diff options
Diffstat (limited to 'sm/certchain.c')
| -rw-r--r-- | sm/certchain.c | 2380 |
1 files changed, 2380 insertions, 0 deletions
diff --git a/sm/certchain.c b/sm/certchain.c new file mode 100644 index 0000000..d2a1800 --- /dev/null +++ b/sm/certchain.c @@ -0,0 +1,2380 @@ +/* certchain.c - certificate chain validation + * Copyright (C) 2001, 2002, 2003, 2004, 2005, + * 2006, 2007, 2008, 2011 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 3 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, see <https://www.gnu.org/licenses/>. + */ + +#include <config.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <unistd.h> +#include <time.h> +#include <stdarg.h> +#include <assert.h> + +#include "gpgsm.h" +#include <gcrypt.h> +#include <ksba.h> + +#include "keydb.h" +#include "../kbx/keybox.h" /* for KEYBOX_FLAG_* */ +#include "../common/i18n.h" +#include "../common/tlv.h" + + +/* The OID for the authorityInfoAccess's caIssuers. */ +static const char oidstr_caIssuers[] = "1.3.6.1.5.5.7.48.2"; + + +/* Object to keep track of certain root certificates. */ +struct marktrusted_info_s +{ + struct marktrusted_info_s *next; + unsigned char fpr[20]; +}; +static struct marktrusted_info_s *marktrusted_info; + + +/* While running the validation function we want to keep track of the + certificates in the chain. This type is used for that. */ +struct chain_item_s +{ + struct chain_item_s *next; + ksba_cert_t cert; /* The certificate. */ + int is_root; /* The certificate is the root certificate. */ +}; +typedef struct chain_item_s *chain_item_t; + + +static int is_root_cert (ksba_cert_t cert, + const char *issuerdn, const char *subjectdn); +static int get_regtp_ca_info (ctrl_t ctrl, ksba_cert_t cert, int *chainlen); + + +/* This function returns true if we already asked during this session + whether the root certificate CERT shall be marked as trusted. */ +static int +already_asked_marktrusted (ksba_cert_t cert) +{ + unsigned char fpr[20]; + struct marktrusted_info_s *r; + + gpgsm_get_fingerprint (cert, GCRY_MD_SHA1, fpr, NULL); + /* No context switches in the loop! */ + for (r=marktrusted_info; r; r= r->next) + if (!memcmp (r->fpr, fpr, 20)) + return 1; + return 0; +} + +/* Flag certificate CERT as already asked whether it shall be marked + as trusted. */ +static void +set_already_asked_marktrusted (ksba_cert_t cert) +{ + unsigned char fpr[20]; + struct marktrusted_info_s *r; + + gpgsm_get_fingerprint (cert, GCRY_MD_SHA1, fpr, NULL); + for (r=marktrusted_info; r; r= r->next) + if (!memcmp (r->fpr, fpr, 20)) + return; /* Already marked. */ + r = xtrycalloc (1, sizeof *r); + if (!r) + return; + memcpy (r->fpr, fpr, 20); + r->next = marktrusted_info; + marktrusted_info = r; +} + +/* If LISTMODE is true, print FORMAT using LISTMODE to FP. If + LISTMODE is false, use the string to print an log_info or, if + IS_ERROR is true, and log_error. */ +static void +do_list (int is_error, int listmode, estream_t fp, const char *format, ...) +{ + va_list arg_ptr; + + va_start (arg_ptr, format) ; + if (listmode) + { + if (fp) + { + es_fputs (" [", fp); + es_vfprintf (fp, format, arg_ptr); + es_fputs ("]\n", fp); + } + } + else + { + log_logv (is_error? GPGRT_LOG_ERROR: GPGRT_LOG_INFO, format, arg_ptr); + log_printf ("\n"); + } + va_end (arg_ptr); +} + +/* Return 0 if A and B are equal. */ +static int +compare_certs (ksba_cert_t a, ksba_cert_t b) +{ + const unsigned char *img_a, *img_b; + size_t len_a, len_b; + + img_a = ksba_cert_get_image (a, &len_a); + if (!img_a) + return 1; + img_b = ksba_cert_get_image (b, &len_b); + if (!img_b) + return 1; + return !(len_a == len_b && !memcmp (img_a, img_b, len_a)); +} + + +/* Return true if CERT has the validityModel extensions and defines + the use of the chain model. */ +static int +has_validation_model_chain (ksba_cert_t cert, int listmode, estream_t listfp) +{ + gpg_error_t err; + int idx, yes; + const char *oid; + size_t off, derlen, objlen, hdrlen; + const unsigned char *der; + int class, tag, constructed, ndef; + char *oidbuf; + + for (idx=0; !(err=ksba_cert_get_extension (cert, idx, + &oid, NULL, &off, &derlen));idx++) + if (!strcmp (oid, "1.3.6.1.4.1.8301.3.5") ) + break; + if (err) + return 0; /* Not found. */ + der = ksba_cert_get_image (cert, NULL); + if (!der) + { + err = gpg_error (GPG_ERR_INV_OBJ); /* Oops */ + goto leave; + } + der += off; + + err = parse_ber_header (&der, &derlen, &class, &tag, &constructed, + &ndef, &objlen, &hdrlen); + if (!err && (objlen > derlen || tag != TAG_SEQUENCE)) + err = gpg_error (GPG_ERR_INV_OBJ); + if (err) + goto leave; + derlen = objlen; + err = parse_ber_header (&der, &derlen, &class, &tag, &constructed, + &ndef, &objlen, &hdrlen); + if (!err && (objlen > derlen || tag != TAG_OBJECT_ID)) + err = gpg_error (GPG_ERR_INV_OBJ); + if (err) + goto leave; + oidbuf = ksba_oid_to_str (der, objlen); + if (!oidbuf) + { + err = gpg_error_from_syserror (); + goto leave; + } + + if (opt.verbose) + do_list (0, listmode, listfp, + _("validation model requested by certificate: %s"), + !strcmp (oidbuf, "1.3.6.1.4.1.8301.3.5.1")? _("chain") : + !strcmp (oidbuf, "1.3.6.1.4.1.8301.3.5.2")? _("shell") : + /* */ oidbuf); + yes = !strcmp (oidbuf, "1.3.6.1.4.1.8301.3.5.1"); + ksba_free (oidbuf); + return yes; + + + leave: + log_error ("error parsing validityModel: %s\n", gpg_strerror (err)); + return 0; +} + + + +static int +unknown_criticals (ksba_cert_t cert, int listmode, estream_t fp) +{ + static const char *known[] = { + "2.5.29.15", /* keyUsage */ + "2.5.29.17", /* subjectAltName + Japanese DoCoMo certs mark them as critical. PKIX + only requires them as critical if subjectName is + empty. I don't know whether our code gracefully + handles such empry subjectNames but that is + another story. */ + "2.5.29.19", /* basic Constraints */ + "2.5.29.32", /* certificatePolicies */ + "2.5.29.37", /* extendedKeyUsage - handled by certlist.c */ + "1.3.6.1.4.1.8301.3.5", /* validityModel - handled here. */ + NULL + }; + int rc = 0, i, idx, crit; + const char *oid; + gpg_error_t err; + int unsupported; + strlist_t sl; + + 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++) + ; + unsupported = !known[i]; + + /* If this critical extension is not supported. Check the list + of to be ignored extensions to see whether we claim that it + is supported. */ + if (unsupported && opt.ignored_cert_extensions) + { + for (sl=opt.ignored_cert_extensions; + sl && strcmp (sl->d, oid); sl = sl->next) + ; + if (sl) + unsupported = 0; + } + if (unsupported) + { + do_list (1, listmode, fp, + _("critical certificate extension %s is not supported"), + oid); + rc = gpg_error (GPG_ERR_UNSUPPORTED_CERT); + } + } + /* We ignore the error codes EOF as well as no-value. The later will + occur for certificates with no extensions at all. */ + if (err + && gpg_err_code (err) != GPG_ERR_EOF + && gpg_err_code (err) != GPG_ERR_NO_VALUE) + rc = err; + + return rc; +} + + +/* Check whether CERT is an allowed certificate. This requires that + CERT matches all requirements for such a CA, i.e. the + BasicConstraints extension. The function returns 0 on success and + the allowed length of the chain at CHAINLEN. */ +static int +allowed_ca (ctrl_t ctrl, + ksba_cert_t cert, int *chainlen, int listmode, estream_t fp) +{ + gpg_error_t err; + int flag; + + err = ksba_cert_is_ca (cert, &flag, chainlen); + if (err) + return err; + if (!flag) + { + if (get_regtp_ca_info (ctrl, cert, chainlen)) + { + /* Note that dirmngr takes a different way to cope with such + certs. */ + return 0; /* RegTP issued certificate. */ + } + + do_list (1, listmode, fp,_("issuer certificate is not marked as a CA")); + return gpg_error (GPG_ERR_BAD_CA_CERT); + } + return 0; +} + + +static int +check_cert_policy (ksba_cert_t cert, int listmode, estream_t fplist) +{ + gpg_error_t err; + char *policies; + estream_t fp; + int any_critical; + + err = ksba_cert_get_cert_policies (cert, &policies); + if (gpg_err_code (err) == GPG_ERR_NO_DATA) + return 0; /* No policy given. */ + if (err) + return err; + + /* STRING is a line delimited list of certificate policies as stored + in the certificate. The line itself is colon delimited where the + first field is the OID of the policy and the second field either + N or C for normal or critical extension */ + + if (opt.verbose > 1 && !listmode) + log_info ("certificate's policy list: %s\n", policies); + + /* The check is very minimal but won't give false positives */ + any_critical = !!strstr (policies, ":C"); + + if (!opt.policy_file) + { + xfree (policies); + if (any_critical) + { + do_list (1, listmode, fplist, + _("critical marked policy without configured policies")); + return gpg_error (GPG_ERR_NO_POLICY_MATCH); + } + return 0; + } + + fp = es_fopen (opt.policy_file, "r"); + if (!fp) + { + if (opt.verbose || errno != ENOENT) + log_info (_("failed to open '%s': %s\n"), + opt.policy_file, strerror (errno)); + xfree (policies); + /* With no critical policies this is only a warning */ + if (!any_critical) + { + if (!opt.quiet) + do_list (0, listmode, fplist, + _("Note: non-critical certificate policy not allowed")); + return 0; + } + do_list (1, listmode, fplist, + _("certificate policy not allowed")); + return gpg_error (GPG_ERR_NO_POLICY_MATCH); + } + + for (;;) + { + int c; + char *p, line[256]; + char *haystack, *allowed; + + /* read line */ + do + { + if (!es_fgets (line, DIM(line)-1, fp) ) + { + gpg_error_t tmperr = gpg_error_from_syserror (); + + xfree (policies); + if (es_feof (fp)) + { + es_fclose (fp); + /* With no critical policies this is only a warning */ + if (!any_critical) + { + do_list (0, listmode, fplist, + _("Note: non-critical certificate policy not allowed")); + return 0; + } + do_list (1, listmode, fplist, + _("certificate policy not allowed")); + return gpg_error (GPG_ERR_NO_POLICY_MATCH); + } + es_fclose (fp); + return tmperr; + } + + if (!*line || line[strlen(line)-1] != '\n') + { + /* eat until end of line */ + while ((c = es_getc (fp)) != EOF && c != '\n') + ; + es_fclose (fp); + xfree (policies); + return gpg_error (*line? GPG_ERR_LINE_TOO_LONG + : GPG_ERR_INCOMPLETE_LINE); + } + + /* Allow for empty lines and spaces */ + for (p=line; spacep (p); p++) + ; + } + while (!*p || *p == '\n' || *p == '#'); + + /* Parse line. Note that the line has always a LF and spacep + does not consider a LF a space. Thus strpbrk will always + succeed. */ + for (allowed=line; spacep (allowed); allowed++) + ; + p = strpbrk (allowed, " :\n"); + if (!*p || p == allowed) + { + es_fclose (fp); + xfree (policies); + return gpg_error (GPG_ERR_CONFIGURATION); + } + *p = 0; /* strip the rest of the line */ + /* See whether we find ALLOWED (which is an OID) in POLICIES */ + for (haystack=policies; (p=strstr (haystack, allowed)); haystack = p+1) + { + if ( !(p == policies || p[-1] == '\n') ) + continue; /* Does not match the begin of a line. */ + if (p[strlen (allowed)] != ':') + continue; /* The length does not match. */ + /* Yep - it does match so return okay. */ + es_fclose (fp); + xfree (policies); + return 0; + } + } +} + + +/* Helper function for find_up. This resets the key handle and search + for an issuer ISSUER with a subjectKeyIdentifier of KEYID. Returns + 0 on success or -1 when not found. */ +static int +find_up_search_by_keyid (ctrl_t ctrl, KEYDB_HANDLE kh, + const char *issuer, ksba_sexp_t keyid) +{ + int rc; + ksba_cert_t cert = NULL; + ksba_sexp_t subj = NULL; + ksba_isotime_t not_before, not_after, last_not_before, ne_last_not_before; + ksba_cert_t found_cert = NULL; + ksba_cert_t ne_found_cert = NULL; + + keydb_search_reset (kh); + while (!(rc = keydb_search_subject (ctrl, kh, issuer))) + { + ksba_cert_release (cert); cert = NULL; + rc = keydb_get_cert (kh, &cert); + if (rc) + { + log_error ("keydb_get_cert() failed: rc=%d\n", rc); + rc = -1; + goto leave; + } + xfree (subj); + if (!ksba_cert_get_subj_key_id (cert, NULL, &subj)) + { + if (!cmp_simple_canon_sexp (keyid, subj)) + { + /* Found matching cert. */ + rc = ksba_cert_get_validity (cert, 0, not_before); + if (!rc) + rc = ksba_cert_get_validity (cert, 1, not_after); + if (rc) + { + log_error ("keydb_get_validity() failed: rc=%d\n", rc); + rc = -1; + goto leave; + } + + if (!found_cert + || strcmp (last_not_before, not_before) < 0) + { + /* This certificate is the first one found or newer + * than the previous one. This copes with + * re-issuing CA certificates while keeping the same + * key information. */ + gnupg_copy_time (last_not_before, not_before); + ksba_cert_release (found_cert); + ksba_cert_ref ((found_cert = cert)); + keydb_push_found_state (kh); + } + + if (*not_after && strcmp (ctrl->current_time, not_after) > 0 ) + ; /* CERT has expired - don't consider it. */ + else if (!ne_found_cert + || strcmp (ne_last_not_before, not_before) < 0) + { + /* This certificate is the first non-expired one + * found or newer than the previous non-expired one. */ + gnupg_copy_time (ne_last_not_before, not_before); + ksba_cert_release (ne_found_cert); + ksba_cert_ref ((ne_found_cert = cert)); + } + } + } + } + + if (!found_cert) + goto leave; + + /* Take the last saved one. Note that push/pop_found_state are + * misnomers because there is no stack of states. Renaming them to + * save/restore_found_state would be better. */ + keydb_pop_found_state (kh); + rc = 0; /* Ignore EOF or other error after the first cert. */ + + /* We need to consider some corner cases. It is possible that we + * have a long term certificate (e.g. valid from 2008 to 2033) as + * well as a re-issued (i.e. using the same key material) short term + * certificate (say from 2016 to 2019). Using the short term + * certificate is the proper solution. But we need to take care if + * there is no re-issued new short term certificate (e.g. from 2020 + * to 2023) available. In that case it is better to use the long + * term certificate which is still valid. The code may run into + * minor problems in the case of the chain validation mode. Given + * that this corner case is due to non-diligent PKI management we + * ignore this problem. */ + + /* The most common case is that the found certificate is not expired + * and thus identical to the one found from the list of non-expired + * certs. We can stop here. */ + if (found_cert == ne_found_cert) + goto leave; + /* If we do not have a non expired certificate the actual cert is + * expired and we can also stop here. */ + if (!ne_found_cert) + goto leave; + /* Now we need to see whether the found certificate is expired and + * only in this case we return the certificate found in the list of + * non-expired certs. */ + rc = ksba_cert_get_validity (found_cert, 1, not_after); + if (rc) + { + log_error ("keydb_get_validity() failed: rc=%d\n", rc); + rc = -1; + goto leave; + } + if (*not_after && strcmp (ctrl->current_time, not_after) > 0 ) + { /* CERT has expired. Use the NE_FOUND_CERT. Because we have no + * found state for this we need to search for it again. */ + unsigned char fpr[20]; + + gpgsm_get_fingerprint (ne_found_cert, GCRY_MD_SHA1, fpr, NULL); + keydb_search_reset (kh); + rc = keydb_search_fpr (ctrl, kh, fpr); + if (rc) + { + log_error ("keydb_search_fpr() failed: rc=%d\n", rc); + rc = -1; + goto leave; + } + /* Ready. The NE_FOUND_CERT is availabale via keydb_get_cert. */ + } + + leave: + ksba_cert_release (found_cert); + ksba_cert_release (ne_found_cert); + ksba_cert_release (cert); + xfree (subj); + return rc? -1:0; +} + + +struct find_up_store_certs_s +{ + ctrl_t ctrl; + int count; + unsigned int want_fpr:1; + unsigned int got_fpr:1; + unsigned char fpr[20]; +}; + +static void +find_up_store_certs_cb (void *cb_value, ksba_cert_t cert) +{ + struct find_up_store_certs_s *parm = cb_value; + + if (keydb_store_cert (parm->ctrl, cert, 1, NULL)) + log_error ("error storing issuer certificate as ephemeral\n"); + else if (parm->want_fpr && !parm->got_fpr) + { + if (!gpgsm_get_fingerprint (cert, 0, parm->fpr, NULL)) + log_error (_("failed to get the fingerprint\n")); + else + parm->got_fpr = 1; + } + parm->count++; +} + + +/* Helper for find_up(). Locate the certificate for ISSUER using an + external lookup. KH is the keydb context we are currently using. + On success 0 is returned and the certificate may be retrieved from + the keydb using keydb_get_cert(). KEYID is the keyIdentifier from + the AKI or NULL. */ +static int +find_up_external (ctrl_t ctrl, KEYDB_HANDLE kh, + const char *issuer, ksba_sexp_t keyid) +{ + int rc; + strlist_t names = NULL; + struct find_up_store_certs_s find_up_store_certs_parm; + char *pattern; + const char *s; + + find_up_store_certs_parm.ctrl = ctrl; + find_up_store_certs_parm.want_fpr = 0; + find_up_store_certs_parm.got_fpr = 0; + find_up_store_certs_parm.count = 0; + + if (opt.verbose) + log_info (_("looking up issuer at external location\n")); + /* The Dirmngr process is confused about unknown attributes. As a + quick and ugly hack we locate the CN and use the issuer string + starting at this attribite. Fixme: we should have far better + parsing for external lookups in the Dirmngr. */ + s = strstr (issuer, "CN="); + if (!s || s == issuer || s[-1] != ',') + s = issuer; + pattern = xtrymalloc (strlen (s)+2); + if (!pattern) + return gpg_error_from_syserror (); + strcpy (stpcpy (pattern, "/"), s); + add_to_strlist (&names, pattern); + xfree (pattern); + + rc = gpgsm_dirmngr_lookup (ctrl, names, NULL, 0, find_up_store_certs_cb, + &find_up_store_certs_parm); + free_strlist (names); + + if (opt.verbose) + log_info (_("number of issuers matching: %d\n"), + find_up_store_certs_parm.count); + if (rc) + { + log_error ("external key lookup failed: %s\n", gpg_strerror (rc)); + rc = -1; + } + else if (!find_up_store_certs_parm.count) + rc = -1; + else + { + int old; + /* The issuers are currently stored in the ephemeral key DB, so + we temporary switch to ephemeral mode. */ + old = keydb_set_ephemeral (kh, 1); + if (keyid) + rc = find_up_search_by_keyid (ctrl, kh, issuer, keyid); + else + { + keydb_search_reset (kh); + rc = keydb_search_subject (ctrl, kh, issuer); + } + keydb_set_ephemeral (kh, old); + } + return rc; +} + + +/* Helper for find_up(). Locate the certificate for CERT using the + * caIssuer from the authorityInfoAccess. KH is the keydb context we + * are currently using. On success 0 is returned and the certificate + * may be retrieved from the keydb using keydb_get_cert(). If no + * suitable authorityInfoAccess is encoded in the certificate + * GPG_ERR_NOT_FOUND is returned. */ +static gpg_error_t +find_up_via_auth_info_access (ctrl_t ctrl, KEYDB_HANDLE kh, ksba_cert_t cert) +{ + gpg_error_t err; + struct find_up_store_certs_s find_up_store_certs_parm; + char *url, *ldapurl; + int idx, i; + char *oid; + ksba_name_t name; + + find_up_store_certs_parm.ctrl = ctrl; + find_up_store_certs_parm.want_fpr = 1; + find_up_store_certs_parm.got_fpr = 0; + find_up_store_certs_parm.count = 0; + + /* Find suitable URLs; if there is a http scheme we prefer that. */ + url = ldapurl = NULL; + for (idx=0; + !url && !(err = ksba_cert_get_authority_info_access (cert, idx, + &oid, &name)); + idx++) + { + if (!strcmp (oid, oidstr_caIssuers)) + { + for (i=0; !url && ksba_name_enum (name, i); i++) + { + char *p = ksba_name_get_uri (name, i); + if (p) + { + if (!strncmp (p, "http:", 5) || !strncmp (p, "https:", 6)) + url = p; + else if (ldapurl) + xfree (p); /* We already got one. */ + else if (!strncmp (p, "ldap:",5) || !strncmp (p, "ldaps:",6)) + ldapurl = p; + } + else + xfree (p); + } + } + ksba_name_release (name); + ksba_free (oid); + } + if (err && gpg_err_code (err) != GPG_ERR_EOF) + { + log_error (_("can't get authorityInfoAccess: %s\n"), gpg_strerror (err)); + return err; + } + if (!url && ldapurl) + { + /* No HTTP scheme; fallback to LDAP if available. */ + url = ldapurl; + ldapurl = NULL; + } + xfree (ldapurl); + if (!url) + return gpg_error (GPG_ERR_NOT_FOUND); + + if (opt.verbose) + log_info ("looking up issuer via authorityInfoAccess.caIssuers\n"); + + err = gpgsm_dirmngr_lookup (ctrl, NULL, url, 0, find_up_store_certs_cb, + &find_up_store_certs_parm); + + /* Although we might receive several certificates we use only the + * first one. Or more exacty the first one for which we retrieved + * the fingerprint. */ + if (opt.verbose) + log_info ("number of caIssuers found: %d\n", + find_up_store_certs_parm.count); + if (err) + { + log_error ("external URL lookup failed: %s\n", gpg_strerror (err)); + err = gpg_error (GPG_ERR_NOT_FOUND); + } + else if (!find_up_store_certs_parm.got_fpr) + err = gpg_error (GPG_ERR_NOT_FOUND); + else + { + int old; + /* The retrieved certificates are currently stored in the + * ephemeral key DB, so we temporary switch to ephemeral + * mode. */ + old = keydb_set_ephemeral (kh, 1); + keydb_search_reset (kh); + err = keydb_search_fpr (ctrl, kh, find_up_store_certs_parm.fpr); + keydb_set_ephemeral (kh, old); + } + + return err; +} + + +/* Helper for find_up(). Ask the dirmngr for the certificate for + ISSUER with optional SERIALNO. KH is the keydb context we are + currently using. With SUBJECT_MODE set, ISSUER is searched as the + subject. On success 0 is returned and the certificate is available + in the ephemeral DB. */ +static int +find_up_dirmngr (ctrl_t ctrl, KEYDB_HANDLE kh, + ksba_sexp_t serialno, const char *issuer, int subject_mode) +{ + int rc; + strlist_t names = NULL; + struct find_up_store_certs_s find_up_store_certs_parm; + char *pattern; + + (void)kh; + + find_up_store_certs_parm.ctrl = ctrl; + find_up_store_certs_parm.count = 0; + + if (opt.verbose) + log_info (_("looking up issuer from the Dirmngr cache\n")); + if (subject_mode) + { + pattern = xtrymalloc (strlen (issuer)+2); + if (pattern) + strcpy (stpcpy (pattern, "/"), issuer); + } + else if (serialno) + pattern = gpgsm_format_sn_issuer (serialno, issuer); + else + { + pattern = xtrymalloc (strlen (issuer)+3); + if (pattern) + strcpy (stpcpy (pattern, "#/"), issuer); + } + if (!pattern) + return gpg_error_from_syserror (); + add_to_strlist (&names, pattern); + xfree (pattern); + + rc = gpgsm_dirmngr_lookup (ctrl, names, NULL, 1, find_up_store_certs_cb, + &find_up_store_certs_parm); + free_strlist (names); + + if (opt.verbose) + log_info (_("number of matching certificates: %d\n"), + find_up_store_certs_parm.count); + if (rc && !opt.quiet) + log_info (_("dirmngr cache-only key lookup failed: %s\n"), + gpg_strerror (rc)); + return (!rc && find_up_store_certs_parm.count)? 0 : -1; +} + + + +/* Locate issuing certificate for CERT. ISSUER is the name of the + issuer used as a fallback if the other methods don't work. If + FIND_NEXT is true, the function shall return the next possible + issuer. The certificate itself is not directly returned but a + keydb_get_cert on the keydb context KH will return it. Returns 0 + on success, -1 if not found or an error code. */ +static int +find_up (ctrl_t ctrl, KEYDB_HANDLE kh, + ksba_cert_t cert, const char *issuer, int find_next) +{ + ksba_name_t authid; + ksba_sexp_t authidno; + ksba_sexp_t keyid; + int rc = -1; + + if (DBG_X509) + log_debug ("looking for parent certificate\n"); + if (!ksba_cert_get_auth_key_id (cert, &keyid, &authid, &authidno)) + { + const char *s = ksba_name_enum (authid, 0); + if (s && *authidno) + { + rc = keydb_search_issuer_sn (ctrl, kh, s, authidno); + if (rc) + keydb_search_reset (kh); + + if (!rc && DBG_X509) + log_debug (" found via authid and sn+issuer\n"); + + /* In case of an error, try to get the certificate from the + dirmngr. That is done by trying to put that certifcate + into the ephemeral DB and let the code below do the + actual retrieve. Thus there is no error checking. + Skipped in find_next mode as usual. */ + if (rc == -1 && !find_next) + find_up_dirmngr (ctrl, kh, authidno, s, 0); + + /* In case of an error try the ephemeral DB. We can't do + that in find_next mode because we can't keep the search + state then. */ + if (rc == -1 && !find_next) + { + int old = keydb_set_ephemeral (kh, 1); + if (!old) + { + rc = keydb_search_issuer_sn (ctrl, kh, s, authidno); + if (rc) + keydb_search_reset (kh); + + if (!rc && DBG_X509) + log_debug (" found via authid and sn+issuer (ephem)\n"); + } + keydb_set_ephemeral (kh, old); + } + if (rc) + rc = -1; /* Need to make sure to have this error code. */ + } + + if (rc == -1 && keyid && !find_next) + { + /* Not found by AKI.issuer_sn. Lets try the AKI.ki + instead. Loop over all certificates with that issuer as + subject and stop for the one with a matching + subjectKeyIdentifier. */ + /* Fixme: Should we also search in the dirmngr? */ + rc = find_up_search_by_keyid (ctrl, kh, issuer, keyid); + if (!rc && DBG_X509) + log_debug (" found via authid and keyid\n"); + if (rc) + { + int old = keydb_set_ephemeral (kh, 1); + if (!old) + rc = find_up_search_by_keyid (ctrl, kh, issuer, keyid); + if (!rc && DBG_X509) + log_debug (" found via authid and keyid (ephem)\n"); + keydb_set_ephemeral (kh, old); + } + if (rc) + rc = -1; /* Need to make sure to have this error code. */ + } + + /* If we still didn't found it, try to find it via the subject + from the dirmngr-cache. */ + if (rc == -1 && !find_next) + { + if (!find_up_dirmngr (ctrl, kh, NULL, issuer, 1)) + { + int old = keydb_set_ephemeral (kh, 1); + if (keyid) + rc = find_up_search_by_keyid (ctrl, kh, issuer, keyid); + else + { + keydb_search_reset (kh); + rc = keydb_search_subject (ctrl, kh, issuer); + } + keydb_set_ephemeral (kh, old); + } + if (rc) + rc = -1; /* Need to make sure to have this error code. */ + + if (!rc && DBG_X509) + log_debug (" found via authid and issuer from dirmngr cache\n"); + } + + /* If we still didn't found it, try an external lookup. */ + if (rc == -1 && !find_next && !ctrl->offline) + { + /* We allow AIA also if CRLs are enabled; both can be used + * as a web bug so it does not make sense to not use AIA if + * CRL checks are enabled. */ + if ((opt.auto_issuer_key_retrieve || !opt.no_crl_check) + && !find_up_via_auth_info_access (ctrl, kh, cert)) + { + if (DBG_X509) + log_debug (" found via authorityInfoAccess.caIssuers\n"); + rc = 0; + } + else if (opt.auto_issuer_key_retrieve) + { + rc = find_up_external (ctrl, kh, issuer, keyid); + if (!rc && DBG_X509) + log_debug (" found via authid and external lookup\n"); + } + } + + + /* Print a note so that the user does not feel too helpless when + an issuer certificate was found and gpgsm prints BAD + signature because it is not the correct one. */ + if (rc == -1 && opt.quiet) + ; + else if (rc == -1) + { + log_info ("%sissuer certificate ", find_next?"next ":""); + if (keyid) + { + log_printf ("{"); + gpgsm_dump_serial (keyid); + log_printf ("} "); + } + if (authidno) + { + log_printf ("(#"); + gpgsm_dump_serial (authidno); + log_printf ("/"); + gpgsm_dump_string (s); + log_printf (") "); + } + log_printf ("not found using authorityKeyIdentifier\n"); + } + else if (rc) + log_error ("failed to find authorityKeyIdentifier: rc=%d\n", rc); + xfree (keyid); + ksba_name_release (authid); + xfree (authidno); + } + + if (rc) /* Not found via authorithyKeyIdentifier, try regular issuer name. */ + rc = keydb_search_subject (ctrl, kh, issuer); + if (rc == -1 && !find_next) + { + int old; + + /* Also try to get it from the Dirmngr cache. The function + merely puts it into the ephemeral database. */ + find_up_dirmngr (ctrl, kh, NULL, issuer, 0); + + /* Not found, let us see whether we have one in the ephemeral key DB. */ + old = keydb_set_ephemeral (kh, 1); + if (!old) + { + keydb_search_reset (kh); + rc = keydb_search_subject (ctrl, kh, issuer); + } + keydb_set_ephemeral (kh, old); + + if (!rc && DBG_X509) + log_debug (" found via issuer\n"); + } + + /* Still not found. If enabled, try an external lookup. */ + if (rc == -1 && !find_next && !ctrl->offline) + { + if ((opt.auto_issuer_key_retrieve || !opt.no_crl_check) + && !find_up_via_auth_info_access (ctrl, kh, cert)) + { + if (DBG_X509) + log_debug (" found via authorityInfoAccess.caIssuers\n"); + rc = 0; + } + else if (opt.auto_issuer_key_retrieve) + { + rc = find_up_external (ctrl, kh, issuer, NULL); + if (!rc && DBG_X509) + log_debug (" found via issuer and external lookup\n"); + } + } + + return rc; +} + + +/* Return the next certificate up in the chain starting at START. + Returns -1 when there are no more certificates. */ +int +gpgsm_walk_cert_chain (ctrl_t ctrl, ksba_cert_t start, ksba_cert_t *r_next) +{ + int rc = 0; + char *issuer = NULL; + char *subject = NULL; + KEYDB_HANDLE kh = keydb_new (); + + *r_next = NULL; + if (!kh) + { + log_error (_("failed to allocate keyDB handle\n")); + rc = gpg_error (GPG_ERR_GENERAL); + goto leave; + } + + issuer = ksba_cert_get_issuer (start, 0); + subject = ksba_cert_get_subject (start, 0); + if (!issuer) + { + log_error ("no issuer found in certificate\n"); + rc = gpg_error (GPG_ERR_BAD_CERT); + goto leave; + } + if (!subject) + { + log_error ("no subject found in certificate\n"); + rc = gpg_error (GPG_ERR_BAD_CERT); + goto leave; + } + + if (is_root_cert (start, issuer, subject)) + { + rc = -1; /* we are at the root */ + goto leave; + } + + rc = find_up (ctrl, kh, start, issuer, 0); + if (rc) + { + /* It is quite common not to have a certificate, so better don't + print an error here. */ + if (rc != -1 && opt.verbose > 1) + log_error ("failed to find issuer's certificate: rc=%d\n", rc); + rc = gpg_error (GPG_ERR_MISSING_ISSUER_CERT); + goto leave; + } + + rc = keydb_get_cert (kh, r_next); + if (rc) + { + log_error ("keydb_get_cert() failed: rc=%d\n", rc); + rc = gpg_error (GPG_ERR_GENERAL); + } + + leave: + xfree (issuer); + xfree (subject); + keydb_release (kh); + return rc; +} + + +/* Helper for gpgsm_is_root_cert. This one is used if the subject and + issuer DNs are already known. */ +static int +is_root_cert (ksba_cert_t cert, const char *issuerdn, const char *subjectdn) +{ + gpg_error_t err; + int result = 0; + ksba_sexp_t serialno; + ksba_sexp_t ak_keyid; + ksba_name_t ak_name; + ksba_sexp_t ak_sn; + const char *ak_name_str; + ksba_sexp_t subj_keyid = NULL; + + if (!issuerdn || !subjectdn) + return 0; /* No. */ + + if (strcmp (issuerdn, subjectdn)) + return 0; /* No. */ + + err = ksba_cert_get_auth_key_id (cert, &ak_keyid, &ak_name, &ak_sn); + if (err) + { + if (gpg_err_code (err) == GPG_ERR_NO_DATA) + return 1; /* Yes. Without a authorityKeyIdentifier this needs + to be the Root certifcate (our trust anchor). */ + log_error ("error getting authorityKeyIdentifier: %s\n", + gpg_strerror (err)); + return 0; /* Well, it is broken anyway. Return No. */ + } + + serialno = ksba_cert_get_serial (cert); + if (!serialno) + { + log_error ("error getting serialno: %s\n", gpg_strerror (err)); + goto leave; + } + + /* Check whether the auth name's matches the issuer name+sn. If + that is the case this is a root certificate. */ + ak_name_str = ksba_name_enum (ak_name, 0); + if (ak_name_str + && !strcmp (ak_name_str, issuerdn) + && !cmp_simple_canon_sexp (ak_sn, serialno)) + { + result = 1; /* Right, CERT is self-signed. */ + goto leave; + } + + /* Similar for the ak_keyid. */ + if (ak_keyid && !ksba_cert_get_subj_key_id (cert, NULL, &subj_keyid) + && !cmp_simple_canon_sexp (ak_keyid, subj_keyid)) + { + result = 1; /* Right, CERT is self-signed. */ + goto leave; + } + + + leave: + ksba_free (subj_keyid); + ksba_free (ak_keyid); + ksba_name_release (ak_name); + ksba_free (ak_sn); + ksba_free (serialno); + return result; +} + + + +/* Check whether the CERT is a root certificate. Returns True if this + is the case. */ +int +gpgsm_is_root_cert (ksba_cert_t cert) +{ + char *issuer; + char *subject; + int yes; + + issuer = ksba_cert_get_issuer (cert, 0); + subject = ksba_cert_get_subject (cert, 0); + yes = is_root_cert (cert, issuer, subject); + xfree (issuer); + xfree (subject); + return yes; +} + + +/* This is a helper for gpgsm_validate_chain. */ +static gpg_error_t +is_cert_still_valid (ctrl_t ctrl, int force_ocsp, int lm, estream_t fp, + ksba_cert_t subject_cert, ksba_cert_t issuer_cert, + int *any_revoked, int *any_no_crl, int *any_crl_too_old) +{ + gpg_error_t err; + + if (ctrl->offline || (opt.no_crl_check && !ctrl->use_ocsp)) + { + audit_log_ok (ctrl->audit, AUDIT_CRL_CHECK, + gpg_error (GPG_ERR_NOT_ENABLED)); + return 0; + } + + + if (!(force_ocsp || ctrl->use_ocsp) + && !opt.enable_issuer_based_crl_check) + { + err = ksba_cert_get_crl_dist_point (subject_cert, 0, NULL, NULL, NULL); + if (gpg_err_code (err) == GPG_ERR_EOF) + { + /* No DP specified in the certificate. Thus the CA does not + * consider a CRL useful and the user of the certificate + * also does not consider this to be a critical thing. In + * this case we can conclude that the certificate shall not + * be revocable. Note that we reach this point here only if + * no OCSP responder shall be used. */ + audit_log_ok (ctrl->audit, AUDIT_CRL_CHECK, gpg_error (GPG_ERR_TRUE)); + return 0; + } + } + + err = gpgsm_dirmngr_isvalid (ctrl, + subject_cert, issuer_cert, + force_ocsp? 2 : !!ctrl->use_ocsp); + audit_log_ok (ctrl->audit, AUDIT_CRL_CHECK, err); + + if (err) + { + if (!lm) + gpgsm_cert_log_name (NULL, subject_cert); + switch (gpg_err_code (err)) + { + case GPG_ERR_CERT_REVOKED: + do_list (1, lm, fp, _("certificate has been revoked")); + *any_revoked = 1; + /* Store that in the keybox so that key listings are able to + return the revoked flag. We don't care about error, + though. */ + keydb_set_cert_flags (ctrl, subject_cert, 1, KEYBOX_FLAG_VALIDITY, 0, + ~0, VALIDITY_REVOKED); + break; + + case GPG_ERR_NO_CRL_KNOWN: + do_list (1, lm, fp, _("no CRL found for certificate")); + *any_no_crl = 1; + break; + + case GPG_ERR_NO_DATA: + do_list (1, lm, fp, _("the status of the certificate is unknown")); + *any_no_crl = 1; + break; + + case GPG_ERR_CRL_TOO_OLD: + do_list (1, lm, fp, _("the available CRL is too old")); + if (!lm) + log_info (_("please make sure that the " + "\"dirmngr\" is properly installed\n")); + *any_crl_too_old = 1; + break; + + default: + do_list (1, lm, fp, _("checking the CRL failed: %s"), + gpg_strerror (err)); + return err; + } + } + return 0; +} + + +/* Helper for gpgsm_validate_chain to check the validity period of + SUBJECT_CERT. The caller needs to pass EXPTIME which will be + updated to the nearest expiration time seen. A DEPTH of 0 indicates + the target certificate, -1 the final root certificate and other + values intermediate certificates. */ +static gpg_error_t +check_validity_period (ksba_isotime_t current_time, + ksba_cert_t subject_cert, + ksba_isotime_t exptime, + int listmode, estream_t listfp, int depth) +{ + gpg_error_t err; + ksba_isotime_t not_before, not_after; + + err = ksba_cert_get_validity (subject_cert, 0, not_before); + if (!err) + err = ksba_cert_get_validity (subject_cert, 1, not_after); + if (err) + { + do_list (1, listmode, listfp, + _("certificate with invalid validity: %s"), gpg_strerror (err)); + return gpg_error (GPG_ERR_BAD_CERT); + } + + if (*not_after) + { + if (!*exptime) + gnupg_copy_time (exptime, not_after); + else if (strcmp (not_after, exptime) < 0 ) + gnupg_copy_time (exptime, not_after); + } + + if (*not_before && strcmp (current_time, not_before) < 0 ) + { + do_list (1, listmode, listfp, + depth == 0 ? _("certificate not yet valid") : + depth == -1 ? _("root certificate not yet valid") : + /* other */ _("intermediate certificate not yet valid")); + if (!listmode) + { + log_info (" (valid from "); + dump_isotime (not_before); + log_printf (")\n"); + } + return gpg_error (GPG_ERR_CERT_TOO_YOUNG); + } + + if (*not_after && strcmp (current_time, not_after) > 0 ) + { + do_list (opt.ignore_expiration?0:1, listmode, listfp, + depth == 0 ? _("certificate has expired") : + depth == -1 ? _("root certificate has expired") : + /* other */ _("intermediate certificate has expired")); + if (!listmode) + { + log_info (" (expired at "); + dump_isotime (not_after); + log_printf (")\n"); + } + if (opt.ignore_expiration) + log_info ("WARNING: ignoring expiration\n"); + else + return gpg_error (GPG_ERR_CERT_EXPIRED); + } + + return 0; +} + +/* This is a variant of check_validity_period used with the chain + model. The dextra contraint here is that notBefore and notAfter + must exists and if the additional argument CHECK_TIME is given this + time is used to check the validity period of SUBJECT_CERT. */ +static gpg_error_t +check_validity_period_cm (ksba_isotime_t current_time, + ksba_isotime_t check_time, + ksba_cert_t subject_cert, + ksba_isotime_t exptime, + int listmode, estream_t listfp, int depth) +{ + gpg_error_t err; + ksba_isotime_t not_before, not_after; + + err = ksba_cert_get_validity (subject_cert, 0, not_before); + if (!err) + err = ksba_cert_get_validity (subject_cert, 1, not_after); + if (err) + { + do_list (1, listmode, listfp, + _("certificate with invalid validity: %s"), gpg_strerror (err)); + return gpg_error (GPG_ERR_BAD_CERT); + } + if (!*not_before || !*not_after) + { + do_list (1, listmode, listfp, + _("required certificate attributes missing: %s%s%s"), + !*not_before? "notBefore":"", + (!*not_before && !*not_after)? ", ":"", + !*not_before? "notAfter":""); + return gpg_error (GPG_ERR_BAD_CERT); + } + if (strcmp (not_before, not_after) > 0 ) + { + do_list (1, listmode, listfp, + _("certificate with invalid validity")); + log_info (" (valid from "); + dump_isotime (not_before); + log_printf (" expired at "); + dump_isotime (not_after); + log_printf (")\n"); + return gpg_error (GPG_ERR_BAD_CERT); + } + + if (!*exptime) + gnupg_copy_time (exptime, not_after); + else if (strcmp (not_after, exptime) < 0 ) + gnupg_copy_time (exptime, not_after); + + if (strcmp (current_time, not_before) < 0 ) + { + do_list (1, listmode, listfp, + depth == 0 ? _("certificate not yet valid") : + depth == -1 ? _("root certificate not yet valid") : + /* other */ _("intermediate certificate not yet valid")); + if (!listmode) + { + log_info (" (valid from "); + dump_isotime (not_before); + log_printf (")\n"); + } + return gpg_error (GPG_ERR_CERT_TOO_YOUNG); + } + + if (*check_time + && (strcmp (check_time, not_before) < 0 + || strcmp (check_time, not_after) > 0)) + { + /* Note that we don't need a case for the root certificate + because its own consitency has already been checked. */ + do_list(opt.ignore_expiration?0:1, listmode, listfp, + depth == 0 ? + _("signature not created during lifetime of certificate") : + depth == 1 ? + _("certificate not created during lifetime of issuer") : + _("intermediate certificate not created during lifetime " + "of issuer")); + if (!listmode) + { + log_info (depth== 0? _(" ( signature created at ") : + /* */ _(" (certificate created at ") ); + dump_isotime (check_time); + log_printf (")\n"); + log_info (depth==0? _(" (certificate valid from ") : + /* */ _(" ( issuer valid from ") ); + dump_isotime (not_before); + log_info (" to "); + dump_isotime (not_after); + log_printf (")\n"); + } + if (opt.ignore_expiration) + log_info ("WARNING: ignoring expiration\n"); + else + return gpg_error (GPG_ERR_CERT_EXPIRED); + } + + return 0; +} + + + +/* Ask the user whether he wants to mark the certificate CERT trusted. + Returns true if the CERT is the trusted. We also check whether the + agent is at all enabled to allow marktrusted and don't call it in + this session again if it is not. */ +static int +ask_marktrusted (ctrl_t ctrl, ksba_cert_t cert, int listmode) +{ + static int no_more_questions; + int rc; + char *fpr; + int success = 0; + + fpr = gpgsm_get_fingerprint_string (cert, GCRY_MD_SHA1); + log_info (_("fingerprint=%s\n"), fpr? fpr : "?"); + xfree (fpr); + + if (no_more_questions) + rc = gpg_error (GPG_ERR_NOT_SUPPORTED); + else + rc = gpgsm_agent_marktrusted (ctrl, cert); + if (!rc) + { + log_info (_("root certificate has now been marked as trusted\n")); + success = 1; + } + else if (!listmode) + { + gpgsm_dump_cert ("issuer", cert); + log_info ("after checking the fingerprint, you may want " + "to add it manually to the list of trusted certificates.\n"); + } + + if (gpg_err_code (rc) == GPG_ERR_NOT_SUPPORTED) + { + if (!no_more_questions) + log_info (_("interactive marking as trusted " + "not enabled in gpg-agent\n")); + no_more_questions = 1; + } + else if (gpg_err_code (rc) == GPG_ERR_CANCELED) + { + log_info (_("interactive marking as trusted " + "disabled for this session\n")); + no_more_questions = 1; + } + else + set_already_asked_marktrusted (cert); + + return success; +} + + + + +/* Validate a chain and optionally return the nearest expiration time + in R_EXPTIME. With LISTMODE set to 1 a special listmode is + activated where only information about the certificate is printed + to LISTFP and no output is send to the usual log stream. If + CHECKTIME_ARG is set, it is used only in the chain model instead of the + current time. + + Defined flag bits + + VALIDATE_FLAG_NO_DIRMNGR - Do not do any dirmngr isvalid checks. + VALIDATE_FLAG_CHAIN_MODEL - Check according to chain model. + VALIDATE_FLAG_STEED - Check according to the STEED model. +*/ +static int +do_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime_arg, + ksba_isotime_t r_exptime, + int listmode, estream_t listfp, unsigned int flags, + struct rootca_flags_s *rootca_flags) +{ + int rc = 0, depth, maxdepth; + char *issuer = NULL; + char *subject = NULL; + KEYDB_HANDLE kh = NULL; + ksba_cert_t subject_cert = NULL, issuer_cert = NULL; + ksba_isotime_t current_time; + ksba_isotime_t check_time; + ksba_isotime_t exptime; + int any_expired = 0; + int any_revoked = 0; + int any_no_crl = 0; + int any_crl_too_old = 0; + int any_no_policy_match = 0; + int is_qualified = -1; /* Indicates whether the certificate stems + from a qualified root certificate. + -1 = unknown, 0 = no, 1 = yes. */ + chain_item_t chain = NULL; /* A list of all certificates in the chain. */ + + + gnupg_get_isotime (current_time); + gnupg_copy_time (ctrl->current_time, current_time); + + if ( (flags & VALIDATE_FLAG_CHAIN_MODEL) ) + { + if (!strcmp (checktime_arg, "19700101T000000")) + { + do_list (1, listmode, listfp, + _("WARNING: creation time of signature not known - " + "assuming current time")); + gnupg_copy_time (check_time, current_time); + } + else + gnupg_copy_time (check_time, checktime_arg); + } + else + *check_time = 0; + + if (r_exptime) + *r_exptime = 0; + *exptime = 0; + + if (opt.no_chain_validation && !listmode) + { + log_info ("WARNING: bypassing certificate chain validation\n"); + return 0; + } + + kh = keydb_new (); + if (!kh) + { + log_error (_("failed to allocate keyDB handle\n")); + rc = gpg_error (GPG_ERR_GENERAL); + goto leave; + } + + if (DBG_X509 && !listmode) + gpgsm_dump_cert ("target", cert); + + subject_cert = cert; + ksba_cert_ref (subject_cert); + maxdepth = 50; + depth = 0; + + for (;;) + { + int is_root; + gpg_error_t istrusted_rc = -1; + + /* Put the certificate on our list. */ + { + chain_item_t ci; + + ci = xtrycalloc (1, sizeof *ci); + if (!ci) + { + rc = gpg_error_from_syserror (); + goto leave; + } + ksba_cert_ref (subject_cert); + ci->cert = subject_cert; + ci->next = chain; + chain = ci; + } + + xfree (issuer); + xfree (subject); + issuer = ksba_cert_get_issuer (subject_cert, 0); + subject = ksba_cert_get_subject (subject_cert, 0); + + if (!issuer) + { + do_list (1, listmode, listfp, _("no issuer found in certificate")); + rc = gpg_error (GPG_ERR_BAD_CERT); + goto leave; + } + + + /* Is this a self-issued certificate (i.e. the root certificate)? */ + is_root = is_root_cert (subject_cert, issuer, subject); + if (is_root) + { + chain->is_root = 1; + /* Check early whether the certificate is listed as trusted. + We used to do this only later but changed it to call the + check right here so that we can access special flags + associated with that specific root certificate. */ + if (gpgsm_cert_has_well_known_private_key (subject_cert)) + { + memset (rootca_flags, 0, sizeof *rootca_flags); + istrusted_rc = ((flags & VALIDATE_FLAG_STEED) + ? 0 : gpg_error (GPG_ERR_NOT_TRUSTED)); + } + else + istrusted_rc = gpgsm_agent_istrusted (ctrl, subject_cert, NULL, + rootca_flags); + audit_log_cert (ctrl->audit, AUDIT_ROOT_TRUSTED, + subject_cert, istrusted_rc); + /* If the chain model extended attribute is used, make sure + that our chain model flag is set. */ + if (!(flags & VALIDATE_FLAG_STEED) + && has_validation_model_chain (subject_cert, listmode, listfp)) + rootca_flags->chain_model = 1; + } + + + /* Check the validity period. */ + if ( (flags & VALIDATE_FLAG_CHAIN_MODEL) ) + rc = check_validity_period_cm (current_time, check_time, subject_cert, + exptime, listmode, listfp, + (depth && is_root)? -1: depth); + else + rc = check_validity_period (current_time, subject_cert, + exptime, listmode, listfp, + (depth && is_root)? -1: depth); + if (gpg_err_code (rc) == GPG_ERR_CERT_EXPIRED) + any_expired = 1; + else if (rc) + goto leave; + + + /* Assert that we understand all critical extensions. */ + rc = unknown_criticals (subject_cert, listmode, listfp); + if (rc) + goto leave; + + /* Do a policy check. */ + if (!opt.no_policy_check) + { + rc = check_cert_policy (subject_cert, listmode, listfp); + if (gpg_err_code (rc) == GPG_ERR_NO_POLICY_MATCH) + { + any_no_policy_match = 1; + rc = 1; /* Be on the safe side and set RC. */ + } + else if (rc) + goto leave; + } + + + /* If this is the root certificate we are at the end of the chain. */ + if (is_root) + { + if (!istrusted_rc) + ; /* No need to check the certificate for a trusted one. */ + else if (gpgsm_check_cert_sig (subject_cert, subject_cert) ) + { + /* We only check the signature if the certificate is not + trusted for better diagnostics. */ + do_list (1, listmode, listfp, + _("self-signed certificate has a BAD signature")); + if (DBG_X509) + { + gpgsm_dump_cert ("self-signing cert", subject_cert); + } + rc = gpg_error (depth? GPG_ERR_BAD_CERT_CHAIN + : GPG_ERR_BAD_CERT); + goto leave; + } + if (!rootca_flags->relax) + { + rc = allowed_ca (ctrl, subject_cert, NULL, listmode, listfp); + if (rc) + goto leave; + } + + + /* Set the flag for qualified signatures. This flag is + deduced from a list of root certificates allowed for + qualified signatures. */ + if (is_qualified == -1 && !(flags & VALIDATE_FLAG_STEED)) + { + gpg_error_t err; + size_t buflen; + char buf[1]; + + if (!ksba_cert_get_user_data (cert, "is_qualified", + &buf, sizeof (buf), + &buflen) && buflen) + { + /* We already checked this for this certificate, + thus we simply take it from the user data. */ + is_qualified = !!*buf; + } + else + { + /* Need to consult the list of root certificates for + qualified signatures. */ + err = gpgsm_is_in_qualified_list (ctrl, subject_cert, NULL); + if (!err) + is_qualified = 1; + else if ( gpg_err_code (err) == GPG_ERR_NOT_FOUND) + is_qualified = 0; + else + log_error ("checking the list of qualified " + "root certificates failed: %s\n", + gpg_strerror (err)); + if ( is_qualified != -1 ) + { + /* Cache the result but don't care too much + about an error. */ + buf[0] = !!is_qualified; + err = ksba_cert_set_user_data (subject_cert, + "is_qualified", buf, 1); + if (err) + log_error ("set_user_data(is_qualified) failed: %s\n", + gpg_strerror (err)); + } + } + } + + + /* Act on the check for a trusted root certificates. */ + rc = istrusted_rc; + if (!rc) + ; + else if (gpg_err_code (rc) == GPG_ERR_NOT_TRUSTED) + { + do_list (0, listmode, listfp, + _("root certificate is not marked trusted")); + /* If we already figured out that the certificate is + expired it does not make much sense to ask the user + whether they want to trust the root certificate. We + should do this only if the certificate under question + will then be usable. If the certificate has a well + known private key asking the user does not make any + sense. */ + if ( !any_expired + && !gpgsm_cert_has_well_known_private_key (subject_cert) + && (!listmode || !already_asked_marktrusted (subject_cert)) + && ask_marktrusted (ctrl, subject_cert, listmode) ) + rc = 0; + } + else + { + log_error (_("checking the trust list failed: %s\n"), + gpg_strerror (rc)); + } + + if (rc) + goto leave; + + /* Check for revocations etc. */ + if ((flags & VALIDATE_FLAG_NO_DIRMNGR)) + ; + else if ((flags & VALIDATE_FLAG_STEED)) + ; /* Fixme: check revocations via DNS. */ + else if (opt.no_trusted_cert_crl_check || rootca_flags->relax) + ; + else + rc = is_cert_still_valid (ctrl, + (flags & VALIDATE_FLAG_CHAIN_MODEL), + listmode, listfp, + subject_cert, subject_cert, + &any_revoked, &any_no_crl, + &any_crl_too_old); + if (rc) + goto leave; + + break; /* Okay: a self-signed certicate is an end-point. */ + } /* End is_root. */ + + + /* Take care that the chain does not get too long. */ + if ((depth+1) > maxdepth) + { + do_list (1, listmode, listfp, _("certificate chain too long\n")); + rc = gpg_error (GPG_ERR_BAD_CERT_CHAIN); + goto leave; + } + + /* Find the next cert up the tree. */ + keydb_search_reset (kh); + rc = find_up (ctrl, kh, subject_cert, issuer, 0); + if (rc) + { + if (rc == -1) + { + do_list (0, listmode, listfp, _("issuer certificate not found")); + if (!listmode) + { + log_info ("issuer certificate: #/"); + gpgsm_dump_string (issuer); + log_printf ("\n"); + } + } + else + log_error ("failed to find issuer's certificate: rc=%d\n", rc); + rc = gpg_error (GPG_ERR_MISSING_ISSUER_CERT); + goto leave; + } + + ksba_cert_release (issuer_cert); issuer_cert = NULL; + rc = keydb_get_cert (kh, &issuer_cert); + if (rc) + { + log_error ("keydb_get_cert() failed: rc=%d\n", rc); + rc = gpg_error (GPG_ERR_GENERAL); + goto leave; + } + + try_another_cert: + if (DBG_X509) + { + log_debug ("got issuer's certificate:\n"); + gpgsm_dump_cert ("issuer", issuer_cert); + } + + rc = gpgsm_check_cert_sig (issuer_cert, subject_cert); + if (rc) + { + do_list (0, listmode, listfp, _("certificate has a BAD signature")); + if (DBG_X509) + { + gpgsm_dump_cert ("signing issuer", issuer_cert); + gpgsm_dump_cert ("signed subject", subject_cert); + } + if (gpg_err_code (rc) == GPG_ERR_BAD_SIGNATURE) + { + /* We now try to find other issuer certificates which + might have been used. This is required because some + CAs are reusing the issuer and subject DN for new + root certificates. */ + /* FIXME: Do this only if we don't have an + AKI.keyIdentifier */ + rc = find_up (ctrl, kh, subject_cert, issuer, 1); + if (!rc) + { + ksba_cert_t tmp_cert; + + rc = keydb_get_cert (kh, &tmp_cert); + if (rc || !compare_certs (issuer_cert, tmp_cert)) + { + /* The find next did not work or returned an + identical certificate. We better stop here + to avoid infinite checks. */ + /* No need to set RC because it is not used: + rc = gpg_error (GPG_ERR_BAD_SIGNATURE); */ + ksba_cert_release (tmp_cert); + } + else + { + do_list (0, listmode, listfp, + _("found another possible matching " + "CA certificate - trying again")); + ksba_cert_release (issuer_cert); + issuer_cert = tmp_cert; + goto try_another_cert; + } + } + } + + /* We give a more descriptive error code than the one + returned from the signature checking. */ + rc = gpg_error (GPG_ERR_BAD_CERT_CHAIN); + goto leave; + } + + is_root = gpgsm_is_root_cert (issuer_cert); + istrusted_rc = -1; + + + /* Check that a CA is allowed to issue certificates. */ + { + int chainlen; + + rc = allowed_ca (ctrl, issuer_cert, &chainlen, listmode, listfp); + if (rc) + { + /* Not allowed. Check whether this is a trusted root + certificate and whether we allow special exceptions. + We could carry the result of the test over to the + regular root check at the top of the loop but for + clarity we won't do that. Given that the majority of + certificates carry proper BasicContraints our way of + overriding an error in the way is justified for + performance reasons. */ + if (is_root) + { + if (gpgsm_cert_has_well_known_private_key (issuer_cert)) + { + memset (rootca_flags, 0, sizeof *rootca_flags); + istrusted_rc = ((flags & VALIDATE_FLAG_STEED) + ? 0 : gpg_error (GPG_ERR_NOT_TRUSTED)); + } + else + istrusted_rc = gpgsm_agent_istrusted + (ctrl, issuer_cert, NULL, rootca_flags); + + if (!istrusted_rc && rootca_flags->relax) + { + /* Ignore the error due to the relax flag. */ + rc = 0; + chainlen = -1; + } + } + } + if (rc) + goto leave; + if (chainlen >= 0 && depth > chainlen) + { + do_list (1, listmode, listfp, + _("certificate chain longer than allowed by CA (%d)"), + chainlen); + rc = gpg_error (GPG_ERR_BAD_CERT_CHAIN); + goto leave; + } + } + + /* Is the certificate allowed to sign other certificates. */ + if (!listmode) + { + rc = gpgsm_cert_use_cert_p (issuer_cert); + if (rc) + { + char numbuf[50]; + sprintf (numbuf, "%d", rc); + gpgsm_status2 (ctrl, STATUS_ERROR, "certcert.issuer.keyusage", + numbuf, NULL); + goto leave; + } + } + + /* Check for revocations etc. Note that for a root certificate + this test is done a second time later. This should eventually + be fixed. */ + if ((flags & VALIDATE_FLAG_NO_DIRMNGR)) + rc = 0; + else if ((flags & VALIDATE_FLAG_STEED)) + rc = 0; /* Fixme: XXX */ + else if (is_root && (opt.no_trusted_cert_crl_check + || (!istrusted_rc && rootca_flags->relax))) + rc = 0; + else + rc = is_cert_still_valid (ctrl, + (flags & VALIDATE_FLAG_CHAIN_MODEL), + listmode, listfp, + subject_cert, issuer_cert, + &any_revoked, &any_no_crl, &any_crl_too_old); + if (rc) + goto leave; + + + if (opt.verbose && !listmode) + log_info (depth == 0 ? _("certificate is good\n") : + !is_root ? _("intermediate certificate is good\n") : + /* other */ _("root certificate is good\n")); + + /* Under the chain model the next check time is the creation + time of the subject certificate. */ + if ( (flags & VALIDATE_FLAG_CHAIN_MODEL) ) + { + rc = ksba_cert_get_validity (subject_cert, 0, check_time); + if (rc) + { + /* That will never happen as we have already checked + this above. */ + BUG (); + } + } + + /* For the next round the current issuer becomes the new subject. */ + keydb_search_reset (kh); + ksba_cert_release (subject_cert); + subject_cert = issuer_cert; + issuer_cert = NULL; + depth++; + } /* End chain traversal. */ + + if (!listmode && !opt.quiet) + { + if (opt.no_policy_check) + log_info ("policies not checked due to %s option\n", + "--disable-policy-checks"); + if (ctrl->offline || (opt.no_crl_check && !ctrl->use_ocsp)) + log_info ("CRLs not checked due to %s option\n", + ctrl->offline ? "offline" : "--disable-crl-checks"); + } + + if (!rc) + { /* If we encountered an error somewhere during the checks, set + the error code to the most critical one */ + if (any_revoked) + rc = gpg_error (GPG_ERR_CERT_REVOKED); + else if (any_expired) + rc = gpg_error (GPG_ERR_CERT_EXPIRED); + else if (any_no_crl) + rc = gpg_error (GPG_ERR_NO_CRL_KNOWN); + else if (any_crl_too_old) + rc = gpg_error (GPG_ERR_CRL_TOO_OLD); + else if (any_no_policy_match) + rc = gpg_error (GPG_ERR_NO_POLICY_MATCH); + } + + leave: + /* If we have traversed a complete chain up to the root we will + reset the ephemeral flag for all these certificates. This is done + regardless of any error because those errors may only be + transient. */ + if (chain && chain->is_root) + { + gpg_error_t err; + chain_item_t ci; + + for (ci = chain; ci; ci = ci->next) + { + /* Note that it is possible for the last certificate in the + chain (i.e. our target certificate) that it has not yet + been stored in the keybox and thus the flag can't be set. + We ignore this error because it will later be stored + anyway. */ + err = keydb_set_cert_flags (ctrl, ci->cert, 1, KEYBOX_FLAG_BLOB, 0, + KEYBOX_FLAG_BLOB_EPHEMERAL, 0); + if (!ci->next && gpg_err_code (err) == GPG_ERR_NOT_FOUND) + ; + else if (err) + log_error ("clearing ephemeral flag failed: %s\n", + gpg_strerror (err)); + } + } + + /* If we have figured something about the qualified signature + capability of the certificate under question, store the result as + user data in all certificates of the chain. We do this even if the + validation itself failed. */ + if (is_qualified != -1 && !(flags & VALIDATE_FLAG_STEED)) + { + gpg_error_t err; + chain_item_t ci; + char buf[1]; + + buf[0] = !!is_qualified; + + for (ci = chain; ci; ci = ci->next) + { + err = ksba_cert_set_user_data (ci->cert, "is_qualified", buf, 1); + if (err) + { + log_error ("set_user_data(is_qualified) failed: %s\n", + gpg_strerror (err)); + if (!rc) + rc = err; + } + } + } + + /* If auditing has been enabled, record what is in the chain. */ + if (ctrl->audit) + { + chain_item_t ci; + + audit_log (ctrl->audit, AUDIT_CHAIN_BEGIN); + for (ci = chain; ci; ci = ci->next) + { + audit_log_cert (ctrl->audit, + ci->is_root? AUDIT_CHAIN_ROOTCERT : AUDIT_CHAIN_CERT, + ci->cert, 0); + } + audit_log (ctrl->audit, AUDIT_CHAIN_END); + } + + if (r_exptime) + gnupg_copy_time (r_exptime, exptime); + xfree (issuer); + xfree (subject); + keydb_release (kh); + while (chain) + { + chain_item_t ci_next = chain->next; + ksba_cert_release (chain->cert); + xfree (chain); + chain = ci_next; + } + ksba_cert_release (issuer_cert); + ksba_cert_release (subject_cert); + return rc; +} + + +/* Validate a certificate chain. For a description see + do_validate_chain. This function is a wrapper to handle a root + certificate with the chain_model flag set. If RETFLAGS is not + NULL, flags indicating now the verification was done are stored + there. The only defined vits for RETFLAGS are + VALIDATE_FLAG_CHAIN_MODEL and VALIDATE_FLAG_STEED. + + If you are verifying a signature you should set CHECKTIME to the + creation time of the signature. If your are verifying a + certificate, set it nil (i.e. the empty string). If the creation + date of the signature is not known use the special date + "19700101T000000" which is treated in a special way here. */ +int +gpgsm_validate_chain (ctrl_t ctrl, ksba_cert_t cert, ksba_isotime_t checktime, + ksba_isotime_t r_exptime, + int listmode, estream_t listfp, unsigned int flags, + unsigned int *retflags) +{ + int rc; + struct rootca_flags_s rootca_flags; + unsigned int dummy_retflags; + + if (!retflags) + retflags = &dummy_retflags; + + /* If the session requested a certain validation mode make sure the + corresponding flags are set. */ + if (ctrl->validation_model == 1) + flags |= VALIDATE_FLAG_CHAIN_MODEL; + else if (ctrl->validation_model == 2) + flags |= VALIDATE_FLAG_STEED; + + /* If the chain model was forced, set this immediately into + RETFLAGS. */ + *retflags = (flags & VALIDATE_FLAG_CHAIN_MODEL); + + memset (&rootca_flags, 0, sizeof rootca_flags); + + rc = do_validate_chain (ctrl, cert, checktime, + r_exptime, listmode, listfp, flags, + &rootca_flags); + if (!rc && (flags & VALIDATE_FLAG_STEED)) + { + *retflags |= VALIDATE_FLAG_STEED; + } + else if (gpg_err_code (rc) == GPG_ERR_CERT_EXPIRED + && !(flags & VALIDATE_FLAG_CHAIN_MODEL) + && (rootca_flags.valid && rootca_flags.chain_model)) + { + do_list (0, listmode, listfp, _("switching to chain model")); + rc = do_validate_chain (ctrl, cert, checktime, + r_exptime, listmode, listfp, + (flags |= VALIDATE_FLAG_CHAIN_MODEL), + &rootca_flags); + *retflags |= VALIDATE_FLAG_CHAIN_MODEL; + } + + if (opt.verbose) + do_list (0, listmode, listfp, _("validation model used: %s"), + (*retflags & VALIDATE_FLAG_STEED)? + "steed" : + (*retflags & VALIDATE_FLAG_CHAIN_MODEL)? + _("chain"):_("shell")); + + 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 (ctrl_t ctrl, ksba_cert_t cert) +{ + int rc = 0; + char *issuer = NULL; + char *subject = NULL; + KEYDB_HANDLE kh; + ksba_cert_t issuer_cert = NULL; + + if (opt.no_chain_validation) + { + log_info ("WARNING: bypassing basic certificate checks\n"); + return 0; + } + + kh = keydb_new (); + if (!kh) + { + log_error (_("failed to allocate keyDB handle\n")); + rc = gpg_error (GPG_ERR_GENERAL); + goto leave; + } + + issuer = ksba_cert_get_issuer (cert, 0); + subject = ksba_cert_get_subject (cert, 0); + if (!issuer) + { + log_error ("no issuer found in certificate\n"); + rc = gpg_error (GPG_ERR_BAD_CERT); + goto leave; + } + + if (is_root_cert (cert, issuer, subject)) + { + rc = gpgsm_check_cert_sig (cert, cert); + if (rc) + { + log_error ("self-signed certificate has a BAD signature: %s\n", + gpg_strerror (rc)); + if (DBG_X509) + { + gpgsm_dump_cert ("self-signing cert", cert); + } + rc = gpg_error (GPG_ERR_BAD_CERT); + goto leave; + } + } + else + { + /* Find the next cert up the tree. */ + keydb_search_reset (kh); + rc = find_up (ctrl, kh, cert, issuer, 0); + if (rc) + { + if (rc == -1) + { + log_info ("issuer certificate (#/"); + gpgsm_dump_string (issuer); + log_printf (") not found\n"); + } + else + log_error ("failed to find issuer's certificate: rc=%d\n", rc); + rc = gpg_error (GPG_ERR_MISSING_ISSUER_CERT); + goto leave; + } + + ksba_cert_release (issuer_cert); issuer_cert = NULL; + rc = keydb_get_cert (kh, &issuer_cert); + if (rc) + { + log_error ("keydb_get_cert() failed: rc=%d\n", rc); + rc = gpg_error (GPG_ERR_GENERAL); + goto leave; + } + + rc = gpgsm_check_cert_sig (issuer_cert, cert); + if (rc) + { + log_error ("certificate has a BAD signature: %s\n", + gpg_strerror (rc)); + if (DBG_X509) + { + gpgsm_dump_cert ("signing issuer", issuer_cert); + gpgsm_dump_cert ("signed subject", cert); + } + rc = gpg_error (GPG_ERR_BAD_CERT); + goto leave; + } + if (opt.verbose) + log_info (_("certificate is good\n")); + } + + leave: + xfree (issuer); + xfree (subject); + keydb_release (kh); + ksba_cert_release (issuer_cert); + return rc; +} + + + +/* Check whether the certificate CERT has been issued by the German + authority for qualified signature. They do not set the + basicConstraints and thus we need this workaround. It works by + looking up the root certificate and checking whether that one is + listed as a qualified certificate for Germany. + + We also try to cache this data but as long as don't keep a + reference to the certificate this won't be used. + + Returns: True if CERT is a RegTP issued CA cert (i.e. the root + certificate itself or one of the CAs). In that case CHAINLEN will + receive the length of the chain which is either 0 or 1. +*/ +static int +get_regtp_ca_info (ctrl_t ctrl, ksba_cert_t cert, int *chainlen) +{ + gpg_error_t err; + ksba_cert_t next; + int rc = 0; + int i, depth; + char country[3]; + ksba_cert_t array[4]; + char buf[2]; + size_t buflen; + int dummy_chainlen; + + if (!chainlen) + chainlen = &dummy_chainlen; + + *chainlen = 0; + err = ksba_cert_get_user_data (cert, "regtp_ca_chainlen", + &buf, sizeof (buf), &buflen); + if (!err) + { + /* Got info. */ + if (buflen < 2 || !*buf) + return 0; /* Nothing found. */ + *chainlen = buf[1]; + return 1; /* This is a regtp CA. */ + } + else if (gpg_err_code (err) != GPG_ERR_NOT_FOUND) + { + log_error ("ksba_cert_get_user_data(%s) failed: %s\n", + "regtp_ca_chainlen", gpg_strerror (err)); + return 0; /* Nothing found. */ + } + + /* Need to gather the info. This requires to walk up the chain + until we have found the root. Because we are only interested in + German Bundesnetzagentur (former RegTP) derived certificates 3 + levels are enough. (The German signature law demands a 3 tier + hierarchy; thus there is only one CA between the EE and the Root + CA.) */ + memset (&array, 0, sizeof array); + + depth = 0; + ksba_cert_ref (cert); + array[depth++] = cert; + ksba_cert_ref (cert); + while (depth < DIM(array) && !(rc=gpgsm_walk_cert_chain (ctrl, cert, &next))) + { + ksba_cert_release (cert); + ksba_cert_ref (next); + array[depth++] = next; + cert = next; + } + ksba_cert_release (cert); + if (rc != -1 || !depth || depth == DIM(array) ) + { + /* We did not reached the root. */ + goto leave; + } + + /* If this is a German signature law issued certificate, we store + additional information. */ + if (!gpgsm_is_in_qualified_list (NULL, array[depth-1], country) + && !strcmp (country, "de")) + { + /* Setting the pathlen for the root CA and the CA flag for the + next one is all what we need to do. */ + err = ksba_cert_set_user_data (array[depth-1], "regtp_ca_chainlen", + "\x01\x01", 2); + if (!err && depth > 1) + err = ksba_cert_set_user_data (array[depth-2], "regtp_ca_chainlen", + "\x01\x00", 2); + if (err) + log_error ("ksba_set_user_data(%s) failed: %s\n", + "regtp_ca_chainlen", gpg_strerror (err)); + for (i=0; i < depth; i++) + ksba_cert_release (array[i]); + *chainlen = (depth>1? 0:1); + return 1; + } + + leave: + /* Nothing special with this certificate. Mark the target + certificate anyway to avoid duplicate lookups. */ + err = ksba_cert_set_user_data (cert, "regtp_ca_chainlen", "", 1); + if (err) + log_error ("ksba_set_user_data(%s) failed: %s\n", + "regtp_ca_chainlen", gpg_strerror (err)); + for (i=0; i < depth; i++) + ksba_cert_release (array[i]); + return 0; +} |