/* * Copyright 1999-2023 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the Apache License 2.0 (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy * in the file LICENSE in the source distribution or at * https://www.openssl.org/source/license.html */ #include #include "internal/cryptlib.h" #include "internal/numbers.h" #include #include #include "crypto/x509.h" #include "internal/tsan_assist.h" #include "x509_local.h" static int check_ssl_ca(const X509 *x); static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int non_leaf); static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int non_leaf); static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int non_leaf); static int purpose_smime(const X509 *x, int non_leaf); static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int non_leaf); static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int non_leaf); static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int non_leaf); static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, int non_leaf); static int check_purpose_code_sign(const X509_PURPOSE *xp, const X509 *x, int non_leaf); static int no_check_purpose(const X509_PURPOSE *xp, const X509 *x, int non_leaf); static int check_purpose_ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int non_leaf); static int xp_cmp(const X509_PURPOSE *const *a, const X509_PURPOSE *const *b); static void xptable_free(X509_PURPOSE *p); static X509_PURPOSE xstandard[] = { {X509_PURPOSE_SSL_CLIENT, X509_TRUST_SSL_CLIENT, 0, check_purpose_ssl_client, "SSL client", "sslclient", NULL}, {X509_PURPOSE_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ssl_server, "SSL server", "sslserver", NULL}, {X509_PURPOSE_NS_SSL_SERVER, X509_TRUST_SSL_SERVER, 0, check_purpose_ns_ssl_server, "Netscape SSL server", "nssslserver", NULL}, {X509_PURPOSE_SMIME_SIGN, X509_TRUST_EMAIL, 0, check_purpose_smime_sign, "S/MIME signing", "smimesign", NULL}, {X509_PURPOSE_SMIME_ENCRYPT, X509_TRUST_EMAIL, 0, check_purpose_smime_encrypt, "S/MIME encryption", "smimeencrypt", NULL}, {X509_PURPOSE_CRL_SIGN, X509_TRUST_COMPAT, 0, check_purpose_crl_sign, "CRL signing", "crlsign", NULL}, {X509_PURPOSE_ANY, X509_TRUST_DEFAULT, 0, no_check_purpose, "Any Purpose", "any", NULL}, {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, check_purpose_ocsp_helper, "OCSP helper", "ocsphelper", NULL}, {X509_PURPOSE_TIMESTAMP_SIGN, X509_TRUST_TSA, 0, check_purpose_timestamp_sign, "Time Stamp signing", "timestampsign", NULL}, {X509_PURPOSE_CODE_SIGN, X509_TRUST_OBJECT_SIGN, 0, check_purpose_code_sign, "Code signing", "codesign", NULL}, }; #define X509_PURPOSE_COUNT OSSL_NELEM(xstandard) static STACK_OF(X509_PURPOSE) *xptable = NULL; static int xp_cmp(const X509_PURPOSE *const *a, const X509_PURPOSE *const *b) { return (*a)->purpose - (*b)->purpose; } /* * As much as I'd like to make X509_check_purpose use a "const" X509* I really * can't because it does recalculate hashes and do other non-const things. * If id == -1 it just calls x509v3_cache_extensions() for its side-effect. * Returns 1 on success, 0 if x does not allow purpose, -1 on (internal) error. */ int X509_check_purpose(X509 *x, int id, int non_leaf) { int idx; const X509_PURPOSE *pt; if (!ossl_x509v3_cache_extensions(x)) return -1; if (id == -1) return 1; idx = X509_PURPOSE_get_by_id(id); if (idx == -1) return -1; pt = X509_PURPOSE_get0(idx); return pt->check_purpose(pt, x, non_leaf); } int X509_PURPOSE_set(int *p, int purpose) { if (X509_PURPOSE_get_by_id(purpose) == -1) { ERR_raise(ERR_LIB_X509V3, X509V3_R_INVALID_PURPOSE); return 0; } *p = purpose; return 1; } int X509_PURPOSE_get_count(void) { if (!xptable) return X509_PURPOSE_COUNT; return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT; } X509_PURPOSE *X509_PURPOSE_get0(int idx) { if (idx < 0) return NULL; if (idx < (int)X509_PURPOSE_COUNT) return xstandard + idx; return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT); } int X509_PURPOSE_get_by_sname(const char *sname) { int i; X509_PURPOSE *xptmp; for (i = 0; i < X509_PURPOSE_get_count(); i++) { xptmp = X509_PURPOSE_get0(i); if (strcmp(xptmp->sname, sname) == 0) return i; } return -1; } /* Returns -1 on error, else an index => 0 in standard/extended purpose table */ int X509_PURPOSE_get_by_id(int purpose) { X509_PURPOSE tmp; int idx; if (purpose >= X509_PURPOSE_MIN && purpose <= X509_PURPOSE_MAX) return purpose - X509_PURPOSE_MIN; if (xptable == NULL) return -1; tmp.purpose = purpose; idx = sk_X509_PURPOSE_find(xptable, &tmp); if (idx < 0) return -1; return idx + X509_PURPOSE_COUNT; } int X509_PURPOSE_add(int id, int trust, int flags, int (*ck) (const X509_PURPOSE *, const X509 *, int), const char *name, const char *sname, void *arg) { int idx; X509_PURPOSE *ptmp; /* This is set according to what we change: application can't set it */ flags &= ~X509_PURPOSE_DYNAMIC; /* This will always be set for application modified trust entries */ flags |= X509_PURPOSE_DYNAMIC_NAME; /* Get existing entry if any */ idx = X509_PURPOSE_get_by_id(id); /* Need a new entry */ if (idx == -1) { if ((ptmp = OPENSSL_malloc(sizeof(*ptmp))) == NULL) return 0; ptmp->flags = X509_PURPOSE_DYNAMIC; } else { ptmp = X509_PURPOSE_get0(idx); } /* OPENSSL_free existing name if dynamic */ if ((ptmp->flags & X509_PURPOSE_DYNAMIC_NAME) != 0) { OPENSSL_free(ptmp->name); OPENSSL_free(ptmp->sname); } /* Dup supplied name */ ptmp->name = OPENSSL_strdup(name); ptmp->sname = OPENSSL_strdup(sname); if (ptmp->name == NULL || ptmp->sname == NULL) goto err; /* Keep the dynamic flag of existing entry */ ptmp->flags &= X509_PURPOSE_DYNAMIC; /* Set all other flags */ ptmp->flags |= flags; ptmp->purpose = id; ptmp->trust = trust; ptmp->check_purpose = ck; ptmp->usr_data = arg; /* If its a new entry manage the dynamic table */ if (idx == -1) { if (xptable == NULL && (xptable = sk_X509_PURPOSE_new(xp_cmp)) == NULL) { ERR_raise(ERR_LIB_X509V3, ERR_R_CRYPTO_LIB); goto err; } if (!sk_X509_PURPOSE_push(xptable, ptmp)) { ERR_raise(ERR_LIB_X509V3, ERR_R_CRYPTO_LIB); goto err; } } return 1; err: if (idx == -1) { OPENSSL_free(ptmp->name); OPENSSL_free(ptmp->sname); OPENSSL_free(ptmp); } return 0; } static void xptable_free(X509_PURPOSE *p) { if (p == NULL) return; if ((p->flags & X509_PURPOSE_DYNAMIC) != 0) { if ((p->flags & X509_PURPOSE_DYNAMIC_NAME) != 0) { OPENSSL_free(p->name); OPENSSL_free(p->sname); } OPENSSL_free(p); } } void X509_PURPOSE_cleanup(void) { sk_X509_PURPOSE_pop_free(xptable, xptable_free); xptable = NULL; } int X509_PURPOSE_get_id(const X509_PURPOSE *xp) { return xp->purpose; } char *X509_PURPOSE_get0_name(const X509_PURPOSE *xp) { return xp->name; } char *X509_PURPOSE_get0_sname(const X509_PURPOSE *xp) { return xp->sname; } int X509_PURPOSE_get_trust(const X509_PURPOSE *xp) { return xp->trust; } static int nid_cmp(const int *a, const int *b) { return *a - *b; } DECLARE_OBJ_BSEARCH_CMP_FN(int, int, nid); IMPLEMENT_OBJ_BSEARCH_CMP_FN(int, int, nid); int X509_supported_extension(X509_EXTENSION *ex) { /* * This table is a list of the NIDs of supported extensions: that is * those which are used by the verify process. If an extension is * critical and doesn't appear in this list then the verify process will * normally reject the certificate. The list must be kept in numerical * order because it will be searched using bsearch. */ static const int supported_nids[] = { NID_netscape_cert_type, /* 71 */ NID_key_usage, /* 83 */ NID_subject_alt_name, /* 85 */ NID_basic_constraints, /* 87 */ NID_certificate_policies, /* 89 */ NID_crl_distribution_points, /* 103 */ NID_ext_key_usage, /* 126 */ #ifndef OPENSSL_NO_RFC3779 NID_sbgp_ipAddrBlock, /* 290 */ NID_sbgp_autonomousSysNum, /* 291 */ #endif NID_id_pkix_OCSP_noCheck, /* 369 */ NID_policy_constraints, /* 401 */ NID_proxyCertInfo, /* 663 */ NID_name_constraints, /* 666 */ NID_policy_mappings, /* 747 */ NID_inhibit_any_policy /* 748 */ }; int ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex)); if (ex_nid == NID_undef) return 0; if (OBJ_bsearch_nid(&ex_nid, supported_nids, OSSL_NELEM(supported_nids))) return 1; return 0; } /* Returns 1 on success, 0 if x is invalid, -1 on (internal) error. */ static int setup_dp(const X509 *x, DIST_POINT *dp) { const X509_NAME *iname = NULL; int i; if (dp->distpoint == NULL && sk_GENERAL_NAME_num(dp->CRLissuer) <= 0) { ERR_raise(ERR_LIB_X509, X509_R_INVALID_DISTPOINT); return 0; } if (dp->reasons != NULL) { if (dp->reasons->length > 0) dp->dp_reasons = dp->reasons->data[0]; if (dp->reasons->length > 1) dp->dp_reasons |= (dp->reasons->data[1] << 8); dp->dp_reasons &= CRLDP_ALL_REASONS; } else { dp->dp_reasons = CRLDP_ALL_REASONS; } if (dp->distpoint == NULL || dp->distpoint->type != 1) return 1; /* Handle name fragment given by nameRelativeToCRLIssuer */ /* * Note that the below way of determining iname is not really compliant * with https://tools.ietf.org/html/rfc5280#section-4.2.1.13 * According to it, sk_GENERAL_NAME_num(dp->CRLissuer) MUST be <= 1 * and any CRLissuer could be of type different to GEN_DIRNAME. */ for (i = 0; i < sk_GENERAL_NAME_num(dp->CRLissuer); i++) { GENERAL_NAME *gen = sk_GENERAL_NAME_value(dp->CRLissuer, i); if (gen->type == GEN_DIRNAME) { iname = gen->d.directoryName; break; } } if (iname == NULL) iname = X509_get_issuer_name(x); return DIST_POINT_set_dpname(dp->distpoint, iname) ? 1 : -1; } /* Return 1 on success, 0 if x is invalid, -1 on (internal) error. */ static int setup_crldp(X509 *x) { int i; x->crldp = X509_get_ext_d2i(x, NID_crl_distribution_points, &i, NULL); if (x->crldp == NULL && i != -1) return 0; for (i = 0; i < sk_DIST_POINT_num(x->crldp); i++) { int res = setup_dp(x, sk_DIST_POINT_value(x->crldp, i)); if (res < 1) return res; } return 1; } /* Check that issuer public key algorithm matches subject signature algorithm */ static int check_sig_alg_match(const EVP_PKEY *issuer_key, const X509 *subject) { int subj_sig_nid; if (issuer_key == NULL) return X509_V_ERR_NO_ISSUER_PUBLIC_KEY; if (OBJ_find_sigid_algs(OBJ_obj2nid(subject->cert_info.signature.algorithm), NULL, &subj_sig_nid) == 0) return X509_V_ERR_UNSUPPORTED_SIGNATURE_ALGORITHM; if (EVP_PKEY_is_a(issuer_key, OBJ_nid2sn(subj_sig_nid)) || (EVP_PKEY_is_a(issuer_key, "RSA") && subj_sig_nid == NID_rsassaPss)) return X509_V_OK; return X509_V_ERR_SIGNATURE_ALGORITHM_MISMATCH; } #define V1_ROOT (EXFLAG_V1 | EXFLAG_SS) #define ku_reject(x, usage) \ (((x)->ex_flags & EXFLAG_KUSAGE) != 0 && ((x)->ex_kusage & (usage)) == 0) #define xku_reject(x, usage) \ (((x)->ex_flags & EXFLAG_XKUSAGE) != 0 && ((x)->ex_xkusage & (usage)) == 0) #define ns_reject(x, usage) \ (((x)->ex_flags & EXFLAG_NSCERT) != 0 && ((x)->ex_nscert & (usage)) == 0) /* * Cache info on various X.509v3 extensions and further derived information, * e.g., if cert 'x' is self-issued, in x->ex_flags and other internal fields. * x->sha1_hash is filled in, or else EXFLAG_NO_FINGERPRINT is set in x->flags. * X509_SIG_INFO_VALID is set in x->flags if x->siginf was filled successfully. * Set EXFLAG_INVALID and return 0 in case the certificate is invalid. */ int ossl_x509v3_cache_extensions(X509 *x) { BASIC_CONSTRAINTS *bs; PROXY_CERT_INFO_EXTENSION *pci; ASN1_BIT_STRING *usage; ASN1_BIT_STRING *ns; EXTENDED_KEY_USAGE *extusage; int i; int res; #ifdef tsan_ld_acq /* Fast lock-free check, see end of the function for details. */ if (tsan_ld_acq((TSAN_QUALIFIER int *)&x->ex_cached)) return (x->ex_flags & EXFLAG_INVALID) == 0; #endif if (!CRYPTO_THREAD_write_lock(x->lock)) return 0; if ((x->ex_flags & EXFLAG_SET) != 0) { /* Cert has already been processed */ CRYPTO_THREAD_unlock(x->lock); return (x->ex_flags & EXFLAG_INVALID) == 0; } ERR_set_mark(); /* Cache the SHA1 digest of the cert */ if (!X509_digest(x, EVP_sha1(), x->sha1_hash, NULL)) x->ex_flags |= EXFLAG_NO_FINGERPRINT; /* V1 should mean no extensions ... */ if (X509_get_version(x) == X509_VERSION_1) x->ex_flags |= EXFLAG_V1; /* Handle basic constraints */ x->ex_pathlen = -1; if ((bs = X509_get_ext_d2i(x, NID_basic_constraints, &i, NULL)) != NULL) { if (bs->ca) x->ex_flags |= EXFLAG_CA; if (bs->pathlen != NULL) { /* * The error case !bs->ca is checked by check_chain() * in case ctx->param->flags & X509_V_FLAG_X509_STRICT */ if (bs->pathlen->type == V_ASN1_NEG_INTEGER) { ERR_raise(ERR_LIB_X509V3, X509V3_R_NEGATIVE_PATHLEN); x->ex_flags |= EXFLAG_INVALID; } else { x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen); } } BASIC_CONSTRAINTS_free(bs); x->ex_flags |= EXFLAG_BCONS; } else if (i != -1) { x->ex_flags |= EXFLAG_INVALID; } /* Handle proxy certificates */ if ((pci = X509_get_ext_d2i(x, NID_proxyCertInfo, &i, NULL)) != NULL) { if ((x->ex_flags & EXFLAG_CA) != 0 || X509_get_ext_by_NID(x, NID_subject_alt_name, -1) >= 0 || X509_get_ext_by_NID(x, NID_issuer_alt_name, -1) >= 0) { x->ex_flags |= EXFLAG_INVALID; } if (pci->pcPathLengthConstraint != NULL) x->ex_pcpathlen = ASN1_INTEGER_get(pci->pcPathLengthConstraint); else x->ex_pcpathlen = -1; PROXY_CERT_INFO_EXTENSION_free(pci); x->ex_flags |= EXFLAG_PROXY; } else if (i != -1) { x->ex_flags |= EXFLAG_INVALID; } /* Handle (basic) key usage */ if ((usage = X509_get_ext_d2i(x, NID_key_usage, &i, NULL)) != NULL) { x->ex_kusage = 0; if (usage->length > 0) { x->ex_kusage = usage->data[0]; if (usage->length > 1) x->ex_kusage |= usage->data[1] << 8; } x->ex_flags |= EXFLAG_KUSAGE; ASN1_BIT_STRING_free(usage); /* Check for empty key usage according to RFC 5280 section 4.2.1.3 */ if (x->ex_kusage == 0) { ERR_raise(ERR_LIB_X509V3, X509V3_R_EMPTY_KEY_USAGE); x->ex_flags |= EXFLAG_INVALID; } } else if (i != -1) { x->ex_flags |= EXFLAG_INVALID; } /* Handle extended key usage */ x->ex_xkusage = 0; if ((extusage = X509_get_ext_d2i(x, NID_ext_key_usage, &i, NULL)) != NULL) { x->ex_flags |= EXFLAG_XKUSAGE; for (i = 0; i < sk_ASN1_OBJECT_num(extusage); i++) { switch (OBJ_obj2nid(sk_ASN1_OBJECT_value(extusage, i))) { case NID_server_auth: x->ex_xkusage |= XKU_SSL_SERVER; break; case NID_client_auth: x->ex_xkusage |= XKU_SSL_CLIENT; break; case NID_email_protect: x->ex_xkusage |= XKU_SMIME; break; case NID_code_sign: x->ex_xkusage |= XKU_CODE_SIGN; break; case NID_ms_sgc: case NID_ns_sgc: x->ex_xkusage |= XKU_SGC; break; case NID_OCSP_sign: x->ex_xkusage |= XKU_OCSP_SIGN; break; case NID_time_stamp: x->ex_xkusage |= XKU_TIMESTAMP; break; case NID_dvcs: x->ex_xkusage |= XKU_DVCS; break; case NID_anyExtendedKeyUsage: x->ex_xkusage |= XKU_ANYEKU; break; default: /* Ignore unknown extended key usage */ break; } } sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free); } else if (i != -1) { x->ex_flags |= EXFLAG_INVALID; } /* Handle legacy Netscape extension */ if ((ns = X509_get_ext_d2i(x, NID_netscape_cert_type, &i, NULL)) != NULL) { if (ns->length > 0) x->ex_nscert = ns->data[0]; else x->ex_nscert = 0; x->ex_flags |= EXFLAG_NSCERT; ASN1_BIT_STRING_free(ns); } else if (i != -1) { x->ex_flags |= EXFLAG_INVALID; } /* Handle subject key identifier and issuer/authority key identifier */ x->skid = X509_get_ext_d2i(x, NID_subject_key_identifier, &i, NULL); if (x->skid == NULL && i != -1) x->ex_flags |= EXFLAG_INVALID; x->akid = X509_get_ext_d2i(x, NID_authority_key_identifier, &i, NULL); if (x->akid == NULL && i != -1) x->ex_flags |= EXFLAG_INVALID; /* Check if subject name matches issuer */ if (X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x)) == 0) { x->ex_flags |= EXFLAG_SI; /* Cert is self-issued */ if (X509_check_akid(x, x->akid) == X509_V_OK /* SKID matches AKID */ /* .. and the signature alg matches the PUBKEY alg: */ && check_sig_alg_match(X509_get0_pubkey(x), x) == X509_V_OK) x->ex_flags |= EXFLAG_SS; /* indicate self-signed */ /* This is very related to ossl_x509_likely_issued(x, x) == X509_V_OK */ } /* Handle subject alternative names and various other extensions */ x->altname = X509_get_ext_d2i(x, NID_subject_alt_name, &i, NULL); if (x->altname == NULL && i != -1) x->ex_flags |= EXFLAG_INVALID; x->nc = X509_get_ext_d2i(x, NID_name_constraints, &i, NULL); if (x->nc == NULL && i != -1) x->ex_flags |= EXFLAG_INVALID; /* Handle CRL distribution point entries */ res = setup_crldp(x); if (res == 0) x->ex_flags |= EXFLAG_INVALID; #ifndef OPENSSL_NO_RFC3779 x->rfc3779_addr = X509_get_ext_d2i(x, NID_sbgp_ipAddrBlock, &i, NULL); if (x->rfc3779_addr == NULL && i != -1) x->ex_flags |= EXFLAG_INVALID; x->rfc3779_asid = X509_get_ext_d2i(x, NID_sbgp_autonomousSysNum, &i, NULL); if (x->rfc3779_asid == NULL && i != -1) x->ex_flags |= EXFLAG_INVALID; #endif for (i = 0; i < X509_get_ext_count(x); i++) { X509_EXTENSION *ex = X509_get_ext(x, i); int nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex)); if (nid == NID_freshest_crl) x->ex_flags |= EXFLAG_FRESHEST; if (!X509_EXTENSION_get_critical(ex)) continue; if (!X509_supported_extension(ex)) { x->ex_flags |= EXFLAG_CRITICAL; break; } switch (nid) { case NID_basic_constraints: x->ex_flags |= EXFLAG_BCONS_CRITICAL; break; case NID_authority_key_identifier: x->ex_flags |= EXFLAG_AKID_CRITICAL; break; case NID_subject_key_identifier: x->ex_flags |= EXFLAG_SKID_CRITICAL; break; case NID_subject_alt_name: x->ex_flags |= EXFLAG_SAN_CRITICAL; break; default: break; } } /* Set x->siginf, ignoring errors due to unsupported algos */ (void)ossl_x509_init_sig_info(x); x->ex_flags |= EXFLAG_SET; /* Indicate that cert has been processed */ #ifdef tsan_st_rel tsan_st_rel((TSAN_QUALIFIER int *)&x->ex_cached, 1); /* * Above store triggers fast lock-free check in the beginning of the * function. But one has to ensure that the structure is "stable", i.e. * all stores are visible on all processors. Hence the release fence. */ #endif ERR_pop_to_mark(); if ((x->ex_flags & EXFLAG_INVALID) == 0) { CRYPTO_THREAD_unlock(x->lock); return 1; } CRYPTO_THREAD_unlock(x->lock); ERR_raise(ERR_LIB_X509V3, X509V3_R_INVALID_CERTIFICATE); return 0; } /*- * CA checks common to all purposes * return codes: * 0 not a CA * 1 is a CA * 2 Only possible in older versions of openSSL when basicConstraints are absent * new versions will not return this value. May be a CA * 3 basicConstraints absent but self-signed V1. * 4 basicConstraints absent but keyUsage present and keyCertSign asserted. * 5 Netscape specific CA Flags present */ static int check_ca(const X509 *x) { /* keyUsage if present should allow cert signing */ if (ku_reject(x, KU_KEY_CERT_SIGN)) return 0; if ((x->ex_flags & EXFLAG_BCONS) != 0) { /* If basicConstraints says not a CA then say so */ return (x->ex_flags & EXFLAG_CA) != 0; } else { /* We support V1 roots for... uh, I don't really know why. */ if ((x->ex_flags & V1_ROOT) == V1_ROOT) return 3; /* * If key usage present it must have certSign so tolerate it */ else if ((x->ex_flags & EXFLAG_KUSAGE) != 0) return 4; /* Older certificates could have Netscape-specific CA types */ else if ((x->ex_flags & EXFLAG_NSCERT) != 0 && (x->ex_nscert & NS_ANY_CA) != 0) return 5; /* Can this still be regarded a CA certificate? I doubt it. */ return 0; } } void X509_set_proxy_flag(X509 *x) { if (CRYPTO_THREAD_write_lock(x->lock)) { x->ex_flags |= EXFLAG_PROXY; CRYPTO_THREAD_unlock(x->lock); } } void X509_set_proxy_pathlen(X509 *x, long l) { x->ex_pcpathlen = l; } int X509_check_ca(X509 *x) { /* Note 0 normally means "not a CA" - but in this case means error. */ if (!ossl_x509v3_cache_extensions(x)) return 0; return check_ca(x); } /* Check SSL CA: common checks for SSL client and server. */ static int check_ssl_ca(const X509 *x) { int ca_ret = check_ca(x); if (ca_ret == 0) return 0; /* Check nsCertType if present */ return ca_ret != 5 || (x->ex_nscert & NS_SSL_CA) != 0; } static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int non_leaf) { if (xku_reject(x, XKU_SSL_CLIENT)) return 0; if (non_leaf) return check_ssl_ca(x); /* We need to do digital signatures or key agreement */ if (ku_reject(x, KU_DIGITAL_SIGNATURE | KU_KEY_AGREEMENT)) return 0; /* nsCertType if present should allow SSL client use */ if (ns_reject(x, NS_SSL_CLIENT)) return 0; return 1; } /* * Key usage needed for TLS/SSL server: digital signature, encipherment or * key agreement. The ssl code can check this more thoroughly for individual * key types. */ #define KU_TLS \ KU_DIGITAL_SIGNATURE | KU_KEY_ENCIPHERMENT | KU_KEY_AGREEMENT static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int non_leaf) { if (xku_reject(x, XKU_SSL_SERVER | XKU_SGC)) return 0; if (non_leaf) return check_ssl_ca(x); if (ns_reject(x, NS_SSL_SERVER)) return 0; if (ku_reject(x, KU_TLS)) return 0; return 1; } static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int non_leaf) { int ret = check_purpose_ssl_server(xp, x, non_leaf); if (!ret || non_leaf) return ret; /* We need to encipher or Netscape complains */ return ku_reject(x, KU_KEY_ENCIPHERMENT) ? 0 : ret; } /* common S/MIME checks */ static int purpose_smime(const X509 *x, int non_leaf) { if (xku_reject(x, XKU_SMIME)) return 0; if (non_leaf) { int ca_ret = check_ca(x); if (ca_ret == 0) return 0; /* Check nsCertType if present */ if (ca_ret != 5 || (x->ex_nscert & NS_SMIME_CA) != 0) return ca_ret; else return 0; } if ((x->ex_flags & EXFLAG_NSCERT) != 0) { if ((x->ex_nscert & NS_SMIME) != 0) return 1; /* Workaround for some buggy certificates */ return (x->ex_nscert & NS_SSL_CLIENT) != 0 ? 2 : 0; } return 1; } static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int non_leaf) { int ret = purpose_smime(x, non_leaf); if (!ret || non_leaf) return ret; return ku_reject(x, KU_DIGITAL_SIGNATURE | KU_NON_REPUDIATION) ? 0 : ret; } static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int non_leaf) { int ret = purpose_smime(x, non_leaf); if (!ret || non_leaf) return ret; return ku_reject(x, KU_KEY_ENCIPHERMENT) ? 0 : ret; } static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int non_leaf) { if (non_leaf) { int ca_ret = check_ca(x); return ca_ret == 2 ? 0 : ca_ret; } return !ku_reject(x, KU_CRL_SIGN); } /* * OCSP helper: this is *not* a full OCSP check. It just checks that each CA * is valid. Additional checks must be made on the chain. */ static int check_purpose_ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int non_leaf) { /* * Must be a valid CA. Should we really support the "I don't know" value * (2)? */ if (non_leaf) return check_ca(x); /* Leaf certificate is checked in OCSP_verify() */ return 1; } static int check_purpose_timestamp_sign(const X509_PURPOSE *xp, const X509 *x, int non_leaf) { int i_ext; /* * If non_leaf is true we must check if this is a valid CA certificate. * The extra requirements by the CA/Browser Forum are not checked. */ if (non_leaf) return check_ca(x); /* * Key Usage is checked according to RFC 5280 and * Extended Key Usage attributes is checked according to RFC 3161. * The extra (and somewhat conflicting) CA/Browser Forum * Baseline Requirements for the Issuance and Management of * Publicly‐Trusted Code Signing Certificates, Version 3.0.0, * Section 7.1.2.3: Code signing and Timestamp Certificate are not checked. */ /* * Check the optional key usage field: * if Key Usage is present, it must be one of digitalSignature * and/or nonRepudiation (other values are not consistent and shall * be rejected). */ if ((x->ex_flags & EXFLAG_KUSAGE) != 0 && ((x->ex_kusage & ~(KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)) || !(x->ex_kusage & (KU_NON_REPUDIATION | KU_DIGITAL_SIGNATURE)))) return 0; /* Only timestamp key usage is permitted and it's required. */ if ((x->ex_flags & EXFLAG_XKUSAGE) == 0 || x->ex_xkusage != XKU_TIMESTAMP) return 0; /* Extended Key Usage MUST be critical */ i_ext = X509_get_ext_by_NID(x, NID_ext_key_usage, -1); if (i_ext >= 0 && !X509_EXTENSION_get_critical(X509_get_ext((X509 *)x, i_ext))) return 0; return 1; } static int check_purpose_code_sign(const X509_PURPOSE *xp, const X509 *x, int non_leaf) { int i_ext; /* * If non_leaf is true we must check if this is a valid CA certificate. * The extra requirements by the CA/Browser Forum are not checked. */ if (non_leaf) return check_ca(x); /* * Check the key usage and extended key usage fields: * * Reference: CA/Browser Forum, * Baseline Requirements for the Issuance and Management of * Publicly‐Trusted Code Signing Certificates, Version 3.0.0, * Section 7.1.2.3: Code signing and Timestamp Certificate * * Checking covers Key Usage and Extended Key Usage attributes. * The certificatePolicies, cRLDistributionPoints (CDP), and * authorityInformationAccess (AIA) extensions are so far not checked. */ /* Key Usage */ if ((x->ex_flags & EXFLAG_KUSAGE) == 0) return 0; if ((x->ex_kusage & KU_DIGITAL_SIGNATURE) == 0) return 0; if ((x->ex_kusage & (KU_KEY_CERT_SIGN | KU_CRL_SIGN)) != 0) return 0; /* Key Usage MUST be critical */ i_ext = X509_get_ext_by_NID(x, NID_key_usage, -1); if (i_ext < 0) return 0; if (i_ext >= 0) { X509_EXTENSION *ext = X509_get_ext((X509 *)x, i_ext); if (!X509_EXTENSION_get_critical(ext)) return 0; } /* Extended Key Usage */ if ((x->ex_flags & EXFLAG_XKUSAGE) == 0) return 0; if ((x->ex_xkusage & XKU_CODE_SIGN) == 0) return 0; if ((x->ex_xkusage & (XKU_ANYEKU | XKU_SSL_SERVER)) != 0) return 0; return 1; } static int no_check_purpose(const X509_PURPOSE *xp, const X509 *x, int non_leaf) { return 1; } /*- * Various checks to see if one certificate potentially issued the second. * This can be used to prune a set of possible issuer certificates which * have been looked up using some simple method such as by subject name. * These are: * 1. issuer_name(subject) == subject_name(issuer) * 2. If akid(subject) exists, it matches the respective issuer fields. * 3. subject signature algorithm == issuer public key algorithm * 4. If key_usage(issuer) exists, it allows for signing subject. * Note that this does not include actually checking the signature. * Returns 0 for OK, or positive for reason for mismatch * where reason codes match those for X509_verify_cert(). */ int X509_check_issued(X509 *issuer, X509 *subject) { int ret; if ((ret = ossl_x509_likely_issued(issuer, subject)) != X509_V_OK) return ret; return ossl_x509_signing_allowed(issuer, subject); } /* do the checks 1., 2., and 3. as described above for X509_check_issued() */ int ossl_x509_likely_issued(X509 *issuer, X509 *subject) { int ret; if (X509_NAME_cmp(X509_get_subject_name(issuer), X509_get_issuer_name(subject)) != 0) return X509_V_ERR_SUBJECT_ISSUER_MISMATCH; /* set issuer->skid and subject->akid */ if (!ossl_x509v3_cache_extensions(issuer) || !ossl_x509v3_cache_extensions(subject)) return X509_V_ERR_UNSPECIFIED; ret = X509_check_akid(issuer, subject->akid); if (ret != X509_V_OK) return ret; /* Check if the subject signature alg matches the issuer's PUBKEY alg */ return check_sig_alg_match(X509_get0_pubkey(issuer), subject); } /*- * Check if certificate I is allowed to issue certificate I * according to the B field of I if present * depending on any proxyCertInfo extension of I. * Returns 0 for OK, or positive for reason for rejection * where reason codes match those for X509_verify_cert(). */ int ossl_x509_signing_allowed(const X509 *issuer, const X509 *subject) { if ((subject->ex_flags & EXFLAG_PROXY) != 0) { if (ku_reject(issuer, KU_DIGITAL_SIGNATURE)) return X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE; } else if (ku_reject(issuer, KU_KEY_CERT_SIGN)) { return X509_V_ERR_KEYUSAGE_NO_CERTSIGN; } return X509_V_OK; } int X509_check_akid(const X509 *issuer, const AUTHORITY_KEYID *akid) { if (akid == NULL) return X509_V_OK; /* Check key ids (if present) */ if (akid->keyid && issuer->skid && ASN1_OCTET_STRING_cmp(akid->keyid, issuer->skid)) return X509_V_ERR_AKID_SKID_MISMATCH; /* Check serial number */ if (akid->serial && ASN1_INTEGER_cmp(X509_get0_serialNumber(issuer), akid->serial)) return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; /* Check issuer name */ if (akid->issuer) { /* * Ugh, for some peculiar reason AKID includes SEQUENCE OF * GeneralName. So look for a DirName. There may be more than one but * we only take any notice of the first. */ GENERAL_NAMES *gens = akid->issuer; GENERAL_NAME *gen; X509_NAME *nm = NULL; int i; for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) { gen = sk_GENERAL_NAME_value(gens, i); if (gen->type == GEN_DIRNAME) { nm = gen->d.dirn; break; } } if (nm != NULL && X509_NAME_cmp(nm, X509_get_issuer_name(issuer)) != 0) return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; } return X509_V_OK; } uint32_t X509_get_extension_flags(X509 *x) { /* Call for side-effect of computing hash and caching extensions */ X509_check_purpose(x, -1, 0); return x->ex_flags; } uint32_t X509_get_key_usage(X509 *x) { /* Call for side-effect of computing hash and caching extensions */ if (X509_check_purpose(x, -1, 0) != 1) return 0; return (x->ex_flags & EXFLAG_KUSAGE) != 0 ? x->ex_kusage : UINT32_MAX; } uint32_t X509_get_extended_key_usage(X509 *x) { /* Call for side-effect of computing hash and caching extensions */ if (X509_check_purpose(x, -1, 0) != 1) return 0; return (x->ex_flags & EXFLAG_XKUSAGE) != 0 ? x->ex_xkusage : UINT32_MAX; } const ASN1_OCTET_STRING *X509_get0_subject_key_id(X509 *x) { /* Call for side-effect of computing hash and caching extensions */ if (X509_check_purpose(x, -1, 0) != 1) return NULL; return x->skid; } const ASN1_OCTET_STRING *X509_get0_authority_key_id(X509 *x) { /* Call for side-effect of computing hash and caching extensions */ if (X509_check_purpose(x, -1, 0) != 1) return NULL; return (x->akid != NULL ? x->akid->keyid : NULL); } const GENERAL_NAMES *X509_get0_authority_issuer(X509 *x) { /* Call for side-effect of computing hash and caching extensions */ if (X509_check_purpose(x, -1, 0) != 1) return NULL; return (x->akid != NULL ? x->akid->issuer : NULL); } const ASN1_INTEGER *X509_get0_authority_serial(X509 *x) { /* Call for side-effect of computing hash and caching extensions */ if (X509_check_purpose(x, -1, 0) != 1) return NULL; return (x->akid != NULL ? x->akid->serial : NULL); } long X509_get_pathlen(X509 *x) { /* Called for side effect of caching extensions */ if (X509_check_purpose(x, -1, 0) != 1 || (x->ex_flags & EXFLAG_BCONS) == 0) return -1; return x->ex_pathlen; } long X509_get_proxy_pathlen(X509 *x) { /* Called for side effect of caching extensions */ if (X509_check_purpose(x, -1, 0) != 1 || (x->ex_flags & EXFLAG_PROXY) == 0) return -1; return x->ex_pcpathlen; }