/* v3_purp.c */

 /* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL

  * project 2001.

  */

 /* ====================================================================

  * Copyright (c) 1999-2004 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).

  *

  */

 /*

  © Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.

  */

 #include <stdio.h>

 #include "cryptlib.h"

 #include <openssl/x509v3.h>

 #include <openssl/x509_vfy.h>

 #if (defined(SYMBIAN) && (defined(__WINSCW__) || defined(__WINS__)))

 #include "libcrypto_wsd_macros.h"

 #include "libcrypto_wsd.h"

 #endif

 static void x509v3_cache_extensions(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);

 #ifndef EMULATOR

 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},

 };

 #else

 static const 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},

 };

 #endif

 #define X509_PURPOSE_COUNT (sizeof(xstandard)/sizeof(X509_PURPOSE))

 IMPLEMENT_STACK_OF(X509_PURPOSE)

 #ifndef EMULATOR

 static STACK_OF(X509_PURPOSE) *xptable = NULL;

 #else

 GET_STATIC_VAR_FROM_TLS(xptable,v3_purp,STACK_OF(X509_PURPOSE)*)

 #define xptable (*GET_WSD_VAR_NAME(xptable,v3_purp, s)())

 #endif

 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. */

 EXPORT_C 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);

 }

 EXPORT_C 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;

 }

 EXPORT_C int X509_PURPOSE_get_count(void)

 {

 	if(!xptable) return X509_PURPOSE_COUNT;

 	return sk_X509_PURPOSE_num(xptable) + X509_PURPOSE_COUNT;

 }

 EXPORT_C X509_PURPOSE * X509_PURPOSE_get0(int idx)

 {

 	if(idx < 0) return NULL;

 	if(idx < (int)X509_PURPOSE_COUNT) return ((X509_PURPOSE *)xstandard + idx);

 	return sk_X509_PURPOSE_value(xptable, idx - X509_PURPOSE_COUNT);

 }

 EXPORT_C 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;

 }

 EXPORT_C 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;

 }

 EXPORT_C 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);

 		}

 	}

 EXPORT_C void X509_PURPOSE_cleanup(void)

 {

 	unsigned int i;

 	sk_X509_PURPOSE_pop_free(xptable, xptable_free);

 	for(i = 0; i < X509_PURPOSE_COUNT; i++) xptable_free((X509_PURPOSE *)xstandard + i);

 	xptable = NULL;

 }

 EXPORT_C int X509_PURPOSE_get_id(X509_PURPOSE *xp)

 {

 	return xp->purpose;

 }

 EXPORT_C char *X509_PURPOSE_get0_name(X509_PURPOSE *xp)

 {

 	return xp->name;

 }

 EXPORT_C char *X509_PURPOSE_get0_sname(X509_PURPOSE *xp)

 {

 	return xp->sname;

 }

 EXPORT_C int X509_PURPOSE_get_trust(X509_PURPOSE *xp)

 {

 	return xp->trust;

 }

 static int nid_cmp(int *a, int *b)

 	{

 	return *a - *b;

 	}

 EXPORT_C 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.

 	 */

 #ifndef EMULATOR

 	static 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_ext_key_usage,	/* 126 */

 		NID_proxyCertInfo	/* 661 */

 	};

 #else

 	static const 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 */

 		NID_proxyCertInfo	/* 661 */

 	};

 #endif

 	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;

 	PROXY_CERT_INFO_EXTENSION *pci;

 	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 proxy certificates */

 	if((pci=X509_get_ext_d2i(x, NID_proxyCertInfo, NULL, NULL))) {

 		if (x->ex_flags & EXFLAG_CA

 		    || X509_get_ext_by_NID(x, NID_subject_alt_name, 0) >= 0

 		    || X509_get_ext_by_NID(x, NID_issuer_alt_name, 0) >= 0) {

 			x->ex_flags |= EXFLAG_INVALID;

 		}

 		if (pci->pcPathLengthConstraint) {

 			x->ex_pcpathlen =

 				ASN1_INTEGER_get(pci->pcPathLengthConstraint);

 		} else x->ex_pcpathlen = -1;

 		PROXY_CERT_INFO_EXTENSION_free(pci);

 		x->ex_flags |= EXFLAG_PROXY;

 	}

 	/* 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.

  * 4 basicConstraints absent but keyUsage present and keyCertSign asserted.

  */

 #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 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) {

 		if(x->ex_flags & EXFLAG_CA) return 1;

 		/* If basicConstraints says not a CA then say so */

 		else return 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) return 4;

 		/* Older certificates could have Netscape-specific CA types */

 		else if (x->ex_flags & EXFLAG_NSCERT

 			 && x->ex_nscert & NS_ANY_CA) return 5;

 		/* can this still be regarded a CA certificate?  I doubt it */

 		return 0;

 	}

 }

 EXPORT_C int X509_check_ca(X509 *x)

 {

 	if(!(x->ex_flags & EXFLAG_SET)) {

 		CRYPTO_w_lock(CRYPTO_LOCK_X509);

 		x509v3_cache_extensions(x);

 		CRYPTO_w_unlock(CRYPTO_LOCK_X509);

 	}

 	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;

 	ca_ret = check_ca(x);

 	if(!ca_ret) return 0;

 	/* check nsCertType if present */

 	if(ca_ret != 5 || x->ex_nscert & NS_SSL_CA) 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 = check_ca(x);

 		if(!ca_ret) return 0;

 		/* check nsCertType if present */

 		if(ca_ret != 5 || x->ex_nscert & NS_SMIME_CA) 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 = check_ca(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.  Should we really support the "I don't know"

 	   value (2)? */

 	if(ca) return check_ca(x);

 	/* 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()

  */

 EXPORT_C 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(subject->ex_flags & EXFLAG_PROXY)

 		{

 		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;

 }