File: pkinit_srv.c

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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
 * COPYRIGHT (C) 2006,2007
 * THE REGENTS OF THE UNIVERSITY OF MICHIGAN
 * ALL RIGHTS RESERVED
 *
 * Permission is granted to use, copy, create derivative works
 * and redistribute this software and such derivative works
 * for any purpose, so long as the name of The University of
 * Michigan is not used in any advertising or publicity
 * pertaining to the use of distribution of this software
 * without specific, written prior authorization.  If the
 * above copyright notice or any other identification of the
 * University of Michigan is included in any copy of any
 * portion of this software, then the disclaimer below must
 * also be included.
 *
 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
 * FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
 * PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
 * MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
 * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
 * REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
 * FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
 * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGES.
 */

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>

#include <k5-int.h>
#include "pkinit.h"

static krb5_error_code
pkinit_init_kdc_req_context(krb5_context, pkinit_kdc_req_context *blob);

static void
pkinit_fini_kdc_req_context(krb5_context context, void *blob);

static void
pkinit_server_plugin_fini_realm(krb5_context context,
                                pkinit_kdc_context plgctx);

static void
pkinit_server_plugin_fini(krb5_context context,
                          krb5_kdcpreauth_moddata moddata);

static pkinit_kdc_context
pkinit_find_realm_context(krb5_context context,
                          krb5_kdcpreauth_moddata moddata,
                          krb5_principal princ);

static krb5_error_code
pkinit_create_edata(krb5_context context,
                    pkinit_plg_crypto_context plg_cryptoctx,
                    pkinit_req_crypto_context req_cryptoctx,
                    pkinit_identity_crypto_context id_cryptoctx,
                    pkinit_plg_opts *opts,
                    krb5_error_code err_code,
                    krb5_pa_data ***e_data_out)
{
    krb5_error_code retval = KRB5KRB_ERR_GENERIC;

    pkiDebug("pkinit_create_edata: creating edata for error %d (%s)\n",
             err_code, error_message(err_code));
    switch(err_code) {
    case KRB5KDC_ERR_CANT_VERIFY_CERTIFICATE:
        retval = pkinit_create_td_trusted_certifiers(context,
                                                     plg_cryptoctx, req_cryptoctx, id_cryptoctx, e_data_out);
        break;
    case KRB5KDC_ERR_DH_KEY_PARAMETERS_NOT_ACCEPTED:
        retval = pkinit_create_td_dh_parameters(context, plg_cryptoctx,
                                                req_cryptoctx, id_cryptoctx, opts, e_data_out);
        break;
    case KRB5KDC_ERR_INVALID_CERTIFICATE:
    case KRB5KDC_ERR_REVOKED_CERTIFICATE:
        retval = pkinit_create_td_invalid_certificate(context,
                                                      plg_cryptoctx, req_cryptoctx, id_cryptoctx, e_data_out);
        break;
    default:
        pkiDebug("no edata needed for error %d (%s)\n",
                 err_code, error_message(err_code));
        retval = 0;
        goto cleanup;
    }

cleanup:

    return retval;
}

static void
pkinit_server_get_edata(krb5_context context,
                        krb5_kdc_req *request,
                        krb5_kdcpreauth_callbacks cb,
                        krb5_kdcpreauth_rock rock,
                        krb5_kdcpreauth_moddata moddata,
                        krb5_preauthtype pa_type,
                        krb5_kdcpreauth_edata_respond_fn respond,
                        void *arg)
{
    krb5_error_code retval = 0;
    pkinit_kdc_context plgctx = NULL;

    pkiDebug("pkinit_server_get_edata: entered!\n");


    /*
     * If we don't have a realm context for the given realm,
     * don't tell the client that we support pkinit!
     */
    plgctx = pkinit_find_realm_context(context, moddata, request->server);
    if (plgctx == NULL)
        retval = EINVAL;

    (*respond)(arg, retval, NULL);
}

static krb5_error_code
verify_client_san(krb5_context context,
                  pkinit_kdc_context plgctx,
                  pkinit_kdc_req_context reqctx,
                  krb5_principal client,
                  int *valid_san)
{
    krb5_error_code retval;
    krb5_principal *princs = NULL;
    krb5_principal *upns = NULL;
    int i;
#ifdef DEBUG_SAN_INFO
    char *client_string = NULL, *san_string;
#endif

    retval = crypto_retrieve_cert_sans(context, plgctx->cryptoctx,
                                       reqctx->cryptoctx, plgctx->idctx,
                                       &princs,
                                       plgctx->opts->allow_upn ? &upns : NULL,
                                       NULL);
    if (retval) {
        pkiDebug("%s: error from retrieve_certificate_sans()\n", __FUNCTION__);
        retval = KRB5KDC_ERR_CLIENT_NAME_MISMATCH;
        goto out;
    }
    /* XXX Verify this is consistent with client side XXX */
#if 0
    retval = call_san_checking_plugins(context, plgctx, reqctx, princs,
                                       upns, NULL, &plugin_decision, &ignore);
    pkiDebug("%s: call_san_checking_plugins() returned retval %d\n",
             __FUNCTION__);
    if (retval) {
        retval = KRB5KDC_ERR_CLIENT_NAME_MISMATCH;
        goto cleanup;
    }
    pkiDebug("%s: call_san_checking_plugins() returned decision %d\n",
             __FUNCTION__, plugin_decision);
    if (plugin_decision != NO_DECISION) {
        retval = plugin_decision;
        goto out;
    }
#endif

#ifdef DEBUG_SAN_INFO
    krb5_unparse_name(context, client, &client_string);
#endif
    pkiDebug("%s: Checking pkinit sans\n", __FUNCTION__);
    for (i = 0; princs != NULL && princs[i] != NULL; i++) {
#ifdef DEBUG_SAN_INFO
        krb5_unparse_name(context, princs[i], &san_string);
        pkiDebug("%s: Comparing client '%s' to pkinit san value '%s'\n",
                 __FUNCTION__, client_string, san_string);
        krb5_free_unparsed_name(context, san_string);
#endif
        if (krb5_principal_compare(context, princs[i], client)) {
            pkiDebug("%s: pkinit san match found\n", __FUNCTION__);
            *valid_san = 1;
            retval = 0;
            goto out;
        }
    }
    pkiDebug("%s: no pkinit san match found\n", __FUNCTION__);
    /*
     * XXX if cert has names but none match, should we
     * be returning KRB5KDC_ERR_CLIENT_NAME_MISMATCH here?
     */

    if (upns == NULL) {
        pkiDebug("%s: no upn sans (or we wouldn't accept them anyway)\n",
                 __FUNCTION__);
        retval = KRB5KDC_ERR_CLIENT_NAME_MISMATCH;
        goto out;
    }

    pkiDebug("%s: Checking upn sans\n", __FUNCTION__);
    for (i = 0; upns[i] != NULL; i++) {
#ifdef DEBUG_SAN_INFO
        krb5_unparse_name(context, upns[i], &san_string);
        pkiDebug("%s: Comparing client '%s' to upn san value '%s'\n",
                 __FUNCTION__, client_string, san_string);
        krb5_free_unparsed_name(context, san_string);
#endif
        if (krb5_principal_compare(context, upns[i], client)) {
            pkiDebug("%s: upn san match found\n", __FUNCTION__);
            *valid_san = 1;
            retval = 0;
            goto out;
        }
    }
    pkiDebug("%s: no upn san match found\n", __FUNCTION__);

    /* We found no match */
    if (princs != NULL || upns != NULL) {
        *valid_san = 0;
        /* XXX ??? If there was one or more name in the cert, but
         * none matched the client name, then return mismatch? */
        retval = KRB5KDC_ERR_CLIENT_NAME_MISMATCH;
    }
    retval = 0;

out:
    if (princs != NULL) {
        for (i = 0; princs[i] != NULL; i++)
            krb5_free_principal(context, princs[i]);
        free(princs);
    }
    if (upns != NULL) {
        for (i = 0; upns[i] != NULL; i++)
            krb5_free_principal(context, upns[i]);
        free(upns);
    }
#ifdef DEBUG_SAN_INFO
    if (client_string != NULL)
        krb5_free_unparsed_name(context, client_string);
#endif
    pkiDebug("%s: returning retval %d, valid_san %d\n",
             __FUNCTION__, retval, *valid_san);
    return retval;
}

static krb5_error_code
verify_client_eku(krb5_context context,
                  pkinit_kdc_context plgctx,
                  pkinit_kdc_req_context reqctx,
                  int *eku_accepted)
{
    krb5_error_code retval;

    *eku_accepted = 0;

    if (plgctx->opts->require_eku == 0) {
        pkiDebug("%s: configuration requests no EKU checking\n", __FUNCTION__);
        *eku_accepted = 1;
        retval = 0;
        goto out;
    }

    retval = crypto_check_cert_eku(context, plgctx->cryptoctx,
                                   reqctx->cryptoctx, plgctx->idctx,
                                   0, /* kdc cert */
                                   plgctx->opts->accept_secondary_eku,
                                   eku_accepted);
    if (retval) {
        pkiDebug("%s: Error from crypto_check_cert_eku %d (%s)\n",
                 __FUNCTION__, retval, error_message(retval));
        goto out;
    }

out:
    pkiDebug("%s: returning retval %d, eku_accepted %d\n",
             __FUNCTION__, retval, *eku_accepted);
    return retval;
}

static void
pkinit_server_verify_padata(krb5_context context,
                            krb5_data *req_pkt,
                            krb5_kdc_req * request,
                            krb5_enc_tkt_part * enc_tkt_reply,
                            krb5_pa_data * data,
                            krb5_kdcpreauth_callbacks cb,
                            krb5_kdcpreauth_rock rock,
                            krb5_kdcpreauth_moddata moddata,
                            krb5_kdcpreauth_verify_respond_fn respond,
                            void *arg)
{
    krb5_error_code retval = 0;
    krb5_data authp_data = {0, 0, NULL}, krb5_authz = {0, 0, NULL};
    krb5_pa_pk_as_req *reqp = NULL;
    krb5_pa_pk_as_req_draft9 *reqp9 = NULL;
    krb5_auth_pack *auth_pack = NULL;
    krb5_auth_pack_draft9 *auth_pack9 = NULL;
    pkinit_kdc_context plgctx = NULL;
    pkinit_kdc_req_context reqctx = NULL;
    krb5_checksum cksum = {0, 0, 0, NULL};
    krb5_data *der_req = NULL;
    int valid_eku = 0, valid_san = 0;
    krb5_data k5data;
    int is_signed = 1;
    krb5_pa_data **e_data = NULL;
    krb5_kdcpreauth_modreq modreq = NULL;

    pkiDebug("pkinit_verify_padata: entered!\n");
    if (data == NULL || data->length <= 0 || data->contents == NULL) {
        (*respond)(arg, EINVAL, NULL, NULL, NULL);
        return;
    }


    if (moddata == NULL) {
        (*respond)(arg, EINVAL, NULL, NULL, NULL);
        return;
    }

    plgctx = pkinit_find_realm_context(context, moddata, request->server);
    if (plgctx == NULL) {
        (*respond)(arg, EINVAL, NULL, NULL, NULL);
        return;
    }

#ifdef DEBUG_ASN1
    print_buffer_bin(data->contents, data->length, "/tmp/kdc_as_req");
#endif
    /* create a per-request context */
    retval = pkinit_init_kdc_req_context(context, &reqctx);
    if (retval)
        goto cleanup;
    reqctx->pa_type = data->pa_type;

    PADATA_TO_KRB5DATA(data, &k5data);

    switch ((int)data->pa_type) {
    case KRB5_PADATA_PK_AS_REQ:
        pkiDebug("processing KRB5_PADATA_PK_AS_REQ\n");
        retval = k5int_decode_krb5_pa_pk_as_req(&k5data, &reqp);
        if (retval) {
            pkiDebug("decode_krb5_pa_pk_as_req failed\n");
            goto cleanup;
        }
#ifdef DEBUG_ASN1
        print_buffer_bin(reqp->signedAuthPack.data,
                         reqp->signedAuthPack.length,
                         "/tmp/kdc_signed_data");
#endif
        retval = cms_signeddata_verify(context, plgctx->cryptoctx,
                                       reqctx->cryptoctx, plgctx->idctx, CMS_SIGN_CLIENT,
                                       plgctx->opts->require_crl_checking,
                                       (unsigned char *)
                                       reqp->signedAuthPack.data, reqp->signedAuthPack.length,
                                       (unsigned char **)&authp_data.data,
                                       &authp_data.length,
                                       (unsigned char **)&krb5_authz.data,
                                       &krb5_authz.length, &is_signed);
        break;
    case KRB5_PADATA_PK_AS_REP_OLD:
    case KRB5_PADATA_PK_AS_REQ_OLD:
        pkiDebug("processing KRB5_PADATA_PK_AS_REQ_OLD\n");
        retval = k5int_decode_krb5_pa_pk_as_req_draft9(&k5data, &reqp9);
        if (retval) {
            pkiDebug("decode_krb5_pa_pk_as_req_draft9 failed\n");
            goto cleanup;
        }
#ifdef DEBUG_ASN1
        print_buffer_bin(reqp9->signedAuthPack.data,
                         reqp9->signedAuthPack.length,
                         "/tmp/kdc_signed_data_draft9");
#endif

        retval = cms_signeddata_verify(context, plgctx->cryptoctx,
                                       reqctx->cryptoctx, plgctx->idctx, CMS_SIGN_DRAFT9,
                                       plgctx->opts->require_crl_checking,
                                       (unsigned char *)
                                       reqp9->signedAuthPack.data, reqp9->signedAuthPack.length,
                                       (unsigned char **)&authp_data.data,
                                       &authp_data.length,
                                       (unsigned char **)&krb5_authz.data,
                                       &krb5_authz.length, NULL);
        break;
    default:
        pkiDebug("unrecognized pa_type = %d\n", data->pa_type);
        retval = EINVAL;
        goto cleanup;
    }
    if (retval) {
        pkiDebug("pkcs7_signeddata_verify failed\n");
        goto cleanup;
    }
    if (is_signed) {

        retval = verify_client_san(context, plgctx, reqctx, request->client,
                                   &valid_san);
        if (retval)
            goto cleanup;
        if (!valid_san) {
            pkiDebug("%s: did not find an acceptable SAN in user "
                     "certificate\n", __FUNCTION__);
            retval = KRB5KDC_ERR_CLIENT_NAME_MISMATCH;
            goto cleanup;
        }
        retval = verify_client_eku(context, plgctx, reqctx, &valid_eku);
        if (retval)
            goto cleanup;

        if (!valid_eku) {
            pkiDebug("%s: did not find an acceptable EKU in user "
                     "certificate\n", __FUNCTION__);
            retval = KRB5KDC_ERR_INCONSISTENT_KEY_PURPOSE;
            goto cleanup;
        }
    } else { /* !is_signed */
        if (!krb5_principal_compare(context, request->client,
                                    krb5_anonymous_principal())) {
            retval = KRB5KDC_ERR_PREAUTH_FAILED;
            krb5_set_error_message(context, retval,
                                   _("Pkinit request not signed, but client "
                                     "not anonymous."));
            goto cleanup;
        }
    }
#ifdef DEBUG_ASN1
    print_buffer_bin(authp_data.data, authp_data.length, "/tmp/kdc_auth_pack");
#endif

    OCTETDATA_TO_KRB5DATA(&authp_data, &k5data);
    switch ((int)data->pa_type) {
    case KRB5_PADATA_PK_AS_REQ:
        retval = k5int_decode_krb5_auth_pack(&k5data, &auth_pack);
        if (retval) {
            pkiDebug("failed to decode krb5_auth_pack\n");
            goto cleanup;
        }

        /* check dh parameters */
        if (auth_pack->clientPublicValue != NULL) {
            retval = server_check_dh(context, plgctx->cryptoctx,
                                     reqctx->cryptoctx, plgctx->idctx,
                                     &auth_pack->clientPublicValue->algorithm.parameters,
                                     plgctx->opts->dh_min_bits);

            if (retval) {
                pkiDebug("bad dh parameters\n");
                goto cleanup;
            }
        } else if (!is_signed) {
            /*Anonymous pkinit requires DH*/
            retval = KRB5KDC_ERR_PREAUTH_FAILED;
            krb5_set_error_message(context, retval,
                                   _("Anonymous pkinit without DH public "
                                     "value not supported."));
            goto cleanup;
        }
        der_req = cb->request_body(context, rock);
        retval = krb5_c_make_checksum(context, CKSUMTYPE_NIST_SHA, NULL,
                                      0, der_req, &cksum);
        if (retval) {
            pkiDebug("unable to calculate AS REQ checksum\n");
            goto cleanup;
        }
        if (cksum.length != auth_pack->pkAuthenticator.paChecksum.length ||
            k5_bcmp(cksum.contents,
                    auth_pack->pkAuthenticator.paChecksum.contents,
                    cksum.length) != 0) {
            pkiDebug("failed to match the checksum\n");
#ifdef DEBUG_CKSUM
            pkiDebug("calculating checksum on buf size (%d)\n",
                     req_pkt->length);
            print_buffer(req_pkt->data, req_pkt->length);
            pkiDebug("received checksum type=%d size=%d ",
                     auth_pack->pkAuthenticator.paChecksum.checksum_type,
                     auth_pack->pkAuthenticator.paChecksum.length);
            print_buffer(auth_pack->pkAuthenticator.paChecksum.contents,
                         auth_pack->pkAuthenticator.paChecksum.length);
            pkiDebug("expected checksum type=%d size=%d ",
                     cksum.checksum_type, cksum.length);
            print_buffer(cksum.contents, cksum.length);
#endif

            retval = KRB5KDC_ERR_PA_CHECKSUM_MUST_BE_INCLUDED;
            goto cleanup;
        }

        /* check if kdcPkId present and match KDC's subjectIdentifier */
        if (reqp->kdcPkId.data != NULL) {
            int valid_kdcPkId = 0;
            retval = pkinit_check_kdc_pkid(context, plgctx->cryptoctx,
                                           reqctx->cryptoctx, plgctx->idctx,
                                           (unsigned char *)reqp->kdcPkId.data,
                                           reqp->kdcPkId.length, &valid_kdcPkId);
            if (retval)
                goto cleanup;
            if (!valid_kdcPkId)
                pkiDebug("kdcPkId in AS_REQ does not match KDC's cert"
                         "RFC says to ignore and proceed\n");

        }
        /* remember the decoded auth_pack for verify_padata routine */
        reqctx->rcv_auth_pack = auth_pack;
        auth_pack = NULL;
        break;
    case KRB5_PADATA_PK_AS_REP_OLD:
    case KRB5_PADATA_PK_AS_REQ_OLD:
        retval = k5int_decode_krb5_auth_pack_draft9(&k5data, &auth_pack9);
        if (retval) {
            pkiDebug("failed to decode krb5_auth_pack_draft9\n");
            goto cleanup;
        }
        if (auth_pack9->clientPublicValue != NULL) {
            retval = server_check_dh(context, plgctx->cryptoctx,
                                     reqctx->cryptoctx, plgctx->idctx,
                                     &auth_pack9->clientPublicValue->algorithm.parameters,
                                     plgctx->opts->dh_min_bits);

            if (retval) {
                pkiDebug("bad dh parameters\n");
                goto cleanup;
            }
        }
        /* remember the decoded auth_pack for verify_padata routine */
        reqctx->rcv_auth_pack9 = auth_pack9;
        auth_pack9 = NULL;
        break;
    }

    /* remember to set the PREAUTH flag in the reply */
    enc_tkt_reply->flags |= TKT_FLG_PRE_AUTH;
    modreq = (krb5_kdcpreauth_modreq)reqctx;
    reqctx = NULL;

cleanup:
    if (retval && data->pa_type == KRB5_PADATA_PK_AS_REQ) {
        pkiDebug("pkinit_verify_padata failed: creating e-data\n");
        if (pkinit_create_edata(context, plgctx->cryptoctx, reqctx->cryptoctx,
                                plgctx->idctx, plgctx->opts, retval, &e_data))
            pkiDebug("pkinit_create_edata failed\n");
    }

    switch ((int)data->pa_type) {
    case KRB5_PADATA_PK_AS_REQ:
        free_krb5_pa_pk_as_req(&reqp);
        free(cksum.contents);
        break;
    case KRB5_PADATA_PK_AS_REP_OLD:
    case KRB5_PADATA_PK_AS_REQ_OLD:
        free_krb5_pa_pk_as_req_draft9(&reqp9);
    }
    free(authp_data.data);
    free(krb5_authz.data);
    if (reqctx != NULL)
        pkinit_fini_kdc_req_context(context, reqctx);
    free_krb5_auth_pack(&auth_pack);
    free_krb5_auth_pack_draft9(context, &auth_pack9);

    (*respond)(arg, retval, modreq, e_data, NULL);
}
static krb5_error_code
return_pkinit_kx(krb5_context context, krb5_kdc_req *request,
                 krb5_kdc_rep *reply, krb5_keyblock *encrypting_key,
                 krb5_pa_data **out_padata)
{
    krb5_error_code ret = 0;
    krb5_keyblock *session = reply->ticket->enc_part2->session;
    krb5_keyblock *new_session = NULL;
    krb5_pa_data *pa = NULL;
    krb5_enc_data enc;
    krb5_data *scratch = NULL;

    *out_padata = NULL;
    enc.ciphertext.data = NULL;
    if (!krb5_principal_compare(context, request->client,
                                krb5_anonymous_principal()))
        return 0;
    /*
     * The KDC contribution key needs to be a fresh key of an enctype supported
     * by the client and server. The existing session key meets these
     * requirements so we use it.
     */
    ret = krb5_c_fx_cf2_simple(context, session, "PKINIT",
                               encrypting_key, "KEYEXCHANGE",
                               &new_session);
    if (ret)
        goto cleanup;
    ret = encode_krb5_encryption_key( session, &scratch);
    if (ret)
        goto cleanup;
    ret = krb5_encrypt_helper(context, encrypting_key,
                              KRB5_KEYUSAGE_PA_PKINIT_KX, scratch, &enc);
    if (ret)
        goto cleanup;
    memset(scratch->data, 0, scratch->length);
    krb5_free_data(context, scratch);
    scratch = NULL;
    ret = encode_krb5_enc_data(&enc, &scratch);
    if (ret)
        goto cleanup;
    pa = malloc(sizeof(krb5_pa_data));
    if (pa == NULL) {
        ret = ENOMEM;
        goto cleanup;
    }
    pa->pa_type = KRB5_PADATA_PKINIT_KX;
    pa->length = scratch->length;
    pa->contents = (krb5_octet *) scratch->data;
    *out_padata = pa;
    scratch->data = NULL;
    memset(session->contents, 0, session->length);
    krb5_free_keyblock_contents(context, session);
    *session = *new_session;
    new_session->contents = NULL;
cleanup:
    krb5_free_data_contents(context, &enc.ciphertext);
    krb5_free_keyblock(context, new_session);
    krb5_free_data(context, scratch);
    return ret;
}

static krb5_error_code
pkinit_pick_kdf_alg(krb5_context context, krb5_data **kdf_list,
                    krb5_data **alg_oid)
{
    krb5_error_code retval = 0;
    krb5_data *req_oid = NULL;
    const krb5_data *supp_oid = NULL;
    krb5_data *tmp_oid = NULL;
    int i, j = 0;

    /* if we don't find a match, return NULL value */
    *alg_oid = NULL;

    /* for each of the OIDs that the server supports... */
    for (i = 0; NULL != (supp_oid = supported_kdf_alg_ids[i]); i++) {
        /* if the requested OID is in the client's list, use it. */
        for (j = 0; NULL != (req_oid = kdf_list[j]); j++) {
            if ((req_oid->length == supp_oid->length) &&
                (0 == memcmp(req_oid->data, supp_oid->data, req_oid->length))) {
                tmp_oid = k5alloc(sizeof(krb5_data), &retval);
                if (retval)
                    goto cleanup;
                tmp_oid->data = k5memdup(supp_oid->data, supp_oid->length,
                                         &retval);
                if (retval)
                    goto cleanup;
                tmp_oid->length = supp_oid->length;
                *alg_oid = tmp_oid;
                /* don't free the OID in clean-up if we are returning it */
                tmp_oid = NULL;
                goto cleanup;
            }
        }
    }
cleanup:
    if (tmp_oid)
        krb5_free_data(context, tmp_oid);
    return retval;
}

static krb5_error_code
pkinit_server_return_padata(krb5_context context,
                            krb5_pa_data * padata,
                            krb5_data *req_pkt,
                            krb5_kdc_req * request,
                            krb5_kdc_rep * reply,
                            krb5_keyblock * encrypting_key,
                            krb5_pa_data ** send_pa,
                            krb5_kdcpreauth_callbacks cb,
                            krb5_kdcpreauth_rock rock,
                            krb5_kdcpreauth_moddata moddata,
                            krb5_kdcpreauth_modreq modreq)
{
    krb5_error_code retval = 0;
    krb5_data scratch = {0, 0, NULL};
    krb5_pa_pk_as_req *reqp = NULL;
    krb5_pa_pk_as_req_draft9 *reqp9 = NULL;
    int i = 0;

    unsigned char *subjectPublicKey = NULL;
    unsigned char *dh_pubkey = NULL, *server_key = NULL;
    unsigned int subjectPublicKey_len = 0;
    unsigned int server_key_len = 0, dh_pubkey_len = 0;

    krb5_kdc_dh_key_info dhkey_info;
    krb5_data *encoded_dhkey_info = NULL;
    krb5_pa_pk_as_rep *rep = NULL;
    krb5_pa_pk_as_rep_draft9 *rep9 = NULL;
    krb5_data *out_data = NULL;
    krb5_data secret;

    krb5_enctype enctype = -1;

    krb5_reply_key_pack *key_pack = NULL;
    krb5_reply_key_pack_draft9 *key_pack9 = NULL;
    krb5_data *encoded_key_pack = NULL;

    pkinit_kdc_context plgctx;
    pkinit_kdc_req_context reqctx;

    int fixed_keypack = 0;

    *send_pa = NULL;
    if (padata->pa_type == KRB5_PADATA_PKINIT_KX) {
        return return_pkinit_kx(context, request, reply,
                                encrypting_key, send_pa);
    }
    if (padata->length <= 0 || padata->contents == NULL)
        return 0;

    if (modreq == NULL) {
        pkiDebug("missing request context \n");
        return EINVAL;
    }

    plgctx = pkinit_find_realm_context(context, moddata, request->server);
    if (plgctx == NULL) {
        pkiDebug("Unable to locate correct realm context\n");
        return ENOENT;
    }

    pkiDebug("pkinit_return_padata: entered!\n");
    reqctx = (pkinit_kdc_req_context)modreq;

    if (encrypting_key->contents) {
        free(encrypting_key->contents);
        encrypting_key->length = 0;
        encrypting_key->contents = NULL;
    }

    for(i = 0; i < request->nktypes; i++) {
        enctype = request->ktype[i];
        if (!krb5_c_valid_enctype(enctype))
            continue;
        else {
            pkiDebug("KDC picked etype = %d\n", enctype);
            break;
        }
    }

    if (i == request->nktypes) {
        retval = KRB5KDC_ERR_ETYPE_NOSUPP;
        goto cleanup;
    }

    switch((int)reqctx->pa_type) {
    case KRB5_PADATA_PK_AS_REQ:
        init_krb5_pa_pk_as_rep(&rep);
        if (rep == NULL) {
            retval = ENOMEM;
            goto cleanup;
        }
        /* let's assume it's RSA. we'll reset it to DH if needed */
        rep->choice = choice_pa_pk_as_rep_encKeyPack;
        break;
    case KRB5_PADATA_PK_AS_REP_OLD:
    case KRB5_PADATA_PK_AS_REQ_OLD:
        init_krb5_pa_pk_as_rep_draft9(&rep9);
        if (rep9 == NULL) {
            retval = ENOMEM;
            goto cleanup;
        }
        rep9->choice = choice_pa_pk_as_rep_draft9_encKeyPack;
        break;
    default:
        retval = KRB5KDC_ERR_PREAUTH_FAILED;
        goto cleanup;
    }

    if (reqctx->rcv_auth_pack != NULL &&
        reqctx->rcv_auth_pack->clientPublicValue != NULL) {
        subjectPublicKey = (unsigned char *)
            reqctx->rcv_auth_pack->clientPublicValue->subjectPublicKey.data;
        subjectPublicKey_len =
            reqctx->rcv_auth_pack->clientPublicValue->subjectPublicKey.length;
        rep->choice = choice_pa_pk_as_rep_dhInfo;
    } else if (reqctx->rcv_auth_pack9 != NULL &&
               reqctx->rcv_auth_pack9->clientPublicValue != NULL) {
        subjectPublicKey = (unsigned char *)
            reqctx->rcv_auth_pack9->clientPublicValue->subjectPublicKey.data;
        subjectPublicKey_len =
            reqctx->rcv_auth_pack9->clientPublicValue->subjectPublicKey.length;
        rep9->choice = choice_pa_pk_as_rep_draft9_dhSignedData;
    }

    /* if this DH, then process finish computing DH key */
    if (rep != NULL && (rep->choice == choice_pa_pk_as_rep_dhInfo ||
                        rep->choice == choice_pa_pk_as_rep_draft9_dhSignedData)) {
        pkiDebug("received DH key delivery AS REQ\n");
        retval = server_process_dh(context, plgctx->cryptoctx,
                                   reqctx->cryptoctx, plgctx->idctx, subjectPublicKey,
                                   subjectPublicKey_len, &dh_pubkey, &dh_pubkey_len,
                                   &server_key, &server_key_len);
        if (retval) {
            pkiDebug("failed to process/create dh paramters\n");
            goto cleanup;
        }
    }
    if ((rep9 != NULL &&
         rep9->choice == choice_pa_pk_as_rep_draft9_dhSignedData) ||
        (rep != NULL && rep->choice == choice_pa_pk_as_rep_dhInfo)) {

        /*
         * This is DH, so don't generate the key until after we
         * encode the reply, because the encoded reply is needed
         * to generate the key in some cases.
         */

        dhkey_info.subjectPublicKey.length = dh_pubkey_len;
        dhkey_info.subjectPublicKey.data = (char *)dh_pubkey;
        dhkey_info.nonce = request->nonce;
        dhkey_info.dhKeyExpiration = 0;

        retval = k5int_encode_krb5_kdc_dh_key_info(&dhkey_info,
                                                   &encoded_dhkey_info);
        if (retval) {
            pkiDebug("encode_krb5_kdc_dh_key_info failed\n");
            goto cleanup;
        }
#ifdef DEBUG_ASN1
        print_buffer_bin((unsigned char *)encoded_dhkey_info->data,
                         encoded_dhkey_info->length,
                         "/tmp/kdc_dh_key_info");
#endif

        switch ((int)padata->pa_type) {
        case KRB5_PADATA_PK_AS_REQ:
            retval = cms_signeddata_create(context, plgctx->cryptoctx,
                                           reqctx->cryptoctx, plgctx->idctx, CMS_SIGN_SERVER, 1,
                                           (unsigned char *)
                                           encoded_dhkey_info->data,
                                           encoded_dhkey_info->length,
                                           (unsigned char **)
                                           &rep->u.dh_Info.dhSignedData.data,
                                           &rep->u.dh_Info.dhSignedData.length);
            if (retval) {
                pkiDebug("failed to create pkcs7 signed data\n");
                goto cleanup;
            }
            break;
        case KRB5_PADATA_PK_AS_REP_OLD:
        case KRB5_PADATA_PK_AS_REQ_OLD:
            retval = cms_signeddata_create(context, plgctx->cryptoctx,
                                           reqctx->cryptoctx, plgctx->idctx, CMS_SIGN_DRAFT9, 1,
                                           (unsigned char *)
                                           encoded_dhkey_info->data,
                                           encoded_dhkey_info->length,
                                           (unsigned char **)
                                           &rep9->u.dhSignedData.data,
                                           &rep9->u.dhSignedData.length);
            if (retval) {
                pkiDebug("failed to create pkcs7 signed data\n");
                goto cleanup;
            }
            break;
        }

    } else {
        pkiDebug("received RSA key delivery AS REQ\n");

        retval = krb5_c_make_random_key(context, enctype, encrypting_key);
        if (retval) {
            pkiDebug("unable to make a session key\n");
            goto cleanup;
        }

        /* check if PA_TYPE of KRB5_PADATA_AS_CHECKSUM (132) is present which
         * means the client is requesting that a checksum is send back instead
         * of the nonce.
         */
        for (i = 0; request->padata[i] != NULL; i++) {
            pkiDebug("%s: Checking pa_type 0x%08x\n",
                     __FUNCTION__, request->padata[i]->pa_type);
            if (request->padata[i]->pa_type == KRB5_PADATA_AS_CHECKSUM)
                fixed_keypack = 1;
        }
        pkiDebug("%s: return checksum instead of nonce = %d\n",
                 __FUNCTION__, fixed_keypack);

        /* if this is an RFC reply or draft9 client requested a checksum
         * in the reply instead of the nonce, create an RFC-style keypack
         */
        if ((int)padata->pa_type == KRB5_PADATA_PK_AS_REQ || fixed_keypack) {
            init_krb5_reply_key_pack(&key_pack);
            if (key_pack == NULL) {
                retval = ENOMEM;
                goto cleanup;
            }

            retval = krb5_c_make_checksum(context, 0,
                                          encrypting_key, KRB5_KEYUSAGE_TGS_REQ_AUTH_CKSUM,
                                          req_pkt, &key_pack->asChecksum);
            if (retval) {
                pkiDebug("unable to calculate AS REQ checksum\n");
                goto cleanup;
            }
#ifdef DEBUG_CKSUM
            pkiDebug("calculating checksum on buf size = %d\n", req_pkt->length);
            print_buffer(req_pkt->data, req_pkt->length);
            pkiDebug("checksum size = %d\n", key_pack->asChecksum.length);
            print_buffer(key_pack->asChecksum.contents,
                         key_pack->asChecksum.length);
            pkiDebug("encrypting key (%d)\n", encrypting_key->length);
            print_buffer(encrypting_key->contents, encrypting_key->length);
#endif

            krb5_copy_keyblock_contents(context, encrypting_key,
                                        &key_pack->replyKey);

            retval = k5int_encode_krb5_reply_key_pack(key_pack,
                                                      &encoded_key_pack);
            if (retval) {
                pkiDebug("failed to encode reply_key_pack\n");
                goto cleanup;
            }
        }

        switch ((int)padata->pa_type) {
        case KRB5_PADATA_PK_AS_REQ:
            rep->choice = choice_pa_pk_as_rep_encKeyPack;
            retval = cms_envelopeddata_create(context, plgctx->cryptoctx,
                                              reqctx->cryptoctx, plgctx->idctx, padata->pa_type, 1,
                                              (unsigned char *)
                                              encoded_key_pack->data,
                                              encoded_key_pack->length,
                                              (unsigned char **)
                                              &rep->u.encKeyPack.data,
                                              &rep->u.encKeyPack.length);
            break;
        case KRB5_PADATA_PK_AS_REP_OLD:
        case KRB5_PADATA_PK_AS_REQ_OLD:
            /* if the request is from the broken draft9 client that
             * expects back a nonce, create it now
             */
            if (!fixed_keypack) {
                init_krb5_reply_key_pack_draft9(&key_pack9);
                if (key_pack9 == NULL) {
                    retval = ENOMEM;
                    goto cleanup;
                }
                key_pack9->nonce = reqctx->rcv_auth_pack9->pkAuthenticator.nonce;
                krb5_copy_keyblock_contents(context, encrypting_key,
                                            &key_pack9->replyKey);

                retval = k5int_encode_krb5_reply_key_pack_draft9(key_pack9,
                                                                 &encoded_key_pack);
                if (retval) {
                    pkiDebug("failed to encode reply_key_pack\n");
                    goto cleanup;
                }
            }

            rep9->choice = choice_pa_pk_as_rep_draft9_encKeyPack;
            retval = cms_envelopeddata_create(context, plgctx->cryptoctx,
                                              reqctx->cryptoctx, plgctx->idctx, padata->pa_type, 1,
                                              (unsigned char *)
                                              encoded_key_pack->data,
                                              encoded_key_pack->length,
                                              (unsigned char **)
                                              &rep9->u.encKeyPack.data, &rep9->u.encKeyPack.length);
            break;
        }
        if (retval) {
            pkiDebug("failed to create pkcs7 enveloped data: %s\n",
                     error_message(retval));
            goto cleanup;
        }
#ifdef DEBUG_ASN1
        print_buffer_bin((unsigned char *)encoded_key_pack->data,
                         encoded_key_pack->length,
                         "/tmp/kdc_key_pack");
        switch ((int)padata->pa_type) {
        case KRB5_PADATA_PK_AS_REQ:
            print_buffer_bin(rep->u.encKeyPack.data,
                             rep->u.encKeyPack.length,
                             "/tmp/kdc_enc_key_pack");
            break;
        case KRB5_PADATA_PK_AS_REP_OLD:
        case KRB5_PADATA_PK_AS_REQ_OLD:
            print_buffer_bin(rep9->u.encKeyPack.data,
                             rep9->u.encKeyPack.length,
                             "/tmp/kdc_enc_key_pack");
            break;
        }
#endif
    }

    if ((rep != NULL && rep->choice == choice_pa_pk_as_rep_dhInfo) &&
        ((reqctx->rcv_auth_pack != NULL &&
          reqctx->rcv_auth_pack->supportedKDFs != NULL))) {

        /* If using the alg-agility KDF, put the algorithm in the reply
         * before encoding it.
         */
        if (reqctx->rcv_auth_pack != NULL &&
            reqctx->rcv_auth_pack->supportedKDFs != NULL) {
            retval = pkinit_pick_kdf_alg(context, reqctx->rcv_auth_pack->supportedKDFs,
                                         &(rep->u.dh_Info.kdfID));
            if (retval) {
                pkiDebug("pkinit_pick_kdf_alg failed: %s\n",
                         error_message(retval));
                goto cleanup;
            }
        }
    }

    switch ((int)padata->pa_type) {
    case KRB5_PADATA_PK_AS_REQ:
        retval = k5int_encode_krb5_pa_pk_as_rep(rep, &out_data);
        break;
    case KRB5_PADATA_PK_AS_REP_OLD:
    case KRB5_PADATA_PK_AS_REQ_OLD:
        retval = k5int_encode_krb5_pa_pk_as_rep_draft9(rep9, &out_data);
        break;
    }
    if (retval) {
        pkiDebug("failed to encode AS_REP\n");
        goto cleanup;
    }
#ifdef DEBUG_ASN1
    if (out_data != NULL)
        print_buffer_bin((unsigned char *)out_data->data, out_data->length,
                         "/tmp/kdc_as_rep");
#endif

    /* If this is DH, we haven't computed the key yet, so do it now. */
    if ((rep9 != NULL &&
         rep9->choice == choice_pa_pk_as_rep_draft9_dhSignedData) ||
        (rep != NULL && rep->choice == choice_pa_pk_as_rep_dhInfo)) {

	/* If we're not doing draft 9, and mutually supported KDFs were found,
	 * use the algorithm agility KDF. */
        if (rep != NULL && rep->u.dh_Info.kdfID) {
            secret.data = (char *)server_key;
            secret.length = server_key_len;

            retval = pkinit_alg_agility_kdf(context, &secret,
                                            rep->u.dh_Info.kdfID,
                                            request->client, request->server,
                                            enctype, req_pkt, out_data,
                                            encrypting_key);
            if (retval) {
                pkiDebug("pkinit_alg_agility_kdf failed: %s\n",
                         error_message(retval));
                goto cleanup;
            }

            /* Otherwise, use the older octetstring2key() function */
        } else {
            retval = pkinit_octetstring2key(context, enctype, server_key,
                                            server_key_len, encrypting_key);
            if (retval) {
                pkiDebug("pkinit_octetstring2key failed: %s\n",
                         error_message(retval));
                goto cleanup;
            }
        }
    }

    *send_pa = malloc(sizeof(krb5_pa_data));
    if (*send_pa == NULL) {
        retval = ENOMEM;
        free(out_data->data);
        free(out_data);
        out_data = NULL;
        goto cleanup;
    }
    (*send_pa)->magic = KV5M_PA_DATA;
    switch ((int)padata->pa_type) {
    case KRB5_PADATA_PK_AS_REQ:
        (*send_pa)->pa_type = KRB5_PADATA_PK_AS_REP;
        break;
    case KRB5_PADATA_PK_AS_REQ_OLD:
    case KRB5_PADATA_PK_AS_REP_OLD:
        (*send_pa)->pa_type = KRB5_PADATA_PK_AS_REP_OLD;
        break;
    }
    (*send_pa)->length = out_data->length;
    (*send_pa)->contents = (krb5_octet *) out_data->data;

cleanup:
    pkinit_fini_kdc_req_context(context, reqctx);
    free(scratch.data);
    free(out_data);
    if (encoded_dhkey_info != NULL)
        krb5_free_data(context, encoded_dhkey_info);
    if (encoded_key_pack != NULL)
        krb5_free_data(context, encoded_key_pack);
    free(dh_pubkey);
    free(server_key);

    switch ((int)padata->pa_type) {
    case KRB5_PADATA_PK_AS_REQ:
        free_krb5_pa_pk_as_req(&reqp);
        free_krb5_pa_pk_as_rep(&rep);
        free_krb5_reply_key_pack(&key_pack);
        break;
    case KRB5_PADATA_PK_AS_REP_OLD:
    case KRB5_PADATA_PK_AS_REQ_OLD:
        free_krb5_pa_pk_as_req_draft9(&reqp9);
        free_krb5_pa_pk_as_rep_draft9(&rep9);
        if (!fixed_keypack)
            free_krb5_reply_key_pack_draft9(&key_pack9);
        else
            free_krb5_reply_key_pack(&key_pack);
        break;
    }

    if (retval)
        pkiDebug("pkinit_verify_padata failure");

    return retval;
}

static int
pkinit_server_get_flags(krb5_context kcontext, krb5_preauthtype patype)
{
    if (patype == KRB5_PADATA_PKINIT_KX)
        return PA_INFO;
    return PA_SUFFICIENT | PA_REPLACES_KEY | PA_TYPED_E_DATA;
}

static krb5_preauthtype supported_server_pa_types[] = {
    KRB5_PADATA_PK_AS_REQ,
    KRB5_PADATA_PK_AS_REQ_OLD,
    KRB5_PADATA_PK_AS_REP_OLD,
    KRB5_PADATA_PKINIT_KX,
    0
};

static void
pkinit_fini_kdc_profile(krb5_context context, pkinit_kdc_context plgctx)
{
    /*
     * There is nothing currently allocated by pkinit_init_kdc_profile()
     * which needs to be freed here.
     */
}

static krb5_error_code
pkinit_init_kdc_profile(krb5_context context, pkinit_kdc_context plgctx)
{
    krb5_error_code retval;
    char *eku_string = NULL;

    pkiDebug("%s: entered for realm %s\n", __FUNCTION__, plgctx->realmname);
    retval = pkinit_kdcdefault_string(context, plgctx->realmname,
                                      KRB5_CONF_PKINIT_IDENTITY,
                                      &plgctx->idopts->identity);
    if (retval != 0 || NULL == plgctx->idopts->identity) {
        retval = EINVAL;
        krb5_set_error_message(context, retval,
                               _("No pkinit_identity supplied for realm %s"),
                               plgctx->realmname);
        goto errout;
    }

    retval = pkinit_kdcdefault_strings(context, plgctx->realmname,
                                       KRB5_CONF_PKINIT_ANCHORS,
                                       &plgctx->idopts->anchors);
    if (retval != 0 || NULL == plgctx->idopts->anchors) {
        retval = EINVAL;
        krb5_set_error_message(context, retval,
                               _("No pkinit_anchors supplied for realm %s"),
                               plgctx->realmname);
        goto errout;
    }

    pkinit_kdcdefault_strings(context, plgctx->realmname,
                              KRB5_CONF_PKINIT_POOL,
                              &plgctx->idopts->intermediates);

    pkinit_kdcdefault_strings(context, plgctx->realmname,
                              KRB5_CONF_PKINIT_REVOKE,
                              &plgctx->idopts->crls);

    pkinit_kdcdefault_string(context, plgctx->realmname,
                             KRB5_CONF_PKINIT_KDC_OCSP,
                             &plgctx->idopts->ocsp);

    pkinit_kdcdefault_string(context, plgctx->realmname,
                             KRB5_CONF_PKINIT_MAPPING_FILE,
                             &plgctx->idopts->dn_mapping_file);

    pkinit_kdcdefault_integer(context, plgctx->realmname,
                              KRB5_CONF_PKINIT_DH_MIN_BITS,
                              PKINIT_DEFAULT_DH_MIN_BITS,
                              &plgctx->opts->dh_min_bits);
    if (plgctx->opts->dh_min_bits < PKINIT_DH_MIN_CONFIG_BITS) {
        pkiDebug("%s: invalid value (%d < %d) for pkinit_dh_min_bits, "
                 "using default value (%d) instead\n", __FUNCTION__,
                 plgctx->opts->dh_min_bits, PKINIT_DH_MIN_CONFIG_BITS,
                 PKINIT_DEFAULT_DH_MIN_BITS);
        plgctx->opts->dh_min_bits = PKINIT_DEFAULT_DH_MIN_BITS;
    }

    pkinit_kdcdefault_boolean(context, plgctx->realmname,
                              KRB5_CONF_PKINIT_ALLOW_UPN,
                              0, &plgctx->opts->allow_upn);

    pkinit_kdcdefault_boolean(context, plgctx->realmname,
                              KRB5_CONF_PKINIT_REQUIRE_CRL_CHECKING,
                              0, &plgctx->opts->require_crl_checking);

    pkinit_kdcdefault_string(context, plgctx->realmname,
                             KRB5_CONF_PKINIT_EKU_CHECKING,
                             &eku_string);
    if (eku_string != NULL) {
        if (strcasecmp(eku_string, "kpClientAuth") == 0) {
            plgctx->opts->require_eku = 1;
            plgctx->opts->accept_secondary_eku = 0;
        } else if (strcasecmp(eku_string, "scLogin") == 0) {
            plgctx->opts->require_eku = 1;
            plgctx->opts->accept_secondary_eku = 1;
        } else if (strcasecmp(eku_string, "none") == 0) {
            plgctx->opts->require_eku = 0;
            plgctx->opts->accept_secondary_eku = 0;
        } else {
            pkiDebug("%s: Invalid value for pkinit_eku_checking: '%s'\n",
                     __FUNCTION__, eku_string);
        }
        free(eku_string);
    }


    return 0;
errout:
    pkinit_fini_kdc_profile(context, plgctx);
    return retval;
}

static pkinit_kdc_context
pkinit_find_realm_context(krb5_context context,
                          krb5_kdcpreauth_moddata moddata,
                          krb5_principal princ)
{
    int i;
    pkinit_kdc_context *realm_contexts = (pkinit_kdc_context *)moddata;

    if (moddata == NULL)
        return NULL;

    for (i = 0; realm_contexts[i] != NULL; i++) {
        pkinit_kdc_context p = realm_contexts[i];

        if ((p->realmname_len == princ->realm.length) &&
            (strncmp(p->realmname, princ->realm.data, p->realmname_len) == 0)) {
            pkiDebug("%s: returning context at %p for realm '%s'\n",
                     __FUNCTION__, p, p->realmname);
            return p;
        }
    }
    pkiDebug("%s: unable to find realm context for realm '%.*s'\n",
             __FUNCTION__, princ->realm.length, princ->realm.data);
    return NULL;
}

static int
pkinit_server_plugin_init_realm(krb5_context context, const char *realmname,
                                pkinit_kdc_context *pplgctx)
{
    krb5_error_code retval = ENOMEM;
    pkinit_kdc_context plgctx = NULL;

    *pplgctx = NULL;

    plgctx = calloc(1, sizeof(*plgctx));
    if (plgctx == NULL)
        goto errout;

    pkiDebug("%s: initializing context at %p for realm '%s'\n",
             __FUNCTION__, plgctx, realmname);
    memset(plgctx, 0, sizeof(*plgctx));
    plgctx->magic = PKINIT_CTX_MAGIC;

    plgctx->realmname = strdup(realmname);
    if (plgctx->realmname == NULL)
        goto errout;
    plgctx->realmname_len = strlen(plgctx->realmname);

    retval = pkinit_init_plg_crypto(&plgctx->cryptoctx);
    if (retval)
        goto errout;

    retval = pkinit_init_plg_opts(&plgctx->opts);
    if (retval)
        goto errout;

    retval = pkinit_init_identity_crypto(&plgctx->idctx);
    if (retval)
        goto errout;

    retval = pkinit_init_identity_opts(&plgctx->idopts);
    if (retval)
        goto errout;

    retval = pkinit_init_kdc_profile(context, plgctx);
    if (retval)
        goto errout;

    retval = pkinit_identity_initialize(context, plgctx->cryptoctx, NULL,
                                        plgctx->idopts, plgctx->idctx,
                                        NULL, NULL, NULL);
    if (retval)
        goto errout;
    retval = pkinit_identity_prompt(context, plgctx->cryptoctx, NULL,
                                    plgctx->idopts, plgctx->idctx,
                                    NULL, NULL, 0, NULL);
    if (retval)
        goto errout;

    pkiDebug("%s: returning context at %p for realm '%s'\n",
             __FUNCTION__, plgctx, realmname);
    *pplgctx = plgctx;
    retval = 0;

errout:
    if (retval)
        pkinit_server_plugin_fini_realm(context, plgctx);

    return retval;
}

static int
pkinit_server_plugin_init(krb5_context context,
                          krb5_kdcpreauth_moddata *moddata_out,
                          const char **realmnames)
{
    krb5_error_code retval = ENOMEM;
    pkinit_kdc_context plgctx, *realm_contexts = NULL;
    size_t  i, j;
    size_t numrealms;

    retval = pkinit_accessor_init();
    if (retval)
        return retval;

    /* Determine how many realms we may need to support */
    for (i = 0; realmnames[i] != NULL; i++) {};
    numrealms = i;

    realm_contexts = calloc(numrealms+1, sizeof(pkinit_kdc_context));
    if (realm_contexts == NULL)
        return ENOMEM;

    for (i = 0, j = 0; i < numrealms; i++) {
        pkiDebug("%s: processing realm '%s'\n", __FUNCTION__, realmnames[i]);
        retval = pkinit_server_plugin_init_realm(context, realmnames[i], &plgctx);
        if (retval == 0 && plgctx != NULL)
            realm_contexts[j++] = plgctx;
    }

    if (j == 0) {
        retval = EINVAL;
        krb5_set_error_message(context, retval,
                               _("No realms configured correctly for pkinit "
                                 "support"));
        goto errout;
    }

    *moddata_out = (krb5_kdcpreauth_moddata)realm_contexts;
    retval = 0;
    pkiDebug("%s: returning context at %p\n", __FUNCTION__, realm_contexts);

errout:
    if (retval) {
        pkinit_server_plugin_fini(context,
                                  (krb5_kdcpreauth_moddata)realm_contexts);
    }

    return retval;
}

static void
pkinit_server_plugin_fini_realm(krb5_context context, pkinit_kdc_context plgctx)
{
    if (plgctx == NULL)
        return;

    pkinit_fini_kdc_profile(context, plgctx);
    pkinit_fini_identity_opts(plgctx->idopts);
    pkinit_fini_identity_crypto(plgctx->idctx);
    pkinit_fini_plg_crypto(plgctx->cryptoctx);
    pkinit_fini_plg_opts(plgctx->opts);
    free(plgctx->realmname);
    free(plgctx);
}

static void
pkinit_server_plugin_fini(krb5_context context,
                          krb5_kdcpreauth_moddata moddata)
{
    pkinit_kdc_context *realm_contexts = (pkinit_kdc_context *)moddata;
    int i;

    if (realm_contexts == NULL)
        return;

    for (i = 0; realm_contexts[i] != NULL; i++) {
        pkinit_server_plugin_fini_realm(context, realm_contexts[i]);
    }
    pkiDebug("%s: freeing context at %p\n", __FUNCTION__, realm_contexts);
    free(realm_contexts);
}

static krb5_error_code
pkinit_init_kdc_req_context(krb5_context context, pkinit_kdc_req_context *ctx)
{
    krb5_error_code retval = ENOMEM;
    pkinit_kdc_req_context reqctx = NULL;

    reqctx = malloc(sizeof(*reqctx));
    if (reqctx == NULL)
        return retval;
    memset(reqctx, 0, sizeof(*reqctx));
    reqctx->magic = PKINIT_CTX_MAGIC;

    retval = pkinit_init_req_crypto(&reqctx->cryptoctx);
    if (retval)
        goto cleanup;
    reqctx->rcv_auth_pack = NULL;
    reqctx->rcv_auth_pack9 = NULL;

    pkiDebug("%s: returning reqctx at %p\n", __FUNCTION__, reqctx);
    *ctx = reqctx;
    retval = 0;
cleanup:
    if (retval)
        pkinit_fini_kdc_req_context(context, reqctx);

    return retval;
}

static void
pkinit_fini_kdc_req_context(krb5_context context, void *ctx)
{
    pkinit_kdc_req_context reqctx = (pkinit_kdc_req_context)ctx;

    if (reqctx == NULL || reqctx->magic != PKINIT_CTX_MAGIC) {
        pkiDebug("pkinit_fini_kdc_req_context: got bad reqctx (%p)!\n", reqctx);
        return;
    }
    pkiDebug("%s: freeing reqctx at %p\n", __FUNCTION__, reqctx);

    pkinit_fini_req_crypto(reqctx->cryptoctx);
    if (reqctx->rcv_auth_pack != NULL)
        free_krb5_auth_pack(&reqctx->rcv_auth_pack);
    if (reqctx->rcv_auth_pack9 != NULL)
        free_krb5_auth_pack_draft9(context, &reqctx->rcv_auth_pack9);

    free(reqctx);
}

krb5_error_code
kdcpreauth_pkinit_initvt(krb5_context context, int maj_ver, int min_ver,
                         krb5_plugin_vtable vtable);

krb5_error_code
kdcpreauth_pkinit_initvt(krb5_context context, int maj_ver, int min_ver,
                         krb5_plugin_vtable vtable)
{
    krb5_kdcpreauth_vtable vt;

    if (maj_ver != 1)
        return KRB5_PLUGIN_VER_NOTSUPP;
    vt = (krb5_kdcpreauth_vtable)vtable;
    vt->name = "pkinit";
    vt->pa_type_list = supported_server_pa_types;
    vt->init = pkinit_server_plugin_init;
    vt->fini = pkinit_server_plugin_fini;
    vt->flags = pkinit_server_get_flags;
    vt->edata = pkinit_server_get_edata;
    vt->verify = pkinit_server_verify_padata;
    vt->return_padata = pkinit_server_return_padata;
    return 0;
}