crypto/x509v3/v3_purp.c - third_party/openssl - Git at Google

 /* v3_purp.c */
 /* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
  * project 1999.
  */
 /* ====================================================================
  * Copyright (c) 1999 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 <stdio.h>
 #include "cryptlib.h"
 #include <openssl/x509v3.h>
 #include <openssl/x509_vfy.h>


 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 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},
 };

 #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_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 void x509v3_cache_extensions(X509 *x)
 {
 	BASIC_CONSTRAINTS *bs;
 	ASN1_BIT_STRING *usage;
 	ASN1_BIT_STRING *ns;
 	STACK_OF(ASN1_OBJECT) *extusage;

 	int i;
 	if(x->ex_flags & EXFLAG_SET) return;
 #ifndef 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;
 			}
 		}
 		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);
 	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;
 		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)) 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;
 }

 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.
 			 */
 			STACK_OF(GENERAL_NAME) *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;
 }
	/* v3_purp.c */
	/* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
	* project 1999.
	*/
	/* ====================================================================
	* Copyright (c) 1999 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 <stdio.h>
	#include "cryptlib.h"
	#include <openssl/x509v3.h>
	#include <openssl/x509_vfy.h>


	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 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},
	};

	#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_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 void x509v3_cache_extensions(X509 *x)
	{
	BASIC_CONSTRAINTS *bs;
	ASN1_BIT_STRING *usage;
	ASN1_BIT_STRING *ns;
	STACK_OF(ASN1_OBJECT) *extusage;

	int i;
	if(x->ex_flags & EXFLAG_SET) return;
	#ifndef 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;
	}
	}
	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);
	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;
	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)) 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;
	}

	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.
	*/
	STACK_OF(GENERAL_NAME) *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;
	}