate )
 303         ndays = (u16)((sk->expiredate - sk->timestamp) / 86400L);
 304       else
 305         ndays = 0;
 306       write_16(a, ndays);
 307     }
 308
 309   iobuf_put (a, sk->pubkey_algo );
 310
 311   /* Get number of secret and public parameters.  They are held in one
 312      array first the public ones, then the secret ones.  */
 313   nskey = pubkey_get_nskey ( sk->pubkey_algo );
 314   npkey = pubkey_get_npkey ( sk->pubkey_algo );
 315
 316   /* If we don't have any public parameters - which is the case if we
 317      don't know the algorithm used - the parameters are stored as one
 318      blob in a faked (opaque) MPI. */
 319   if ( !npkey )
 320     {
 321       write_fake_data( a, sk->skey[0] );
 322       goto leave;
 323     }
 324   assert ( npkey < nskey );
 325
 326   /* Writing the public parameters is easy. */
 327   for (i=0; i < npkey; i++ )
 328     if ((rc = mpi_write (a, sk->skey[i])))
 329       goto leave;
 330
 331   /* Build the header for protected (encrypted) secret parameters.  */
 332   if ( sk->is_protected )
 333     {
 334       if ( is_RSA(sk->pubkey_algo)
 335            && sk->version < 4
 336            && !sk->protect.s2k.mode )
 337         {
 338           /* The simple rfc1991 (v3) way. */
 339           iobuf_put (a, sk->protect.algo );
 340           iobuf_write (a, sk->protect.iv, sk->protect.ivlen );
 341         }
 342       else
 343         {
 344           /* OpenPGP protection according to rfc2440. */
 345           iobuf_put(a, sk->protect.sha1chk? 0xfe : 0xff );
 346           iobuf_put(a, sk->protect.algo );
 347           if ( sk->protect.s2k.mode >= 1000 )
 348             {
 349               /* These modes are not possible in OpenPGP, we use them
 350                  to implement our extensions, 101 can be seen as a
 351                  private/experimental extension (this is not specified
 352                  in rfc2440 but the same scheme is used for all other
 353                  algorithm identifiers) */
 354               iobuf_put(a, 101 );
 355               iobuf_put(a, sk->protect.s2k.hash_algo );
 356               iobuf_write(a, "GNU", 3 );
 357               iobuf_put(a, sk->protect.s2k.mode - 1000 );
 358             }
 359           else
 360             {
 361               iobuf_put(a, sk->protect.s2k.mode );
 362               iobuf_put(a, sk->protect.s2k.hash_algo );
 363             }
 364           if ( sk->protect.s2k.mode == 1
 365                || sk->protect.s2k.mode == 3 )
 366             iobuf_write (a, sk->protect.s2k.salt, 8 );
 367
 368           if ( sk->protect.s2k.mode == 3 )
 369             iobuf_put (a, sk->protect.s2k.count );
 370
 371           /* For our special modes 1001, 1002 we do not need an IV. */
 372           if ( sk->protect.s2k.mode != 1001
 373                && sk->protect.s2k.mode != 1002 )
 374             iobuf_write (a, sk->protect.iv, sk->protect.ivlen );
 375         }
 376     }
 377   else
 378     iobuf_put (a, 0 );
 379
 380   if ( sk->protect.s2k.mode == 1001 )
 381     ; /* GnuPG extension - don't write a secret key at all. */
 382   else if ( sk->protect.s2k.mode == 1002 )
 383     {
 384       /* GnuPG extension - divert to OpenPGP smartcard. */
 385       iobuf_put(a, sk->protect.ivlen ); /* Length of the serial number
 386                                            or 0 for no serial
 387                                            number. */
 388       /* The serial number gets stored in the IV field. */
 389       iobuf_write(a, sk->protect.iv, sk->protect.ivlen);
 390     }
 391   else if ( sk->is_protected && sk->version >= 4 )
 392     {
 393       /* The secret key is protected - write it out as it is.  */
 394       byte *p;
 395       unsigned int ndatabits;
 396
 397       assert (gcry_mpi_get_flag (sk->skey[npkey], GCRYMPI_FLAG_OPAQUE));
 398       p = gcry_mpi_get_opaque (sk->skey[npkey], &ndatabits );
 399       iobuf_write (a, p, (ndatabits+7)/8 );
 400     }
 401   else if ( sk->is_protected )
 402     {
 403       /* The secret key is protected the old v4 way. */
 404       for ( ; i < nskey; i++ )
 405         {
 406           byte *p;
 407           unsigned int ndatabits;
 408
 409           assert (gcry_mpi_get_flag (sk->skey[i], GCRYMPI_FLAG_OPAQUE));
 410           p = gcry_mpi_get_opaque (sk->skey[i], &ndatabits);
 411           iobuf_write (a, p, (ndatabits+7)/8);
 412         }
 413       write_16(a, sk->csum );
 414     }
 415   else
 416     {
 417       /* Non-protected key. */
 418       for ( ; i < nskey; i++ )
 419         if ( (rc = mpi_write (a, sk->skey[i])))
 420           goto leave;
 421       write_16 (a, sk->csum );
 422     }
 423
 424  leave:
 425   if (!rc)
 426     {
 427       /* Build the header of the packet - which we must do after
 428          writing all the other stuff, so that we know the length of
 429          the packet */
 430       write_header2(out, ctb, iobuf_get_temp_length(a), sk->hdrbytes);
 431       /* And finally write it out the real stream */
 432       rc = iobuf_write_temp( out, a );
 433     }
 434
 435   iobuf_close(a); /* Close the remporary buffer */
 436   return rc;
 437 }
 438
 439 static int
 440 do_symkey_enc( IOBUF out, int ctb, PKT_symkey_enc *enc )
 441 {
 442     int rc = 0;
 443     IOBUF a = iobuf_temp();
 444
 445     assert( enc->version == 4 );
 446     switch( enc->s2k.mode ) {
 447       case 0: case 1: case 3: break;
 448       default: log_bug("do_symkey_enc: s2k=%d\n", enc->s2k.mode );
 449     }
 450     iobuf_put( a, enc->version );
 451     iobuf_put( a, enc->cipher_algo );
 452     iobuf_put( a, enc->s2k.mode );
 453     iobuf_put( a, enc->s2k.hash_algo );
 454     if( enc->s2k.mode == 1 || enc->s2k.mode == 3 ) {
 455         iobuf_write(a, enc->s2k.salt, 8 );
 456         if( enc->s2k.mode == 3 )
 457             iobuf_put(a, enc->s2k.count);
 458     }
 459     if( enc->seskeylen )
 460         iobuf_write(a, enc->seskey, enc->seskeylen );
 461
 462     write_header(out, ctb, iobuf_get_temp_length(a) );
 463     rc = iobuf_write_temp( out, a );
 464
 465     iobuf_close(a);
 466     return rc;
 467 }
 468
 469
 470 static int
 471 do_pubkey_enc( IOBUF out, int ctb, PKT_pubkey_enc *enc )
 472 {
 473   int rc = 0;
 474   int n, i;
 475   IOBUF a = iobuf_temp();
 476
 477   write_version( a, ctb );
 478   if ( enc->throw_keyid )
 479     {
 480       write_32(a, 0 );  /* Don't tell Eve who can decrypt the message.  */
 481       write_32(a, 0 );
 482     }
 483   else
 484     {
 485       write_32(a, enc->keyid[0] );
 486       write_32(a, enc->keyid[1] );
 487     }
 488   iobuf_put(a,enc->pubkey_algo );
 489   n = pubkey_get_nenc( enc->pubkey_algo );
 490   if ( !n )
 491     write_fake_data( a, enc->data[0] );
 492   for (i=0; i < n && !rc ; i++ )
 493     rc = mpi_write(a, enc->data[i] );
 494
 495   if (!rc)
 496     {
 497       write_header(out, ctb, iobuf_get_temp_length(a) );
 498       rc = iobuf_write_temp( out, a );
 499     }
 500   iobuf_close(a);
 501   return rc;
 502 }
 503
 504
 505 static u32
 506 calc_plaintext( PKT_plaintext *pt )
 507 {
 508   /* Truncate namelen to the maximum 255 characters.  Note this means
 509      that a function that calls build_packet with an illegal literal
 510      packet will get it back legalized. */
 511
 512   if(pt->namelen>255)
 513     pt->namelen=255;
 514
 515   return pt->len? (1 + 1 + pt->namelen + 4 + pt->len) : 0;
 516 }
 517
 518 static int
 519 do_plaintext( IOBUF out, int ctb, PKT_plaintext *pt )
 520 {
 521     int i, rc = 0;
 522     u32 n;
 523     byte buf[1000]; /* this buffer has the plaintext! */
 524     int nbytes;
 525
 526     write_header(out, ctb, calc_plaintext( pt ) );
 527     iobuf_put(out, pt->mode );
 528     iobuf_put(out, pt->namelen );
 529     for(i=0; i < pt->namelen; i++ )
 530         iobuf_put(out, pt->name[i] );
 531     rc = write_32(out, pt->timestamp );
 532     if (rc)
 533       return rc;
 534
 535     n = 0;
 536     while( (nbytes=iobuf_read(pt->buf, buf, 1000)) != -1 ) {
 537       rc = iobuf_write (out, buf, nbytes);
 538       if (rc)
 539         break;
 540       n += nbytes;
 541     }
 542     wipememory(buf,1000); /* burn the buffer */
 543     if( (ctb&0x40) && !pt->len )
 544       iobuf_set_partial_block_mode(out, 0 ); /* turn off partial */
 545     if( pt->len && n != pt->len )
 546       log_error("do_plaintext(): wrote %lu bytes but expected %lu bytes\n",
 547                 (ulong)n, (ulong)pt->len );
 548
 549     return rc;
 550 }
 551
 552
 553
 554 static int
 555 do_encrypted( IOBUF out, int ctb, PKT_encrypted *ed )
 556 {
 557     int rc = 0;
 558     u32 n;
 559
 560     n = ed->len ? (ed->len + ed->extralen) : 0;
 561     write_header(out, ctb, n );
 562
 563     /* This is all. The caller has to write the real data */
 564
 565     return rc;
 566 }
 567
 568 static int
 569 do_encrypted_mdc( IOBUF out, int ctb, PKT_encrypted *ed )
 570 {
 571     int rc = 0;
 572     u32 n;
 573
 574     assert( ed->mdc_method );
 575
 576     /* Take version number and the following MDC packet in account. */
 577     n = ed->len ? (ed->len + ed->extralen + 1 + 22) : 0;
 578     write_header(out, ctb, n );
 579     iobuf_put(out, 1 );  /* version */
 580
 581     /* This is all. The caller has to write the real data */
 582
 583     return rc;
 584 }
 585
 586
 587 static int
 588 do_compressed( IOBUF out, int ctb, PKT_compressed *cd )
 589 {
 590     int rc = 0;
 591
 592     /* We must use the old convention and don't use blockmode for the
 593        sake of PGP 2 compatibility.  However if the new_ctb flag was
 594        set, CTB is already formatted as new style and write_header2
 595        does create a partial length encoding using new the new
 596        style. */
 597     write_header2(out, ctb, 0, 0);
 598     iobuf_put(out, cd->algorithm );
 599
 600     /* This is all. The caller has to write the real data */
 601
 602     return rc;
 603 }
 604
 605
 606 /****************
 607  * Delete all subpackets of type REQTYPE and return a bool whether a packet
 608  * was deleted.
 609  */
 610 int
 611 delete_sig_subpkt (subpktarea_t *area, sigsubpkttype_t reqtype )
 612 {
 613     int buflen;
 614     sigsubpkttype_t type;
 615     byte *buffer, *bufstart;
 616     size_t n;
 617     size_t unused = 0;
 618     int okay = 0;
 619
 620     if( !area )
 621         return 0;
 622     buflen = area->len;
 623     buffer = area->data;
 624     for(;;) {
 625         if( !buflen ) {
 626             okay = 1;
 627             break;
 628         }
 629         bufstart = buffer;
 630         n = *buffer++; buflen--;
 631         if( n == 255 ) {
 632             if( buflen < 4 )
 633                 break;
 634             n = (buffer[0] << 24) | (buffer[1] << 16)
 635                 | (buffer[2] << 8) | buffer[3];
 636             buffer += 4;
 637             buflen -= 4;
 638         }
 639         else if( n >= 192 ) {
 640             if( buflen < 2 )
 641                 break;
 642             n = (( n - 192 ) << 8) + *buffer + 192;
 643             buffer++;
 644             buflen--;
 645         }
 646         if( buflen < n )
 647             break;
 648
 649         type = *buffer & 0x7f;
 650         if( type == reqtype ) {
 651             buffer++;
 652             buflen--;
 653             n--;
 654             if( n > buflen )
 655                 break;
 656             buffer += n; /* point to next subpkt */
 657             buflen -= n;
 658             memmove (bufstart, buffer, buflen); /* shift */
 659             unused +=  buffer - bufstart;
 660             buffer = bufstart;
 661         }
 662         else {
 663             buffer += n; buflen -=n;
 664         }
 665     }
 666
 667     if (!okay)
 668         log_error ("delete_subpkt: buffer shorter than subpacket\n");
 669     assert (unused <= area->len);
 670     area->len -= unused;
 671     return !!unused;
 672 }
 673
 674
 675 /****************
 676  * Create or update a signature subpacket for SIG of TYPE.  This
 677  * functions knows where to put the data (hashed or unhashed).  The
 678  * function may move data from the unhashed part to the hashed one.
 679  * Note: All pointers into sig->[un]hashed (e.g. returned by
 680  * parse_sig_subpkt) are not valid after a call to this function.  The
 681  * data to put into the subpaket should be in a buffer with a length
 682  * of buflen.
 683  */
 684 void
 685 build_sig_subpkt (PKT_signature *sig, sigsubpkttype_t type,
 686                   const byte *buffer, size_t buflen )
 687 {
 688     byte *p;
 689     int critical, hashed;
 690     subpktarea_t *oldarea, *newarea;
 691     size_t nlen, n, n0;
 692
 693     critical = (type & SIGSUBPKT_FLAG_CRITICAL);
 694     type &= ~SIGSUBPKT_FLAG_CRITICAL;
 695
 696     /* Sanity check buffer sizes */
 697     if(parse_one_sig_subpkt(buffer,buflen,type)<0)
 698       BUG();
 699
 700     switch(type)
 701       {
 702       case SIGSUBPKT_NOTATION:
 703       case SIGSUBPKT_POLICY:
 704       case SIGSUBPKT_REV_KEY:
 705       case SIGSUBPKT_SIGNATURE:
 706         /* we do allow multiple subpackets */
 707         break;
 708
 709       default:
 710         /* we don't allow multiple subpackets */
 711         delete_sig_subpkt(sig->hashed,type);
 712         delete_sig_subpkt(sig->unhashed,type);
 713         break;
 714       }
 715
 716     /* Any special magic that needs to be done for this type so the
 717        packet doesn't need to be reparsed? */
 718     switch(type)
 719       {
 720       case SIGSUBPKT_NOTATION:
 721         sig->flags.notation=1;
 722         break;
 723
 724       case SIGSUBPKT_POLICY:
 725         sig->flags.policy_url=1;
 726         break;
 727
 728       case SIGSUBPKT_PREF_KS:
 729         sig->flags.pref_ks=1;
 730         break;
 731
 732       case SIGSUBPKT_EXPORTABLE:
 733         if(buffer[0])
 734           sig->flags.exportable=1;
 735         else
 736           sig->flags.exportable=0;
 737         break;
 738
 739       case SIGSUBPKT_REVOCABLE:
 740         if(buffer[0])
 741           sig->flags.revocable=1;
 742         else
 743           sig->flags.revocable=0;
 744         break;
 745
 746       case SIGSUBPKT_TRUST:
 747         sig->trust_depth=buffer[0];
 748         sig->trust_value=buffer[1];
 749         break;
 750
 751       case SIGSUBPKT_REGEXP:
 752         sig->trust_regexp=buffer;
 753         break;
 754
 755         /* This should never happen since we don't currently allow
 756            creating such a subpacket, but just in case... */
 757       case SIGSUBPKT_SIG_EXPIRE:
 758         if(buffer_to_u32(buffer)+sig->timestamp<=make_timestamp())
 759           sig->flags.expired=1;
 760         else
 761           sig->flags.expired=0;
 762         break;
 763
 764       default:
 765         break;
 766       }
 767
 768     if( (buflen+1) >= 8384 )
 769         nlen = 5; /* write 5 byte length header */
 770     else if( (buflen+1) >= 192 )
 771         nlen = 2; /* write 2 byte length header */
 772     else
 773         nlen = 1; /* just a 1 byte length header */
 774
 775     switch( type )
 776       {
 777         /* The issuer being unhashed is a historical oddity.  It
 778            should work equally as well hashed.  Of course, if even an
 779            unhashed issuer is tampered with, it makes it awfully hard
 780            to verify the sig... */
 781       case SIGSUBPKT_ISSUER:
 782       case SIGSUBPKT_SIGNATURE:
 783         hashed = 0;
 784         break;
 785       default:
 786         hashed = 1;
 787         break;
 788       }
 789
 790     if( critical )
 791         type |= SIGSUBPKT_FLAG_CRITICAL;
 792
 793     oldarea = hashed? sig->hashed : sig->unhashed;
 794
 795     /* Calculate new size of the area and allocate */
 796     n0 = oldarea? oldarea->len : 0;
 797     n = n0 + nlen + 1 + buflen; /* length, type, buffer */
 798     if (oldarea && n <= oldarea->size) { /* fits into the unused space */
 799         newarea = oldarea;
 800         /*log_debug ("updating area for type %d\n", type );*/
 801     }
 802     else if (oldarea) {
 803         newarea = xrealloc (oldarea, sizeof (*newarea) + n - 1);
 804         newarea->size = n;
 805         /*log_debug ("reallocating area for type %d\n", type );*/
 806     }
 807     else {
 808         newarea = xmalloc (sizeof (*newarea) + n - 1);
 809         newarea->size = n;
 810         /*log_debug ("allocating area for type %d\n", type );*/
 811     }
 812     newarea->len = n;
 813
 814     p = newarea->data + n0;
 815     if (nlen == 5) {
 816         *p++ = 255;
 817         *p++ = (buflen+1) >> 24;
 818         *p++ = (buflen+1) >> 16;
 819         *p++ = (buflen+1) >>  8;
 820         *p++ = (buflen+1);
 821         *p++ = type;
 822         memcpy (p, buffer, buflen);
 823     }
 824     else if (nlen == 2) {
 825         *p++ = (buflen+1-192) / 256 + 192;
 826         *p++ = (buflen+1-192) % 256;
 827         *p++ = type;
 828         memcpy (p, buffer, buflen);
 829     }
 830     else {
 831         *p++ = buflen+1;
 832         *p++ = type;
 833         memcpy (p, buffer, buflen);
 834     }
 835
 836     if (hashed)
 837         sig->hashed = newarea;
 838     else
 839         sig->unhashed = newarea;
 840 }
 841
 842 /****************
 843  * Put all the required stuff from SIG into subpackets of sig.
 844  * Hmmm, should we delete those subpackets which are in a wrong area?
 845  */
 846 void
 847 build_sig_subpkt_from_sig( PKT_signature *sig )
 848 {
 849     u32  u;
 850     byte buf[8];
 851
 852     u = sig->keyid[0];
 853     buf[0] = (u >> 24) & 0xff;
 854     buf[1] = (u >> 16) & 0xff;
 855     buf[2] = (u >>  8) & 0xff;
 856     buf[3] = u & 0xff;
 857     u = sig->keyid[1];
 858     buf[4] = (u >> 24) & 0xff;
 859     buf[5] = (u >> 16) & 0xff;
 860     buf[6] = (u >>  8) & 0xff;
 861     buf[7] = u & 0xff;
 862     build_sig_subpkt( sig, SIGSUBPKT_ISSUER, buf, 8 );
 863
 864     u = sig->timestamp;
 865     buf[0] = (u >> 24) & 0xff;
 866     buf[1] = (u >> 16) & 0xff;
 867     buf[2] = (u >>  8) & 0xff;
 868     buf[3] = u & 0xff;
 869     build_sig_subpkt( sig, SIGSUBPKT_SIG_CREATED, buf, 4 );
 870
 871     if(sig->expiredate)
 872       {
 873         if(sig->expiredate>sig->timestamp)
 874           u=sig->expiredate-sig->timestamp;
 875         else
 876           u=1; /* A 1-second expiration time is the shortest one
 877                   OpenPGP has */
 878
 879         buf[0] = (u >> 24) & 0xff;
 880         buf[1] = (u >> 16) & 0xff;
 881         buf[2] = (u >>  8) & 0xff;
 882         buf[3] = u & 0xff;
 883
 884         /* Mark this CRITICAL, so if any implementation doesn't
 885            understand sigs that can expire, it'll just disregard this
 886            sig altogether. */
 887
 888         build_sig_subpkt( sig, SIGSUBPKT_SIG_EXPIRE | SIGSUBPKT_FLAG_CRITICAL,
 889                           buf, 4 );
 890       }
 891 }
 892
 893 void
 894 build_attribute_subpkt(PKT_user_id *uid,byte type,
 895                        const void *buf,u32 buflen,
 896                        const void *header,u32 headerlen)
 897 {
 898   byte *attrib;
 899   int idx;
 900
 901   if(1+headerlen+buflen>8383)
 902     idx=5;
 903   else if(1+headerlen+buflen>191)
 904     idx=2;
 905   else
 906     idx=1;
 907
 908   /* realloc uid->attrib_data to the right size */
 909
 910   uid->attrib_data=xrealloc(uid->attrib_data,
 911                              uid->attrib_len+idx+1+headerlen+buflen);
 912
 913   attrib=&uid->attrib_data[uid->attrib_len];
 914
 915   if(idx==5)
 916     {
 917       attrib[0]=255;
 918       attrib[1]=(1+headerlen+buflen) >> 24;
 919       attrib[2]=(1+headerlen+buflen) >> 16;
 920       attrib[3]=(1+headerlen+buflen) >> 8;
 921       attrib[4]=1+headerlen+buflen;
 922     }
 923   else if(idx==2)
 924     {
 925       attrib[0]=(1+headerlen+buflen-192) / 256 + 192;
 926       attrib[1]=(1+headerlen+buflen-192) % 256;
 927     }
 928   else
 929     attrib[0]=1+headerlen+buflen; /* Good luck finding a JPEG this small! */
 930
 931   attrib[idx++]=type;
 932
 933   /* Tack on our data at the end */
 934
 935   if(headerlen>0)
 936     memcpy(&attrib[idx],header,headerlen);
 937   memcpy(&attrib[idx+headerlen],buf,buflen);
 938   uid->attrib_len+=idx+headerlen+buflen;
 939 }
 940
 941 struct notation *
 942 string_to_notation(const char *string,int is_utf8)
 943 {
 944   const char *s;
 945   int saw_at=0;
 946   struct notation *notation;
 947
 948   notation=xmalloc_clear(sizeof(*notation));
 949
 950   if(*string=='-')
 951     {
 952       notation->flags.ignore=1;
 953       string++;
 954     }
 955
 956   if(*string=='!')
 957     {
 958       notation->flags.critical=1;
 959       string++;
 960     }
 961
 962   /* If and when the IETF assigns some official name tags, we'll have
 963      to add them here. */
 964
 965   for( s=string ; *s != '='; s++ )
 966     {
 967       if( *s=='@')
 968         saw_at++;
 969
 970       /* -notationname is legal without an = sign */
 971       if(!*s && notation->flags.ignore)
 972         break;
 973
 974       if( !*s || !isascii (*s) || (!isgraph(*s) && !isspace(*s)) )
 975         {
 976           log_error(_("a notation name must have only printable characters"
 977                       " or spaces, and end with an '='\n") );
 978           goto fail;
 979         }
 980     }
 981
 982   notation->name=xmalloc((s-string)+1);
 983   strncpy(notation->name,string,s-string);
 984   notation->name[s-string]='\0';
 985
 986   if(!saw_at && !opt.expert)
 987     {
 988       log_error(_("a user notation name must contain the '@' character\n"));
 989       goto fail;
 990     }
 991
 992   if (saw_at > 1)
 993     {
 994       log_error(_("a notation name must not contain more than"
 995                   " one '@' character\n"));
 996       goto fail;
 997     }
 998
 999   if(*s)
1000     {
1001       const char *i=s+1;
1002       int highbit=0;
1003
1004       /* we only support printable text - therefore we enforce the use
1005          of only printable characters (an empty value is valid) */
1006       for(s++; *s ; s++ )
1007         {
1008           if ( !isascii (*s) )
1009             highbit=1;
1010           else if (iscntrl(*s))
1011             {
1012               log_error(_("a notation value must not use any"
1013                           " control characters\n"));
1014               goto fail;
1015             }
1016         }
1017
1018       if(!highbit || is_utf8)
1019         notation->value=xstrdup(i);
1020       else
1021         notation->value=native_to_utf8(i);
1022     }
1023
1024   return notation;
1025
1026  fail:
1027   free_notation(notation);
1028   return NULL;
1029 }
1030
1031 struct notation *
1032 sig_to_notation(PKT_signature *sig)
1033 {
1034   const byte *p;
1035   size_t len;
1036   int seq=0,crit;
1037   struct notation *list=NULL;
1038
1039   while((p=enum_sig_subpkt(sig->hashed,SIGSUBPKT_NOTATION,&len,&seq,&crit)))
1040     {
1041       int n1,n2;
1042       struct notation *n=NULL;
1043
1044       if(len<8)
1045         {
1046           log_info(_("WARNING: invalid notation data found\n"));
1047           continue;
1048         }
1049
1050       n1=(p[4]<<8)|p[5];
1051       n2=(p[6]<<8)|p[7];
1052
1053       if(8+n1+n2!=len)
1054         {
1055           log_info(_("WARNING: invalid notation data found\n"));
1056           continue;
1057         }
1058
1059       n=xmalloc_clear(sizeof(*n));
1060       n->name=xmalloc(n1+1);
1061
1062       memcpy(n->name,&p[8],n1);
1063       n->name[n1]='\0';
1064
1065       if(p[0]&0x80)
1066         {
1067           n->value=xmalloc(n2+1);
1068           memcpy(n->value,&p[8+n1],n2);
1069           n->value[n2]='\0';
1070         }
1071       else
1072         {
1073           n->bdat=xmalloc(n2);
1074           n->blen=n2;
1075           memcpy(n->bdat,&p[8+n1],n2);
1076
1077           n->value=xmalloc(2+strlen(_("not human readable"))+2+1);
1078           strcpy(n->value,"[ ");
1079           strcat(n->value,_("not human readable"));
1080           strcat(n->value," ]");
1081         }
1082
1083       n->flags.critical=crit;
1084
1085       n->next=list;
1086       list=n;
1087     }
1088
1089   return list;
1090 }
1091
1092 void
1093 free_notation(struct notation *notation)
1094 {
1095   while(notation)
1096     {
1097       struct notation *n=notation;
1098
1099       xfree(n->name);
1100       xfree(n->value);
1101       xfree(n->altvalue);
1102       xfree(n->bdat);
1103       notation=n->next;
1104       xfree(n);
1105     }
1106 }
1107
1108 static int
1109 do_signature( IOBUF out, int ctb, PKT_signature *sig )
1110 {
1111   int rc = 0;
1112   int n, i;
1113   IOBUF a = iobuf_temp();
1114
1115   if ( !sig->version )
1116     iobuf_put( a, 3 );
1117   else
1118     iobuf_put( a, sig->version );
1119   if ( sig->version < 4 )
1120     iobuf_put (a, 5 ); /* Constant */
1121   iobuf_put (a, sig->sig_class );
1122   if ( sig->version < 4 )
1123     {
1124       write_32(a, sig->timestamp );
1125       write_32(a, sig->keyid[0] );
1126       write_32(a, sig->keyid[1] );
1127     }
1128   iobuf_put(a, sig->pubkey_algo );
1129   iobuf_put(a, sig->digest_algo );
1130   if ( sig->version >= 4 )
1131     {
1132       size_t nn;
1133       /* Timestamp and keyid must have been packed into the subpackets
1134          prior to the call of this function, because these subpackets
1135          are hashed. */
1136       nn = sig->hashed? sig->hashed->len : 0;
1137       write_16(a, nn);
1138       if (nn)
1139         iobuf_write( a, sig->hashed->data, nn );
1140       nn = sig->unhashed? sig->unhashed->len : 0;
1141       write_16(a, nn);
1142       if (nn)
1143         iobuf_write( a, sig->unhashed->data, nn );
1144     }
1145   iobuf_put(a, sig->digest_start[0] );
1146   iobuf_put(a, sig->digest_start[1] );
1147   n = pubkey_get_nsig( sig->pubkey_algo );
1148   if ( !n )
1149     write_fake_data( a, sig->data[0] );
1150   for (i=0; i < n && !rc ; i++ )
1151     rc = mpi_write(a, sig->data[i] );
1152
1153   if (!rc)
1154     {
1155       if ( is_RSA(sig->pubkey_algo) && sig->version < 4 )
1156         write_sign_packet_header(out, ctb, iobuf_get_temp_length(a) );
1157       else
1158         write_header(out, ctb, iobuf_get_temp_length(a) );
1159       rc = iobuf_write_temp( out, a );
1160     }
1161
1162   iobuf_close(a);
1163   return rc;
1164 }
1165
1166
1167 static int
1168 do_onepass_sig( IOBUF out, int ctb, PKT_onepass_sig *ops )
1169 {
1170     int rc = 0;
1171     IOBUF a = iobuf_temp();
1172
1173     write_version( a, ctb );
1174     iobuf_put(a, ops->sig_class );
1175     iobuf_put(a, ops->digest_algo );
1176     iobuf_put(a, ops->pubkey_algo );
1177     write_32(a, ops->keyid[0] );
1178     write_32(a, ops->keyid[1] );
1179     iobuf_put(a, ops->last );
1180
1181     write_header(out, ctb, iobuf_get_temp_length(a) );
1182     rc = iobuf_write_temp( out, a );
1183
1184     iobuf_close(a);
1185     return rc;
1186 }
1187
1188
1189 static int
1190 write_16(IOBUF out, u16 a)
1191 {
1192     iobuf_put(out, a>>8);
1193     if( iobuf_put(out,a) )
1194         return -1;
1195     return 0;
1196 }
1197
1198 static int
1199 write_32(IOBUF out, u32 a)
1200 {
1201     iobuf_put(out, a>> 24);
1202     iobuf_put(out, a>> 16);
1203     iobuf_put(out, a>> 8);
1204     return iobuf_put(out, a);
1205 }
1206
1207
1208 /****************
1209  * calculate the length of a header
1210  */
1211 static int
1212 calc_header_length( u32 len, int new_ctb )
1213 {
1214     if( !len )
1215         return 1; /* only the ctb */
1216
1217     if( new_ctb ) {
1218         if( len < 192 )
1219             return 2;
1220         if( len < 8384 )
1221             return 3;
1222         else
1223             return 6;
1224     }
1225     if( len < 256 )
1226         return 2;
1227     if( len < 65536 )
1228         return 3;
1229
1230     return 5;
1231 }
1232
1233 /****************
1234  * Write the CTB and the packet length
1235  */
1236 static int
1237 write_header( IOBUF out, int ctb, u32 len )
1238 {
1239     return write_header2( out, ctb, len, 0 );
1240 }
1241
1242
1243 static int
1244 write_sign_packet_header (IOBUF out, int ctb, u32 len)
1245 {
1246   (void)ctb;
1247
1248   /* Work around a bug in the pgp read function for signature packets,
1249      which are not correctly coded and silently assume at some point 2
1250      byte length headers.*/
1251   iobuf_put (out, 0x89 );
1252   iobuf_put (out, len >> 8 );
1253   return iobuf_put (out, len) == -1 ? -1:0;
1254 }
1255
1256 /****************
1257  * If HDRLEN is > 0, try to build a header of this length.  We need
1258  * this so that we can hash packets without reading them again.  If
1259  * len is 0, write a partial or indeterminate length header, unless
1260  * hdrlen is specified in which case write an actual zero length
1261  * (using the specified hdrlen).
1262  */
1263 static int
1264 write_header2( IOBUF out, int ctb, u32 len, int hdrlen )
1265 {
1266   if( ctb & 0x40 )
1267     return write_new_header( out, ctb, len, hdrlen );
1268
1269   if( hdrlen )
1270     {
1271       if( hdrlen == 2 && len < 256 )
1272         ;
1273       else if( hdrlen == 3 && len < 65536 )
1274         ctb |= 1;
1275       else
1276         ctb |= 2;
1277     }
1278   else
1279     {
1280       if( !len )
1281         ctb |= 3;
1282       else if( len < 256 )
1283         ;
1284       else if( len < 65536 )
1285         ctb |= 1;
1286       else
1287         ctb |= 2;
1288     }
1289
1290   if( iobuf_put(out, ctb ) )
1291     return -1;
1292
1293   if( len || hdrlen )
1294     {
1295       if( ctb & 2 )
1296         {
1297           if(iobuf_put(out, len >> 24 ))
1298             return -1;
1299           if(iobuf_put(out, len >> 16 ))
1300             return -1;
1301         }
1302
1303       if( ctb & 3 )
1304         if(iobuf_put(out, len >> 8 ))
1305           return -1;
1306
1307       if( iobuf_put(out, len ) )
1308         return -1;
1309     }
1310
1311   return 0;
1312 }
1313
1314
1315 static int
1316 write_new_header( IOBUF out, int ctb, u32 len, int hdrlen )
1317 {
1318     if( hdrlen )
1319         log_bug("can't cope with hdrlen yet\n");
1320
1321     if( iobuf_put(out, ctb ) )
1322         return -1;
1323     if( !len ) {
1324         iobuf_set_partial_block_mode(out, 512 );
1325     }
1326     else {
1327         if( len < 192 ) {
1328             if( iobuf_put(out, len ) )
1329                 return -1;
1330         }
1331         else if( len < 8384 ) {
1332             len -= 192;
1333             if( iobuf_put( out, (len / 256) + 192) )
1334                 return -1;
1335             if( iobuf_put( out, (len % 256) )  )
1336                 return -1;
1337         }
1338         else {
1339             if( iobuf_put( out, 0xff ) )
1340                 return -1;
1341             if( iobuf_put( out, (len >> 24)&0xff ) )
1342                 return -1;
1343             if( iobuf_put( out, (len >> 16)&0xff ) )
1344                 return -1;
1345             if( iobuf_put( out, (len >> 8)&0xff )  )
1346                 return -1;
1347             if( iobuf_put( out, len & 0xff ) )
1348                 return -1;
1349         }
1350     }
1351     return 0;
1352 }
1353
1354 static int
1355 write_version (IOBUF out, int ctb)
1356 {
1357   (void)ctb;
1358
1359   if (iobuf_put (out, 3))
1360     return -1;
1361   return 0;
1362 }