1 /* sign.c - Sign a message
2 * Copyright (C) 2001, 2002, 2003, 2008 Free Software Foundation, Inc.
4 * This file is part of GnuPG.
6 * GnuPG is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 3 of the License, or
9 * (at your option) any later version.
11 * GnuPG is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
37 /* Hash the data and return if something was hashed. Return -1 on error. */
39 hash_data (int fd, gcry_md_hd_t md)
46 fp = fdopen ( dup (fd), "rb");
49 log_error ("fdopen(%d) failed: %s\n", fd, strerror (errno));
55 nread = fread (buffer, 1, DIM(buffer), fp);
56 gcry_md_write (md, buffer, nread);
61 log_error ("read error on fd %d: %s\n", fd, strerror (errno));
69 hash_and_copy_data (int fd, gcry_md_hd_t md, ksba_writer_t writer)
78 fp = fdopen ( dup (fd), "rb");
81 gpg_error_t tmperr = gpg_error (gpg_err_code_from_errno (errno));
82 log_error ("fdopen(%d) failed: %s\n", fd, strerror (errno));
88 nread = fread (buffer, 1, DIM(buffer), fp);
92 gcry_md_write (md, buffer, nread);
93 err = ksba_writer_write_octet_string (writer, buffer, nread, 0);
96 log_error ("write failed: %s\n", gpg_strerror (err));
101 while (nread && !rc);
104 rc = gpg_error (gpg_err_code_from_errno (errno));
105 log_error ("read error on fd %d: %s\n", fd, strerror (errno));
110 /* We can't allow to sign an empty message because it does not
111 make much sense and more seriously, ksba-cms_build has
112 already written the tag for data and now expects an octet
113 string but an octet string of zeize 0 is illegal. */
114 log_error ("cannot sign an empty message\n");
115 rc = gpg_error (GPG_ERR_NO_DATA);
119 err = ksba_writer_write_octet_string (writer, NULL, 0, 1);
122 log_error ("write failed: %s\n", gpg_strerror (err));
131 /* Get the default certificate which is defined as the first
132 certificate capable of signing returned by the keyDB and has a
133 secret key available. */
135 gpgsm_get_default_cert (ctrl_t ctrl, ksba_cert_t *r_cert)
138 ksba_cert_t cert = NULL;
144 return gpg_error (GPG_ERR_GENERAL);
145 rc = keydb_search_first (hd);
154 rc = keydb_get_cert (hd, &cert);
157 log_error ("keydb_get_cert failed: %s\n", gpg_strerror (rc));
162 if (!gpgsm_cert_use_sign_p (cert))
164 p = gpgsm_get_keygrip_hexstring (cert);
167 if (!gpgsm_agent_havekey (ctrl, p))
172 return 0; /* got it */
178 ksba_cert_release (cert);
181 while (!(rc = keydb_search_next (hd)));
183 log_error ("keydb_search_next failed: %s\n", gpg_strerror (rc));
185 ksba_cert_release (cert);
192 get_default_signer (ctrl_t ctrl)
194 KEYDB_SEARCH_DESC desc;
195 ksba_cert_t cert = NULL;
196 KEYDB_HANDLE kh = NULL;
201 rc = gpgsm_get_default_cert (ctrl, &cert);
205 log_debug ("failed to find default certificate: %s\n",
212 rc = keydb_classify_name (opt.local_user, &desc);
215 log_error ("failed to find default signer: %s\n", gpg_strerror (rc));
223 rc = keydb_search (kh, &desc, 1);
226 log_debug ("failed to find default certificate: rc=%d\n", rc);
230 rc = keydb_get_cert (kh, &cert);
233 log_debug ("failed to get cert: rc=%d\n", rc);
241 /* Depending on the options in CTRL add the certificate CERT as well as
242 other certificate up in the chain to the Root-CA to the CMS
245 add_certificate_list (ctrl_t ctrl, ksba_cms_t cms, ksba_cert_t cert)
249 ksba_cert_t next = NULL;
253 ksba_cert_ref (cert);
255 n = ctrl->include_certs;
256 log_debug ("adding certificates at level %d\n", n);
263 n = 50; /* We better apply an upper bound */
265 /* First add my own certificate unless we don't want any certificate
269 if (not_root && gpgsm_is_root_cert (cert))
272 err = ksba_cms_add_cert (cms, cert);
278 /* Walk the chain to include all other certificates. Note that a -1
279 used for N makes sure that there is no limit and all certs get
281 while ( n-- && !(rc = gpgsm_walk_cert_chain (ctrl, cert, &next)) )
283 if (not_root && gpgsm_is_root_cert (next))
286 err = ksba_cms_add_cert (cms, next);
287 ksba_cert_release (cert);
288 cert = next; next = NULL;
292 ksba_cert_release (cert);
294 return rc == -1? 0: rc;
297 ksba_cert_release (cert);
298 log_error ("ksba_cms_add_cert failed: %s\n", gpg_strerror (err));
305 /* Perform a sign operation.
307 Sign the data received on DATA-FD in embedded mode or in detached
308 mode when DETACHED is true. Write the signature to OUT_FP. The
309 keys used to sign are taken from SIGNERLIST or the default one will
310 be used if the value of this argument is NULL. */
312 gpgsm_sign (ctrl_t ctrl, certlist_t signerlist,
313 int data_fd, int detached, FILE *out_fp)
317 Base64Context b64writer = NULL;
318 ksba_writer_t writer;
319 ksba_cms_t cms = NULL;
320 ksba_stop_reason_t stopreason;
321 KEYDB_HANDLE kh = NULL;
322 gcry_md_hd_t data_md = NULL;
326 ksba_isotime_t signed_at;
328 int release_signerlist = 0;
330 audit_set_type (ctrl->audit, AUDIT_TYPE_SIGN);
335 log_error (_("failed to allocated keyDB handle\n"));
336 rc = gpg_error (GPG_ERR_GENERAL);
340 ctrl->pem_name = "SIGNED MESSAGE";
341 rc = gpgsm_create_writer (&b64writer, ctrl, out_fp, NULL, &writer);
344 log_error ("can't create writer: %s\n", gpg_strerror (rc));
348 err = ksba_cms_new (&cms);
355 err = ksba_cms_set_reader_writer (cms, NULL, writer);
358 log_debug ("ksba_cms_set_reader_writer failed: %s\n",
364 /* We are going to create signed data with data as encap. content */
365 err = ksba_cms_set_content_type (cms, 0, KSBA_CT_SIGNED_DATA);
367 err = ksba_cms_set_content_type (cms, 1, KSBA_CT_DATA);
370 log_debug ("ksba_cms_set_content_type failed: %s\n",
376 /* If no list of signers is given, use the default certificate. */
379 ksba_cert_t cert = get_default_signer (ctrl);
382 log_error ("no default signer found\n");
383 gpgsm_status2 (ctrl, STATUS_INV_SGNR,
384 get_inv_recpsgnr_code (GPG_ERR_NO_SECKEY), NULL);
385 rc = gpg_error (GPG_ERR_GENERAL);
389 /* Although we don't check for ambigious specification we will
390 check that the signer's certificate is usable and valid. */
391 rc = gpgsm_cert_use_sign_p (cert);
393 rc = gpgsm_validate_chain (ctrl, cert, "", NULL, 0, NULL, 0, NULL);
398 tmpfpr = gpgsm_get_fingerprint_hexstring (cert, 0);
399 gpgsm_status2 (ctrl, STATUS_INV_SGNR,
400 get_inv_recpsgnr_code (rc), tmpfpr, NULL);
405 /* That one is fine - create signerlist. */
406 signerlist = xtrycalloc (1, sizeof *signerlist);
410 ksba_cert_release (cert);
413 signerlist->cert = cert;
414 release_signerlist = 1;
417 /* Figure out the hash algorithm to use. We do not want to use the
418 one for the certificate but if possible an OID for the plain
420 if (opt.forced_digest_algo && opt.verbose)
421 log_info ("user requested hash algorithm %d\n", opt.forced_digest_algo);
422 for (i=0, cl=signerlist; cl; cl = cl->next, i++)
426 if (opt.forced_digest_algo)
429 cl->hash_algo = opt.forced_digest_algo;
433 oid = ksba_cert_get_digest_algo (cl->cert);
434 cl->hash_algo = oid ? gcry_md_map_name (oid) : 0;
436 switch (cl->hash_algo)
438 case GCRY_MD_SHA1: oid = "1.3.14.3.2.26"; break;
439 case GCRY_MD_RMD160: oid = "1.3.36.3.2.1"; break;
440 case GCRY_MD_SHA224: oid = "2.16.840.1.101.3.4.2.4"; break;
441 case GCRY_MD_SHA256: oid = "2.16.840.1.101.3.4.2.1"; break;
442 case GCRY_MD_SHA384: oid = "2.16.840.1.101.3.4.2.2"; break;
443 case GCRY_MD_SHA512: oid = "2.16.840.1.101.3.4.2.3"; break;
444 /* case GCRY_MD_WHIRLPOOL: oid = "No OID yet"; break; */
446 case GCRY_MD_MD5: /* We don't want to use MD5. */
447 case 0: /* No algorithm found in cert. */
448 default: /* Other algorithms. */
449 log_info (_("hash algorithm %d (%s) for signer %d not supported;"
451 cl->hash_algo, oid? oid: "?", i,
452 gcry_md_algo_name (GCRY_MD_SHA1));
453 cl->hash_algo = GCRY_MD_SHA1;
454 oid = "1.3.14.3.2.26";
457 cl->hash_algo_oid = oid;
462 for (i=0, cl=signerlist; cl; cl = cl->next, i++)
463 log_info (_("hash algorithm used for signer %d: %s (%s)\n"),
464 i, gcry_md_algo_name (cl->hash_algo), cl->hash_algo_oid);
468 /* Gather certificates of signers and store them in the CMS object. */
469 for (cl=signerlist; cl; cl = cl->next)
471 rc = gpgsm_cert_use_sign_p (cl->cert);
475 err = ksba_cms_add_signer (cms, cl->cert);
478 log_error ("ksba_cms_add_signer failed: %s\n", gpg_strerror (err));
482 rc = add_certificate_list (ctrl, cms, cl->cert);
485 log_error ("failed to store list of certificates: %s\n",
489 /* Set the hash algorithm we are going to use */
490 err = ksba_cms_add_digest_algo (cms, cl->hash_algo_oid);
493 log_debug ("ksba_cms_add_digest_algo failed: %s\n",
501 /* Check whether one of the certificates is qualified. Note that we
502 already validated the certificate and thus the user data stored
503 flag must be available. */
504 for (cl=signerlist; cl; cl = cl->next)
509 err = ksba_cert_get_user_data (cl->cert, "is_qualified",
510 &buffer, sizeof (buffer), &buflen);
513 log_error (_("checking for qualified certificate failed: %s\n"),
519 err = gpgsm_qualified_consent (ctrl, cl->cert);
521 err = gpgsm_not_qualified_warning (ctrl, cl->cert);
529 /* Prepare hashing (actually we are figuring out what we have set
531 rc = gcry_md_open (&data_md, 0, 0);
534 log_error ("md_open failed: %s\n", gpg_strerror (rc));
538 gcry_md_start_debug (data_md, "sign.data");
540 for (i=0; (algoid=ksba_cms_get_digest_algo_list (cms, i)); i++)
542 algo = gcry_md_map_name (algoid);
545 log_error ("unknown hash algorithm `%s'\n", algoid? algoid:"?");
546 rc = gpg_error (GPG_ERR_BUG);
549 gcry_md_enable (data_md, algo);
550 audit_log_i (ctrl->audit, AUDIT_DATA_HASH_ALGO, algo);
553 audit_log (ctrl->audit, AUDIT_SETUP_READY);
556 { /* We hash the data right now so that we can store the message
557 digest. ksba_cms_build() takes this as an flag that detached
559 unsigned char *digest;
562 if (!hash_data (data_fd, data_md))
563 audit_log (ctrl->audit, AUDIT_GOT_DATA);
564 for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
566 digest = gcry_md_read (data_md, cl->hash_algo);
567 digest_len = gcry_md_get_algo_dlen (cl->hash_algo);
568 if ( !digest || !digest_len )
570 log_error ("problem getting the hash of the data\n");
571 rc = gpg_error (GPG_ERR_BUG);
574 err = ksba_cms_set_message_digest (cms, signer, digest, digest_len);
577 log_error ("ksba_cms_set_message_digest failed: %s\n",
585 gnupg_get_isotime (signed_at);
586 for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
588 err = ksba_cms_set_signing_time (cms, signer, signed_at);
591 log_error ("ksba_cms_set_signing_time failed: %s\n",
598 /* We need to write at least a minimal list of our capabilities to
599 try to convince some MUAs to use 3DES and not the crippled
605 err = ksba_cms_add_smime_capability (cms, "2.16.840.1.101.3.4.1.2", NULL, 0);
607 err = ksba_cms_add_smime_capability (cms, "1.2.840.113549.3.7", NULL, 0);
610 log_error ("ksba_cms_add_smime_capability failed: %s\n",
616 /* Main building loop. */
619 err = ksba_cms_build (cms, &stopreason);
622 log_debug ("ksba_cms_build failed: %s\n", gpg_strerror (err));
627 if (stopreason == KSBA_SR_BEGIN_DATA)
629 /* Hash the data and store the message digest. */
630 unsigned char *digest;
635 rc = hash_and_copy_data (data_fd, data_md, writer);
638 audit_log (ctrl->audit, AUDIT_GOT_DATA);
639 for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
641 digest = gcry_md_read (data_md, cl->hash_algo);
642 digest_len = gcry_md_get_algo_dlen (cl->hash_algo);
643 if ( !digest || !digest_len )
645 log_error ("problem getting the hash of the data\n");
646 rc = gpg_error (GPG_ERR_BUG);
649 err = ksba_cms_set_message_digest (cms, signer,
653 log_error ("ksba_cms_set_message_digest failed: %s\n",
660 else if (stopreason == KSBA_SR_NEED_SIG)
662 /* Compute the signature for all signers. */
665 rc = gcry_md_open (&md, 0, 0);
668 log_error ("md_open failed: %s\n", gpg_strerror (rc));
672 gcry_md_start_debug (md, "sign.attr");
673 ksba_cms_set_hash_function (cms, HASH_FNC, md);
674 for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
676 unsigned char *sigval = NULL;
679 audit_log_i (ctrl->audit, AUDIT_NEW_SIG, signer);
685 for (cl_tmp=signerlist; cl_tmp; cl_tmp = cl_tmp->next)
687 gcry_md_enable (md, cl_tmp->hash_algo);
688 audit_log_i (ctrl->audit, AUDIT_ATTR_HASH_ALGO,
693 rc = ksba_cms_hash_signed_attrs (cms, signer);
696 log_debug ("hashing signed attrs failed: %s\n",
702 rc = gpgsm_create_cms_signature (ctrl, cl->cert,
703 md, cl->hash_algo, &sigval);
706 audit_log_cert (ctrl->audit, AUDIT_SIGNED_BY, cl->cert, rc);
711 err = ksba_cms_set_sig_val (cms, signer, sigval);
715 audit_log_cert (ctrl->audit, AUDIT_SIGNED_BY, cl->cert, err);
716 log_error ("failed to store the signature: %s\n",
723 /* write a status message */
724 fpr = gpgsm_get_fingerprint_hexstring (cl->cert, GCRY_MD_SHA1);
727 rc = gpg_error (GPG_ERR_ENOMEM);
733 int pkalgo = gpgsm_get_key_algo_info (cl->cert, NULL);
734 buf = xtryasprintf ("%c %d %d 00 %s %s",
741 rc = gpg_error_from_syserror ();
749 gpgsm_status (ctrl, STATUS_SIG_CREATED, buf);
751 audit_log_cert (ctrl->audit, AUDIT_SIGNED_BY, cl->cert, 0);
756 while (stopreason != KSBA_SR_READY);
758 rc = gpgsm_finish_writer (b64writer);
761 log_error ("write failed: %s\n", gpg_strerror (rc));
765 audit_log (ctrl->audit, AUDIT_SIGNING_DONE);
766 log_info ("signature created\n");
771 log_error ("error creating signature: %s <%s>\n",
772 gpg_strerror (rc), gpg_strsource (rc) );
773 if (release_signerlist)
774 gpgsm_release_certlist (signerlist);
775 ksba_cms_release (cms);
776 gpgsm_destroy_writer (b64writer);
778 gcry_md_close (data_md);