diff options
Diffstat (limited to 'sm/certlist.c')
| -rw-r--r-- | sm/certlist.c | 618 |
1 files changed, 618 insertions, 0 deletions
diff --git a/sm/certlist.c b/sm/certlist.c new file mode 100644 index 0000000..b1ae58c --- /dev/null +++ b/sm/certlist.c @@ -0,0 +1,618 @@ +/* certlist.c - build list of certificates + * Copyright (C) 2001, 2003, 2004, 2005, 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 <assert.h> + +#include "gpgsm.h" +#include <gcrypt.h> +#include <ksba.h> + +#include "keydb.h" +#include "../common/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, int silent) +{ + gpg_error_t err; + unsigned int use; + unsigned int encr_bits, sign_bits; + 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 && !silent) + 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; + if (!silent) + log_info (_("certificate should not have " + "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; + if (!silent) + log_info (_("certificate should not have " + "been used for OCSP response signing\n")); + return gpg_error (GPG_ERR_WRONG_KEY_USAGE); + } + + encr_bits = (KSBA_KEYUSAGE_KEY_ENCIPHERMENT|KSBA_KEYUSAGE_DATA_ENCIPHERMENT); + if ((opt.compat_flags & COMPAT_ALLOW_KA_TO_ENCR)) + encr_bits |= KSBA_KEYUSAGE_KEY_AGREEMENT; + + sign_bits = (KSBA_KEYUSAGE_DIGITAL_SIGNATURE|KSBA_KEYUSAGE_NON_REPUDIATION); + + if ((use & ((mode&1)? encr_bits : sign_bits))) + return 0; + + if (!silent) + log_info + (mode==3? _("certificate should not have been used for encryption\n"): + mode==2? _("certificate should not have 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, int silent) +{ + return cert_usage_p (cert, 0, silent); +} + + +/* 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, 0); +} + +int +gpgsm_cert_use_verify_p (ksba_cert_t cert) +{ + return cert_usage_p (cert, 2, 0); +} + +int +gpgsm_cert_use_decrypt_p (ksba_cert_t cert) +{ + return cert_usage_p (cert, 3, 0); +} + +int +gpgsm_cert_use_cert_p (ksba_cert_t cert) +{ + return cert_usage_p (cert, 4, 0); +} + +int +gpgsm_cert_use_ocsp_p (ksba_cert_t cert) +{ + return cert_usage_p (cert, 5, 0); +} + + +/* Return true if CERT has the well known private key extension. */ +int +gpgsm_cert_has_well_known_private_key (ksba_cert_t cert) +{ + int idx; + const char *oid; + + for (idx=0; !ksba_cert_get_extension (cert, idx, + &oid, NULL, NULL, NULL);idx++) + if (!strcmp (oid, "1.3.6.1.4.1.11591.2.2.2") ) + return 1; /* Yes. */ + return 0; /* No. */ +} + + +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_issuer (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_A is the same as CERT_B. */ +int +gpgsm_certs_identical_p (ksba_cert_t cert_a, ksba_cert_t cert_b) +{ + const unsigned char *img_a, *img_b; + size_t len_a, len_b; + + img_a = ksba_cert_get_image (cert_a, &len_a); + if (img_a) + { + img_b = ksba_cert_get_image (cert_b, &len_b); + if (img_b && len_a == len_b && !memcmp (img_a, img_b, len_a)) + return 1; /* Identical. */ + } + return 0; +} + + +/* 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) +{ + (void)ctrl; + + if (!is_cert_in_certlist (cert, *listaddr)) + { + certlist_t cl = xtrycalloc (1, sizeof *cl); + if (!cl) + return out_of_core (); + 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_t *listaddr, int is_encrypt_to) +{ + int rc; + KEYDB_SEARCH_DESC desc; + KEYDB_HANDLE kh = NULL; + ksba_cert_t cert = NULL; + + rc = classify_user_id (name, &desc, 0); + if (!rc) + { + kh = keydb_new (); + if (!kh) + rc = gpg_error (GPG_ERR_ENOMEM); + else + { + int wrong_usage = 0; + char *first_subject = NULL; + char *first_issuer = NULL; + + get_next: + rc = keydb_search (ctrl, kh, &desc, 1); + if (!rc) + rc = keydb_get_cert (kh, &cert); + if (!rc) + { + if (!first_subject) + { + /* Save the subject and the issuer for key usage + and ambiguous name tests. */ + first_subject = ksba_cert_get_subject (cert, 0); + first_issuer = ksba_cert_get_issuer (cert, 0); + } + rc = secret? gpgsm_cert_use_sign_p (cert, 0) + : 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; + ksba_cert_release (cert); + cert = NULL; + goto get_next; + } + else if (same_subject_issuer (first_subject, first_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) + { + certlist_t dup_certs = NULL; + + next_ambigious: + rc = keydb_search (ctrl, kh, &desc, 1); + if (rc == -1) + rc = 0; + else if (!rc) + { + ksba_cert_t cert2 = NULL; + + /* If this is the first possible duplicate, add the original + certificate to our list of duplicates. */ + if (!dup_certs) + gpgsm_add_cert_to_certlist (ctrl, cert, &dup_certs, 0); + + /* We have to ignore ambiguous names as long as + there only fault is a bad key usage. This is + required to support encryption and signing + certificates of the same subject. + + Further we ignore them if they are due to an + identical certificate (which may happen if a + certificate is accidential duplicated in the + keybox). */ + if (!keydb_get_cert (kh, &cert2)) + { + int tmp = (same_subject_issuer (first_subject, + first_issuer, + cert2) + && ((gpg_err_code ( + secret? gpgsm_cert_use_sign_p (cert2,0) + : gpgsm_cert_use_encrypt_p (cert2) + ) + ) == GPG_ERR_WRONG_KEY_USAGE)); + if (tmp) + gpgsm_add_cert_to_certlist (ctrl, cert2, + &dup_certs, 0); + else + { + if (is_cert_in_certlist (cert2, dup_certs)) + tmp = 1; + } + + ksba_cert_release (cert2); + if (tmp) + goto next_ambigious; + } + rc = gpg_error (GPG_ERR_AMBIGUOUS_NAME); + } + gpgsm_release_certlist (dup_certs); + } + xfree (first_subject); + xfree (first_issuer); + first_subject = NULL; + first_issuer = NULL; + + 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, NULL); + if (!rc) + { + certlist_t cl = xtrycalloc (1, sizeof *cl); + if (!cl) + rc = out_of_core (); + 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_t list) +{ + while (list) + { + certlist_t 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. If KEYID is not NULL it is taken as an + additional filter value which must match the + subjectKeyIdentifier. */ +int +gpgsm_find_cert (ctrl_t ctrl, + const char *name, ksba_sexp_t keyid, ksba_cert_t *r_cert, + int allow_ambiguous) +{ + int rc; + KEYDB_SEARCH_DESC desc; + KEYDB_HANDLE kh = NULL; + + *r_cert = NULL; + rc = classify_user_id (name, &desc, 0); + if (!rc) + { + kh = keydb_new (); + if (!kh) + rc = gpg_error (GPG_ERR_ENOMEM); + else + { + nextone: + rc = keydb_search (ctrl, kh, &desc, 1); + if (!rc) + { + rc = keydb_get_cert (kh, r_cert); + if (!rc && keyid) + { + ksba_sexp_t subj; + + rc = ksba_cert_get_subj_key_id (*r_cert, NULL, &subj); + if (!rc) + { + if (cmp_simple_canon_sexp (keyid, subj)) + { + xfree (subj); + goto nextone; + } + xfree (subj); + /* Okay: Here we know that the certificate's + subjectKeyIdentifier matches the requested + one. */ + } + else if (gpg_err_code (rc) == GPG_ERR_NO_DATA) + goto nextone; + } + } + + /* If we don't have the KEYID filter we need to check for + ambiguous search results. Note, that it is somehwat + reasonable to assume that a specification of a KEYID + won't lead to ambiguous names. */ + if (!rc && !keyid) + { + ksba_isotime_t notbefore = ""; + const unsigned char *image = NULL; + size_t length = 0; + if (allow_ambiguous) + { + /* We want to return the newest certificate */ + if (ksba_cert_get_validity (*r_cert, 0, notbefore)) + *notbefore = '\0'; + image = ksba_cert_get_image (*r_cert, &length); + } + next_ambiguous: + rc = keydb_search (ctrl, kh, &desc, 1); + if (rc == -1) + rc = 0; + else + { + if (!rc) + { + ksba_cert_t cert2 = NULL; + ksba_isotime_t notbefore2 = ""; + const unsigned char *image2 = NULL; + size_t length2 = 0; + int cmp = 0; + + if (!keydb_get_cert (kh, &cert2)) + { + if (gpgsm_certs_identical_p (*r_cert, cert2)) + { + ksba_cert_release (cert2); + goto next_ambiguous; + } + if (allow_ambiguous) + { + if (ksba_cert_get_validity (cert2, 0, notbefore2)) + *notbefore2 = '\0'; + image2 = ksba_cert_get_image (cert2, &length2); + cmp = strcmp (notbefore, notbefore2); + /* use certificate image bits as last resort for stable ordering */ + if (!cmp) + cmp = memcmp (image, image2, length < length2 ? length : length2); + if (!cmp) + cmp = length < length2 ? -1 : length > length2 ? 1 : 0; + if (cmp < 0) + { + ksba_cert_release (*r_cert); + *r_cert = cert2; + strcpy (notbefore, notbefore2); + image = image2; + length = length2; + } + else + ksba_cert_release (cert2); + goto next_ambiguous; + } + ksba_cert_release (cert2); + } + 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; +} |