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gnupg/sm/certlist.c

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/* certlist.c - build list of certificates
* Copyright (C) 2001, 2003 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* GnuPG is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <time.h>
#include <assert.h>
#include "gpgsm.h"
#include <gcrypt.h>
#include <ksba.h>
#include "keydb.h"
#include "i18n.h"
/* Return 0 if the cert is usable for encryption. A MODE of 0 checks
for signing a MODE of 1 checks for encryption, a MODE of 2 checks
for verification and a MODE of 3 for decryption (just for
debugging) */
static int
cert_usage_p (ksba_cert_t cert, int mode)
{
gpg_error_t err;
unsigned int use;
err = ksba_cert_get_key_usage (cert, &use);
if (gpg_err_code (err) == GPG_ERR_NO_DATA)
{
if (opt.verbose && mode < 2)
log_info (mode?
_("no key usage specified - accepted for encryption\n"):
_("no key usage specified - accepted for signing\n"));
return 0;
}
if (err)
{
log_error (_("error getting key usage information: %s\n"),
gpg_strerror (err));
return err;
}
if (mode == 4)
{
if ((use & (KSBA_KEYUSAGE_KEY_CERT_SIGN)))
return 0;
log_info ( _("certificate should have not been used certification\n"));
return gpg_error (GPG_ERR_WRONG_KEY_USAGE);
}
if ((use & ((mode&1)?
(KSBA_KEYUSAGE_KEY_ENCIPHERMENT|KSBA_KEYUSAGE_DATA_ENCIPHERMENT):
(KSBA_KEYUSAGE_DIGITAL_SIGNATURE|KSBA_KEYUSAGE_NON_REPUDIATION)))
)
return 0;
log_info (mode==3? _("certificate should have not been used for encryption\n"):
mode==2? _("certificate should have not been used for signing\n"):
mode==1? _("certificate is not usable for encryption\n"):
_("certificate is not usable for signing\n"));
return gpg_error (GPG_ERR_WRONG_KEY_USAGE);
}
/* Return 0 if the cert is usable for signing */
int
gpgsm_cert_use_sign_p (ksba_cert_t cert)
{
return cert_usage_p (cert, 0);
}
/* Return 0 if the cert is usable for encryption */
int
gpgsm_cert_use_encrypt_p (ksba_cert_t cert)
{
return cert_usage_p (cert, 1);
}
int
gpgsm_cert_use_verify_p (ksba_cert_t cert)
{
return cert_usage_p (cert, 2);
}
int
gpgsm_cert_use_decrypt_p (ksba_cert_t cert)
{
return cert_usage_p (cert, 3);
}
int
gpgsm_cert_use_cert_p (ksba_cert_t cert)
{
return cert_usage_p (cert, 4);
}
static int
same_subject_issuer (const char *subject, const char *issuer, ksba_cert_t cert)
{
char *subject2 = ksba_cert_get_subject (cert, 0);
char *issuer2 = ksba_cert_get_subject (cert, 0);
int tmp;
tmp = (subject && subject2
&& !strcmp (subject, subject2)
&& issuer && issuer2
&& !strcmp (issuer, issuer2));
xfree (subject2);
xfree (issuer2);
return tmp;
}
/* Return true if CERT is already contained in CERTLIST. */
static int
is_cert_in_certlist (ksba_cert_t cert, certlist_t certlist)
{
const unsigned char *img_a, *img_b;
size_t len_a, len_b;
img_a = ksba_cert_get_image (cert, &len_a);
if (img_a)
{
for ( ; certlist; certlist = certlist->next)
{
img_b = ksba_cert_get_image (certlist->cert, &len_b);
if (img_b && len_a == len_b && !memcmp (img_a, img_b, len_a))
return 1; /* Already contained. */
}
}
return 0;
}
/* Add CERT to the list of certificates at CERTADDR but avoid
duplicates. */
int
gpgsm_add_cert_to_certlist (ctrl_t ctrl, ksba_cert_t cert,
certlist_t *listaddr, int is_encrypt_to)
{
if (!is_cert_in_certlist (cert, *listaddr))
{
certlist_t cl = xtrycalloc (1, sizeof *cl);
if (!cl)
return OUT_OF_CORE (errno);
cl->cert = cert;
ksba_cert_ref (cert);
cl->next = *listaddr;
cl->is_encrypt_to = is_encrypt_to;
*listaddr = cl;
}
return 0;
}
/* Add a certificate to a list of certificate and make sure that it is
a valid certificate. With SECRET set to true a secret key must be
available for the certificate. IS_ENCRYPT_TO sets the corresponding
flag in the new create LISTADDR item. */
int
gpgsm_add_to_certlist (CTRL ctrl, const char *name, int secret,
CERTLIST *listaddr, int is_encrypt_to)
{
int rc;
KEYDB_SEARCH_DESC desc;
KEYDB_HANDLE kh = NULL;
ksba_cert_t cert = NULL;
rc = keydb_classify_name (name, &desc);
if (!rc)
{
kh = keydb_new (0);
if (!kh)
rc = gpg_error (GPG_ERR_ENOMEM);
else
{
int wrong_usage = 0;
char *subject = NULL;
char *issuer = NULL;
get_next:
rc = keydb_search (kh, &desc, 1);
if (!rc)
rc = keydb_get_cert (kh, &cert);
if (!rc)
{
rc = secret? gpgsm_cert_use_sign_p (cert)
: gpgsm_cert_use_encrypt_p (cert);
if (gpg_err_code (rc) == GPG_ERR_WRONG_KEY_USAGE)
{
/* There might be another certificate with the
correct usage, so we try again */
if (!wrong_usage)
{ /* save the first match */
wrong_usage = rc;
subject = ksba_cert_get_subject (cert, 0);
issuer = ksba_cert_get_subject (cert, 0);
ksba_cert_release (cert);
cert = NULL;
goto get_next;
}
else if (same_subject_issuer (subject, issuer, cert))
{
wrong_usage = rc;
ksba_cert_release (cert);
cert = NULL;
goto get_next;
}
else
wrong_usage = rc;
}
}
/* We want the error code from the first match in this case. */
if (rc && wrong_usage)
rc = wrong_usage;
if (!rc)
{
next_ambigious:
rc = keydb_search (kh, &desc, 1);
if (rc == -1)
rc = 0;
else if (!rc)
{
ksba_cert_t cert2 = NULL;
/* We have to ignore ambigious names as long as
there only fault is a bad key usage */
if (!keydb_get_cert (kh, &cert2))
{
int tmp = (same_subject_issuer (subject, issuer, cert2)
&& ((gpg_err_code (
secret? gpgsm_cert_use_sign_p (cert2)
: gpgsm_cert_use_encrypt_p (cert2)
)
) == GPG_ERR_WRONG_KEY_USAGE));
ksba_cert_release (cert2);
if (tmp)
goto next_ambigious;
}
rc = gpg_error (GPG_ERR_AMBIGUOUS_NAME);
}
}
xfree (subject);
xfree (issuer);
if (!rc && !is_cert_in_certlist (cert, *listaddr))
{
if (!rc && secret)
{
char *p;
rc = gpg_error (GPG_ERR_NO_SECKEY);
p = gpgsm_get_keygrip_hexstring (cert);
if (p)
{
if (!gpgsm_agent_havekey (p))
rc = 0;
xfree (p);
}
}
if (!rc)
rc = gpgsm_validate_chain (ctrl, cert, NULL);
if (!rc)
{
CERTLIST cl = xtrycalloc (1, sizeof *cl);
if (!cl)
rc = OUT_OF_CORE (errno);
else
{
cl->cert = cert; cert = NULL;
cl->next = *listaddr;
cl->is_encrypt_to = is_encrypt_to;
*listaddr = cl;
}
}
}
}
}
keydb_release (kh);
ksba_cert_release (cert);
return rc == -1? gpg_error (GPG_ERR_NO_PUBKEY): rc;
}
void
gpgsm_release_certlist (CERTLIST list)
{
while (list)
{
CERTLIST cl = list->next;
ksba_cert_release (list->cert);
xfree (list);
list = cl;
}
}
/* Like gpgsm_add_to_certlist, but look only for one certificate. No
chain validation is done */
int
gpgsm_find_cert (const char *name, ksba_cert_t *r_cert)
{
int rc;
KEYDB_SEARCH_DESC desc;
KEYDB_HANDLE kh = NULL;
*r_cert = NULL;
rc = keydb_classify_name (name, &desc);
if (!rc)
{
kh = keydb_new (0);
if (!kh)
rc = gpg_error (GPG_ERR_ENOMEM);
else
{
rc = keydb_search (kh, &desc, 1);
if (!rc)
rc = keydb_get_cert (kh, r_cert);
if (!rc)
{
rc = keydb_search (kh, &desc, 1);
if (rc == -1)
rc = 0;
else
{
if (!rc)
rc = gpg_error (GPG_ERR_AMBIGUOUS_NAME);
ksba_cert_release (*r_cert);
*r_cert = NULL;
}
}
}
}
keydb_release (kh);
return rc == -1? gpg_error (GPG_ERR_NO_PUBKEY): rc;
}