/*
 * Copyright (c) 2006 - 2010 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * 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. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS 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 INSTITUTE OR 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.
 */

#include "hx_locl.h"
#include <pkinit_asn1.h>

/**
 * @page page_ca Hx509 CA functions
 *
 * See the library functions here: @ref hx509_ca
 */

struct hx509_ca_tbs {
    hx509_name subject;
    SubjectPublicKeyInfo spki;
    ExtKeyUsage eku;
    GeneralNames san;
    unsigned key_usage;
    heim_integer serial;
    struct {
        unsigned int proxy:1;
        unsigned int ca:1;
        unsigned int key:1;
        unsigned int serial:1;
        unsigned int domaincontroller:1;
        unsigned int xUniqueID:1;
    } flags;
    time_t notBefore;
    time_t notAfter;
    int pathLenConstraint; /* both for CA and Proxy */
    CRLDistributionPoints crldp;
    heim_bit_string subjectUniqueID;
    heim_bit_string issuerUniqueID;

};

/**
 * Allocate an to-be-signed certificate object that will be converted
 * into an certificate.
 *
 * @param context A hx509 context.
 * @param tbs returned to-be-signed certicate object, free with
 * hx509_ca_tbs_free().
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_init(hx509_context context, hx509_ca_tbs *tbs)
{
    *tbs = calloc(1, sizeof(**tbs));
    if (*tbs == NULL)
        return ENOMEM;

    return 0;
}

/**
 * Free an To Be Signed object.
 *
 * @param tbs object to free.
 *
 * @ingroup hx509_ca
 */

void
hx509_ca_tbs_free(hx509_ca_tbs *tbs)
{
    if (tbs == NULL || *tbs == NULL)
        return;

    free_SubjectPublicKeyInfo(&(*tbs)->spki);
    free_GeneralNames(&(*tbs)->san);
    free_ExtKeyUsage(&(*tbs)->eku);
    der_free_heim_integer(&(*tbs)->serial);
    free_CRLDistributionPoints(&(*tbs)->crldp);
    der_free_bit_string(&(*tbs)->subjectUniqueID);
    der_free_bit_string(&(*tbs)->issuerUniqueID);
    hx509_name_free(&(*tbs)->subject);

    memset(*tbs, 0, sizeof(**tbs));
    free(*tbs);
    *tbs = NULL;
}

/**
 * Set the absolute time when the certificate is valid from. If not
 * set the current time will be used.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param t time the certificated will start to be valid
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_set_notBefore(hx509_context context,
                           hx509_ca_tbs tbs,
                           time_t t)
{
    tbs->notBefore = t;
    return 0;
}

/**
 * Set the absolute time when the certificate is valid to.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param t time when the certificate will expire
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_set_notAfter(hx509_context context,
                           hx509_ca_tbs tbs,
                           time_t t)
{
    tbs->notAfter = t;
    return 0;
}

/**
 * Set the relative time when the certificiate is going to expire.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param delta seconds to the certificate is going to expire.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_set_notAfter_lifetime(hx509_context context,
                                   hx509_ca_tbs tbs,
                                   time_t delta)
{
    return hx509_ca_tbs_set_notAfter(context, tbs, time(NULL) + delta);
}

static const struct units templatebits[] = {
    { "ExtendedKeyUsage", HX509_CA_TEMPLATE_EKU },
    { "KeyUsage", HX509_CA_TEMPLATE_KU },
    { "SPKI", HX509_CA_TEMPLATE_SPKI },
    { "notAfter", HX509_CA_TEMPLATE_NOTAFTER },
    { "notBefore", HX509_CA_TEMPLATE_NOTBEFORE },
    { "serial", HX509_CA_TEMPLATE_SERIAL },
    { "subject", HX509_CA_TEMPLATE_SUBJECT },
    { NULL, 0 }
};

/**
 * Make of template units, use to build flags argument to
 * hx509_ca_tbs_set_template() with parse_units().
 *
 * @return an units structure.
 *
 * @ingroup hx509_ca
 */

const struct units *
hx509_ca_tbs_template_units(void)
{
    return templatebits;
}

/**
 * Initialize the to-be-signed certificate object from a template certifiate.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param flags bit field selecting what to copy from the template
 * certifiate.
 * @param cert template certificate.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_set_template(hx509_context context,
                          hx509_ca_tbs tbs,
                          int flags,
                          hx509_cert cert)
{
    int ret;

    if (flags & HX509_CA_TEMPLATE_SUBJECT) {
        if (tbs->subject)
            hx509_name_free(&tbs->subject);
        ret = hx509_cert_get_subject(cert, &tbs->subject);
        if (ret) {
            hx509_set_error_string(context, 0, ret,
                                   "Failed to get subject from template");
            return ret;
        }
    }
    if (flags & HX509_CA_TEMPLATE_SERIAL) {
        der_free_heim_integer(&tbs->serial);
        ret = hx509_cert_get_serialnumber(cert, &tbs->serial);
        tbs->flags.serial = !ret;
        if (ret) {
            hx509_set_error_string(context, 0, ret,
                                   "Failed to copy serial number");
            return ret;
        }
    }
    if (flags & HX509_CA_TEMPLATE_NOTBEFORE)
        tbs->notBefore = hx509_cert_get_notBefore(cert);
    if (flags & HX509_CA_TEMPLATE_NOTAFTER)
        tbs->notAfter = hx509_cert_get_notAfter(cert);
    if (flags & HX509_CA_TEMPLATE_SPKI) {
        free_SubjectPublicKeyInfo(&tbs->spki);
        ret = hx509_cert_get_SPKI(context, cert, &tbs->spki);
        tbs->flags.key = !ret;
        if (ret)
            return ret;
    }
    if (flags & HX509_CA_TEMPLATE_KU) {
        KeyUsage ku;
        ret = _hx509_cert_get_keyusage(context, cert, &ku);
        if (ret)
            return ret;
        tbs->key_usage = KeyUsage2int(ku);
    }
    if (flags & HX509_CA_TEMPLATE_EKU) {
        ExtKeyUsage eku;
        size_t i;
        ret = _hx509_cert_get_eku(context, cert, &eku);
        if (ret)
            return ret;
        for (i = 0; i < eku.len; i++) {
            ret = hx509_ca_tbs_add_eku(context, tbs, &eku.val[i]);
            if (ret) {
                free_ExtKeyUsage(&eku);
                return ret;
            }
        }
        free_ExtKeyUsage(&eku);
    }
    return 0;
}

/**
 * Make the to-be-signed certificate object a CA certificate. If the
 * pathLenConstraint is negative path length constraint is used.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param pathLenConstraint path length constraint, negative, no
 * constraint.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_set_ca(hx509_context context,
                    hx509_ca_tbs tbs,
                    int pathLenConstraint)
{
    tbs->flags.ca = 1;
    tbs->pathLenConstraint = pathLenConstraint;
    return 0;
}

/**
 * Make the to-be-signed certificate object a proxy certificate. If the
 * pathLenConstraint is negative path length constraint is used.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param pathLenConstraint path length constraint, negative, no
 * constraint.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_set_proxy(hx509_context context,
                       hx509_ca_tbs tbs,
                       int pathLenConstraint)
{
    tbs->flags.proxy = 1;
    tbs->pathLenConstraint = pathLenConstraint;
    return 0;
}


/**
 * Make the to-be-signed certificate object a windows domain controller certificate.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_set_domaincontroller(hx509_context context,
                                  hx509_ca_tbs tbs)
{
    tbs->flags.domaincontroller = 1;
    return 0;
}

/**
 * Set the subject public key info (SPKI) in the to-be-signed certificate
 * object. SPKI is the public key and key related parameters in the
 * certificate.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param spki subject public key info to use for the to-be-signed certificate object.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_set_spki(hx509_context context,
                      hx509_ca_tbs tbs,
                      const SubjectPublicKeyInfo *spki)
{
    int ret;
    free_SubjectPublicKeyInfo(&tbs->spki);
    ret = copy_SubjectPublicKeyInfo(spki, &tbs->spki);
    tbs->flags.key = !ret;
    return ret;
}

/**
 * Set the serial number to use for to-be-signed certificate object.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param serialNumber serial number to use for the to-be-signed
 * certificate object.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_set_serialnumber(hx509_context context,
                              hx509_ca_tbs tbs,
                              const heim_integer *serialNumber)
{
    int ret;
    der_free_heim_integer(&tbs->serial);
    ret = der_copy_heim_integer(serialNumber, &tbs->serial);
    tbs->flags.serial = !ret;
    return ret;
}

/**
 * An an extended key usage to the to-be-signed certificate object.
 * Duplicates will detected and not added.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param oid extended key usage to add.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_add_eku(hx509_context context,
                     hx509_ca_tbs tbs,
                     const heim_oid *oid)
{
    void *ptr;
    int ret;
    unsigned i;

    /* search for duplicates */
    for (i = 0; i < tbs->eku.len; i++) {
        if (der_heim_oid_cmp(oid, &tbs->eku.val[i]) == 0)
            return 0;
    }

    ptr = realloc(tbs->eku.val, sizeof(tbs->eku.val[0]) * (tbs->eku.len + 1));
    if (ptr == NULL) {
        hx509_set_error_string(context, 0, ENOMEM, "out of memory");
        return ENOMEM;
    }
    tbs->eku.val = ptr;
    ret = der_copy_oid(oid, &tbs->eku.val[tbs->eku.len]);
    if (ret) {
        hx509_set_error_string(context, 0, ret, "out of memory");
        return ret;
    }
    tbs->eku.len += 1;
    return 0;
}

/**
 * Add CRL distribution point URI to the to-be-signed certificate
 * object.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param uri uri to the CRL.
 * @param issuername name of the issuer.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_add_crl_dp_uri(hx509_context context,
                            hx509_ca_tbs tbs,
                            const char *uri,
                            hx509_name issuername)
{
    DistributionPoint dp;
    int ret;

    memset(&dp, 0, sizeof(dp));

    dp.distributionPoint = ecalloc(1, sizeof(*dp.distributionPoint));

    {
        DistributionPointName name;
        GeneralName gn;
        size_t size;

        name.element = choice_DistributionPointName_fullName;
        name.u.fullName.len = 1;
        name.u.fullName.val = &gn;

        gn.element = choice_GeneralName_uniformResourceIdentifier;
        gn.u.uniformResourceIdentifier.data = rk_UNCONST(uri);
        gn.u.uniformResourceIdentifier.length = strlen(uri);

        ASN1_MALLOC_ENCODE(DistributionPointName,
                           dp.distributionPoint->data,
                           dp.distributionPoint->length,
                           &name, &size, ret);
        if (ret) {
            hx509_set_error_string(context, 0, ret,
                                   "Failed to encoded DistributionPointName");
            goto out;
        }
        if (dp.distributionPoint->length != size)
            _hx509_abort("internal ASN.1 encoder error");
    }

    if (issuername) {
#if 1
        /**
         * issuername not supported
         */
        hx509_set_error_string(context, 0, EINVAL,
                               "CRLDistributionPoints.name.issuername not yet supported");
        return EINVAL;
#else
        GeneralNames *crlissuer;
        GeneralName gn;
        Name n;

        crlissuer = calloc(1, sizeof(*crlissuer));
        if (crlissuer == NULL) {
            return ENOMEM;
        }
        memset(&gn, 0, sizeof(gn));

        gn.element = choice_GeneralName_directoryName;
        ret = hx509_name_to_Name(issuername, &n);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "out of memory");
            goto out;
        }

        gn.u.directoryName.element = n.element;
        gn.u.directoryName.u.rdnSequence = n.u.rdnSequence;

        ret = add_GeneralNames(&crlissuer, &gn);
        free_Name(&n);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "out of memory");
            goto out;
        }

        dp.cRLIssuer = &crlissuer;
#endif
    }

    ret = add_CRLDistributionPoints(&tbs->crldp, &dp);
    if (ret) {
        hx509_set_error_string(context, 0, ret, "out of memory");
        goto out;
    }

out:
    free_DistributionPoint(&dp);

    return ret;
}

/**
 * Add Subject Alternative Name otherName to the to-be-signed
 * certificate object.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param oid the oid of the OtherName.
 * @param os data in the other name.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_add_san_otherName(hx509_context context,
                               hx509_ca_tbs tbs,
                               const heim_oid *oid,
                               const heim_octet_string *os)
{
    GeneralName gn;

    memset(&gn, 0, sizeof(gn));
    gn.element = choice_GeneralName_otherName;
    gn.u.otherName.type_id = *oid;
    gn.u.otherName.value = *os;

    return add_GeneralNames(&tbs->san, &gn);
}

/**
 * Add Kerberos Subject Alternative Name to the to-be-signed
 * certificate object. The principal string is a UTF8 string.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param principal Kerberos principal to add to the certificate.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_add_san_pkinit(hx509_context context,
                            hx509_ca_tbs tbs,
                            const char *principal)
{
    heim_octet_string os;
    KRB5PrincipalName p;
    size_t size;
    int ret;
    char *s = NULL;

    memset(&p, 0, sizeof(p));

    /* parse principal */
    {
        const char *str;
        char *q;
        int n;

        /* count number of component */
        n = 1;
        for(str = principal; *str != '\0' && *str != '@'; str++){
            if(*str=='\\'){
                if(str[1] == '\0' || str[1] == '@') {
                    ret = HX509_PARSING_NAME_FAILED;
                    hx509_set_error_string(context, 0, ret,
                                           "trailing \\ in principal name");
                    goto out;
                }
                str++;
            } else if(*str == '/')
                n++;
        }
        p.principalName.name_string.val =
            calloc(n, sizeof(*p.principalName.name_string.val));
        if (p.principalName.name_string.val == NULL) {
            ret = ENOMEM;
            hx509_set_error_string(context, 0, ret, "malloc: out of memory");
            goto out;
        }
        p.principalName.name_string.len = n;

        p.principalName.name_type = KRB5_NT_PRINCIPAL;
        q = s = strdup(principal);
        if (q == NULL) {
            ret = ENOMEM;
            hx509_set_error_string(context, 0, ret, "malloc: out of memory");
            goto out;
        }
        p.realm = strrchr(q, '@');
        if (p.realm == NULL) {
            ret = HX509_PARSING_NAME_FAILED;
            hx509_set_error_string(context, 0, ret, "Missing @ in principal");
            goto out;
        };
        *p.realm++ = '\0';

        n = 0;
        while (q) {
            p.principalName.name_string.val[n++] = q;
            q = strchr(q, '/');
            if (q)
                *q++ = '\0';
        }
    }

    ASN1_MALLOC_ENCODE(KRB5PrincipalName, os.data, os.length, &p, &size, ret);
    if (ret) {
        hx509_set_error_string(context, 0, ret, "Out of memory");
        goto out;
    }
    if (size != os.length)
        _hx509_abort("internal ASN.1 encoder error");

    ret = hx509_ca_tbs_add_san_otherName(context,
                                         tbs,
                                         &asn1_oid_id_pkinit_san,
                                         &os);
    free(os.data);
out:
    if (p.principalName.name_string.val)
        free (p.principalName.name_string.val);
    if (s)
        free(s);
    return ret;
}

/*
 *
 */

static int
add_utf8_san(hx509_context context,
             hx509_ca_tbs tbs,
             const heim_oid *oid,
             const char *string)
{
    const PKIXXmppAddr ustring = (const PKIXXmppAddr)(intptr_t)string;
    heim_octet_string os;
    size_t size;
    int ret;

    os.length = 0;
    os.data = NULL;

    ASN1_MALLOC_ENCODE(PKIXXmppAddr, os.data, os.length, &ustring, &size, ret);
    if (ret) {
        hx509_set_error_string(context, 0, ret, "Out of memory");
        goto out;
    }
    if (size != os.length)
        _hx509_abort("internal ASN.1 encoder error");

    ret = hx509_ca_tbs_add_san_otherName(context,
                                         tbs,
                                         oid,
                                         &os);
    free(os.data);
out:
    return ret;
}

/**
 * Add Microsoft UPN Subject Alternative Name to the to-be-signed
 * certificate object. The principal string is a UTF8 string.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param principal Microsoft UPN string.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_add_san_ms_upn(hx509_context context,
                            hx509_ca_tbs tbs,
                            const char *principal)
{
    return add_utf8_san(context, tbs, &asn1_oid_id_pkinit_ms_san, principal);
}

/**
 * Add a Jabber/XMPP jid Subject Alternative Name to the to-be-signed
 * certificate object. The jid is an UTF8 string.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param jid string of an a jabber id in UTF8.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_add_san_jid(hx509_context context,
                         hx509_ca_tbs tbs,
                         const char *jid)
{
    return add_utf8_san(context, tbs, &asn1_oid_id_pkix_on_xmppAddr, jid);
}


/**
 * Add a Subject Alternative Name hostname to to-be-signed certificate
 * object. A domain match starts with ., an exact match does not.
 *
 * Example of a an domain match: .domain.se matches the hostname
 * host.domain.se.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param dnsname a hostame.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_add_san_hostname(hx509_context context,
                              hx509_ca_tbs tbs,
                              const char *dnsname)
{
    GeneralName gn;

    memset(&gn, 0, sizeof(gn));
    gn.element = choice_GeneralName_dNSName;
    gn.u.dNSName.data = rk_UNCONST(dnsname);
    gn.u.dNSName.length = strlen(dnsname);

    return add_GeneralNames(&tbs->san, &gn);
}

/**
 * Add a Subject Alternative Name rfc822 (email address) to
 * to-be-signed certificate object.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param rfc822Name a string to a email address.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_add_san_rfc822name(hx509_context context,
                                hx509_ca_tbs tbs,
                                const char *rfc822Name)
{
    GeneralName gn;

    memset(&gn, 0, sizeof(gn));
    gn.element = choice_GeneralName_rfc822Name;
    gn.u.rfc822Name.data = rk_UNCONST(rfc822Name);
    gn.u.rfc822Name.length = strlen(rfc822Name);

    return add_GeneralNames(&tbs->san, &gn);
}

/**
 * Set the subject name of a to-be-signed certificate object.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param subject the name to set a subject.
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_set_subject(hx509_context context,
                         hx509_ca_tbs tbs,
                         hx509_name subject)
{
    if (tbs->subject)
        hx509_name_free(&tbs->subject);
    return hx509_name_copy(context, subject, &tbs->subject);
}

/**
 * Set the issuerUniqueID and subjectUniqueID
 *
 * These are only supposed to be used considered with version 2
 * certificates, replaced by the two extensions SubjectKeyIdentifier
 * and IssuerKeyIdentifier. This function is to allow application
 * using legacy protocol to issue them.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param issuerUniqueID to be set
 * @param subjectUniqueID to be set
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_set_unique(hx509_context context,
                        hx509_ca_tbs tbs,
                        const heim_bit_string *subjectUniqueID,
                        const heim_bit_string *issuerUniqueID)
{
    int ret;

    der_free_bit_string(&tbs->subjectUniqueID);
    der_free_bit_string(&tbs->issuerUniqueID);

    if (subjectUniqueID) {
        ret = der_copy_bit_string(subjectUniqueID, &tbs->subjectUniqueID);
        if (ret)
            return ret;
    }

    if (issuerUniqueID) {
        ret = der_copy_bit_string(issuerUniqueID, &tbs->issuerUniqueID);
        if (ret)
            return ret;
    }

    return 0;
}

/**
 * Expand the the subject name in the to-be-signed certificate object
 * using hx509_name_expand().
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param env enviroment variable to expand variables in the subject
 * name, see hx509_env_init().
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_tbs_subject_expand(hx509_context context,
                            hx509_ca_tbs tbs,
                            hx509_env env)
{
    return hx509_name_expand(context, tbs->subject, env);
}

/*
 *
 */

static int
add_extension(hx509_context context,
              TBSCertificate *tbsc,
              int critical_flag,
              const heim_oid *oid,
              const heim_octet_string *data)
{
    Extension ext;
    int ret;

    memset(&ext, 0, sizeof(ext));

    if (critical_flag) {
        ext.critical = malloc(sizeof(*ext.critical));
        if (ext.critical == NULL) {
            ret = ENOMEM;
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        *ext.critical = TRUE;
    }

    ret = der_copy_oid(oid, &ext.extnID);
    if (ret) {
        hx509_set_error_string(context, 0, ret, "Out of memory");
        goto out;
    }
    ret = der_copy_octet_string(data, &ext.extnValue);
    if (ret) {
        hx509_set_error_string(context, 0, ret, "Out of memory");
        goto out;
    }
    ret = add_Extensions(tbsc->extensions, &ext);
    if (ret) {
        hx509_set_error_string(context, 0, ret, "Out of memory");
        goto out;
    }
out:
    free_Extension(&ext);
    return ret;
}

static int
build_proxy_prefix(hx509_context context, const Name *issuer, Name *subject)
{
    char *tstr;
    time_t t;
    int ret;

    ret = copy_Name(issuer, subject);
    if (ret) {
        hx509_set_error_string(context, 0, ret,
                               "Failed to copy subject name");
        return ret;
    }

    t = time(NULL);
    asprintf(&tstr, "ts-%lu", (unsigned long)t);
    if (tstr == NULL) {
        hx509_set_error_string(context, 0, ENOMEM,
                               "Failed to copy subject name");
        return ENOMEM;
    }
    /* prefix with CN=<ts>,...*/
    ret = _hx509_name_modify(context, subject, 1, &asn1_oid_id_at_commonName, tstr);
    free(tstr);
    if (ret)
        free_Name(subject);
    return ret;
}

static int
ca_sign(hx509_context context,
        hx509_ca_tbs tbs,
        hx509_private_key signer,
        const AuthorityKeyIdentifier *ai,
        const Name *issuername,
        hx509_cert *certificate)
{
    heim_octet_string data;
    Certificate c;
    TBSCertificate *tbsc;
    size_t size;
    int ret;
    const AlgorithmIdentifier *sigalg;
    time_t notBefore;
    time_t notAfter;
    unsigned key_usage;

    sigalg = _hx509_crypto_default_sig_alg;

    memset(&c, 0, sizeof(c));

    /*
     * Default values are: Valid since 24h ago, valid one year into
     * the future, KeyUsage digitalSignature and keyEncipherment set,
     * and keyCertSign for CA certificates.
     */
    notBefore = tbs->notBefore;
    if (notBefore == 0)
        notBefore = time(NULL) - 3600 * 24;
    notAfter = tbs->notAfter;
    if (notAfter == 0)
        notAfter = time(NULL) + 3600 * 24 * 365;

    key_usage = tbs->key_usage;
    if (key_usage == 0) {
        KeyUsage ku;
        memset(&ku, 0, sizeof(ku));
        ku.digitalSignature = 1;
        ku.keyEncipherment = 1;
        key_usage = KeyUsage2int(ku);
    }

    if (tbs->flags.ca) {
        KeyUsage ku;
        memset(&ku, 0, sizeof(ku));
        ku.keyCertSign = 1;
        ku.cRLSign = 1;
        key_usage |= KeyUsage2int(ku);
    }

    /*
     *
     */

    tbsc = &c.tbsCertificate;

    if (tbs->flags.key == 0) {
        ret = EINVAL;
        hx509_set_error_string(context, 0, ret, "No public key set");
        return ret;
    }
    /*
     * Don't put restrictions on proxy certificate's subject name, it
     * will be generated below.
     */
    if (!tbs->flags.proxy) {
        if (tbs->subject == NULL) {
            hx509_set_error_string(context, 0, EINVAL, "No subject name set");
            return EINVAL;
        }
        if (hx509_name_is_null_p(tbs->subject) && tbs->san.len == 0) {
            hx509_set_error_string(context, 0, EINVAL,
                                   "NULL subject and no SubjectAltNames");
            return EINVAL;
        }
    }
    if (tbs->flags.ca && tbs->flags.proxy) {
        hx509_set_error_string(context, 0, EINVAL, "Can't be proxy and CA "
                               "at the same time");
        return EINVAL;
    }
    if (tbs->flags.proxy) {
        if (tbs->san.len > 0) {
            hx509_set_error_string(context, 0, EINVAL,
                                   "Proxy certificate is not allowed "
                                   "to have SubjectAltNames");
            return EINVAL;
        }
    }

    /* version         [0]  Version OPTIONAL, -- EXPLICIT nnn DEFAULT 1, */
    tbsc->version = calloc(1, sizeof(*tbsc->version));
    if (tbsc->version == NULL) {
        ret = ENOMEM;
        hx509_set_error_string(context, 0, ret, "Out of memory");
        goto out;
    }
    *tbsc->version = rfc3280_version_3;
    /* serialNumber         CertificateSerialNumber, */
    if (tbs->flags.serial) {
        ret = der_copy_heim_integer(&tbs->serial, &tbsc->serialNumber);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
    } else {
        tbsc->serialNumber.length = 20;
        tbsc->serialNumber.data = malloc(tbsc->serialNumber.length);
        if (tbsc->serialNumber.data == NULL){
            ret = ENOMEM;
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        /* XXX diffrent */
        RAND_bytes(tbsc->serialNumber.data, tbsc->serialNumber.length);
        ((unsigned char *)tbsc->serialNumber.data)[0] &= 0x7f;
    }
    /* signature            AlgorithmIdentifier, */
    ret = copy_AlgorithmIdentifier(sigalg, &tbsc->signature);
    if (ret) {
        hx509_set_error_string(context, 0, ret, "Failed to copy sigature alg");
        goto out;
    }
    /* issuer               Name, */
    if (issuername)
        ret = copy_Name(issuername, &tbsc->issuer);
    else
        ret = hx509_name_to_Name(tbs->subject, &tbsc->issuer);
    if (ret) {
        hx509_set_error_string(context, 0, ret, "Failed to copy issuer name");
        goto out;
    }
    /* validity             Validity, */
    tbsc->validity.notBefore.element = choice_Time_generalTime;
    tbsc->validity.notBefore.u.generalTime = notBefore;
    tbsc->validity.notAfter.element = choice_Time_generalTime;
    tbsc->validity.notAfter.u.generalTime = notAfter;
    /* subject              Name, */
    if (tbs->flags.proxy) {
        ret = build_proxy_prefix(context, &tbsc->issuer, &tbsc->subject);
        if (ret)
            goto out;
    } else {
        ret = hx509_name_to_Name(tbs->subject, &tbsc->subject);
        if (ret) {
            hx509_set_error_string(context, 0, ret,
                                   "Failed to copy subject name");
            goto out;
        }
    }
    /* subjectPublicKeyInfo SubjectPublicKeyInfo, */
    ret = copy_SubjectPublicKeyInfo(&tbs->spki, &tbsc->subjectPublicKeyInfo);
    if (ret) {
        hx509_set_error_string(context, 0, ret, "Failed to copy spki");
        goto out;
    }
    /* issuerUniqueID  [1]  IMPLICIT BIT STRING OPTIONAL */
    if (tbs->issuerUniqueID.length) {
        tbsc->issuerUniqueID = calloc(1, sizeof(*tbsc->issuerUniqueID));
        if (tbsc->issuerUniqueID == NULL) {
            ret = ENOMEM;
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        ret = der_copy_bit_string(&tbs->issuerUniqueID, tbsc->issuerUniqueID);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
    }
    /* subjectUniqueID [2]  IMPLICIT BIT STRING OPTIONAL */
    if (tbs->subjectUniqueID.length) {
        tbsc->subjectUniqueID = calloc(1, sizeof(*tbsc->subjectUniqueID));
        if (tbsc->subjectUniqueID == NULL) {
            ret = ENOMEM;
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }

        ret = der_copy_bit_string(&tbs->subjectUniqueID, tbsc->subjectUniqueID);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
    }

    /* extensions      [3]  EXPLICIT Extensions OPTIONAL */
    tbsc->extensions = calloc(1, sizeof(*tbsc->extensions));
    if (tbsc->extensions == NULL) {
        ret = ENOMEM;
        hx509_set_error_string(context, 0, ret, "Out of memory");
        goto out;
    }

    /* Add the text BMP string Domaincontroller to the cert */
    if (tbs->flags.domaincontroller) {
        data.data = rk_UNCONST("\x1e\x20\x00\x44\x00\x6f\x00\x6d"
                               "\x00\x61\x00\x69\x00\x6e\x00\x43"
                               "\x00\x6f\x00\x6e\x00\x74\x00\x72"
                               "\x00\x6f\x00\x6c\x00\x6c\x00\x65"
                               "\x00\x72");
        data.length = 34;

        ret = add_extension(context, tbsc, 0,
                            &asn1_oid_id_ms_cert_enroll_domaincontroller,
                            &data);
        if (ret)
            goto out;
    }

    /* add KeyUsage */
    {
        KeyUsage ku;

        ku = int2KeyUsage(key_usage);
        ASN1_MALLOC_ENCODE(KeyUsage, data.data, data.length, &ku, &size, ret);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        if (size != data.length)
            _hx509_abort("internal ASN.1 encoder error");
        ret = add_extension(context, tbsc, 1,
                            &asn1_oid_id_x509_ce_keyUsage, &data);
        free(data.data);
        if (ret)
            goto out;
    }

    /* add ExtendedKeyUsage */
    if (tbs->eku.len > 0) {
        ASN1_MALLOC_ENCODE(ExtKeyUsage, data.data, data.length,
                           &tbs->eku, &size, ret);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        if (size != data.length)
            _hx509_abort("internal ASN.1 encoder error");
        ret = add_extension(context, tbsc, 0,
                            &asn1_oid_id_x509_ce_extKeyUsage, &data);
        free(data.data);
        if (ret)
            goto out;
    }

    /* add Subject Alternative Name */
    if (tbs->san.len > 0) {
        ASN1_MALLOC_ENCODE(GeneralNames, data.data, data.length,
                           &tbs->san, &size, ret);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        if (size != data.length)
            _hx509_abort("internal ASN.1 encoder error");
        ret = add_extension(context, tbsc, 0,
                            &asn1_oid_id_x509_ce_subjectAltName,
                            &data);
        free(data.data);
        if (ret)
            goto out;
    }

    /* Add Authority Key Identifier */
    if (ai) {
        ASN1_MALLOC_ENCODE(AuthorityKeyIdentifier, data.data, data.length,
                           ai, &size, ret);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        if (size != data.length)
            _hx509_abort("internal ASN.1 encoder error");
        ret = add_extension(context, tbsc, 0,
                            &asn1_oid_id_x509_ce_authorityKeyIdentifier,
                            &data);
        free(data.data);
        if (ret)
            goto out;
    }

    /* Add Subject Key Identifier */
    {
        SubjectKeyIdentifier si;
        unsigned char hash[SHA_DIGEST_LENGTH];

        {
            EVP_MD_CTX *ctx;

            ctx = EVP_MD_CTX_create();
            EVP_DigestInit_ex(ctx, EVP_sha1(), NULL);
            EVP_DigestUpdate(ctx, tbs->spki.subjectPublicKey.data,
                             tbs->spki.subjectPublicKey.length / 8);
            EVP_DigestFinal_ex(ctx, hash, NULL);
            EVP_MD_CTX_destroy(ctx);
        }

        si.data = hash;
        si.length = sizeof(hash);

        ASN1_MALLOC_ENCODE(SubjectKeyIdentifier, data.data, data.length,
                           &si, &size, ret);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        if (size != data.length)
            _hx509_abort("internal ASN.1 encoder error");
        ret = add_extension(context, tbsc, 0,
                            &asn1_oid_id_x509_ce_subjectKeyIdentifier,
                            &data);
        free(data.data);
        if (ret)
            goto out;
    }

    /* Add BasicConstraints */
    {
        BasicConstraints bc;
        int aCA = 1;
        unsigned int path;

        memset(&bc, 0, sizeof(bc));

        if (tbs->flags.ca) {
            bc.cA = &aCA;
            if (tbs->pathLenConstraint >= 0) {
                path = tbs->pathLenConstraint;
                bc.pathLenConstraint = &path;
            }
        }

        ASN1_MALLOC_ENCODE(BasicConstraints, data.data, data.length,
                           &bc, &size, ret);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        if (size != data.length)
            _hx509_abort("internal ASN.1 encoder error");
        /* Critical if this is a CA */
        ret = add_extension(context, tbsc, tbs->flags.ca,
                            &asn1_oid_id_x509_ce_basicConstraints,
                            &data);
        free(data.data);
        if (ret)
            goto out;
    }

    /* add Proxy */
    if (tbs->flags.proxy) {
        ProxyCertInfo info;

        memset(&info, 0, sizeof(info));

        if (tbs->pathLenConstraint >= 0) {
            info.pCPathLenConstraint =
                malloc(sizeof(*info.pCPathLenConstraint));
            if (info.pCPathLenConstraint == NULL) {
                ret = ENOMEM;
                hx509_set_error_string(context, 0, ret, "Out of memory");
                goto out;
            }
            *info.pCPathLenConstraint = tbs->pathLenConstraint;
        }

        ret = der_copy_oid(&asn1_oid_id_pkix_ppl_inheritAll,
                           &info.proxyPolicy.policyLanguage);
        if (ret) {
            free_ProxyCertInfo(&info);
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }

        ASN1_MALLOC_ENCODE(ProxyCertInfo, data.data, data.length,
                           &info, &size, ret);
        free_ProxyCertInfo(&info);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        if (size != data.length)
            _hx509_abort("internal ASN.1 encoder error");
        ret = add_extension(context, tbsc, 0,
                            &asn1_oid_id_pkix_pe_proxyCertInfo,
                            &data);
        free(data.data);
        if (ret)
            goto out;
    }

    if (tbs->crldp.len) {

        ASN1_MALLOC_ENCODE(CRLDistributionPoints, data.data, data.length,
                           &tbs->crldp, &size, ret);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        if (size != data.length)
            _hx509_abort("internal ASN.1 encoder error");
        ret = add_extension(context, tbsc, FALSE,
                            &asn1_oid_id_x509_ce_cRLDistributionPoints,
                            &data);
        free(data.data);
        if (ret)
            goto out;
    }

    ASN1_MALLOC_ENCODE(TBSCertificate, data.data, data.length,tbsc, &size, ret);
    if (ret) {
        hx509_set_error_string(context, 0, ret, "malloc out of memory");
        goto out;
    }
    if (data.length != size)
        _hx509_abort("internal ASN.1 encoder error");

    ret = _hx509_create_signature_bitstring(context,
                                            signer,
                                            sigalg,
                                            &data,
                                            &c.signatureAlgorithm,
                                            &c.signatureValue);
    free(data.data);
    if (ret)
        goto out;

    ret = hx509_cert_init(context, &c, certificate);
    if (ret)
        goto out;

    free_Certificate(&c);

    return 0;

out:
    free_Certificate(&c);
    return ret;
}

static int
get_AuthorityKeyIdentifier(hx509_context context,
                           const Certificate *certificate,
                           AuthorityKeyIdentifier *ai)
{
    SubjectKeyIdentifier si;
    int ret;

    ret = _hx509_find_extension_subject_key_id(certificate, &si);
    if (ret == 0) {
        ai->keyIdentifier = calloc(1, sizeof(*ai->keyIdentifier));
        if (ai->keyIdentifier == NULL) {
            free_SubjectKeyIdentifier(&si);
            ret = ENOMEM;
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        ret = der_copy_octet_string(&si, ai->keyIdentifier);
        free_SubjectKeyIdentifier(&si);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
    } else {
        GeneralNames gns;
        GeneralName gn;
        Name name;

        memset(&gn, 0, sizeof(gn));
        memset(&gns, 0, sizeof(gns));
        memset(&name, 0, sizeof(name));

        ai->authorityCertIssuer =
            calloc(1, sizeof(*ai->authorityCertIssuer));
        if (ai->authorityCertIssuer == NULL) {
            ret = ENOMEM;
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
        ai->authorityCertSerialNumber =
            calloc(1, sizeof(*ai->authorityCertSerialNumber));
        if (ai->authorityCertSerialNumber == NULL) {
            ret = ENOMEM;
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }

        /*
         * XXX unbreak when asn1 compiler handle IMPLICIT
         *
         * This is so horrible.
         */

        ret = copy_Name(&certificate->tbsCertificate.subject, &name);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }

        memset(&gn, 0, sizeof(gn));
        gn.element = choice_GeneralName_directoryName;
        gn.u.directoryName.element =
            choice_GeneralName_directoryName_rdnSequence;
        gn.u.directoryName.u.rdnSequence = name.u.rdnSequence;

        ret = add_GeneralNames(&gns, &gn);
        if (ret) {
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }

        ai->authorityCertIssuer->val = gns.val;
        ai->authorityCertIssuer->len = gns.len;

        ret = der_copy_heim_integer(&certificate->tbsCertificate.serialNumber,
                                    ai->authorityCertSerialNumber);
        if (ai->authorityCertSerialNumber == NULL) {
            ret = ENOMEM;
            hx509_set_error_string(context, 0, ret, "Out of memory");
            goto out;
        }
    }
out:
    if (ret)
        free_AuthorityKeyIdentifier(ai);
    return ret;
}


/**
 * Sign a to-be-signed certificate object with a issuer certificate.
 *
 * The caller needs to at least have called the following functions on the
 * to-be-signed certificate object:
 * - hx509_ca_tbs_init()
 * - hx509_ca_tbs_set_subject()
 * - hx509_ca_tbs_set_spki()
 *
 * When done the to-be-signed certificate object should be freed with
 * hx509_ca_tbs_free().
 *
 * When creating self-signed certificate use hx509_ca_sign_self() instead.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param signer the CA certificate object to sign with (need private key).
 * @param certificate return cerificate, free with hx509_cert_free().
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_sign(hx509_context context,
              hx509_ca_tbs tbs,
              hx509_cert signer,
              hx509_cert *certificate)
{
    const Certificate *signer_cert;
    AuthorityKeyIdentifier ai;
    int ret;

    memset(&ai, 0, sizeof(ai));

    signer_cert = _hx509_get_cert(signer);

    ret = get_AuthorityKeyIdentifier(context, signer_cert, &ai);
    if (ret)
        goto out;

    ret = ca_sign(context,
                  tbs,
                  _hx509_cert_private_key(signer),
                  &ai,
                  &signer_cert->tbsCertificate.subject,
                  certificate);

out:
    free_AuthorityKeyIdentifier(&ai);

    return ret;
}

/**
 * Work just like hx509_ca_sign() but signs it-self.
 *
 * @param context A hx509 context.
 * @param tbs object to be signed.
 * @param signer private key to sign with.
 * @param certificate return cerificate, free with hx509_cert_free().
 *
 * @return An hx509 error code, see hx509_get_error_string().
 *
 * @ingroup hx509_ca
 */

int
hx509_ca_sign_self(hx509_context context,
                   hx509_ca_tbs tbs,
                   hx509_private_key signer,
                   hx509_cert *certificate)
{
    return ca_sign(context,
                   tbs,
                   signer,
                   NULL,
                   NULL,
                   certificate);
}