src/rfc2015.c

   1 /*
   2  * Sylpheed -- a GTK+ based, lightweight, and fast e-mail client
   3  * Copyright (C) 2001 Werner Koch (dd9jn)
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #  include "config.h"
  22 #endif
  23
  24 #if USE_GPGME
  25
  26 #include "defs.h"
  27
  28 #include <glib.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31 #include <locale.h>
  32 #include <ctype.h>
  33
  34 #include <gpgme.h>
  35
  36 #include "intl.h"
  37 #include "procmime.h"
  38 #include "procheader.h"
  39 #include "base64.h"
  40 #include "uuencode.h"
  41 #include "unmime.h"
  42 #include "codeconv.h"
  43 #include "utils.h"
  44 #include "prefs_common.h"
  45 #include "passphrase.h"
  46 #include "select-keys.h"
  47 #include "sigstatus.h"
  48 #include "rfc2015.h"
  49
  50 #define DIM(v)     (sizeof(v)/sizeof((v)[0]))
  51
  52 static char *content_names[] = {
  53     "Content-Type",
  54     "Content-Disposition",
  55     "Content-Transfer-Encoding",
  56     NULL
  57 };
  58
  59 static char *mime_version_name[] = {
  60     "Mime-Version",
  61     NULL
  62 };
  63
  64
  65 struct passphrase_cb_info_s {
  66     GpgmeCtx c;
  67     int did_it;
  68 };
  69
  70 static char *create_boundary (void);
  71
  72 static void dump_mimeinfo (const char *text, MimeInfo *x)
  73 {
  74     g_message ("** MimeInfo[%s] %p  level=%d",
  75                text, x, x? x->level:0 );
  76     if (!x)
  77         return;
  78
  79     g_message ("**      enc=`%s' enc_type=%d mime_type=%d",
  80                x->encoding, x->encoding_type, x->mime_type );
  81     g_message ("**      cont_type=`%s' cs=`%s' name=`%s' bnd=`%s'",
  82                x->content_type, x->charset, x->name, x->boundary );
  83     g_message ("**      cont_disp=`%s' fname=`%s' fpos=%ld size=%u, lvl=%d",
  84                x->content_disposition, x->filename, x->fpos, x->size,
  85                x->level );
  86     dump_mimeinfo (".main", x->main );
  87     dump_mimeinfo (".sub", x->sub );
  88     dump_mimeinfo (".next", x->next );
  89     g_message ("** MimeInfo[.parent] %p", x );
  90     dump_mimeinfo (".children", x->children );
  91     dump_mimeinfo (".plaintext", x->plaintext );
  92 }
  93
  94 static void dump_part ( MimeInfo *mimeinfo, FILE *fp )
  95 {
  96     unsigned int size = mimeinfo->size;
  97     int c;
  98
  99     if (fseek (fp, mimeinfo->fpos, SEEK_SET)) {
 100         g_warning ("dump_part: fseek error");
 101         return;
 102     }
 103
 104     g_message ("** --- begin dump_part ----");
 105     while (size-- && (c = getc (fp)) != EOF)
 106         putc (c, stderr);
 107     if (ferror (fp))
 108         g_warning ("dump_part: read error");
 109     g_message ("** --- end dump_part ----");
 110 }
 111
 112 void
 113 rfc2015_disable_all (void)
 114 {
 115     /* FIXME: set a flag, so that we don't bother the user with failed
 116      * gpgme messages */
 117 }
 118
 119
 120 void
 121 rfc2015_secure_remove (const char *fname)
 122 {
 123     if (!fname)
 124         return;
 125     /* fixme: overwrite the file first */
 126     remove (fname);
 127 }
 128
 129
 130 static const gchar *
 131 sig_status_to_string (GpgmeSigStat status)
 132 {
 133     const gchar *result;
 134
 135     switch (status) {
 136       case GPGME_SIG_STAT_NONE:
 137         result = _("Oops: Signature not verified");
 138         break;
 139       case GPGME_SIG_STAT_NOSIG:
 140         result = _("No signature found");
 141         break;
 142       case GPGME_SIG_STAT_GOOD:
 143         result = _("Good signature");
 144         break;
 145       case GPGME_SIG_STAT_BAD:
 146         result = _("BAD signature");
 147         break;
 148       case GPGME_SIG_STAT_NOKEY:
 149         result = _("No public key to verify the signature");
 150         break;
 151       case GPGME_SIG_STAT_ERROR:
 152         result = _("Error verifying the signature");
 153         break;
 154       case GPGME_SIG_STAT_DIFF:
 155         result = _("Different results for signatures");
 156         break;
 157       default:
 158         result = _("Error: Unknown status");
 159         break;
 160     }
 161
 162     return result;
 163 }
 164
 165 static const gchar *
 166 sig_status_with_name (GpgmeSigStat status)
 167 {
 168     const gchar *result;
 169
 170     switch (status) {
 171       case GPGME_SIG_STAT_NONE:
 172         result = _("Oops: Signature not verified");
 173         break;
 174       case GPGME_SIG_STAT_NOSIG:
 175         result = _("No signature found");
 176         break;
 177       case GPGME_SIG_STAT_GOOD:
 178         result = _("Good signature from \"%s\"");
 179         break;
 180       case GPGME_SIG_STAT_BAD:
 181         result = _("BAD signature  from \"%s\"");
 182         break;
 183       case GPGME_SIG_STAT_NOKEY:
 184         result = _("No public key to verify the signature");
 185         break;
 186       case GPGME_SIG_STAT_ERROR:
 187         result = _("Error verifying the signature");
 188         break;
 189       case GPGME_SIG_STAT_DIFF:
 190         result = _("Different results for signatures");
 191         break;
 192       default:
 193         result = _("Error: Unknown status");
 194         break;
 195     }
 196
 197     return result;
 198 }
 199
 200 static void
 201 sig_status_for_key(GString *str, GpgmeCtx ctx, GpgmeSigStat status,
 202                    GpgmeKey key, const gchar *fpr)
 203 {
 204         gint idx = 0;
 205         const char *uid;
 206
 207         uid = gpgme_key_get_string_attr (key, GPGME_ATTR_USERID, NULL, idx);
 208         if (uid == NULL) {
 209                 g_string_sprintfa (str, "%s\n",
 210                                    sig_status_to_string (status));
 211                 if ((fpr != NULL) && (*fpr != '\0'))
 212                         g_string_sprintfa (str, "Key fingerprint: %s\n", fpr);
 213                 g_string_append (str, _("Cannot find user ID for this key."));
 214                 return;
 215         }
 216         g_string_sprintfa (str, sig_status_with_name (status), uid);
 217         g_string_append (str, "\n");
 218
 219         while (1) {
 220                 uid = gpgme_key_get_string_attr (key, GPGME_ATTR_USERID,
 221                                                  NULL, ++idx);
 222                 if (uid == NULL)
 223                         break;
 224                 g_string_sprintfa (str, _("                aka \"%s\"\n"),
 225                                    uid);
 226         }
 227 }
 228
 229 static gchar *
 230 sig_status_full (GpgmeCtx ctx)
 231 {
 232         GString *str;
 233         gint sig_idx = 0;
 234         GpgmeError err;
 235         GpgmeSigStat status;
 236         GpgmeKey key;
 237         const char *fpr;
 238         time_t created;
 239         struct tm *ctime_val;
 240         char ctime_str[80];
 241         gchar *retval;
 242
 243         str = g_string_new ("");
 244
 245         fpr = gpgme_get_sig_status (ctx, sig_idx, &status, &created);
 246         while (fpr != NULL) {
 247                 if (created != 0) {
 248                         ctime_val = localtime (&created);
 249                         strftime (ctime_str, sizeof (ctime_str), "%c",
 250                                   ctime_val);
 251                         g_string_sprintfa (str,
 252                                            _("Signature made %s\n"),
 253                                            ctime_str);
 254                 }
 255                 err = gpgme_get_sig_key (ctx, sig_idx, &key);
 256                 if (err != 0) {
 257                         g_string_sprintfa (str, "%s\n",
 258                                            sig_status_to_string (status));
 259                         if ((fpr != NULL) && (*fpr != '\0'))
 260                                 g_string_sprintfa (str,
 261                                                    _("Key fingerprint: %s\n"),
 262                                                    fpr);
 263                 } else {
 264                         sig_status_for_key (str, ctx, status, key, fpr);
 265                         gpgme_key_unref (key);
 266                 }
 267                 g_string_append (str, "\n\n");
 268
 269                 fpr = gpgme_get_sig_status (ctx, ++sig_idx, &status, &created);
 270         }
 271
 272         retval = str->str;
 273         g_string_free (str, FALSE);
 274         return retval;
 275 }
 276
 277 static void check_signature (MimeInfo *mimeinfo, MimeInfo *partinfo, FILE *fp)
 278 {
 279     GpgmeCtx ctx = NULL;
 280     GpgmeError err;
 281     GpgmeData sig = NULL, text = NULL;
 282     GpgmeSigStat status = GPGME_SIG_STAT_NONE;
 283     GpgmegtkSigStatus statuswindow = NULL;
 284     const char *result = NULL;
 285
 286     if (prefs_common.gpg_signature_popup)
 287         statuswindow = gpgmegtk_sig_status_create ();
 288
 289     err = gpgme_new (&ctx);
 290     if (err) {
 291         g_warning ("gpgme_new failed: %s", gpgme_strerror (err));
 292         goto leave;
 293     }
 294
 295     /* don't include the last character (LF). It does not belong to the
 296      * signed text */
 297     err = gpgme_data_new_from_filepart (&text, NULL, fp,
 298                                         mimeinfo->children->fpos,
 299                                         mimeinfo->children->size ?
 300                                         (mimeinfo->children->size - 1) : 0 );
 301     if (!err)
 302         err = gpgme_data_new_from_filepart (&sig, NULL, fp,
 303                                             partinfo->fpos, partinfo->size);
 304     if (err) {
 305         g_message ("gpgme_data_new_from_filepart failed: %s",
 306                    gpgme_strerror (err));
 307         goto leave;
 308     }
 309
 310     err = gpgme_op_verify (ctx, sig, text, &status);
 311     if (err)
 312         g_message ("gpgme_op_verify failed: %s", gpgme_strerror (err));
 313
 314     /* FIXME: check what the heck this sig_status_full stuff is.
 315      * it should better go into sigstatus.c */
 316     g_free (partinfo->sigstatus_full);
 317     partinfo->sigstatus_full = sig_status_full (ctx);
 318
 319 leave:
 320     result = gpgmegtk_sig_status_to_string(status);
 321     debug_print("verification status: %s\n", result);
 322     if (prefs_common.gpg_signature_popup)
 323         gpgmegtk_sig_status_update (statuswindow,ctx);
 324
 325     g_assert (!err); /* FIXME: Hey: this may indeed happen */
 326     g_free (partinfo->sigstatus);
 327     partinfo->sigstatus = g_strdup (result);
 328
 329     gpgme_data_release (sig);
 330     gpgme_data_release (text);
 331     gpgme_release (ctx);
 332     if (prefs_common.gpg_signature_popup)
 333         gpgmegtk_sig_status_destroy (statuswindow);
 334 }
 335
 336 static const char *
 337 passphrase_cb (void *opaque, const char *desc, void *r_hd)
 338 {
 339     struct passphrase_cb_info_s *info = opaque;
 340     GpgmeCtx ctx = info ? info->c : NULL;
 341     const char *pass;
 342
 343     if (!desc) {
 344         /* FIXME: cleanup by looking at *r_hd */
 345         return NULL;
 346     }
 347
 348     gpgmegtk_set_passphrase_grab (prefs_common.passphrase_grab);
 349     g_message ("%% requesting passphrase for `%s': ", desc );
 350     pass = gpgmegtk_passphrase_mbox (desc);
 351     if (!pass) {
 352         g_message ("%% cancel passphrase entry");
 353         gpgme_cancel (ctx);
 354     }
 355     else
 356         g_message ("%% sending passphrase");
 357
 358     return pass;
 359 }
 360
 361 /*
 362  * Copy a gpgme data object to a temporary file and
 363  * return this filename
 364  */
 365 static char *
 366 copy_gpgmedata_to_temp (GpgmeData data, guint *length)
 367 {
 368     static int id;
 369     char *tmp;
 370     FILE *fp;
 371     char buf[100];
 372     size_t nread;
 373     GpgmeError err;
 374
 375     tmp = g_strdup_printf("%s%cgpgtmp.%08x",
 376                           get_mime_tmp_dir(), G_DIR_SEPARATOR, ++id );
 377
 378     if ((fp = fopen(tmp, "w")) == NULL) {
 379         FILE_OP_ERROR(tmp, "fopen");
 380         g_free(tmp);
 381         return NULL;
 382     }
 383
 384     err = gpgme_data_rewind ( data );
 385     if (err)
 386         g_message ("** gpgme_data_rewind failed: %s", gpgme_strerror (err));
 387
 388     while (!(err = gpgme_data_read (data, buf, 100, &nread))) {
 389         fwrite ( buf, nread, 1, fp );
 390     }
 391
 392     if (err != GPGME_EOF)
 393         g_warning ("** gpgme_data_read failed: %s", gpgme_strerror (err));
 394
 395     fclose (fp);
 396     *length = nread;
 397
 398     return tmp;
 399 }
 400
 401 static GpgmeData
 402 pgp_decrypt (MimeInfo *partinfo, FILE *fp)
 403 {
 404     GpgmeCtx ctx = NULL;
 405     GpgmeError err;
 406     GpgmeData cipher = NULL, plain = NULL;
 407     struct passphrase_cb_info_s info;
 408
 409     memset (&info, 0, sizeof info);
 410
 411     err = gpgme_new (&ctx);
 412     if (err) {
 413         g_message ("gpgme_new failed: %s", gpgme_strerror (err));
 414         goto leave;
 415     }
 416
 417     err = gpgme_data_new_from_filepart (&cipher, NULL, fp,
 418                                         partinfo->fpos, partinfo->size);
 419     if (err) {
 420         g_message ("gpgme_data_new_from_filepart failed: %s",
 421                    gpgme_strerror (err));
 422         goto leave;
 423     }
 424
 425     err = gpgme_data_new (&plain);
 426     if (err) {
 427         g_message ("gpgme_new failed: %s", gpgme_strerror (err));
 428         goto leave;
 429     }
 430
 431     if (!getenv("GPG_AGENT_INFO")) {
 432         info.c = ctx;
 433         gpgme_set_passphrase_cb (ctx, passphrase_cb, &info);
 434     }
 435
 436     err = gpgme_op_decrypt (ctx, cipher, plain);
 437
 438 leave:
 439     gpgme_data_release (cipher);
 440     if (err) {
 441         g_warning ("** decryption failed: %s", gpgme_strerror (err));
 442         gpgme_data_release (plain);
 443         plain = NULL;
 444     }
 445     else
 446         g_message ("** decryption succeeded");
 447
 448     gpgme_release (ctx);
 449     return plain;
 450 }
 451
 452 MimeInfo * rfc2015_find_signature (MimeInfo *mimeinfo)
 453 {
 454     MimeInfo *partinfo;
 455     int n = 0;
 456
 457     if (!mimeinfo)
 458         return NULL;
 459     if (g_strcasecmp (mimeinfo->content_type, "multipart/signed"))
 460         return NULL;
 461
 462     g_message ("** multipart/signed encountered");
 463
 464     /* check that we have at least 2 parts of the correct type */
 465     for (partinfo = mimeinfo->children;
 466          partinfo != NULL; partinfo = partinfo->next) {
 467         if (++n > 1  && !g_strcasecmp (partinfo->content_type,
 468                                        "application/pgp-signature"))
 469             break;
 470     }
 471
 472     return partinfo;
 473 }
 474
 475 gboolean rfc2015_has_signature (MimeInfo *mimeinfo)
 476 {
 477     return rfc2015_find_signature (mimeinfo) != NULL;
 478 }
 479
 480 void rfc2015_check_signature (MimeInfo *mimeinfo, FILE *fp)
 481 {
 482     MimeInfo *partinfo;
 483
 484     partinfo = rfc2015_find_signature (mimeinfo);
 485     if (!partinfo)
 486         return;
 487
 488 #if 0
 489     g_message ("** yep, it is a pgp signature");
 490     dump_mimeinfo ("gpg-signature", partinfo );
 491     dump_part (partinfo, fp );
 492     dump_mimeinfo ("signed text", mimeinfo->children );
 493     dump_part (mimeinfo->children, fp);
 494 #endif
 495
 496     check_signature (mimeinfo, partinfo, fp);
 497 }
 498
 499 int rfc2015_is_encrypted (MimeInfo *mimeinfo)
 500 {
 501     if (!mimeinfo)
 502         return 0;
 503     if (g_strcasecmp (mimeinfo->content_type, "multipart/encrypted"))
 504         return 0;
 505     /* fixme: we should schek the protocol parameter */
 506     return 1;
 507 }
 508
 509 static int
 510 name_cmp(const char *a, const char *b)
 511 {
 512     for( ; *a && *b; a++, b++) {
 513         if(*a != *b
 514            && toupper(*(unsigned char *)a) != toupper(*(unsigned char *)b))
 515             return 1;
 516     }
 517
 518     return *a != *b;
 519 }
 520
 521 static int
 522 headerp(char *p, char **names)
 523 {
 524     int i, c;
 525     char *p2;
 526
 527     p2 = strchr(p, ':');
 528     if(!p2 || p == p2) {
 529         return 0;
 530     }
 531     if(p2[-1] == ' ' || p2[-1] == '\t') {
 532         return 0;
 533     }
 534
 535     if(!names[0])
 536         return 1;
 537
 538     c = *p2;
 539     *p2 = 0;
 540     for(i = 0 ; names[i] != NULL; i++) {
 541         if(!name_cmp (names[i], p))
 542             break;
 543     }
 544     *p2 = c;
 545
 546     return names[i] != NULL;
 547 }
 548
 549
 550 void rfc2015_decrypt_message (MsgInfo *msginfo, MimeInfo *mimeinfo, FILE *fp)
 551 {
 552     static int id;
 553     MimeInfo *partinfo;
 554     int n, found;
 555     int ver_okay=0;
 556     char *fname;
 557     GpgmeData plain;
 558     FILE *dstfp;
 559     size_t nread;
 560     char buf[BUFFSIZE];
 561     GpgmeError err;
 562
 563     g_return_if_fail (mimeinfo->mime_type == MIME_MULTIPART);
 564
 565     g_message ("** multipart/encrypted encountered");
 566
 567     /* skip headers */
 568     if (fseek(fp, mimeinfo->fpos, SEEK_SET) < 0)
 569         perror("fseek");
 570     while (fgets(buf, sizeof(buf), fp) != NULL)
 571         if (buf[0] == '\r' || buf[0] == '\n') break;
 572
 573     procmime_scan_multipart_message(mimeinfo, fp);
 574
 575     /* check that we have the 2 parts */
 576     n = found = 0;
 577     for (partinfo = mimeinfo->children; partinfo; partinfo = partinfo->next) {
 578         if (++n == 1 && !g_strcasecmp (partinfo->content_type,
 579                                        "application/pgp-encrypted")) {
 580             /* Fixme: check that the version is 1 */
 581             ver_okay = 1;
 582         }
 583         else if (n == 2 && !g_strcasecmp (partinfo->content_type,
 584                                           "application/octet-stream")) {
 585             if (partinfo->next)
 586                 g_warning ("** oops: pgp_encrypted with more than 2 parts");
 587             break;
 588         }
 589     }
 590
 591     if (!ver_okay || !partinfo) {
 592         msginfo->decryption_failed = 1;
 593         /* fixme: remove the stuff, that the above procmime_scan_multiparts()
 594          * has appended to mimeino */
 595         return;
 596     }
 597
 598     g_message ("** yep, it is pgp encrypted");
 599
 600     plain = pgp_decrypt (partinfo, fp);
 601     if (!plain) {
 602         msginfo->decryption_failed = 1;
 603         return;
 604     }
 605
 606     fname = g_strdup_printf("%s%cplaintext.%08x",
 607                             get_mime_tmp_dir(), G_DIR_SEPARATOR, ++id);
 608
 609     if ((dstfp = fopen(fname, "w")) == NULL) {
 610         FILE_OP_ERROR(fname, "fopen");
 611         g_free(fname);
 612         msginfo->decryption_failed = 1;
 613         return;
 614     }
 615
 616     /* write the orginal header to the new file */
 617     if (fseek(fp, mimeinfo->fpos, SEEK_SET) < 0)
 618         perror("fseek");
 619
 620     while (fgets(buf, sizeof(buf), fp)) {
 621         if (headerp (buf, content_names))
 622             continue;
 623         if (buf[0] == '\r' || buf[0] == '\n')
 624             break;
 625         fputs (buf, dstfp);
 626     }
 627
 628     err = gpgme_data_rewind (plain);
 629     if (err)
 630         g_message ("** gpgme_data_rewind failed: %s", gpgme_strerror (err));
 631
 632     while (!(err = gpgme_data_read (plain, buf, sizeof(buf), &nread))) {
 633         fwrite (buf, nread, 1, dstfp);
 634     }
 635
 636     if (err != GPGME_EOF) {
 637         g_warning ("** gpgme_data_read failed: %s", gpgme_strerror (err));
 638     }
 639
 640     fclose (dstfp);
 641
 642     msginfo->plaintext_file = fname;
 643     msginfo->decryption_failed = 0;
 644 }
 645
 646
 647 /*
 648  * plain contains an entire mime object.
 649  * Encrypt it and return an GpgmeData object with the encrypted version of
 650  * the file or NULL in case of error.
 651  */
 652 static GpgmeData
 653 pgp_encrypt ( GpgmeData plain, GpgmeRecipients rset )
 654 {
 655     GpgmeCtx ctx = NULL;
 656     GpgmeError err;
 657     GpgmeData cipher = NULL;
 658
 659     err = gpgme_new (&ctx);
 660     if (!err)
 661         err = gpgme_data_new (&cipher);
 662     if (!err) {
 663         gpgme_set_armor (ctx, 1);
 664         err = gpgme_op_encrypt (ctx, rset, plain, cipher);
 665     }
 666
 667     if (err) {
 668         g_warning ("** encryption failed: %s", gpgme_strerror (err));
 669         gpgme_data_release (cipher);
 670         cipher = NULL;
 671     }
 672     else {
 673         g_message ("** encryption succeeded");
 674     }
 675
 676     gpgme_release (ctx);
 677     return cipher;
 678 }
 679
 680
 681 /*
 682  * Encrypt the file by extracting all recipients and finding the
 683  * encryption keys for all of them.  The file content is then replaced
 684  * by the encrypted one.  */
 685 int
 686 rfc2015_encrypt (const char *file, GSList *recp_list)
 687 {
 688     FILE *fp = NULL;
 689     char buf[BUFFSIZE];
 690     int i, clineidx, saved_last;
 691     char *clines[3] = {NULL};
 692     GpgmeError err;
 693     GpgmeData header = NULL;
 694     GpgmeData plain = NULL;
 695     GpgmeData cipher = NULL;
 696     GpgmeRecipients rset = NULL;
 697     size_t nread;
 698     int mime_version_seen = 0;
 699     char *boundary = create_boundary ();
 700
 701     /* Create the list of recipients */
 702     rset = gpgmegtk_recipient_selection (recp_list);
 703     if (!rset) {
 704         g_warning ("error creating recipient list" );
 705         goto failure;
 706     }
 707
 708     /* Open the source file */
 709     if ((fp = fopen(file, "rb")) == NULL) {
 710         FILE_OP_ERROR(file, "fopen");
 711         goto failure;
 712     }
 713
 714     err = gpgme_data_new (&header);
 715     if (!err)
 716         err = gpgme_data_new (&plain);
 717     if (err) {
 718         g_message ("gpgme_data_new failed: %s", gpgme_strerror (err));
 719         goto failure;
 720     }
 721
 722     /* get the content header lines from the source */
 723     clineidx=0;
 724     saved_last = 0;
 725     while (!err && fgets(buf, sizeof(buf), fp)) {
 726         /* fixme: check for overlong lines */
 727         if (headerp (buf, content_names)) {
 728             if (clineidx >= DIM (clines)) {
 729                 g_message ("rfc2015_encrypt: too many content lines");
 730                 goto failure;
 731             }
 732             clines[clineidx++] = g_strdup (buf);
 733             saved_last = 1;
 734             continue;
 735         }
 736         if (saved_last) {
 737             saved_last = 0;
 738             if (*buf == ' ' || *buf == '\t') {
 739                 char *last = clines[clineidx-1];
 740                 clines[clineidx-1] = g_strconcat (last, buf, NULL);
 741                 g_free (last);
 742                 continue;
 743             }
 744         }
 745
 746         if (headerp (buf, mime_version_name))
 747             mime_version_seen = 1;
 748
 749         if (buf[0] == '\r' || buf[0] == '\n')
 750             break;
 751         err = gpgme_data_write (header, buf, strlen (buf));
 752     }
 753     if (ferror (fp)) {
 754         FILE_OP_ERROR (file, "fgets");
 755         goto failure;
 756     }
 757
 758     /* write them to the temp data and add the rest of the message */
 759     for (i = 0; !err && i < clineidx; i++) {
 760         g_message ("%% %s:%d: cline=`%s'", __FILE__ ,__LINE__, clines[i]);
 761         err = gpgme_data_write (plain, clines[i], strlen (clines[i]));
 762     }
 763     if (!err)
 764         err = gpgme_data_write (plain, "\r\n", 2);
 765     while (!err && fgets(buf, sizeof(buf), fp)) {
 766         err = gpgme_data_write (plain, buf, strlen (buf));
 767     }
 768     if (ferror (fp)) {
 769         FILE_OP_ERROR (file, "fgets");
 770         goto failure;
 771     }
 772     if (err) {
 773         g_warning ("** gpgme_data_write failed: %s", gpgme_strerror (err));
 774         goto failure;
 775     }
 776
 777     cipher = pgp_encrypt (plain, rset);
 778     gpgme_data_release (plain); plain = NULL;
 779     gpgme_recipients_release (rset); rset = NULL;
 780     if (!cipher)
 781         goto failure;
 782
 783     /* we have the encrypted message available in cipher and now we
 784      * are going to rewrite the source file. To be sure that file has
 785      * been truncated we use an approach which should work everywhere:
 786      * close the file and then reopen it for writing. It is important
 787      * that this works, otherwise it may happen that parts of the
 788      * plaintext are still in the file (The encrypted stuff is, due to
 789      * compression, usually shorter than the plaintext).
 790      *
 791      * Yes, there is a race condition here, but everyone, who is so
 792      * stupid to store the temp file with the plaintext in a public
 793      * directory has to live with this anyway. */
 794     if (fclose (fp)) {
 795         FILE_OP_ERROR(file, "fclose");
 796         goto failure;
 797     }
 798     if ((fp = fopen(file, "wb")) == NULL) {
 799         FILE_OP_ERROR(file, "fopen");
 800         goto failure;
 801     }
 802
 803     /* Write the header, append new content lines, part 1 and part 2 header */
 804     err = gpgme_data_rewind (header);
 805     if (err) {
 806         g_message ("gpgme_data_rewind failed: %s", gpgme_strerror (err));
 807         goto failure;
 808     }
 809     while (!(err = gpgme_data_read (header, buf, BUFFSIZE, &nread))) {
 810         fwrite (buf, nread, 1, fp);
 811     }
 812     if (err != GPGME_EOF) {
 813         g_warning ("** gpgme_data_read failed: %s", gpgme_strerror (err));
 814         goto failure;
 815     }
 816     if (ferror (fp)) {
 817         FILE_OP_ERROR (file, "fwrite");
 818         goto failure;
 819     }
 820     gpgme_data_release (header); header = NULL;
 821
 822     if (!mime_version_seen)
 823         fputs ("MIME-Version: 1\r\n", fp);
 824
 825     fprintf (fp,
 826              "Content-Type: multipart/encrypted;"
 827              " protocol=\"application/pgp-encrypted\";\r\n"
 828              " boundary=\"%s\"\r\n"
 829              "\r\n"
 830              "--%s\r\n"
 831              "Content-Type: application/pgp-encrypted\r\n"
 832              "\r\n"
 833              "Version: 1\r\n"
 834              "\r\n"
 835              "--%s\r\n"
 836              "Content-Type: application/octet-stream\r\n"
 837              "\r\n",
 838              boundary, boundary, boundary);
 839
 840     /* append the encrypted stuff */
 841     err = gpgme_data_rewind (cipher);
 842     if (err) {
 843         g_warning ("** gpgme_data_rewind on cipher failed: %s",
 844                    gpgme_strerror (err));
 845         goto failure;
 846     }
 847
 848     while (!(err = gpgme_data_read (cipher, buf, BUFFSIZE, &nread))) {
 849         fwrite (buf, nread, 1, fp);
 850     }
 851     if (err != GPGME_EOF) {
 852         g_warning ("** gpgme_data_read failed: %s", gpgme_strerror (err));
 853         goto failure;
 854     }
 855
 856     /* and the final boundary */
 857     fprintf (fp,
 858              "\r\n"
 859              "--%s--\r\n"
 860              "\r\n",
 861              boundary);
 862     fflush (fp);
 863     if (ferror (fp)) {
 864         FILE_OP_ERROR (file, "fwrite");
 865         goto failure;
 866     }
 867     fclose (fp);
 868     gpgme_data_release (cipher);
 869     return 0;
 870
 871 failure:
 872     if (fp)
 873         fclose (fp);
 874     gpgme_data_release (header);
 875     gpgme_data_release (plain);
 876     gpgme_data_release (cipher);
 877     gpgme_recipients_release (rset);
 878     g_free (boundary);
 879     return -1; /* error */
 880 }
 881
 882 int
 883 set_signers (GpgmeCtx ctx, PrefsAccount *ac)
 884 {
 885     GSList *key_list = NULL;
 886     GpgmeCtx list_ctx = NULL;
 887     const char *keyid = NULL;
 888     GSList *p;
 889     GpgmeError err;
 890     GpgmeKey key;
 891
 892     if (ac == NULL)
 893         return 0;
 894
 895     switch (ac->sign_key) {
 896     case SIGN_KEY_DEFAULT:
 897         return 0;               /* nothing to do */
 898
 899     case SIGN_KEY_BY_FROM:
 900         keyid = ac->address;
 901         break;
 902
 903     case SIGN_KEY_CUSTOM:
 904         keyid = ac->sign_key_id;
 905         break;
 906
 907     default:
 908         g_assert_not_reached ();
 909     }
 910
 911     err = gpgme_new (&list_ctx);
 912     if (err)
 913         goto leave;
 914     err = gpgme_op_keylist_start (list_ctx, keyid, 1);
 915     if (err)
 916         goto leave;
 917     while ( !(err = gpgme_op_keylist_next (list_ctx, &key)) ) {
 918         key_list = g_slist_append (key_list, key);
 919     }
 920     if (err != GPGME_EOF)
 921         goto leave;
 922     if (key_list == NULL) {
 923         g_warning ("no keys found for keyid \"%s\"", keyid);
 924     }
 925     gpgme_signers_clear (ctx);
 926     for (p = key_list; p != NULL; p = p->next) {
 927         err = gpgme_signers_add (ctx, (GpgmeKey) p->data);
 928         if (err)
 929             goto leave;
 930     }
 931
 932 leave:
 933     if (err)
 934         g_message ("** set_signers failed: %s", gpgme_strerror (err));
 935     for (p = key_list; p != NULL; p = p->next)
 936         gpgme_key_unref ((GpgmeKey) p->data);
 937     g_slist_free (key_list);
 938     if (list_ctx)
 939         gpgme_release (list_ctx);
 940     return err;
 941 }
 942
 943 /*
 944  * plain contains an entire mime object.  Sign it and return an
 945  * GpgmeData object with the signature of it or NULL in case of error.
 946  */
 947 static GpgmeData
 948 pgp_sign (GpgmeData plain, PrefsAccount *ac)
 949 {
 950     GpgmeCtx ctx = NULL;
 951     GpgmeError err;
 952     GpgmeData sig = NULL;
 953     struct passphrase_cb_info_s info;
 954
 955     memset (&info, 0, sizeof info);
 956
 957     err = gpgme_new (&ctx);
 958     if (err)
 959         goto leave;
 960     err = gpgme_data_new (&sig);
 961     if (err)
 962         goto leave;
 963
 964     if (!getenv("GPG_AGENT_INFO")) {
 965         info.c = ctx;
 966         gpgme_set_passphrase_cb (ctx, passphrase_cb, &info);
 967     }
 968     gpgme_set_textmode (ctx, 1);
 969     gpgme_set_armor (ctx, 1);
 970     err = set_signers (ctx, ac);
 971     if (err)
 972         goto leave;
 973     err = gpgme_op_sign (ctx, plain, sig, GPGME_SIG_MODE_DETACH);
 974
 975 leave:
 976     if (err) {
 977         g_message ("** signing failed: %s", gpgme_strerror (err));
 978         gpgme_data_release (sig);
 979         sig = NULL;
 980     }
 981     else {
 982         g_message ("** signing succeeded");
 983     }
 984
 985     gpgme_release (ctx);
 986     return sig;
 987 }
 988
 989 /*
 990  * Sign the file and replace its content with the signed one.
 991  */
 992 int
 993 rfc2015_sign (const char *file, PrefsAccount *ac)
 994 {
 995     FILE *fp = NULL;
 996     char buf[BUFFSIZE];
 997     int i, clineidx, saved_last;
 998     char *clines[3] = {NULL};
 999     GpgmeError err;
1000     GpgmeData header = NULL;
1001     GpgmeData plain = NULL;
1002     GpgmeData sigdata = NULL;
1003     size_t nread;
1004     int mime_version_seen = 0;
1005     char *boundary = create_boundary ();
1006
1007     /* Open the source file */
1008     if ((fp = fopen(file, "rb")) == NULL) {
1009         FILE_OP_ERROR(file, "fopen");
1010         goto failure;
1011     }
1012
1013     err = gpgme_data_new (&header);
1014     if (!err)
1015         err = gpgme_data_new (&plain);
1016     if (err) {
1017         g_message ("gpgme_data_new failed: %s", gpgme_strerror (err));
1018         goto failure;
1019     }
1020
1021     /* get the content header lines from the source */
1022     clineidx = 0;
1023     saved_last = 0;
1024     while (!err && fgets(buf, sizeof(buf), fp)) {
1025         /* fixme: check for overlong lines */
1026         if (headerp (buf, content_names)) {
1027             if (clineidx >= DIM (clines)) {
1028                 g_message ("rfc2015_sign: too many content lines");
1029                 goto failure;
1030             }
1031             clines[clineidx++] = g_strdup (buf);
1032             saved_last = 1;
1033             continue;
1034         }
1035         if (saved_last) {
1036             saved_last = 0;
1037             if (*buf == ' ' || *buf == '\t') {
1038                 char *last = clines[clineidx - 1];
1039                 clines[clineidx - 1] = g_strconcat (last, buf, NULL);
1040                 g_free (last);
1041                 continue;
1042             }
1043         }
1044
1045         if (headerp (buf, mime_version_name))
1046             mime_version_seen = 1;
1047
1048         if (buf[0] == '\r' || buf[0] == '\n')
1049             break;
1050         err = gpgme_data_write (header, buf, strlen (buf));
1051     }
1052     if (ferror (fp)) {
1053         FILE_OP_ERROR (file, "fgets");
1054         goto failure;
1055     }
1056
1057     /* write them to the temp data and add the rest of the message */
1058     for (i = 0; !err && i < clineidx; i++) {
1059         err = gpgme_data_write (plain, clines[i], strlen (clines[i]));
1060     }
1061     if (!err)
1062         err = gpgme_data_write (plain, "\r\n", 2 );
1063     while (!err && fgets(buf, sizeof(buf), fp)) {
1064         err = gpgme_data_write (plain, buf, strlen (buf));
1065     }
1066     if (ferror (fp)) {
1067         FILE_OP_ERROR (file, "fgets");
1068         goto failure;
1069     }
1070     if (err) {
1071         g_message ("** gpgme_data_write failed: %s", gpgme_strerror (err));
1072         goto failure;
1073     }
1074
1075     sigdata = pgp_sign (plain, ac);
1076     if (!sigdata)
1077         goto failure;
1078
1079     /* we have the signed message available in sigdata and now we are
1080      * going to rewrite the original file. To be sure that file has
1081      * been truncated we use an approach which should work everywhere:
1082      * close the file and then reopen it for writing. */
1083     if (fclose (fp)) {
1084         FILE_OP_ERROR(file, "fclose");
1085         goto failure;
1086     }
1087     if ((fp = fopen(file, "wb")) == NULL) {
1088         FILE_OP_ERROR(file, "fopen");
1089         goto failure;
1090     }
1091
1092     /* Write the rfc822 header and add new content lines */
1093     err = gpgme_data_rewind (header);
1094     if (err)
1095         g_message ("** gpgme_data_rewind failed: %s", gpgme_strerror (err));
1096     while (!(err = gpgme_data_read (header, buf, BUFFSIZE, &nread))) {
1097         fwrite (buf, nread, 1, fp);
1098     }
1099     if (err != GPGME_EOF) {
1100         g_message ("** gpgme_data_read failed: %s", gpgme_strerror (err));
1101         goto failure;
1102     }
1103     if (ferror (fp)) {
1104         FILE_OP_ERROR (file, "fwrite");
1105         goto failure;
1106     }
1107     gpgme_data_release (header);
1108     header = NULL;
1109
1110     if (!mime_version_seen)
1111         fputs ("MIME-Version: 1\r\n", fp);
1112     fprintf (fp, "Content-Type: multipart/signed; "
1113                  "protocol=\"application/pgp-signature\";\r\n"
1114                  " boundary=\"%s\"\r\n", boundary );
1115
1116     /* Part 1: signed material */
1117     fprintf (fp, "\r\n--%s\r\n", boundary);
1118     err = gpgme_data_rewind (plain);
1119     if (err) {
1120         g_message ("** gpgme_data_rewind on plain failed: %s",
1121                    gpgme_strerror (err));
1122         goto failure;
1123     }
1124     while (!(err = gpgme_data_read (plain, buf, BUFFSIZE, &nread))) {
1125         fwrite (buf, nread, 1, fp);
1126     }
1127     if (err != GPGME_EOF) {
1128         g_message ("** gpgme_data_read failed: %s", gpgme_strerror (err));
1129         goto failure;
1130     }
1131
1132     /* Part 2: signature */
1133     fprintf (fp, "\r\n--%s\r\n", boundary);
1134     fputs ("Content-Type: application/pgp-signature\r\n"
1135            "\r\n", fp);
1136
1137     err = gpgme_data_rewind (sigdata);
1138     if (err) {
1139         g_message ("** gpgme_data_rewind on sigdata failed: %s",
1140                    gpgme_strerror (err));
1141         goto failure;
1142     }
1143
1144     while (!(err = gpgme_data_read (sigdata, buf, BUFFSIZE, &nread))) {
1145         fwrite (buf, nread, 1, fp);
1146     }
1147     if (err != GPGME_EOF) {
1148         g_message ("** gpgme_data_read failed: %s", gpgme_strerror (err));
1149         goto failure;
1150     }
1151
1152     /* Final boundary */
1153     fprintf (fp, "\r\n--%s--\r\n\r\n", boundary);
1154     fflush (fp);
1155     if (ferror (fp)) {
1156         FILE_OP_ERROR (file, "fwrite");
1157         goto failure;
1158     }
1159     fclose (fp);
1160     gpgme_data_release (header);
1161     gpgme_data_release (plain);
1162     gpgme_data_release (sigdata);
1163     g_free (boundary);
1164     return 0;
1165
1166 failure:
1167     if (fp)
1168         fclose (fp);
1169     gpgme_data_release (header);
1170     gpgme_data_release (plain);
1171     gpgme_data_release (sigdata);
1172     g_free (boundary);
1173     return -1; /* error */
1174 }
1175
1176
1177 /****************
1178  * Create a new boundary in a way that it is very unlikely that this
1179  * will occur in the following text.  It would be easy to ensure
1180  * uniqueness if everything is either quoted-printable or base64
1181  * encoded (note that conversion is allowed), but because MIME bodies
1182  * may be nested, it may happen that the same boundary has already
1183  * been used. We avoid scanning the message for conflicts and hope the
1184  * best.
1185  *
1186  *   boundary := 0*69<bchars> bcharsnospace
1187  *   bchars := bcharsnospace / " "
1188  *   bcharsnospace := DIGIT / ALPHA / "'" / "(" / ")" /
1189  *                    "+" / "_" / "," / "-" / "." /
1190  *                    "/" / ":" / "=" / "?"
1191  */
1192
1193 static char *
1194 create_boundary (void)
1195 {
1196     static char tbl[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
1197                         "abcdefghijklmnopqrstuvwxyz"
1198                         "1234567890'()+_,./:=?";
1199     char buf[17];
1200     int i, equal;
1201     int pid;
1202
1203     pid = getpid();
1204
1205     /* We make the boundary depend on the pid, so that all running
1206      * processed generate different values even when they have been
1207      * started within the same second and srand48(time(NULL)) has been
1208      * used.  I can't see whether this is really an advantage but it
1209      * doesn't do any harm.
1210      */
1211     equal = -1;
1212     for(i = 0; i < sizeof(buf) - 1; i++) {
1213         buf[i] = tbl[(lrand48() ^ pid) % (sizeof(tbl) - 1)]; /* fill with random */
1214         if(buf[i] == '=' && equal == -1)
1215             equal = i;
1216     }
1217     buf[i] = 0;
1218
1219     /* now make sure that we do have the sequence "=." in it which cannot
1220      * be matched by quoted-printable or base64 encoding */
1221     if(equal != -1 && (equal+1) < i)
1222         buf[equal+1] = '.';
1223     else {
1224         buf[0] = '=';
1225         buf[1] = '.';
1226     }
1227
1228     return g_strdup(buf);
1229 }
1230
1231 #endif /* USE_GPGME */