/* v3_purp.c */ /* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL * project 2001. */ /* ==================================================================== * Copyright (c) 1999-2001 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * licensing@OpenSSL.org. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== * * This product includes cryptographic software written by Eric Young * (eay@cryptsoft.com). This product includes software written by Tim * Hudson (tjh@cryptsoft.com). * */ #include #include "cryptlib.h" #include #include static void x509v3_cache_extensions(X509 *x); static int ca_check(const X509 *x); static int check_ssl_ca(const X509 *x); static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca); static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca); static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca); static int purpose_smime(const X509 *x, int ca); static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca); static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca); static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca); static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca); static int ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca); 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, "Any Purpose", "any", NULL}, {X509_PURPOSE_OCSP_HELPER, X509_TRUST_COMPAT, 0, ocsp_helper, "OCSP helper", "ocsphelper", NULL}, }; #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE)) IMPLEMENT_STACK_OF(X509_PURPOSE) 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. */ int X509_check_purpose(X509 *x, int id, int ca) { int idx; const X509_PURPOSE *pt; if(!(x->ex_flags & EXFLAG_SET)) { CRYPTO_w_lock(CRYPTO_LOCK_X509); x509v3_cache_extensions(x); CRYPTO_w_unlock(CRYPTO_LOCK_X509); } 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, ca); } int X509_PURPOSE_set(int *p, int purpose) { if(X509_PURPOSE_get_by_id(purpose) == -1) { X509V3err(X509V3_F_X509_PURPOSE_SET, 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 < X509_PURPOSE_COUNT) return xstandard + idx; return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT); } int X509_PURPOSE_get_by_sname(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)) return i; } return -1; } 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; tmp.purpose = purpose; if(!xptable) return -1; idx = sk_X509_PURPOSE_find(xptable, &tmp); if(idx == -1) 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), char *name, 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(X509_PURPOSE)))) { X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); 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) { OPENSSL_free(ptmp->name); OPENSSL_free(ptmp->sname); } /* dup supplied name */ ptmp->name = BUF_strdup(name); ptmp->sname = BUF_strdup(sname); if(!ptmp->name || !ptmp->sname) { X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); return 0; } /* 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 && !(xptable = sk_X509_PURPOSE_new(xp_cmp))) { X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); return 0; } if (!sk_X509_PURPOSE_push(xptable, ptmp)) { X509V3err(X509V3_F_X509_PURPOSE_ADD,ERR_R_MALLOC_FAILURE); return 0; } } return 1; } static void xptable_free(X509_PURPOSE *p) { if(!p) return; if (p->flags & X509_PURPOSE_DYNAMIC) { if (p->flags & X509_PURPOSE_DYNAMIC_NAME) { OPENSSL_free(p->name); OPENSSL_free(p->sname); } OPENSSL_free(p); } } void X509_PURPOSE_cleanup(void) { int i; sk_X509_PURPOSE_pop_free(xptable, xptable_free); for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free(xstandard + i); xptable = NULL; } int X509_PURPOSE_get_id(X509_PURPOSE *xp) { return xp->purpose; } char *X509_PURPOSE_get0_name(X509_PURPOSE *xp) { return xp->name; } char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp) { return xp->sname; } int X509_PURPOSE_get_trust(X509_PURPOSE *xp) { return xp->trust; } static int nid_cmp(int *a, int *b) { return *a - *b; } 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 int supported_nids[] = { NID_netscape_cert_type, /* 71 */ NID_key_usage, /* 83 */ NID_subject_alt_name, /* 85 */ NID_basic_constraints, /* 87 */ NID_ext_key_usage /* 126 */ }; int ex_nid; ex_nid = OBJ_obj2nid(X509_EXTENSION_get_object(ex)); if (ex_nid == NID_undef) return 0; if (OBJ_bsearch((char *)&ex_nid, (char *)supported_nids, sizeof(supported_nids)/sizeof(int), sizeof(int), (int (*)(const void *, const void *))nid_cmp)) return 1; return 0; } static void x509v3_cache_extensions(X509 *x) { BASIC_CONSTRAINTS *bs; ASN1_BIT_STRING *usage; ASN1_BIT_STRING *ns; EXTENDED_KEY_USAGE *extusage; X509_EXTENSION *ex; int i; if(x->ex_flags & EXFLAG_SET) return; #ifndef OPENSSL_NO_SHA X509_digest(x, EVP_sha1(), x->sha1_hash, NULL); #endif /* Does subject name match issuer ? */ if(!X509_NAME_cmp(X509_get_subject_name(x), X509_get_issuer_name(x))) x->ex_flags |= EXFLAG_SS; /* V1 should mean no extensions ... */ if(!X509_get_version(x)) x->ex_flags |= EXFLAG_V1; /* Handle basic constraints */ if((bs=X509_get_ext_d2i(x, NID_basic_constraints, NULL, NULL))) { if(bs->ca) x->ex_flags |= EXFLAG_CA; if(bs->pathlen) { if((bs->pathlen->type == V_ASN1_NEG_INTEGER) || !bs->ca) { x->ex_flags |= EXFLAG_INVALID; x->ex_pathlen = 0; } else x->ex_pathlen = ASN1_INTEGER_get(bs->pathlen); } else x->ex_pathlen = -1; BASIC_CONSTRAINTS_free(bs); x->ex_flags |= EXFLAG_BCONS; } /* Handle key usage */ if((usage=X509_get_ext_d2i(x, NID_key_usage, NULL, NULL))) { if(usage->length > 0) { x->ex_kusage = usage->data[0]; if(usage->length > 1) x->ex_kusage |= usage->data[1] << 8; } else x->ex_kusage = 0; x->ex_flags |= EXFLAG_KUSAGE; ASN1_BIT_STRING_free(usage); } x->ex_xkusage = 0; if((extusage=X509_get_ext_d2i(x, NID_ext_key_usage, 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; } } sk_ASN1_OBJECT_pop_free(extusage, ASN1_OBJECT_free); } if((ns=X509_get_ext_d2i(x, NID_netscape_cert_type, 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); } x->skid =X509_get_ext_d2i(x, NID_subject_key_identifier, NULL, NULL); x->akid =X509_get_ext_d2i(x, NID_authority_key_identifier, NULL, NULL); for (i = 0; i < X509_get_ext_count(x); i++) { ex = X509_get_ext(x, i); if (!X509_EXTENSION_get_critical(ex)) continue; if (!X509_supported_extension(ex)) { x->ex_flags |= EXFLAG_CRITICAL; break; } } x->ex_flags |= EXFLAG_SET; } /* CA checks common to all purposes * return codes: * 0 not a CA * 1 is a CA * 2 basicConstraints absent so "maybe" a CA * 3 basicConstraints absent but self signed V1. */ #define V1_ROOT (EXFLAG_V1|EXFLAG_SS) #define ku_reject(x, usage) \ (((x)->ex_flags & EXFLAG_KUSAGE) && !((x)->ex_kusage & (usage))) #define xku_reject(x, usage) \ (((x)->ex_flags & EXFLAG_XKUSAGE) && !((x)->ex_xkusage & (usage))) #define ns_reject(x, usage) \ (((x)->ex_flags & EXFLAG_NSCERT) && !((x)->ex_nscert & (usage))) static int ca_check(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) { if(x->ex_flags & EXFLAG_CA) return 1; /* If basicConstraints says not a CA then say so */ else return 0; } else { 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) return 3; else return 2; } } /* Check SSL CA: common checks for SSL client and server */ static int check_ssl_ca(const X509 *x) { int ca_ret; ca_ret = ca_check(x); if(!ca_ret) return 0; /* check nsCertType if present */ if(x->ex_flags & EXFLAG_NSCERT) { if(x->ex_nscert & NS_SSL_CA) return ca_ret; return 0; } if(ca_ret != 2) return ca_ret; else return 0; } static int check_purpose_ssl_client(const X509_PURPOSE *xp, const X509 *x, int ca) { if(xku_reject(x,XKU_SSL_CLIENT)) return 0; if(ca) return check_ssl_ca(x); /* We need to do digital signatures with it */ if(ku_reject(x,KU_DIGITAL_SIGNATURE)) return 0; /* nsCertType if present should allow SSL client use */ if(ns_reject(x, NS_SSL_CLIENT)) return 0; return 1; } static int check_purpose_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) { if(xku_reject(x,XKU_SSL_SERVER|XKU_SGC)) return 0; if(ca) return check_ssl_ca(x); if(ns_reject(x, NS_SSL_SERVER)) return 0; /* Now as for keyUsage: we'll at least need to sign OR encipher */ if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_KEY_ENCIPHERMENT)) return 0; return 1; } static int check_purpose_ns_ssl_server(const X509_PURPOSE *xp, const X509 *x, int ca) { int ret; ret = check_purpose_ssl_server(xp, x, ca); if(!ret || ca) return ret; /* We need to encipher or Netscape complains */ if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0; return ret; } /* common S/MIME checks */ static int purpose_smime(const X509 *x, int ca) { if(xku_reject(x,XKU_SMIME)) return 0; if(ca) { int ca_ret; ca_ret = ca_check(x); if(!ca_ret) return 0; /* check nsCertType if present */ if(x->ex_flags & EXFLAG_NSCERT) { if(x->ex_nscert & NS_SMIME_CA) return ca_ret; return 0; } if(ca_ret != 2) return ca_ret; else return 0; } if(x->ex_flags & EXFLAG_NSCERT) { if(x->ex_nscert & NS_SMIME) return 1; /* Workaround for some buggy certificates */ if(x->ex_nscert & NS_SSL_CLIENT) return 2; return 0; } return 1; } static int check_purpose_smime_sign(const X509_PURPOSE *xp, const X509 *x, int ca) { int ret; ret = purpose_smime(x, ca); if(!ret || ca) return ret; if(ku_reject(x, KU_DIGITAL_SIGNATURE|KU_NON_REPUDIATION)) return 0; return ret; } static int check_purpose_smime_encrypt(const X509_PURPOSE *xp, const X509 *x, int ca) { int ret; ret = purpose_smime(x, ca); if(!ret || ca) return ret; if(ku_reject(x, KU_KEY_ENCIPHERMENT)) return 0; return ret; } static int check_purpose_crl_sign(const X509_PURPOSE *xp, const X509 *x, int ca) { if(ca) { int ca_ret; if((ca_ret = ca_check(x)) != 2) return ca_ret; else return 0; } if(ku_reject(x, KU_CRL_SIGN)) return 0; return 1; } /* 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 ocsp_helper(const X509_PURPOSE *xp, const X509 *x, int ca) { /* Must be a valid CA */ if(ca) { int ca_ret; ca_ret = ca_check(x); if(ca_ret != 2) return ca_ret; if(x->ex_flags & EXFLAG_NSCERT) { if(x->ex_nscert & NS_ANY_CA) return ca_ret; return 0; } return 0; } /* leaf certificate is checked in OCSP_verify() */ return 1; } static int no_check(const X509_PURPOSE *xp, const X509 *x, int ca) { return 1; } /* Various checks to see if one certificate 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. Check issuer_name(subject) == subject_name(issuer) * 2. If akid(subject) exists check it matches issuer * 3. If key_usage(issuer) exists check it supports certificate signing * returns 0 for OK, positive for reason for mismatch, reasons match * codes for X509_verify_cert() */ int X509_check_issued(X509 *issuer, X509 *subject) { if(X509_NAME_cmp(X509_get_subject_name(issuer), X509_get_issuer_name(subject))) return X509_V_ERR_SUBJECT_ISSUER_MISMATCH; x509v3_cache_extensions(issuer); x509v3_cache_extensions(subject); if(subject->akid) { /* Check key ids (if present) */ if(subject->akid->keyid && issuer->skid && ASN1_OCTET_STRING_cmp(subject->akid->keyid, issuer->skid) ) return X509_V_ERR_AKID_SKID_MISMATCH; /* Check serial number */ if(subject->akid->serial && ASN1_INTEGER_cmp(X509_get_serialNumber(issuer), subject->akid->serial)) return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; /* Check issuer name */ if(subject->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; GENERAL_NAME *gen; X509_NAME *nm = NULL; int i; gens = subject->akid->issuer; 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 && X509_NAME_cmp(nm, X509_get_issuer_name(issuer))) return X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH; } } if(ku_reject(issuer, KU_KEY_CERT_SIGN)) return X509_V_ERR_KEYUSAGE_NO_CERTSIGN; return X509_V_OK; }