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gnupg
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gnupg/sm/certpath.c

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/* certpath.c - path validation
* Copyright (C) 2001 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 <gcrypt.h>
#include <ksba.h>
#include "gpgsm.h"
#include "keydb.h"
#include "i18n.h"
static int
unknown_criticals (KsbaCert cert)
{
static const char *known[] = {
"2.5.29.19", /* basic Constraints */
NULL
};
int rc = 0, i, idx, crit;
const char *oid;
KsbaError err;
for (idx=0; !(err=ksba_cert_get_extension (cert, idx,
&oid, &crit, NULL, NULL));idx++)
{
if (!crit)
continue;
for (i=0; known[i] && strcmp (known[i],oid); i++)
;
if (!known[i])
{
log_error (_("critical certificate extension %s is not supported\n"),
oid);
rc = GNUPG_Unsupported_Certificate;
}
}
if (err && err != -1)
rc = map_ksba_err (err);
return rc;
}
static int
allowed_ca (KsbaCert cert, int *pathlen)
{
KsbaError err;
int flag;
err = ksba_cert_is_ca (cert, &flag, pathlen);
if (err)
return map_ksba_err (err);
if (!flag)
{
log_error (_("issuer certificate is not marked as a CA\n"));
return GNUPG_Bad_CA_Certificate;
}
return 0;
}
int
gpgsm_validate_path (KsbaCert cert)
{
int rc = 0, depth = 0, maxdepth;
char *issuer = NULL;
char *subject = NULL;
KEYDB_HANDLE kh = keydb_new (0);
KsbaCert subject_cert = NULL, issuer_cert = NULL;
time_t current_time = time (NULL);
if (!kh)
{
log_error (_("failed to allocated keyDB handle\n"));
rc = GNUPG_General_Error;
goto leave;
}
if (DBG_X509)
gpgsm_dump_cert ("subject", cert);
subject_cert = cert;
maxdepth = 50;
for (;;)
{
xfree (issuer);
xfree (subject);
issuer = ksba_cert_get_issuer (subject_cert, 0);
subject = ksba_cert_get_subject (subject_cert, 0);
if (!issuer)
{
log_error ("no issuer found in certificate\n");
rc = GNUPG_Bad_Certificate;
goto leave;
}
{
time_t not_before, not_after;
not_before = ksba_cert_get_validity (subject_cert, 0);
not_after = ksba_cert_get_validity (subject_cert, 1);
if (not_before == (time_t)(-1) || not_after == (time_t)(-1))
{
log_error ("certificate with invalid validity\n");
rc = GNUPG_Bad_Certificate;
goto leave;
}
if (current_time < not_before)
{
log_error ("certificate to young; valid from ");
gpgsm_dump_time (not_before);
log_printf ("\n");
rc = GNUPG_Certificate_Too_Young;
goto leave;
}
if (current_time > not_after)
{
log_error ("certificate has expired at ");
gpgsm_dump_time (not_after);
log_printf ("\n");
rc = GNUPG_Certificate_Expired;
goto leave;
}
}
rc = unknown_criticals (subject_cert);
if (rc)
goto leave;
if (!opt.no_crl_check)
{
rc = gpgsm_dirmngr_isvalid (subject_cert);
if (rc)
{
switch (rc)
{
case GNUPG_Certificate_Revoked:
log_error (_("the certificate has been revoked\n"));
break;
case GNUPG_No_CRL_Known:
log_error (_("no CRL found for certificate\n"));
break;
case GNUPG_CRL_Too_Old:
log_error (_("the available CRL is too old\n"));
log_info (_("please make sure that the "
"\"dirmngr\" is properly installed\n"));
break;
default:
log_error (_("checking the CRL failed: %s\n"),
gnupg_strerror (rc));
break;
}
goto leave;
}
}
if (subject && !strcmp (issuer, subject))
{
if (gpgsm_check_cert_sig (subject_cert, subject_cert) )
{
log_error ("selfsigned certificate has a BAD signatures\n");
rc = depth? GNUPG_Bad_Certificate_Path : GNUPG_Bad_Certificate;
goto leave;
}
rc = allowed_ca (subject_cert, NULL);
if (rc)
goto leave;
rc = gpgsm_agent_istrusted (subject_cert);
if (!rc)
;
else if (rc == GNUPG_Not_Trusted)
{
char *fpr = gpgsm_get_fingerprint_string (subject_cert,
GCRY_MD_SHA1);
log_error (_("root certificate is not marked trusted\n"));
log_info (_("fingerprint=%s\n"), fpr? fpr : "?");
xfree (fpr);
/* fixme: print a note while we have not yet the code to
ask whether the cert should be entered into the trust
list */
gpgsm_dump_cert ("issuer", subject_cert);
log_info ("after checking the fingerprint, you may want "
"to enter it into \"~/.gnupg-test/trustlist.txt\"\n");
}
else
{
log_error (_("checking the trust list failed: %s\n"),
gnupg_strerror (rc));
}
break; /* okay, a self-signed certicate is an end-point */
}
depth++;
if (depth > maxdepth)
{
log_error (_("certificate path too long\n"));
rc = GNUPG_Bad_Certificate_Path;
goto leave;
}
/* find the next cert up the tree */
keydb_search_reset (kh);
rc = keydb_search_subject (kh, issuer);
if (rc)
{
log_error ("failed to find issuer's certificate: rc=%d\n", rc);
rc = GNUPG_Missing_Certificate;
goto leave;
}
ksba_cert_release (issuer_cert); issuer_cert = NULL;
rc = keydb_get_cert (kh, &issuer_cert);
if (rc)
{
log_error ("failed to get cert: rc=%d\n", rc);
rc = GNUPG_General_Error;
goto leave;
}
if (DBG_X509)
{
log_debug ("got issuer's certificate:\n");
gpgsm_dump_cert ("issuer", issuer_cert);
}
if (gpgsm_check_cert_sig (issuer_cert, subject_cert) )
{
log_error ("certificate has a BAD signatures\n");
rc = GNUPG_Bad_Certificate_Path;
goto leave;
}
{
int pathlen;
rc = allowed_ca (issuer_cert, &pathlen);
if (rc)
goto leave;
if (pathlen >= 0 && (depth - 1) > pathlen)
{
log_error (_("certificate path longer than allowed by CA (%d)\n"),
pathlen);
rc = GNUPG_Bad_Certificate_Path;
goto leave;
}
}
log_info ("certificate is good\n");
keydb_search_reset (kh);
subject_cert = issuer_cert;
issuer_cert = NULL;
}
if (opt.no_crl_check)
log_info ("CRL was not checked due to --no-crl-cechk option\n");
leave:
xfree (issuer);
keydb_release (kh);
ksba_cert_release (issuer_cert);
if (subject_cert != cert)
ksba_cert_release (subject_cert);
return rc;
}
/* Check that the given certificate is valid but DO NOT check any
constraints. We assume that the issuers certificate is already in
the DB and that this one is valid; which it should be because it
has been checked using this function. */
int
gpgsm_basic_cert_check (KsbaCert cert)
{
int rc = 0;
char *issuer = NULL;
char *subject = NULL;
KEYDB_HANDLE kh = keydb_new (0);
KsbaCert issuer_cert = NULL;
if (!kh)
{
log_error (_("failed to allocated keyDB handle\n"));
rc = GNUPG_General_Error;
goto leave;
}
issuer = ksba_cert_get_issuer (cert, 0);
subject = ksba_cert_get_subject (cert, 0);
if (!issuer)
{
if (DBG_X509)
log_debug ("ERROR: issuer missing\n");
rc = GNUPG_Bad_Certificate;
goto leave;
}
if (subject && !strcmp (issuer, subject))
{
if (gpgsm_check_cert_sig (cert, cert) )
{
log_error ("selfsigned certificate has a BAD signatures\n");
rc = GNUPG_Bad_Certificate;
goto leave;
}
}
else
{
/* find the next cert up the tree */
keydb_search_reset (kh);
rc = keydb_search_subject (kh, issuer);
if (rc)
{
log_error ("failed to find issuer's certificate: rc=%d\n", rc);
rc = GNUPG_Missing_Certificate;
goto leave;
}
ksba_cert_release (issuer_cert); issuer_cert = NULL;
rc = keydb_get_cert (kh, &issuer_cert);
if (rc)
{
log_error ("failed to get cert: rc=%d\n", rc);
rc = GNUPG_General_Error;
goto leave;
}
if (gpgsm_check_cert_sig (issuer_cert, cert) )
{
log_error ("certificate has a BAD signatures\n");
rc = GNUPG_Bad_Certificate;
goto leave;
}
if (opt.verbose)
log_info ("certificate is good\n");
}
leave:
xfree (issuer);
keydb_release (kh);
ksba_cert_release (issuer_cert);
return rc;
}
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