1 /* sign.c - Sign a message
2 * Copyright (C) 2001, 2002, 2003, 2008,
3 * 2010 Free Software Foundation, Inc.
5 * This file is part of GnuPG.
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.
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.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, see <https://www.gnu.org/licenses/>.
38 /* Hash the data and return if something was hashed. Return -1 on error. */
40 hash_data (int fd, gcry_md_hd_t md)
47 fp = es_fdopen_nc (fd, "rb");
50 log_error ("fdopen(%d) failed: %s\n", fd, strerror (errno));
56 nread = es_fread (buffer, 1, DIM(buffer), fp);
57 gcry_md_write (md, buffer, nread);
62 log_error ("read error on fd %d: %s\n", fd, strerror (errno));
71 hash_and_copy_data (int fd, gcry_md_hd_t md, ksba_writer_t writer)
80 fp = es_fdopen_nc (fd, "rb");
83 gpg_error_t tmperr = gpg_error_from_syserror ();
84 log_error ("fdopen(%d) failed: %s\n", fd, strerror (errno));
90 nread = es_fread (buffer, 1, DIM(buffer), fp);
94 gcry_md_write (md, buffer, nread);
95 err = ksba_writer_write_octet_string (writer, buffer, nread, 0);
98 log_error ("write failed: %s\n", gpg_strerror (err));
103 while (nread && !rc);
106 rc = gpg_error_from_syserror ();
107 log_error ("read error on fd %d: %s\n", fd, strerror (errno));
112 /* We can't allow signing an empty message because it does not
113 make much sense and more seriously, ksba_cms_build has
114 already written the tag for data and now expects an octet
115 string and an octet string of size 0 is illegal. */
116 log_error ("cannot sign an empty message\n");
117 rc = gpg_error (GPG_ERR_NO_DATA);
121 err = ksba_writer_write_octet_string (writer, NULL, 0, 1);
124 log_error ("write failed: %s\n", gpg_strerror (err));
133 /* Get the default certificate which is defined as the first
134 certificate capable of signing returned by the keyDB and has a
135 secret key available. */
137 gpgsm_get_default_cert (ctrl_t ctrl, ksba_cert_t *r_cert)
140 ksba_cert_t cert = NULL;
146 return gpg_error (GPG_ERR_GENERAL);
147 rc = keydb_search_first (ctrl, hd);
156 rc = keydb_get_cert (hd, &cert);
159 log_error ("keydb_get_cert failed: %s\n", gpg_strerror (rc));
164 if (!gpgsm_cert_use_sign_p (cert))
166 p = gpgsm_get_keygrip_hexstring (cert);
169 if (!gpgsm_agent_havekey (ctrl, p))
174 return 0; /* got it */
180 ksba_cert_release (cert);
183 while (!(rc = keydb_search_next (ctrl, hd)));
185 log_error ("keydb_search_next failed: %s\n", gpg_strerror (rc));
187 ksba_cert_release (cert);
194 get_default_signer (ctrl_t ctrl)
196 KEYDB_SEARCH_DESC desc;
197 ksba_cert_t cert = NULL;
198 KEYDB_HANDLE kh = NULL;
203 rc = gpgsm_get_default_cert (ctrl, &cert);
207 log_debug ("failed to find default certificate: %s\n",
214 rc = classify_user_id (opt.local_user, &desc, 0);
217 log_error ("failed to find default signer: %s\n", gpg_strerror (rc));
225 rc = keydb_search (ctrl, kh, &desc, 1);
228 log_debug ("failed to find default certificate: rc=%d\n", rc);
232 rc = keydb_get_cert (kh, &cert);
235 log_debug ("failed to get cert: rc=%d\n", rc);
243 /* Depending on the options in CTRL add the certificate CERT as well as
244 other certificate up in the chain to the Root-CA to the CMS
247 add_certificate_list (ctrl_t ctrl, ksba_cms_t cms, ksba_cert_t cert)
251 ksba_cert_t next = NULL;
255 ksba_cert_ref (cert);
257 n = ctrl->include_certs;
258 log_debug ("adding certificates at level %d\n", n);
265 n = 50; /* We better apply an upper bound */
267 /* First add my own certificate unless we don't want any certificate
271 if (not_root && gpgsm_is_root_cert (cert))
274 err = ksba_cms_add_cert (cms, cert);
280 /* Walk the chain to include all other certificates. Note that a -1
281 used for N makes sure that there is no limit and all certs get
283 while ( n-- && !(rc = gpgsm_walk_cert_chain (ctrl, cert, &next)) )
285 if (not_root && gpgsm_is_root_cert (next))
288 err = ksba_cms_add_cert (cms, next);
289 ksba_cert_release (cert);
290 cert = next; next = NULL;
294 ksba_cert_release (cert);
296 return rc == -1? 0: rc;
299 ksba_cert_release (cert);
300 log_error ("ksba_cms_add_cert failed: %s\n", gpg_strerror (err));
307 /* Perform a sign operation.
309 Sign the data received on DATA-FD in embedded mode or in detached
310 mode when DETACHED is true. Write the signature to OUT_FP. The
311 keys used to sign are taken from SIGNERLIST or the default one will
312 be used if the value of this argument is NULL. */
314 gpgsm_sign (ctrl_t ctrl, certlist_t signerlist,
315 int data_fd, int detached, estream_t out_fp)
319 Base64Context b64writer = NULL;
320 ksba_writer_t writer;
321 ksba_cms_t cms = NULL;
322 ksba_stop_reason_t stopreason;
323 KEYDB_HANDLE kh = NULL;
324 gcry_md_hd_t data_md = NULL;
328 ksba_isotime_t signed_at;
330 int release_signerlist = 0;
332 audit_set_type (ctrl->audit, AUDIT_TYPE_SIGN);
337 log_error (_("failed to allocate keyDB handle\n"));
338 rc = gpg_error (GPG_ERR_GENERAL);
342 ctrl->pem_name = "SIGNED MESSAGE";
343 rc = gpgsm_create_writer (&b64writer, ctrl, out_fp, &writer);
346 log_error ("can't create writer: %s\n", gpg_strerror (rc));
350 err = ksba_cms_new (&cms);
357 err = ksba_cms_set_reader_writer (cms, NULL, writer);
360 log_debug ("ksba_cms_set_reader_writer failed: %s\n",
366 /* We are going to create signed data with data as encap. content */
367 err = ksba_cms_set_content_type (cms, 0, KSBA_CT_SIGNED_DATA);
369 err = ksba_cms_set_content_type (cms, 1, KSBA_CT_DATA);
372 log_debug ("ksba_cms_set_content_type failed: %s\n",
378 /* If no list of signers is given, use the default certificate. */
381 ksba_cert_t cert = get_default_signer (ctrl);
384 log_error ("no default signer found\n");
385 gpgsm_status2 (ctrl, STATUS_INV_SGNR,
386 get_inv_recpsgnr_code (GPG_ERR_NO_SECKEY), NULL);
387 rc = gpg_error (GPG_ERR_GENERAL);
391 /* Although we don't check for ambigious specification we will
392 check that the signer's certificate is usable and valid. */
393 rc = gpgsm_cert_use_sign_p (cert);
395 rc = gpgsm_validate_chain (ctrl, cert, "", NULL, 0, NULL, 0, NULL);
400 tmpfpr = gpgsm_get_fingerprint_hexstring (cert, 0);
401 gpgsm_status2 (ctrl, STATUS_INV_SGNR,
402 get_inv_recpsgnr_code (rc), tmpfpr, NULL);
407 /* That one is fine - create signerlist. */
408 signerlist = xtrycalloc (1, sizeof *signerlist);
412 ksba_cert_release (cert);
415 signerlist->cert = cert;
416 release_signerlist = 1;
419 /* Figure out the hash algorithm to use. We do not want to use the
420 one for the certificate but if possible an OID for the plain
422 if (opt.forced_digest_algo && opt.verbose)
423 log_info ("user requested hash algorithm %d\n", opt.forced_digest_algo);
424 for (i=0, cl=signerlist; cl; cl = cl->next, i++)
428 if (opt.forced_digest_algo)
431 cl->hash_algo = opt.forced_digest_algo;
435 oid = ksba_cert_get_digest_algo (cl->cert);
436 cl->hash_algo = oid ? gcry_md_map_name (oid) : 0;
438 switch (cl->hash_algo)
440 case GCRY_MD_SHA1: oid = "1.3.14.3.2.26"; break;
441 case GCRY_MD_RMD160: oid = "1.3.36.3.2.1"; break;
442 case GCRY_MD_SHA224: oid = "2.16.840.1.101.3.4.2.4"; break;
443 case GCRY_MD_SHA256: oid = "2.16.840.1.101.3.4.2.1"; break;
444 case GCRY_MD_SHA384: oid = "2.16.840.1.101.3.4.2.2"; break;
445 case GCRY_MD_SHA512: oid = "2.16.840.1.101.3.4.2.3"; break;
446 /* case GCRY_MD_WHIRLPOOL: oid = "No OID yet"; break; */
448 case GCRY_MD_MD5: /* We don't want to use MD5. */
449 case 0: /* No algorithm found in cert. */
450 default: /* Other algorithms. */
451 log_info (_("hash algorithm %d (%s) for signer %d not supported;"
453 cl->hash_algo, oid? oid: "?", i,
454 gcry_md_algo_name (GCRY_MD_SHA1));
455 cl->hash_algo = GCRY_MD_SHA1;
456 oid = "1.3.14.3.2.26";
459 cl->hash_algo_oid = oid;
464 for (i=0, cl=signerlist; cl; cl = cl->next, i++)
465 log_info (_("hash algorithm used for signer %d: %s (%s)\n"),
466 i, gcry_md_algo_name (cl->hash_algo), cl->hash_algo_oid);
470 /* Gather certificates of signers and store them in the CMS object. */
471 for (cl=signerlist; cl; cl = cl->next)
473 rc = gpgsm_cert_use_sign_p (cl->cert);
477 err = ksba_cms_add_signer (cms, cl->cert);
480 log_error ("ksba_cms_add_signer failed: %s\n", gpg_strerror (err));
484 rc = add_certificate_list (ctrl, cms, cl->cert);
487 log_error ("failed to store list of certificates: %s\n",
491 /* Set the hash algorithm we are going to use */
492 err = ksba_cms_add_digest_algo (cms, cl->hash_algo_oid);
495 log_debug ("ksba_cms_add_digest_algo failed: %s\n",
503 /* Check whether one of the certificates is qualified. Note that we
504 already validated the certificate and thus the user data stored
505 flag must be available. */
506 if (!opt.no_chain_validation)
508 for (cl=signerlist; cl; cl = cl->next)
513 err = ksba_cert_get_user_data (cl->cert, "is_qualified",
514 &buffer, sizeof (buffer), &buflen);
517 log_error (_("checking for qualified certificate failed: %s\n"),
523 err = gpgsm_qualified_consent (ctrl, cl->cert);
525 err = gpgsm_not_qualified_warning (ctrl, cl->cert);
534 /* Prepare hashing (actually we are figuring out what we have set
536 rc = gcry_md_open (&data_md, 0, 0);
539 log_error ("md_open failed: %s\n", gpg_strerror (rc));
543 gcry_md_debug (data_md, "sign.data");
545 for (i=0; (algoid=ksba_cms_get_digest_algo_list (cms, i)); i++)
547 algo = gcry_md_map_name (algoid);
550 log_error ("unknown hash algorithm '%s'\n", algoid? algoid:"?");
551 rc = gpg_error (GPG_ERR_BUG);
554 gcry_md_enable (data_md, algo);
555 audit_log_i (ctrl->audit, AUDIT_DATA_HASH_ALGO, algo);
558 audit_log (ctrl->audit, AUDIT_SETUP_READY);
561 { /* We hash the data right now so that we can store the message
562 digest. ksba_cms_build() takes this as an flag that detached
564 unsigned char *digest;
567 if (!hash_data (data_fd, data_md))
568 audit_log (ctrl->audit, AUDIT_GOT_DATA);
569 for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
571 digest = gcry_md_read (data_md, cl->hash_algo);
572 digest_len = gcry_md_get_algo_dlen (cl->hash_algo);
573 if ( !digest || !digest_len )
575 log_error ("problem getting the hash of the data\n");
576 rc = gpg_error (GPG_ERR_BUG);
579 err = ksba_cms_set_message_digest (cms, signer, digest, digest_len);
582 log_error ("ksba_cms_set_message_digest failed: %s\n",
590 gnupg_get_isotime (signed_at);
591 for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
593 err = ksba_cms_set_signing_time (cms, signer, signed_at);
596 log_error ("ksba_cms_set_signing_time failed: %s\n",
603 /* We need to write at least a minimal list of our capabilities to
604 try to convince some MUAs to use 3DES and not the crippled
610 err = ksba_cms_add_smime_capability (cms, "2.16.840.1.101.3.4.1.2", NULL, 0);
612 err = ksba_cms_add_smime_capability (cms, "1.2.840.113549.3.7", NULL, 0);
615 log_error ("ksba_cms_add_smime_capability failed: %s\n",
621 /* Main building loop. */
624 err = ksba_cms_build (cms, &stopreason);
627 log_debug ("ksba_cms_build failed: %s\n", gpg_strerror (err));
632 if (stopreason == KSBA_SR_BEGIN_DATA)
634 /* Hash the data and store the message digest. */
635 unsigned char *digest;
640 rc = hash_and_copy_data (data_fd, data_md, writer);
643 audit_log (ctrl->audit, AUDIT_GOT_DATA);
644 for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
646 digest = gcry_md_read (data_md, cl->hash_algo);
647 digest_len = gcry_md_get_algo_dlen (cl->hash_algo);
648 if ( !digest || !digest_len )
650 log_error ("problem getting the hash of the data\n");
651 rc = gpg_error (GPG_ERR_BUG);
654 err = ksba_cms_set_message_digest (cms, signer,
658 log_error ("ksba_cms_set_message_digest failed: %s\n",
665 else if (stopreason == KSBA_SR_NEED_SIG)
667 /* Compute the signature for all signers. */
670 rc = gcry_md_open (&md, 0, 0);
673 log_error ("md_open failed: %s\n", gpg_strerror (rc));
677 gcry_md_debug (md, "sign.attr");
678 ksba_cms_set_hash_function (cms, HASH_FNC, md);
679 for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
681 unsigned char *sigval = NULL;
684 audit_log_i (ctrl->audit, AUDIT_NEW_SIG, signer);
690 for (cl_tmp=signerlist; cl_tmp; cl_tmp = cl_tmp->next)
692 gcry_md_enable (md, cl_tmp->hash_algo);
693 audit_log_i (ctrl->audit, AUDIT_ATTR_HASH_ALGO,
698 rc = ksba_cms_hash_signed_attrs (cms, signer);
701 log_debug ("hashing signed attrs failed: %s\n",
707 rc = gpgsm_create_cms_signature (ctrl, cl->cert,
708 md, cl->hash_algo, &sigval);
711 audit_log_cert (ctrl->audit, AUDIT_SIGNED_BY, cl->cert, rc);
716 err = ksba_cms_set_sig_val (cms, signer, sigval);
720 audit_log_cert (ctrl->audit, AUDIT_SIGNED_BY, cl->cert, err);
721 log_error ("failed to store the signature: %s\n",
728 /* write a status message */
729 fpr = gpgsm_get_fingerprint_hexstring (cl->cert, GCRY_MD_SHA1);
732 rc = gpg_error (GPG_ERR_ENOMEM);
738 int pkalgo = gpgsm_get_key_algo_info (cl->cert, NULL);
739 buf = xtryasprintf ("%c %d %d 00 %s %s",
746 rc = gpg_error_from_syserror ();
754 gpgsm_status (ctrl, STATUS_SIG_CREATED, buf);
756 audit_log_cert (ctrl->audit, AUDIT_SIGNED_BY, cl->cert, 0);
761 while (stopreason != KSBA_SR_READY);
763 rc = gpgsm_finish_writer (b64writer);
766 log_error ("write failed: %s\n", gpg_strerror (rc));
770 audit_log (ctrl->audit, AUDIT_SIGNING_DONE);
771 log_info ("signature created\n");
776 log_error ("error creating signature: %s <%s>\n",
777 gpg_strerror (rc), gpg_strsource (rc) );
778 if (release_signerlist)
779 gpgsm_release_certlist (signerlist);
780 ksba_cms_release (cms);
781 gpgsm_destroy_writer (b64writer);
783 gcry_md_close (data_md);