mirror of
git://git.gnupg.org/gnupg.git
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cbd57643a7
* certdump.c (gpgsm_print_serial): Cleaned up cast use in strtoul. (gpgsm_dump_serial): Ditto. * decrypt.c (gpgsm_decrypt): Replaced ERR by RC.
633 lines
16 KiB
C
633 lines
16 KiB
C
/* sign.c - Sign a message
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* Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <time.h>
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#include <assert.h>
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#include "gpgsm.h"
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#include <gcrypt.h>
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#include <ksba.h>
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#include "keydb.h"
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#include "i18n.h"
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static void
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hash_data (int fd, gcry_md_hd_t md)
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{
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FILE *fp;
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char buffer[4096];
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int nread;
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fp = fdopen ( dup (fd), "rb");
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if (!fp)
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{
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log_error ("fdopen(%d) failed: %s\n", fd, strerror (errno));
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return;
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}
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do
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{
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nread = fread (buffer, 1, DIM(buffer), fp);
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gcry_md_write (md, buffer, nread);
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}
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while (nread);
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if (ferror (fp))
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log_error ("read error on fd %d: %s\n", fd, strerror (errno));
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fclose (fp);
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}
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static int
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hash_and_copy_data (int fd, gcry_md_hd_t md, ksba_writer_t writer)
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{
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gpg_error_t err;
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FILE *fp;
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char buffer[4096];
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int nread;
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int rc = 0;
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int any = 0;
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fp = fdopen ( dup (fd), "rb");
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if (!fp)
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{
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gpg_error_t tmperr = gpg_error (gpg_err_code_from_errno (errno));
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log_error ("fdopen(%d) failed: %s\n", fd, strerror (errno));
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return tmperr;
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}
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do
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{
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nread = fread (buffer, 1, DIM(buffer), fp);
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if (nread)
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{
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any = 1;
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gcry_md_write (md, buffer, nread);
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err = ksba_writer_write_octet_string (writer, buffer, nread, 0);
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if (err)
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{
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log_error ("write failed: %s\n", gpg_strerror (err));
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rc = err;
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}
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}
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}
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while (nread && !rc);
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if (ferror (fp))
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{
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rc = gpg_error (gpg_err_code_from_errno (errno));
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log_error ("read error on fd %d: %s\n", fd, strerror (errno));
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}
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fclose (fp);
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if (!any)
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{
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/* We can't allow to sign an empty message because it does not
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make much sense and more seriously, ksba-cms_build has
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already written the tag for data and now expects an octet
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string but an octet string of zeize 0 is illegal. */
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log_error ("cannot sign an empty message\n");
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rc = gpg_error (GPG_ERR_NO_DATA);
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}
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if (!rc)
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{
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err = ksba_writer_write_octet_string (writer, NULL, 0, 1);
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if (err)
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{
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log_error ("write failed: %s\n", gpg_strerror (err));
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rc = err;
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}
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}
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return rc;
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}
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/* Get the default certificate which is defined as the first one our
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keyDB returns and has a secret key available. */
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int
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gpgsm_get_default_cert (ksba_cert_t *r_cert)
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{
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KEYDB_HANDLE hd;
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ksba_cert_t cert = NULL;
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int rc;
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char *p;
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hd = keydb_new (0);
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if (!hd)
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return gpg_error (GPG_ERR_GENERAL);
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rc = keydb_search_first (hd);
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if (rc)
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{
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keydb_release (hd);
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return rc;
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}
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do
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{
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rc = keydb_get_cert (hd, &cert);
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if (rc)
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{
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log_error ("keydb_get_cert failed: %s\n", gpg_strerror (rc));
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keydb_release (hd);
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return rc;
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}
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p = gpgsm_get_keygrip_hexstring (cert);
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if (p)
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{
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if (!gpgsm_agent_havekey (p))
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{
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xfree (p);
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keydb_release (hd);
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*r_cert = cert;
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return 0; /* got it */
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}
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xfree (p);
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}
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ksba_cert_release (cert);
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cert = NULL;
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}
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while (!(rc = keydb_search_next (hd)));
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if (rc && rc != -1)
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log_error ("keydb_search_next failed: %s\n", gpg_strerror (rc));
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ksba_cert_release (cert);
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keydb_release (hd);
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return rc;
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}
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static ksba_cert_t
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get_default_signer (void)
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{
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KEYDB_SEARCH_DESC desc;
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ksba_cert_t cert = NULL;
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KEYDB_HANDLE kh = NULL;
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int rc;
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if (!opt.local_user)
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{
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rc = gpgsm_get_default_cert (&cert);
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if (rc)
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{
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if (rc != -1)
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log_debug ("failed to find default certificate: %s\n",
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gpg_strerror (rc));
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return NULL;
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}
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return cert;
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}
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rc = keydb_classify_name (opt.local_user, &desc);
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if (rc)
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{
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log_error ("failed to find default signer: %s\n", gpg_strerror (rc));
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return NULL;
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}
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kh = keydb_new (0);
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if (!kh)
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return NULL;
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rc = keydb_search (kh, &desc, 1);
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if (rc)
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{
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log_debug ("failed to find default certificate: rc=%d\n", rc);
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}
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else
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{
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rc = keydb_get_cert (kh, &cert);
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if (rc)
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{
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log_debug ("failed to get cert: rc=%d\n", rc);
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}
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}
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keydb_release (kh);
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return cert;
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}
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/* Depending on the options in CTRL add the certificate CERT as well as
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other certificate up in the chain to the Root-CA to the CMS
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object. */
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static int
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add_certificate_list (CTRL ctrl, ksba_cms_t cms, ksba_cert_t cert)
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{
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gpg_error_t err;
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int rc = 0;
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ksba_cert_t next = NULL;
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int n;
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int not_root = 0;
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ksba_cert_ref (cert);
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n = ctrl->include_certs;
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if (n == -2)
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{
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not_root = 1;
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n = -1;
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}
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if (n < 0 || n > 50)
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n = 50; /* We better apply an upper bound */
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if (n)
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{
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if (not_root && gpgsm_is_root_cert (cert))
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err = 0;
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else
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err = ksba_cms_add_cert (cms, cert);
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if (err)
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goto ksba_failure;
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}
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while ( n-- && !(rc = gpgsm_walk_cert_chain (cert, &next)) )
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{
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if (not_root && gpgsm_is_root_cert (next))
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err = 0;
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else
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err = ksba_cms_add_cert (cms, next);
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ksba_cert_release (cert);
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cert = next; next = NULL;
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if (err)
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goto ksba_failure;
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}
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ksba_cert_release (cert);
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return rc == -1? 0: rc;
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ksba_failure:
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ksba_cert_release (cert);
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log_error ("ksba_cms_add_cert failed: %s\n", gpg_strerror (err));
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return err;
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}
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/* Perform a sign operation.
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Sign the data received on DATA-FD in embedded mode or in detached
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mode when DETACHED is true. Write the signature to OUT_FP. The
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keys used to sign are taken from SIGNERLIST or the default one will
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be used if the value of this argument is NULL. */
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int
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gpgsm_sign (CTRL ctrl, CERTLIST signerlist,
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int data_fd, int detached, FILE *out_fp)
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{
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int i, rc;
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gpg_error_t err;
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Base64Context b64writer = NULL;
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ksba_writer_t writer;
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ksba_cms_t cms = NULL;
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ksba_stop_reason_t stopreason;
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KEYDB_HANDLE kh = NULL;
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gcry_md_hd_t data_md = NULL;
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int signer;
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const char *algoid;
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int algo;
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ksba_isotime_t signed_at;
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CERTLIST cl;
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int release_signerlist = 0;
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kh = keydb_new (0);
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if (!kh)
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{
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log_error (_("failed to allocated keyDB handle\n"));
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rc = gpg_error (GPG_ERR_GENERAL);
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goto leave;
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}
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ctrl->pem_name = "SIGNED MESSAGE";
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rc = gpgsm_create_writer (&b64writer, ctrl, out_fp, &writer);
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if (rc)
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{
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log_error ("can't create writer: %s\n", gpg_strerror (rc));
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goto leave;
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}
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err = ksba_cms_new (&cms);
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if (err)
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{
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rc = err;
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goto leave;
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}
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err = ksba_cms_set_reader_writer (cms, NULL, writer);
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if (err)
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{
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log_debug ("ksba_cms_set_reader_writer failed: %s\n",
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gpg_strerror (err));
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rc = err;
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goto leave;
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}
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/* We are going to create signed data with data as encap. content */
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err = ksba_cms_set_content_type (cms, 0, KSBA_CT_SIGNED_DATA);
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if (!err)
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err = ksba_cms_set_content_type (cms, 1, KSBA_CT_DATA);
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if (err)
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{
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log_debug ("ksba_cms_set_content_type failed: %s\n",
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gpg_strerror (err));
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rc = err;
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goto leave;
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}
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/* If no list of signers is given, use a default one. */
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if (!signerlist)
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{
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ksba_cert_t cert = get_default_signer ();
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if (!cert)
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{
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log_error ("no default signer found\n");
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rc = gpg_error (GPG_ERR_GENERAL);
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goto leave;
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}
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/* Although we don't check for ambigious specification we will
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check that the signer's certificate is is usable and
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valid. */
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rc = gpgsm_cert_use_sign_p (cert);
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if (!rc)
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rc = gpgsm_validate_chain (ctrl, cert, NULL);
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if (rc)
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goto leave;
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/* That one is fine - create signerlist. */
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signerlist = xtrycalloc (1, sizeof *signerlist);
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if (!signerlist)
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{
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rc = OUT_OF_CORE (errno);
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ksba_cert_release (cert);
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goto leave;
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}
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signerlist->cert = cert;
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release_signerlist = 1;
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}
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/* Gather certificates of signers and store them in the CMS object. */
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for (cl=signerlist; cl; cl = cl->next)
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{
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rc = gpgsm_cert_use_sign_p (cl->cert);
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if (rc)
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goto leave;
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err = ksba_cms_add_signer (cms, cl->cert);
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if (err)
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{
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log_error ("ksba_cms_add_signer failed: %s\n", gpg_strerror (err));
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rc = err;
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goto leave;
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}
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rc = add_certificate_list (ctrl, cms, cl->cert);
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if (rc)
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{
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log_error ("failed to store list of certificates: %s\n",
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gpg_strerror(rc));
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goto leave;
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}
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/* Set the hash algorithm we are going to use */
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err = ksba_cms_add_digest_algo (cms, "1.3.14.3.2.26" /*SHA-1*/);
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if (err)
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{
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log_debug ("ksba_cms_add_digest_algo failed: %s\n",
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gpg_strerror (err));
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rc = err;
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goto leave;
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}
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}
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/* Prepare hashing (actually we are figuring out what we have set above)*/
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rc = gcry_md_open (&data_md, 0, 0);
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if (rc)
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{
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log_error ("md_open failed: %s\n", gpg_strerror (rc));
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goto leave;
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}
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if (DBG_HASHING)
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gcry_md_start_debug (data_md, "sign.data");
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for (i=0; (algoid=ksba_cms_get_digest_algo_list (cms, i)); i++)
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{
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algo = gcry_md_map_name (algoid);
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if (!algo)
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{
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log_error ("unknown hash algorithm `%s'\n", algoid? algoid:"?");
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rc = gpg_error (GPG_ERR_BUG);
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goto leave;
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}
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gcry_md_enable (data_md, algo);
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}
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if (detached)
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{ /* we hash the data right now so that we can store the message
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digest. ksba_cms_build() takes this as an flag that detached
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data is expected. */
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unsigned char *digest;
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size_t digest_len;
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/* Fixme do this for all signers and get the algo to use from
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the signer's certificate - does not make mich sense, bu we
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should do this consistent as we have already done it above */
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algo = GCRY_MD_SHA1;
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hash_data (data_fd, data_md);
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digest = gcry_md_read (data_md, algo);
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digest_len = gcry_md_get_algo_dlen (algo);
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if ( !digest || !digest_len)
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{
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log_error ("problem getting the hash of the data\n");
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rc = gpg_error (GPG_ERR_BUG);
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goto leave;
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}
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for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
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{
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err = ksba_cms_set_message_digest (cms, signer, digest, digest_len);
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if (err)
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{
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log_error ("ksba_cms_set_message_digest failed: %s\n",
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gpg_strerror (err));
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rc = err;
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goto leave;
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}
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}
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}
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gnupg_get_isotime (signed_at);
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for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
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{
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err = ksba_cms_set_signing_time (cms, signer, signed_at);
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if (err)
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{
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log_error ("ksba_cms_set_signing_time failed: %s\n",
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gpg_strerror (err));
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rc = err;
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goto leave;
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}
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}
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do
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{
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err = ksba_cms_build (cms, &stopreason);
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if (err)
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{
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log_debug ("ksba_cms_build failed: %s\n", gpg_strerror (err));
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rc = err;
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goto leave;
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}
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if (stopreason == KSBA_SR_BEGIN_DATA)
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{ /* hash the data and store the message digest */
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unsigned char *digest;
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size_t digest_len;
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assert (!detached);
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/* Fixme: get the algo to use from the signer's certificate
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- does not make much sense, but we should do this
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consistent as we have already done it above. Code is
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mostly duplicated above. */
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algo = GCRY_MD_SHA1;
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rc = hash_and_copy_data (data_fd, data_md, writer);
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if (rc)
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goto leave;
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digest = gcry_md_read (data_md, algo);
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digest_len = gcry_md_get_algo_dlen (algo);
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if ( !digest || !digest_len)
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{
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log_error ("problem getting the hash of the data\n");
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rc = gpg_error (GPG_ERR_BUG);
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goto leave;
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}
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for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
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{
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err = ksba_cms_set_message_digest (cms, signer,
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digest, digest_len);
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if (err)
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{
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log_error ("ksba_cms_set_message_digest failed: %s\n",
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gpg_strerror (err));
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rc = err;
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goto leave;
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}
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}
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}
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else if (stopreason == KSBA_SR_NEED_SIG)
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{ /* calculate the signature for all signers */
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gcry_md_hd_t md;
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|
||
algo = GCRY_MD_SHA1;
|
||
rc = gcry_md_open (&md, algo, 0);
|
||
if (rc)
|
||
{
|
||
log_error ("md_open failed: %s\n", gpg_strerror (rc));
|
||
goto leave;
|
||
}
|
||
if (DBG_HASHING)
|
||
gcry_md_start_debug (md, "sign.attr");
|
||
ksba_cms_set_hash_function (cms, HASH_FNC, md);
|
||
for (cl=signerlist,signer=0; cl; cl = cl->next, signer++)
|
||
{
|
||
char *sigval = NULL;
|
||
char *buf, *fpr;
|
||
|
||
if (signer)
|
||
gcry_md_reset (md);
|
||
rc = ksba_cms_hash_signed_attrs (cms, signer);
|
||
if (rc)
|
||
{
|
||
log_debug ("hashing signed attrs failed: %s\n",
|
||
gpg_strerror (rc));
|
||
gcry_md_close (md);
|
||
goto leave;
|
||
}
|
||
|
||
rc = gpgsm_create_cms_signature (cl->cert, md, algo, &sigval);
|
||
if (rc)
|
||
{
|
||
gcry_md_close (md);
|
||
goto leave;
|
||
}
|
||
|
||
err = ksba_cms_set_sig_val (cms, signer, sigval);
|
||
xfree (sigval);
|
||
if (err)
|
||
{
|
||
log_error ("failed to store the signature: %s\n",
|
||
gpg_strerror (err));
|
||
rc = err;
|
||
gcry_md_close (md);
|
||
goto leave;
|
||
}
|
||
|
||
/* write a status message */
|
||
fpr = gpgsm_get_fingerprint_hexstring (cl->cert, GCRY_MD_SHA1);
|
||
if (!fpr)
|
||
{
|
||
rc = gpg_error (GPG_ERR_ENOMEM);
|
||
gcry_md_close (md);
|
||
goto leave;
|
||
}
|
||
rc = asprintf (&buf, "%c %d %d 00 %s %s",
|
||
detached? 'D':'S',
|
||
GCRY_PK_RSA, /* FIXME: get pk algo from cert */
|
||
algo,
|
||
signed_at,
|
||
fpr);
|
||
xfree (fpr);
|
||
if (rc < 0)
|
||
{
|
||
rc = gpg_error (GPG_ERR_ENOMEM);
|
||
gcry_md_close (md);
|
||
goto leave;
|
||
}
|
||
rc = 0;
|
||
gpgsm_status (ctrl, STATUS_SIG_CREATED, buf);
|
||
free (buf); /* yes, we must use the regular free() here */
|
||
}
|
||
gcry_md_close (md);
|
||
|
||
}
|
||
}
|
||
while (stopreason != KSBA_SR_READY);
|
||
|
||
rc = gpgsm_finish_writer (b64writer);
|
||
if (rc)
|
||
{
|
||
log_error ("write failed: %s\n", gpg_strerror (rc));
|
||
goto leave;
|
||
}
|
||
|
||
log_info ("signature created\n");
|
||
|
||
|
||
leave:
|
||
if (release_signerlist)
|
||
gpgsm_release_certlist (signerlist);
|
||
ksba_cms_release (cms);
|
||
gpgsm_destroy_writer (b64writer);
|
||
keydb_release (kh);
|
||
gcry_md_close (data_md);
|
||
return rc;
|
||
}
|