/* $OpenBSD: v3_utl.c,v 1.22 2014/07/11 08:44:49 jsing Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project.
 */
/* ====================================================================
 * Copyright (c) 1999-2003 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).
 *
 */
/* X509 v3 extension utilities */

#include <ctype.h>
#include <stdio.h>
#include <string.h>

#include <openssl/bn.h>
#include <openssl/conf.h>
#include <openssl/err.h>
#include <openssl/x509v3.h>

static char *strip_spaces(char *name);
static int sk_strcmp(const char * const *a, const char * const *b);
static STACK_OF(OPENSSL_STRING) *get_email(X509_NAME *name,
    GENERAL_NAMES *gens);
static void str_free(OPENSSL_STRING str);
static int append_ia5(STACK_OF(OPENSSL_STRING) **sk, ASN1_IA5STRING *email);

static int ipv4_from_asc(unsigned char *v4, const char *in);
static int ipv6_from_asc(unsigned char *v6, const char *in);
static int ipv6_cb(const char *elem, int len, void *usr);
static int ipv6_hex(unsigned char *out, const char *in, int inlen);

/* Add a CONF_VALUE name value pair to stack */

int
X509V3_add_value(const char *name, const char *value,
    STACK_OF(CONF_VALUE) **extlist)
{
	CONF_VALUE *vtmp = NULL;
	char *tname = NULL, *tvalue = NULL;

	if (name && !(tname = strdup(name)))
		goto err;
	if (value && !(tvalue = strdup(value)))
		goto err;
	if (!(vtmp = malloc(sizeof(CONF_VALUE))))
		goto err;
	if (!*extlist && !(*extlist = sk_CONF_VALUE_new_null()))
		goto err;
	vtmp->section = NULL;
	vtmp->name = tname;
	vtmp->value = tvalue;
	if (!sk_CONF_VALUE_push(*extlist, vtmp))
		goto err;
	return 1;

err:
	X509V3err(X509V3_F_X509V3_ADD_VALUE, ERR_R_MALLOC_FAILURE);
	free(vtmp);
	free(tname);
	free(tvalue);
	return 0;
}

int
X509V3_add_value_uchar(const char *name, const unsigned char *value,
    STACK_OF(CONF_VALUE) **extlist)
{
	return X509V3_add_value(name, (const char *)value, extlist);
}

/* Free function for STACK_OF(CONF_VALUE) */

void
X509V3_conf_free(CONF_VALUE *conf)
{
	if (!conf)
		return;
	free(conf->name);
	free(conf->value);
	free(conf->section);
	free(conf);
}

int
X509V3_add_value_bool(const char *name, int asn1_bool,
    STACK_OF(CONF_VALUE) **extlist)
{
	if (asn1_bool)
		return X509V3_add_value(name, "TRUE", extlist);
	return X509V3_add_value(name, "FALSE", extlist);
}

int
X509V3_add_value_bool_nf(char *name, int asn1_bool,
    STACK_OF(CONF_VALUE) **extlist)
{
	if (asn1_bool)
		return X509V3_add_value(name, "TRUE", extlist);
	return 1;
}


char *
i2s_ASN1_ENUMERATED(X509V3_EXT_METHOD *method, ASN1_ENUMERATED *a)
{
	BIGNUM *bntmp = NULL;
	char *strtmp = NULL;

	if (!a)
		return NULL;
	if (!(bntmp = ASN1_ENUMERATED_to_BN(a, NULL)) ||
	    !(strtmp = BN_bn2dec(bntmp)))
		X509V3err(X509V3_F_I2S_ASN1_ENUMERATED, ERR_R_MALLOC_FAILURE);
	BN_free(bntmp);
	return strtmp;
}

char *
i2s_ASN1_INTEGER(X509V3_EXT_METHOD *method, ASN1_INTEGER *a)
{
	BIGNUM *bntmp = NULL;
	char *strtmp = NULL;

	if (!a)
		return NULL;
	if (!(bntmp = ASN1_INTEGER_to_BN(a, NULL)) ||
	    !(strtmp = BN_bn2dec(bntmp)))
		X509V3err(X509V3_F_I2S_ASN1_INTEGER, ERR_R_MALLOC_FAILURE);
	BN_free(bntmp);
	return strtmp;
}

ASN1_INTEGER *
s2i_ASN1_INTEGER(X509V3_EXT_METHOD *method, char *value)
{
	BIGNUM *bn = NULL;
	ASN1_INTEGER *aint;
	int isneg, ishex;
	int ret;

	if (!value) {
		X509V3err(X509V3_F_S2I_ASN1_INTEGER,
		    X509V3_R_INVALID_NULL_VALUE);
		return 0;
	}
	bn = BN_new();
	if (value[0] == '-') {
		value++;
		isneg = 1;
	} else
		isneg = 0;

	if (value[0] == '0' && ((value[1] == 'x') || (value[1] == 'X'))) {
		value += 2;
		ishex = 1;
	} else
		ishex = 0;

	if (ishex)
		ret = BN_hex2bn(&bn, value);
	else
		ret = BN_dec2bn(&bn, value);

	if (!ret || value[ret]) {
		BN_free(bn);
		X509V3err(X509V3_F_S2I_ASN1_INTEGER, X509V3_R_BN_DEC2BN_ERROR);
		return 0;
	}

	if (isneg && BN_is_zero(bn))
		isneg = 0;

	aint = BN_to_ASN1_INTEGER(bn, NULL);
	BN_free(bn);
	if (!aint) {
		X509V3err(X509V3_F_S2I_ASN1_INTEGER,
		    X509V3_R_BN_TO_ASN1_INTEGER_ERROR);
		return 0;
	}
	if (isneg)
		aint->type |= V_ASN1_NEG;
	return aint;
}

int
X509V3_add_value_int(const char *name, ASN1_INTEGER *aint,
    STACK_OF(CONF_VALUE) **extlist)
{
	char *strtmp;
	int ret;

	if (!aint)
		return 1;
	if (!(strtmp = i2s_ASN1_INTEGER(NULL, aint)))
		return 0;
	ret = X509V3_add_value(name, strtmp, extlist);
	free(strtmp);
	return ret;
}

int
X509V3_get_value_bool(CONF_VALUE *value, int *asn1_bool)
{
	char *btmp;

	if (!(btmp = value->value))
		goto err;
	if (!strcmp(btmp, "TRUE") || !strcmp(btmp, "true") ||
	    !strcmp(btmp, "Y") || !strcmp(btmp, "y") ||
	    !strcmp(btmp, "YES") || !strcmp(btmp, "yes")) {
		*asn1_bool = 0xff;
		return 1;
	} else if (!strcmp(btmp, "FALSE") || !strcmp(btmp, "false") ||
	    !strcmp(btmp, "N") || !strcmp(btmp, "n") ||
	    !strcmp(btmp, "NO") || !strcmp(btmp, "no")) {
		*asn1_bool = 0;
		return 1;
	}

err:
	X509V3err(X509V3_F_X509V3_GET_VALUE_BOOL,
	    X509V3_R_INVALID_BOOLEAN_STRING);
	X509V3_conf_err(value);
	return 0;
}

int
X509V3_get_value_int(CONF_VALUE *value, ASN1_INTEGER **aint)
{
	ASN1_INTEGER *itmp;

	if (!(itmp = s2i_ASN1_INTEGER(NULL, value->value))) {
		X509V3_conf_err(value);
		return 0;
	}
	*aint = itmp;
	return 1;
}

#define HDR_NAME	1
#define HDR_VALUE	2

/*#define DEBUG*/

STACK_OF(CONF_VALUE) *
X509V3_parse_list(const char *line)
{
	char *p, *q, c;
	char *ntmp, *vtmp;
	STACK_OF(CONF_VALUE) *values = NULL;
	char *linebuf;
	int state;

	/* We are going to modify the line so copy it first */
	if ((linebuf = strdup(line)) == NULL) {
		X509V3err(X509V3_F_X509V3_PARSE_LIST, ERR_R_MALLOC_FAILURE);
		goto err;
	}
	state = HDR_NAME;
	ntmp = NULL;

	/* Go through all characters */
	for (p = linebuf, q = linebuf; (c = *p) && (c != '\r') &&
	    (c != '\n'); p++) {

		switch (state) {
		case HDR_NAME:
			if (c == ':') {
				state = HDR_VALUE;
				*p = 0;
				ntmp = strip_spaces(q);
				if (!ntmp) {
					X509V3err(X509V3_F_X509V3_PARSE_LIST,
					    X509V3_R_INVALID_NULL_NAME);
					goto err;
				}
				q = p + 1;
			} else if (c == ',') {
				*p = 0;
				ntmp = strip_spaces(q);
				q = p + 1;
#if 0
				printf("%s\n", ntmp);
#endif
				if (!ntmp) {
					X509V3err(X509V3_F_X509V3_PARSE_LIST,
					    X509V3_R_INVALID_NULL_NAME);
					goto err;
				}
				X509V3_add_value(ntmp, NULL, &values);
			}
			break;

		case HDR_VALUE:
			if (c == ',') {
				state = HDR_NAME;
				*p = 0;
				vtmp = strip_spaces(q);
#if 0
				printf("%s\n", ntmp);
#endif
				if (!vtmp) {
					X509V3err(X509V3_F_X509V3_PARSE_LIST,
					    X509V3_R_INVALID_NULL_VALUE);
					goto err;
				}
				X509V3_add_value(ntmp, vtmp, &values);
				ntmp = NULL;
				q = p + 1;
			}

		}
	}

	if (state == HDR_VALUE) {
		vtmp = strip_spaces(q);
#if 0
		printf("%s=%s\n", ntmp, vtmp);
#endif
		if (!vtmp) {
			X509V3err(X509V3_F_X509V3_PARSE_LIST,
			    X509V3_R_INVALID_NULL_VALUE);
			goto err;
		}
		X509V3_add_value(ntmp, vtmp, &values);
	} else {
		ntmp = strip_spaces(q);
#if 0
		printf("%s\n", ntmp);
#endif
		if (!ntmp) {
			X509V3err(X509V3_F_X509V3_PARSE_LIST,
			    X509V3_R_INVALID_NULL_NAME);
			goto err;
		}
		X509V3_add_value(ntmp, NULL, &values);
	}
	free(linebuf);
	return values;

err:
	free(linebuf);
	sk_CONF_VALUE_pop_free(values, X509V3_conf_free);
	return NULL;

}

/* Delete leading and trailing spaces from a string */
static char *
strip_spaces(char *name)
{
	char *p, *q;

	/* Skip over leading spaces */
	p = name;
	while (*p && isspace((unsigned char)*p))
		p++;
	if (!*p)
		return NULL;
	q = p + strlen(p) - 1;
	while ((q != p) && isspace((unsigned char)*q))
		q--;
	if (p != q)
		q[1] = 0;
	if (!*p)
		return NULL;
	return p;
}

/* hex string utilities */

/* Given a buffer of length 'len' return a malloc'ed string with its
 * hex representation
 */
char *
hex_to_string(const unsigned char *buffer, long len)
{
	char *tmp, *q;
	const unsigned char *p;
	int i;
	static const char hexdig[] = "0123456789ABCDEF";

	if (!buffer || !len)
		return NULL;
	if (!(tmp = malloc(len * 3 + 1))) {
		X509V3err(X509V3_F_HEX_TO_STRING, ERR_R_MALLOC_FAILURE);
		return NULL;
	}
	q = tmp;
	for (i = 0, p = buffer; i < len; i++, p++) {
		*q++ = hexdig[(*p >> 4) & 0xf];
		*q++ = hexdig[*p & 0xf];
		*q++ = ':';
	}
	q[-1] = 0;
	return tmp;
}

/* Give a string of hex digits convert to
 * a buffer
 */

unsigned char *
string_to_hex(const char *str, long *len)
{
	unsigned char *hexbuf, *q;
	unsigned char ch, cl, *p;
	if (!str) {
		X509V3err(X509V3_F_STRING_TO_HEX,
		    X509V3_R_INVALID_NULL_ARGUMENT);
		return NULL;
	}
	if (!(hexbuf = malloc(strlen(str) >> 1)))
		goto err;
	for (p = (unsigned char *)str, q = hexbuf; *p; ) {
		ch = *p++;
		if (ch == ':')
			continue;
		cl = *p++;
		if (!cl) {
			X509V3err(X509V3_F_STRING_TO_HEX,
			    X509V3_R_ODD_NUMBER_OF_DIGITS);
			free(hexbuf);
			return NULL;
		}
		ch = tolower(ch);
		cl = tolower(cl);

		if ((ch >= '0') && (ch <= '9'))
			ch -= '0';
		else if ((ch >= 'a') && (ch <= 'f'))
			ch -= 'a' - 10;
		else
			goto badhex;

		if ((cl >= '0') && (cl <= '9'))
			cl -= '0';
		else if ((cl >= 'a') && (cl <= 'f'))
			cl -= 'a' - 10;
		else
			goto badhex;

		*q++ = (ch << 4) | cl;
	}

	if (len)
		*len = q - hexbuf;

	return hexbuf;

err:
	free(hexbuf);
	X509V3err(X509V3_F_STRING_TO_HEX, ERR_R_MALLOC_FAILURE);
	return NULL;

badhex:
	free(hexbuf);
	X509V3err(X509V3_F_STRING_TO_HEX, X509V3_R_ILLEGAL_HEX_DIGIT);
	return NULL;
}

/* V2I name comparison function: returns zero if 'name' matches
 * cmp or cmp.*
 */

int
name_cmp(const char *name, const char *cmp)
{
	int len, ret;
	char c;

	len = strlen(cmp);
	if ((ret = strncmp(name, cmp, len)))
		return ret;
	c = name[len];
	if (!c || (c=='.'))
		return 0;
	return 1;
}

static int
sk_strcmp(const char * const *a, const char * const *b)
{
	return strcmp(*a, *b);
}

STACK_OF(OPENSSL_STRING) *X509_get1_email(X509 *x)
{
	GENERAL_NAMES *gens;
	STACK_OF(OPENSSL_STRING) *ret;

	gens = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
	ret = get_email(X509_get_subject_name(x), gens);
	sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
	return ret;
}

STACK_OF(OPENSSL_STRING) *X509_get1_ocsp(X509 *x)
{
	AUTHORITY_INFO_ACCESS *info;
	STACK_OF(OPENSSL_STRING) *ret = NULL;
	int i;

	info = X509_get_ext_d2i(x, NID_info_access, NULL, NULL);
	if (!info)
		return NULL;
	for (i = 0; i < sk_ACCESS_DESCRIPTION_num(info); i++) {
		ACCESS_DESCRIPTION *ad = sk_ACCESS_DESCRIPTION_value(info, i);
		if (OBJ_obj2nid(ad->method) == NID_ad_OCSP) {
			if (ad->location->type == GEN_URI) {
				if (!append_ia5(&ret,
				    ad->location->d.uniformResourceIdentifier))
					break;
			}
		}
	}
	AUTHORITY_INFO_ACCESS_free(info);
	return ret;
}

STACK_OF(OPENSSL_STRING) *X509_REQ_get1_email(X509_REQ *x)
{
	GENERAL_NAMES *gens;
	STACK_OF(X509_EXTENSION) *exts;
	STACK_OF(OPENSSL_STRING) *ret;

	exts = X509_REQ_get_extensions(x);
	gens = X509V3_get_d2i(exts, NID_subject_alt_name, NULL, NULL);
	ret = get_email(X509_REQ_get_subject_name(x), gens);
	sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
	sk_X509_EXTENSION_pop_free(exts, X509_EXTENSION_free);
	return ret;
}


static
STACK_OF(OPENSSL_STRING) *get_email(X509_NAME *name, GENERAL_NAMES *gens)
{
	STACK_OF(OPENSSL_STRING) *ret = NULL;
	X509_NAME_ENTRY *ne;
	ASN1_IA5STRING *email;
	GENERAL_NAME *gen;
	int i;

	/* Now add any email address(es) to STACK */
	i = -1;

	/* First supplied X509_NAME */
	while ((i = X509_NAME_get_index_by_NID(name,
	    NID_pkcs9_emailAddress, i)) >= 0) {
		ne = X509_NAME_get_entry(name, i);
		email = X509_NAME_ENTRY_get_data(ne);
		if (!append_ia5(&ret, email))
			return NULL;
	}
	for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
		gen = sk_GENERAL_NAME_value(gens, i);
		if (gen->type != GEN_EMAIL)
			continue;
		if (!append_ia5(&ret, gen->d.ia5))
			return NULL;
	}
	return ret;
}

static void
str_free(OPENSSL_STRING str)
{
	free(str);
}

static int
append_ia5(STACK_OF(OPENSSL_STRING) **sk, ASN1_IA5STRING *email)
{
	char *emtmp;

	/* First some sanity checks */
	if (email->type != V_ASN1_IA5STRING)
		return 1;
	if (!email->data || !email->length)
		return 1;
	if (!*sk)
		*sk = sk_OPENSSL_STRING_new(sk_strcmp);
	if (!*sk)
		return 0;
	/* Don't add duplicates */
	if (sk_OPENSSL_STRING_find(*sk, (char *)email->data) != -1)
		return 1;
	emtmp = strdup((char *)email->data);
	if (!emtmp || !sk_OPENSSL_STRING_push(*sk, emtmp)) {
		X509_email_free(*sk);
		*sk = NULL;
		return 0;
	}
	return 1;
}

void
X509_email_free(STACK_OF(OPENSSL_STRING) *sk)
{
	sk_OPENSSL_STRING_pop_free(sk, str_free);
}

/* Convert IP addresses both IPv4 and IPv6 into an
 * OCTET STRING compatible with RFC3280.
 */

ASN1_OCTET_STRING *
a2i_IPADDRESS(const char *ipasc)
{
	unsigned char ipout[16];
	ASN1_OCTET_STRING *ret;
	int iplen;

	/* If string contains a ':' assume IPv6 */

	iplen = a2i_ipadd(ipout, ipasc);

	if (!iplen)
		return NULL;

	ret = ASN1_OCTET_STRING_new();
	if (!ret)
		return NULL;
	if (!ASN1_OCTET_STRING_set(ret, ipout, iplen)) {
		ASN1_OCTET_STRING_free(ret);
		return NULL;
	}
	return ret;
}

ASN1_OCTET_STRING *
a2i_IPADDRESS_NC(const char *ipasc)
{
	ASN1_OCTET_STRING *ret = NULL;
	unsigned char ipout[32];
	char *iptmp = NULL, *p;
	int iplen1, iplen2;

	p = strchr(ipasc, '/');
	if (!p)
		return NULL;
	iptmp = strdup(ipasc);
	if (!iptmp)
		return NULL;
	p = iptmp + (p - ipasc);
	*p++ = 0;

	iplen1 = a2i_ipadd(ipout, iptmp);

	if (!iplen1)
		goto err;

	iplen2 = a2i_ipadd(ipout + iplen1, p);

	free(iptmp);
	iptmp = NULL;

	if (!iplen2 || (iplen1 != iplen2))
		goto err;

	ret = ASN1_OCTET_STRING_new();
	if (!ret)
		goto err;
	if (!ASN1_OCTET_STRING_set(ret, ipout, iplen1 + iplen2))
		goto err;

	return ret;

err:
	free(iptmp);
	if (ret)
		ASN1_OCTET_STRING_free(ret);
	return NULL;
}


int
a2i_ipadd(unsigned char *ipout, const char *ipasc)
{
	/* If string contains a ':' assume IPv6 */

	if (strchr(ipasc, ':')) {
		if (!ipv6_from_asc(ipout, ipasc))
			return 0;
		return 16;
	} else {
		if (!ipv4_from_asc(ipout, ipasc))
			return 0;
		return 4;
	}
}

static int
ipv4_from_asc(unsigned char *v4, const char *in)
{
	int a0, a1, a2, a3;
	if (sscanf(in, "%d.%d.%d.%d", &a0, &a1, &a2, &a3) != 4)
		return 0;
	if ((a0 < 0) || (a0 > 255) || (a1 < 0) || (a1 > 255) ||
	    (a2 < 0) || (a2 > 255) || (a3 < 0) || (a3 > 255))
		return 0;
	v4[0] = a0;
	v4[1] = a1;
	v4[2] = a2;
	v4[3] = a3;
	return 1;
}

typedef struct {
	/* Temporary store for IPV6 output */
	unsigned char tmp[16];
	/* Total number of bytes in tmp */
	int total;
	/* The position of a zero (corresponding to '::') */
	int zero_pos;
	/* Number of zeroes */
	int zero_cnt;
} IPV6_STAT;


static int
ipv6_from_asc(unsigned char *v6, const char *in)
{
	IPV6_STAT v6stat;

	v6stat.total = 0;
	v6stat.zero_pos = -1;
	v6stat.zero_cnt = 0;

	/* Treat the IPv6 representation as a list of values
	 * separated by ':'. The presence of a '::' will parse
 	 * as one, two or three zero length elements.
	 */
	if (!CONF_parse_list(in, ':', 0, ipv6_cb, &v6stat))
		return 0;

	/* Now for some sanity checks */

	if (v6stat.zero_pos == -1) {
		/* If no '::' must have exactly 16 bytes */
		if (v6stat.total != 16)
			return 0;
	} else {
		/* If '::' must have less than 16 bytes */
		if (v6stat.total == 16)
			return 0;
		/* More than three zeroes is an error */
		if (v6stat.zero_cnt > 3)
			return 0;
		/* Can only have three zeroes if nothing else present */
		else if (v6stat.zero_cnt == 3) {
			if (v6stat.total > 0)
				return 0;
		}
		/* Can only have two zeroes if at start or end */
		else if (v6stat.zero_cnt == 2) {
			if ((v6stat.zero_pos != 0) &&
			    (v6stat.zero_pos != v6stat.total))
				return 0;
		} else
			/* Can only have one zero if *not* start or end */
		{
			if ((v6stat.zero_pos == 0) ||
			    (v6stat.zero_pos == v6stat.total))
				return 0;
		}
	}

	/* Format result */

	if (v6stat.zero_pos >= 0) {
		/* Copy initial part */
		memcpy(v6, v6stat.tmp, v6stat.zero_pos);
		/* Zero middle */
		memset(v6 + v6stat.zero_pos, 0, 16 - v6stat.total);
		/* Copy final part */
		if (v6stat.total != v6stat.zero_pos)
			memcpy(v6 + v6stat.zero_pos + 16 - v6stat.total,
			    v6stat.tmp + v6stat.zero_pos,
			    v6stat.total - v6stat.zero_pos);
	} else
		memcpy(v6, v6stat.tmp, 16);

	return 1;
}

static int
ipv6_cb(const char *elem, int len, void *usr)
{
	IPV6_STAT *s = usr;

	/* Error if 16 bytes written */
	if (s->total == 16)
		return 0;
	if (len == 0) {
		/* Zero length element, corresponds to '::' */
		if (s->zero_pos == -1)
			s->zero_pos = s->total;
		/* If we've already got a :: its an error */
		else if (s->zero_pos != s->total)
			return 0;
		s->zero_cnt++;
	} else {
		/* If more than 4 characters could be final a.b.c.d form */
		if (len > 4) {
			/* Need at least 4 bytes left */
			if (s->total > 12)
				return 0;
			/* Must be end of string */
			if (elem[len])
				return 0;
			if (!ipv4_from_asc(s->tmp + s->total, elem))
				return 0;
			s->total += 4;
		} else {
			if (!ipv6_hex(s->tmp + s->total, elem, len))
				return 0;
			s->total += 2;
		}
	}
	return 1;
}

/* Convert a string of up to 4 hex digits into the corresponding
 * IPv6 form.
 */

static int
ipv6_hex(unsigned char *out, const char *in, int inlen)
{
	unsigned char c;
	unsigned int num = 0;

	if (inlen > 4)
		return 0;
	while (inlen--) {
		c = *in++;
		num <<= 4;
		if ((c >= '0') && (c <= '9'))
			num |= c - '0';
		else if ((c >= 'A') && (c <= 'F'))
			num |= c - 'A' + 10;
		else if ((c >= 'a') && (c <= 'f'))
			num |=  c - 'a' + 10;
		else
			return 0;
	}
	out[0] = num >> 8;
	out[1] = num & 0xff;
	return 1;
}

int
X509V3_NAME_from_section(X509_NAME *nm, STACK_OF(CONF_VALUE)*dn_sk,
    unsigned long chtype)
{
	CONF_VALUE *v;
	int i, mval;
	char *p, *type;

	if (!nm)
		return 0;

	for (i = 0; i < sk_CONF_VALUE_num(dn_sk); i++) {
		v = sk_CONF_VALUE_value(dn_sk, i);
		type = v->name;
		/* Skip past any leading X. X: X, etc to allow for
		 * multiple instances
		 */
		for (p = type; *p; p++)
			if ((*p == ':') || (*p == ',') || (*p == '.')) {
				p++;
				if (*p)
					type = p;
				break;
			}
		if (*type == '+') {
			mval = -1;
			type++;
		} else
			mval = 0;
		if (!X509_NAME_add_entry_by_txt(nm, type, chtype,
		    (unsigned char *) v->value, -1, -1, mval))
			return 0;
	}
	return 1;
}
