/* certlist.c - build list of certificates * Copyright (C) 2001, 2003, 2004 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 #include #include #include #include #include #include #include #include "gpgsm.h" #include #include #include "keydb.h" #include "i18n.h" static const char oid_kp_serverAuth[] = "1.3.6.1.5.5.7.3.1"; static const char oid_kp_clientAuth[] = "1.3.6.1.5.5.7.3.2"; static const char oid_kp_codeSigning[] = "1.3.6.1.5.5.7.3.3"; static const char oid_kp_emailProtection[]= "1.3.6.1.5.5.7.3.4"; static const char oid_kp_timeStamping[] = "1.3.6.1.5.5.7.3.8"; static const char oid_kp_ocspSigning[] = "1.3.6.1.5.5.7.3.9"; /* 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). MODE 4 is for certificate signing, MODE for COSP response signing. */ static int cert_usage_p (ksba_cert_t cert, int mode) { gpg_error_t err; unsigned int use; char *extkeyusages; int have_ocsp_signing = 0; err = ksba_cert_get_ext_key_usages (cert, &extkeyusages); if (gpg_err_code (err) == GPG_ERR_NO_DATA) err = 0; /* no policy given */ if (!err) { unsigned int extusemask = ~0; /* Allow all. */ if (extkeyusages) { char *p, *pend; int any_critical = 0; extusemask = 0; p = extkeyusages; while (p && (pend=strchr (p, ':'))) { *pend++ = 0; /* Only care about critical flagged usages. */ if ( *pend == 'C' ) { any_critical = 1; if ( !strcmp (p, oid_kp_serverAuth)) extusemask |= (KSBA_KEYUSAGE_DIGITAL_SIGNATURE | KSBA_KEYUSAGE_KEY_ENCIPHERMENT | KSBA_KEYUSAGE_KEY_AGREEMENT); else if ( !strcmp (p, oid_kp_clientAuth)) extusemask |= (KSBA_KEYUSAGE_DIGITAL_SIGNATURE | KSBA_KEYUSAGE_KEY_AGREEMENT); else if ( !strcmp (p, oid_kp_codeSigning)) extusemask |= (KSBA_KEYUSAGE_DIGITAL_SIGNATURE); else if ( !strcmp (p, oid_kp_emailProtection)) extusemask |= (KSBA_KEYUSAGE_DIGITAL_SIGNATURE | KSBA_KEYUSAGE_NON_REPUDIATION | KSBA_KEYUSAGE_KEY_ENCIPHERMENT | KSBA_KEYUSAGE_KEY_AGREEMENT); else if ( !strcmp (p, oid_kp_timeStamping)) extusemask |= (KSBA_KEYUSAGE_DIGITAL_SIGNATURE | KSBA_KEYUSAGE_NON_REPUDIATION); } /* This is a hack to cope with OCSP. Note that we do not yet fully comply with the requirements and that the entire CRL/OCSP checking thing should undergo a thorough review and probably redesign. */ if ( !strcmp (p, oid_kp_ocspSigning)) have_ocsp_signing = 1; if ((p = strchr (pend, '\n'))) p++; } xfree (extkeyusages); extkeyusages = NULL; if (!any_critical) extusemask = ~0; /* Reset to the don't care mask. */ } err = ksba_cert_get_key_usage (cert, &use); if (gpg_err_code (err) == GPG_ERR_NO_DATA) { err = 0; if (opt.verbose && mode < 2) log_info (_("no key usage specified - assuming all usages\n")); use = ~0; } /* Apply extKeyUsage. */ use &= extusemask; } if (err) { log_error (_("error getting key usage information: %s\n"), gpg_strerror (err)); xfree (extkeyusages); return err; } if (mode == 4) { if ((use & (KSBA_KEYUSAGE_KEY_CERT_SIGN))) return 0; log_info (_("certificate should have not " "been used for certification\n")); return gpg_error (GPG_ERR_WRONG_KEY_USAGE); } if (mode == 5) { if (use != ~0 && (have_ocsp_signing || (use & (KSBA_KEYUSAGE_KEY_CERT_SIGN |KSBA_KEYUSAGE_CRL_SIGN)))) return 0; log_info (_("certificate should have not " "been used for OCSP response signing\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); } int gpgsm_cert_use_ocsp_p (ksba_cert_t cert) { return cert_usage_p (cert, 5); } 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_t 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 (ctrl, p)) rc = 0; xfree (p); } } if (!rc) rc = gpgsm_validate_chain (ctrl, cert, NULL, 0, NULL, 0); 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; }