/* 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;

}