xnu-7195.60.75.tar.gz

[apple/xnu.git] / bsd / nfs / gss / gss_krb5_mech.c

/*
 * Copyright (c) 2015 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

/*
 * Copyright (c) 1999 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 KTH 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 KTH AND ITS 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 KTH OR ITS CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdint.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/kpi_mbuf.h>
#include <sys/random.h>
#include <mach_assert.h>
#include <kern/assert.h>
#include <libkern/OSAtomic.h>
#include "gss_krb5_mech.h"

lck_grp_t *gss_krb5_mech_grp;

typedef struct crypt_walker_ctx {
        size_t length;
        const struct ccmode_cbc *ccmode;
        cccbc_ctx *crypt_ctx;
        cccbc_iv *iv;
} *crypt_walker_ctx_t;

typedef struct hmac_walker_ctx {
        const struct ccdigest_info *di;
        struct cchmac_ctx *hmac_ctx;
} *hmac_walker_ctx_t;

typedef size_t (*ccpad_func)(const struct ccmode_cbc *, cccbc_ctx *, cccbc_iv *,
    size_t nbytes, const void *, void *);

static int krb5_n_fold(const void *instr, size_t len, void *foldstr, size_t size);

size_t gss_mbuf_len(mbuf_t, size_t);
errno_t gss_prepend_mbuf(mbuf_t *, uint8_t *, size_t);
errno_t gss_append_mbuf(mbuf_t, uint8_t *, size_t);
errno_t gss_strip_mbuf(mbuf_t, int);
int mbuf_walk(mbuf_t, size_t, size_t, size_t, int (*)(void *, uint8_t *, size_t), void *);

void do_crypt_init(crypt_walker_ctx_t, int, crypto_ctx_t, cccbc_ctx *);
int do_crypt(void *, uint8_t *, size_t);
void do_hmac_init(hmac_walker_ctx_t, crypto_ctx_t, void *);
int do_hmac(void *, uint8_t *, size_t);

void krb5_make_usage(uint32_t, uint8_t, uint8_t[KRB5_USAGE_LEN]);
void krb5_key_derivation(crypto_ctx_t, const void *, size_t, void **, size_t);
void cc_key_schedule_create(crypto_ctx_t);
void gss_crypto_ctx_free(crypto_ctx_t);
int gss_crypto_ctx_init(struct crypto_ctx *, lucid_context_t);

errno_t krb5_crypt_mbuf(crypto_ctx_t, mbuf_t *, size_t, int, cccbc_ctx *);
int krb5_mic(crypto_ctx_t, gss_buffer_t, gss_buffer_t, gss_buffer_t, uint8_t *, int *, int, int);
int krb5_mic_mbuf(crypto_ctx_t, gss_buffer_t, mbuf_t, size_t, size_t, gss_buffer_t, uint8_t *, int *, int, int);

uint32_t gss_krb5_cfx_get_mic(uint32_t *, gss_ctx_id_t, gss_qop_t, gss_buffer_t, gss_buffer_t);
uint32_t gss_krb5_cfx_verify_mic(uint32_t *, gss_ctx_id_t, gss_buffer_t, gss_buffer_t, gss_qop_t *);
uint32_t gss_krb5_cfx_get_mic_mbuf(uint32_t *, gss_ctx_id_t, gss_qop_t, mbuf_t, size_t, size_t, gss_buffer_t);
uint32_t gss_krb5_cfx_verify_mic_mbuf(uint32_t *, gss_ctx_id_t, mbuf_t, size_t, size_t, gss_buffer_t, gss_qop_t *);
errno_t krb5_cfx_crypt_mbuf(crypto_ctx_t, mbuf_t *, size_t *, int, int);
uint32_t gss_krb5_cfx_wrap_mbuf(uint32_t *, gss_ctx_id_t, int, gss_qop_t, mbuf_t *, size_t, int *);
uint32_t gss_krb5_cfx_unwrap_mbuf(uint32_t *, gss_ctx_id_t, mbuf_t *, size_t, int *, gss_qop_t *);

int gss_krb5_mech_is_initialized(void);
void gss_krb5_mech_init(void);

/* Debugging routines */
void
printmbuf(const char *str, mbuf_t mb, uint32_t offset, uint32_t len)
{
        size_t i;
        int cout = 1;

        len = len ? len : ~0;
        printf("%s mbuf = %p offset = %d len = %d:\n", str ? str : "mbuf", mb, offset, len);
        for (; mb && len; mb = mbuf_next(mb)) {
                if (offset >= mbuf_len(mb)) {
                        offset -= mbuf_len(mb);
                        continue;
                }
                for (i = offset; len && i < mbuf_len(mb); i++) {
                        const char *s = (cout % 8) ? " " : (cout % 16) ? "    " : "\n";
                        printf("%02x%s", ((uint8_t *)mbuf_data(mb))[i], s);
                        len--;
                        cout++;
                }
                offset = 0;
        }
        if ((cout - 1) % 16) {
                printf("\n");
        }
        printf("Count chars %d\n", cout - 1);
}

void
printgbuf(const char *str, gss_buffer_t buf)
{
        size_t i;
        size_t len = buf->length > 128 ? 128 : buf->length;

        printf("%s:   len = %d value = %p\n", str ? str : "buffer", (int)buf->length, buf->value);
        for (i = 0; i < len; i++) {
                const char *s = ((i + 1) % 8) ? " " : ((i + 1) % 16) ? "    " : "\n";
                printf("%02x%s", ((uint8_t *)buf->value)[i], s);
        }
        if (i % 16) {
                printf("\n");
        }
}

/*
 * Initialize the data structures for the gss kerberos mech.
 */
#define GSS_KRB5_NOT_INITIALIZED        0
#define GSS_KRB5_INITIALIZING   1
#define GSS_KRB5_INITIALIZED    2
static volatile uint32_t gss_krb5_mech_initted = GSS_KRB5_NOT_INITIALIZED;

int
gss_krb5_mech_is_initialized(void)
{
        return gss_krb5_mech_initted == GSS_KRB5_NOT_INITIALIZED;
}

void
gss_krb5_mech_init(void)
{
        extern void IOSleep(int);

        /* Once initted always initted */
        if (gss_krb5_mech_initted == GSS_KRB5_INITIALIZED) {
                return;
        }

        /* make sure we init only once */
        if (!OSCompareAndSwap(GSS_KRB5_NOT_INITIALIZED, GSS_KRB5_INITIALIZING, &gss_krb5_mech_initted)) {
                /* wait until initialization is complete */
                while (!gss_krb5_mech_is_initialized()) {
                        IOSleep(10);
                }
                return;
        }
        gss_krb5_mech_grp = lck_grp_alloc_init("gss_krb5_mech", LCK_GRP_ATTR_NULL);
        gss_krb5_mech_initted = GSS_KRB5_INITIALIZED;
}

uint32_t
gss_release_buffer(uint32_t *minor, gss_buffer_t buf)
{
        if (minor) {
                *minor = 0;
        }
        if (buf->value) {
                FREE(buf->value, M_TEMP);
        }
        buf->value = NULL;
        buf->length = 0;
        return GSS_S_COMPLETE;
}

/*
 * GSS mbuf routines
 */

size_t
gss_mbuf_len(mbuf_t mb, size_t offset)
{
        size_t len;

        for (len = 0; mb; mb = mbuf_next(mb)) {
                len += mbuf_len(mb);
        }
        return (offset > len) ? 0 : len - offset;
}

/*
 * Split an mbuf in a chain into two mbufs such that the original mbuf
 * points to the original mbuf and the new mbuf points to the rest of the
 * chain. The first mbuf length is the first len bytes and the second
 * mbuf contains the remaining bytes. if len is zero or equals
 * mbuf_len(mb) the don't create a new mbuf. We are already at an mbuf
 * boundary. Return the mbuf that starts at the offset.
 */
static errno_t
split_one_mbuf(mbuf_t mb, size_t offset, mbuf_t *nmb, int join)
{
        errno_t error;

        *nmb = mb;
        /* We don't have an mbuf or we're alread on an mbuf boundary */
        if (mb == NULL || offset == 0) {
                return 0;
        }

        /* If the mbuf length is offset then the next mbuf is the one we want */
        if (mbuf_len(mb) == offset) {
                *nmb = mbuf_next(mb);
                if (!join) {
                        mbuf_setnext(mb, NULL);
                }
                return 0;
        }

        if (offset > mbuf_len(mb)) {
                return EINVAL;
        }

        error = mbuf_split(mb, offset, MBUF_WAITOK, nmb);
        if (error) {
                return error;
        }

        if (mbuf_flags(*nmb) & MBUF_PKTHDR) {
                /* We don't want to copy the pkthdr. mbuf_split does that. */
                error = mbuf_setflags_mask(*nmb, ~MBUF_PKTHDR, MBUF_PKTHDR);
        }

        if (join) {
                /* Join the chain again */
                mbuf_setnext(mb, *nmb);
        }

        return 0;
}

/*
 * Given an mbuf with an offset and length return the chain such that
 * offset and offset + *subchain_length are on mbuf boundaries.  If
 * *mbuf_length is less that the length of the chain after offset
 * return that length in *mbuf_length. The mbuf sub chain starting at
 * offset is returned in *subchain. If an error occurs return the
 * corresponding errno. Note if there are less than offset bytes then
 * subchain will be set to NULL and *subchain_length will be set to
 * zero. If *subchain_length is 0; then set it to the length of the
 * chain starting at offset. Join parameter is used to indicate whether
 * the mbuf chain will be joined again as on chain, just rearranged so
 * that offset and subchain_length are on mbuf boundaries.
 */

errno_t
gss_normalize_mbuf(mbuf_t chain, size_t offset, size_t *subchain_length, mbuf_t *subchain, mbuf_t *tail, int join)
{
        size_t length = *subchain_length ? *subchain_length : ~0;
        size_t len;
        mbuf_t mb, nmb;
        errno_t error;

        if (tail == NULL) {
                tail = &nmb;
        }
        *tail = NULL;
        *subchain = NULL;

        for (len = offset, mb = chain; mb && len > mbuf_len(mb); mb = mbuf_next(mb)) {
                len -= mbuf_len(mb);
        }

        /* if we don't have offset bytes just return */
        if (mb == NULL) {
                return 0;
        }

        error = split_one_mbuf(mb, len, subchain, join);
        if (error) {
                return error;
        }

        assert(subchain != NULL && *subchain != NULL);
        assert(offset == 0 ? mb == *subchain : 1);

        len = gss_mbuf_len(*subchain, 0);
        length =  (length > len) ? len : length;
        *subchain_length = length;

        for (len = length, mb = *subchain; mb && len > mbuf_len(mb); mb = mbuf_next(mb)) {
                len -= mbuf_len(mb);
        }

        error = split_one_mbuf(mb, len, tail, join);

        return error;
}

mbuf_t
gss_join_mbuf(mbuf_t head, mbuf_t body, mbuf_t tail)
{
        mbuf_t mb;

        for (mb = head; mb && mbuf_next(mb); mb = mbuf_next(mb)) {
                ;
        }
        if (mb) {
                mbuf_setnext(mb, body);
        }
        for (mb = body; mb && mbuf_next(mb); mb = mbuf_next(mb)) {
                ;
        }
        if (mb) {
                mbuf_setnext(mb, tail);
        }
        mb = head ? head : (body ? body : tail);
        return mb;
}

/*
 * Prepend size bytes to the mbuf chain.
 */
errno_t
gss_prepend_mbuf(mbuf_t *chain, uint8_t *bytes, size_t size)
{
        uint8_t *data = mbuf_data(*chain);
        size_t leading = mbuf_leadingspace(*chain);
        size_t trailing = mbuf_trailingspace(*chain);
        size_t mlen = mbuf_len(*chain);
        errno_t error;

        if (size > leading && size <= leading + trailing) {
                data = memmove(data + size - leading, data, mlen);
                mbuf_setdata(*chain, data, mlen);
        }

        error = mbuf_prepend(chain, size, MBUF_WAITOK);
        if (error) {
                return error;
        }
        data = mbuf_data(*chain);
        memcpy(data, bytes, size);

        return 0;
}

errno_t
gss_append_mbuf(mbuf_t chain, uint8_t *bytes, size_t size)
{
        size_t len = 0;
        mbuf_t mb;

        if (chain == NULL) {
                return EINVAL;
        }

        for (mb = chain; mb; mb = mbuf_next(mb)) {
                len += mbuf_len(mb);
        }

        return mbuf_copyback(chain, len, size, bytes, MBUF_WAITOK);
}

errno_t
gss_strip_mbuf(mbuf_t chain, int size)
{
        if (chain == NULL) {
                return EINVAL;
        }

        mbuf_adj(chain, size);

        return 0;
}


/*
 * Kerberos mech generic crypto support for mbufs
 */

/*
 * Walk the mbuf after the given offset calling the passed in crypto function
 * for len bytes. Note the length, len should be a multiple of the  blocksize and
 * there should be at least len bytes available after the offset in the mbuf chain.
 * padding should be done before calling this routine.
 */
int
mbuf_walk(mbuf_t mbp, size_t offset, size_t len, size_t blocksize, int (*crypto_fn)(void *, uint8_t *data, size_t length), void *ctx)
{
        mbuf_t mb;
        size_t mlen, residue;
        uint8_t *ptr;
        int error = 0;

        /* Move to the start of the chain */
        for (mb = mbp; mb && len > 0; mb = mbuf_next(mb)) {
                ptr = mbuf_data(mb);
                mlen = mbuf_len(mb);
                if (offset >= mlen) {
                        /* Offset not yet reached */
                        offset -= mlen;
                        continue;
                }
                /* Found starting point in chain */
                ptr += offset;
                mlen -= offset;
                offset = 0;

                /*
                 * Handle the data in this mbuf. If the length to
                 * walk is less than the data in the mbuf, set
                 * the mbuf length left to be the length left
                 */
                mlen = mlen < len ? mlen : len;
                /* Figure out how much is a multple of blocksize */
                residue = mlen % blocksize;
                /* And addjust the mleft length to be the largest multiple of blocksized */
                mlen -= residue;
                /* run our hash/encrypt/decrpyt function */
                if (mlen > 0) {
                        error = crypto_fn(ctx, ptr, mlen);
                        if (error) {
                                break;
                        }
                        ptr += mlen;
                        len -= mlen;
                }
                /*
                 * If we have a residue then to get a full block for our crypto
                 * function, we need to copy the residue into our block size
                 * block and use the next mbuf to get the rest of the data for
                 * the block.  N.B. We generally assume that from the offset
                 * passed in, that the total length, len, is a multple of
                 * blocksize and that there are at least len bytes in the chain
                 * from the offset.  We also assume there is at least (blocksize
                 * - residue) size data in any next mbuf for residue > 0. If not
                 * we attemp to pullup bytes from down the chain.
                 */
                if (residue) {
                        mbuf_t nmb = mbuf_next(mb);
                        uint8_t *nptr = NULL, block[blocksize];

                        assert(nmb);
                        len -= residue;
                        offset = blocksize - residue;
                        if (len < offset) {
                                offset = len;
                                /*
                                 * We don't have enough bytes so zero the block
                                 * so that any trailing bytes will be zero.
                                 */
                                cc_clear(sizeof(block), block);
                        }
                        memcpy(block, ptr, residue);
                        if (len && nmb) {
                                mlen = mbuf_len(nmb);
                                if (mlen < offset) {
                                        error = mbuf_pullup(&nmb, offset - mlen);
                                        if (error) {
                                                mbuf_setnext(mb, NULL);
                                                return error;
                                        }
                                }
                                nptr = mbuf_data(nmb);
                                memcpy(block + residue, nptr, offset);
                        }
                        len -= offset;
                        error = crypto_fn(ctx, block, sizeof(block));
                        if (error) {
                                break;
                        }
                        memcpy(ptr, block, residue);
                        if (nptr) {
                                memcpy(nptr, block + residue, offset);
                        }
                }
        }

        return error;
}

void
do_crypt_init(crypt_walker_ctx_t wctx, int encrypt, crypto_ctx_t cctx, cccbc_ctx *ks)
{
        memset(wctx, 0, sizeof(*wctx));
        wctx->length = 0;
        wctx->ccmode = encrypt ? cctx->enc_mode : cctx->dec_mode;
        wctx->crypt_ctx = ks;
        MALLOC(wctx->iv, cccbc_iv *, wctx->ccmode->block_size, M_TEMP, M_WAITOK | M_ZERO);
        cccbc_set_iv(wctx->ccmode, wctx->iv, NULL);
}

int
do_crypt(void *walker, uint8_t *data, size_t len)
{
        struct crypt_walker_ctx *wctx = (crypt_walker_ctx_t)walker;
        size_t nblocks;

        nblocks = len / wctx->ccmode->block_size;
        assert(len % wctx->ccmode->block_size == 0);
        cccbc_update(wctx->ccmode, wctx->crypt_ctx, wctx->iv, nblocks, data, data);
        wctx->length += len;

        return 0;
}

void
do_hmac_init(hmac_walker_ctx_t wctx, crypto_ctx_t cctx, void *key)
{
        size_t alloc_size = cchmac_di_size(cctx->di);

        wctx->di = cctx->di;
        MALLOC(wctx->hmac_ctx, struct cchmac_ctx *, alloc_size, M_TEMP, M_WAITOK | M_ZERO);
        cchmac_init(cctx->di, wctx->hmac_ctx, cctx->keylen, key);
}

int
do_hmac(void *walker, uint8_t *data, size_t len)
{
        hmac_walker_ctx_t wctx = (hmac_walker_ctx_t)walker;

        cchmac_update(wctx->di, wctx->hmac_ctx, len, data);

        return 0;
}


int
krb5_mic(crypto_ctx_t ctx, gss_buffer_t header, gss_buffer_t bp, gss_buffer_t trailer, uint8_t *mic, int *verify, int ikey, int reverse)
{
        uint8_t digest[ctx->di->output_size];
        cchmac_di_decl(ctx->di, hmac_ctx);
        int kdx = (verify == NULL) ? (reverse ? GSS_RCV : GSS_SND) : (reverse ? GSS_SND : GSS_RCV);
        void *key2use;

        if (ikey) {
                if (!(ctx->flags & CRYPTO_KS_ALLOCED)) {
                        lck_mtx_lock(ctx->lock);
                        if (!(ctx->flags & CRYPTO_KS_ALLOCED)) {
                                cc_key_schedule_create(ctx);
                        }
                        ctx->flags |= CRYPTO_KS_ALLOCED;
                        lck_mtx_unlock(ctx->lock);
                }
                key2use = ctx->ks.ikey[kdx];
        } else {
                key2use = ctx->ckey[kdx];
        }

        cchmac_init(ctx->di, hmac_ctx, ctx->keylen, key2use);

        if (header) {
                cchmac_update(ctx->di, hmac_ctx, header->length, header->value);
        }

        cchmac_update(ctx->di, hmac_ctx, bp->length, bp->value);

        if (trailer) {
                cchmac_update(ctx->di, hmac_ctx, trailer->length, trailer->value);
        }

        cchmac_final(ctx->di, hmac_ctx, digest);

        if (verify) {
                *verify = (memcmp(mic, digest, ctx->digest_size) == 0);
        } else {
                memcpy(mic, digest, ctx->digest_size);
        }

        return 0;
}

int
krb5_mic_mbuf(crypto_ctx_t ctx, gss_buffer_t header,
    mbuf_t mbp, size_t offset, size_t len, gss_buffer_t trailer, uint8_t *mic, int *verify, int ikey, int reverse)
{
        struct hmac_walker_ctx wctx;
        uint8_t digest[ctx->di->output_size];
        int error;
        int kdx = (verify == NULL) ? (reverse ? GSS_RCV : GSS_SND) : (reverse ? GSS_SND : GSS_RCV);
        void *key2use;

        if (ikey) {
                if (!(ctx->flags & CRYPTO_KS_ALLOCED)) {
                        lck_mtx_lock(ctx->lock);
                        if (!(ctx->flags & CRYPTO_KS_ALLOCED)) {
                                cc_key_schedule_create(ctx);
                        }
                        ctx->flags |= CRYPTO_KS_ALLOCED;
                        lck_mtx_unlock(ctx->lock);
                }
                key2use = ctx->ks.ikey[kdx];
        } else {
                key2use = ctx->ckey[kdx];
        }

        do_hmac_init(&wctx, ctx, key2use);

        if (header) {
                cchmac_update(ctx->di, wctx.hmac_ctx, header->length, header->value);
        }

        error = mbuf_walk(mbp, offset, len, 1, do_hmac, &wctx);

        if (error) {
                return error;
        }
        if (trailer) {
                cchmac_update(ctx->di, wctx.hmac_ctx, trailer->length, trailer->value);
        }

        cchmac_final(ctx->di, wctx.hmac_ctx, digest);
        FREE(wctx.hmac_ctx, M_TEMP);

        if (verify) {
                *verify = (memcmp(mic, digest, ctx->digest_size) == 0);
                if (!*verify) {
                        return EBADRPC;
                }
        } else {
                memcpy(mic, digest, ctx->digest_size);
        }

        return 0;
}

errno_t
/* __attribute__((optnone)) */
krb5_crypt_mbuf(crypto_ctx_t ctx, mbuf_t *mbp, size_t len, int encrypt, cccbc_ctx *ks)
{
        struct crypt_walker_ctx wctx;
        const struct ccmode_cbc *ccmode = encrypt ? ctx->enc_mode : ctx->dec_mode;
        size_t plen = len;
        size_t cts_len = 0;
        mbuf_t mb, lmb = NULL;
        int error;

        if (!(ctx->flags & CRYPTO_KS_ALLOCED)) {
                lck_mtx_lock(ctx->lock);
                if (!(ctx->flags & CRYPTO_KS_ALLOCED)) {
                        cc_key_schedule_create(ctx);
                }
                ctx->flags |= CRYPTO_KS_ALLOCED;
                lck_mtx_unlock(ctx->lock);
        }
        if (!ks) {
                ks = encrypt ? ctx->ks.enc : ctx->ks.dec;
        }

        if ((ctx->flags & CRYPTO_CTS_ENABLE) && ctx->mpad == 1) {
                uint8_t block[ccmode->block_size];
                /* if the length is less than or equal to a blocksize. We just encrypt the block */
                if (len <= ccmode->block_size) {
                        if (len < ccmode->block_size) {
                                memset(block, 0, sizeof(block));
                                gss_append_mbuf(*mbp, block, ccmode->block_size);
                        }
                        plen = ccmode->block_size;
                } else {
                        /* determine where the last two blocks are */
                        size_t r = len % ccmode->block_size;

                        cts_len  = r ? r + ccmode->block_size : 2 * ccmode->block_size;
                        plen = len - cts_len;
                        /* If plen is 0 we only have two blocks to crypt with ccpad below */
                        if (plen == 0) {
                                lmb = *mbp;
                        } else {
                                gss_normalize_mbuf(*mbp, 0, &plen, &mb, &lmb, 0);
                                assert(*mbp == mb);
                                assert(plen == len - cts_len);
                                assert(gss_mbuf_len(mb, 0) == plen);
                                assert(gss_mbuf_len(lmb, 0) == cts_len);
                        }
                }
        } else if (len % ctx->mpad) {
                uint8_t pad_block[ctx->mpad];
                size_t padlen = ctx->mpad - (len % ctx->mpad);

                memset(pad_block, 0, padlen);
                error = gss_append_mbuf(*mbp, pad_block, padlen);
                if (error) {
                        return error;
                }
                plen = len + padlen;
        }
        do_crypt_init(&wctx, encrypt, ctx, ks);
        if (plen) {
                error = mbuf_walk(*mbp, 0, plen, ccmode->block_size, do_crypt, &wctx);
                if (error) {
                        return error;
                }
        }

        if ((ctx->flags & CRYPTO_CTS_ENABLE) && cts_len) {
                uint8_t cts_pad[2 * ccmode->block_size];
                ccpad_func do_ccpad = encrypt ? ccpad_cts3_encrypt : ccpad_cts3_decrypt;

                assert(cts_len <= 2 * ccmode->block_size && cts_len > ccmode->block_size);
                memset(cts_pad, 0, sizeof(cts_pad));
                mbuf_copydata(lmb, 0, cts_len, cts_pad);
                mbuf_freem(lmb);
                do_ccpad(ccmode, wctx.crypt_ctx, wctx.iv, cts_len, cts_pad, cts_pad);
                gss_append_mbuf(*mbp, cts_pad, cts_len);
        }
        FREE(wctx.iv, M_TEMP);

        return 0;
}

/*
 * Key derivation routines
 */

static int
rr13(unsigned char *buf, size_t len)
{
        size_t bytes = (len + 7) / 8;
        unsigned char tmp[bytes];
        size_t i;

        if (len == 0) {
                return 0;
        }

        {
                const int bits = 13 % len;
                const int lbit = len % 8;

                memcpy(tmp, buf, bytes);
                if (lbit) {
                        /* pad final byte with inital bits */
                        tmp[bytes - 1] &= 0xff << (8 - lbit);
                        for (i = lbit; i < 8; i += len) {
                                tmp[bytes - 1] |= buf[0] >> i;
                        }
                }
                for (i = 0; i < bytes; i++) {
                        ssize_t bb;
                        ssize_t b1, s1, b2, s2;

                        /* calculate first bit position of this byte */
                        bb = 8 * i - bits;
                        while (bb < 0) {
                                bb += len;
                        }
                        /* byte offset and shift count */
                        b1 = bb / 8;
                        s1 = bb % 8;
                        if ((size_t)bb + 8 > bytes * 8) {
                                /* watch for wraparound */
                                s2 = (len + 8 - s1) % 8;
                        } else {
                                s2 = 8 - s1;
                        }
                        b2 = (b1 + 1) % bytes;
                        buf[i] = 0xff & ((tmp[b1] << s1) | (tmp[b2] >> s2));
                }
        }
        return 0;
}


/* Add `b' to `a', both being one's complement numbers. */
static void
add1(unsigned char *a, unsigned char *b, size_t len)
{
        ssize_t i;
        int carry = 0;

        for (i = len - 1; i >= 0; i--) {
                int x = a[i] + b[i] + carry;
                carry = x > 0xff;
                a[i] = x & 0xff;
        }
        for (i = len - 1; carry && i >= 0; i--) {
                int x = a[i] + carry;
                carry = x > 0xff;
                a[i] = x & 0xff;
        }
}


static int
krb5_n_fold(const void *instr, size_t len, void *foldstr, size_t size)
{
        /* if len < size we need at most N * len bytes, ie < 2 * size;
         *  if len > size we need at most 2 * len */
        int ret = 0;
        size_t maxlen = 2 * lmax(size, len);
        size_t l = 0;
        unsigned char tmp[maxlen];
        unsigned char buf[len];

        memcpy(buf, instr, len);
        memset(foldstr, 0, size);
        do {
                memcpy(tmp + l, buf, len);
                l += len;
                ret = rr13(buf, len * 8);
                if (ret) {
                        goto out;
                }
                while (l >= size) {
                        add1(foldstr, tmp, size);
                        l -= size;
                        if (l == 0) {
                                break;
                        }
                        memmove(tmp, tmp + size, l);
                }
        } while (l != 0);
out:

        return ret;
}

void
krb5_make_usage(uint32_t usage_no, uint8_t suffix, uint8_t usage_string[KRB5_USAGE_LEN])
{
        uint32_t i;

        for (i = 0; i < 4; i++) {
                usage_string[i] = ((usage_no >> 8 * (3 - i)) & 0xff);
        }
        usage_string[i] = suffix;
}

void
krb5_key_derivation(crypto_ctx_t ctx, const void *cons, size_t conslen, void **dkey, size_t dklen)
{
        size_t blocksize = ctx->enc_mode->block_size;
        cccbc_iv_decl(blocksize, iv);
        cccbc_ctx_decl(ctx->enc_mode->size, enc_ctx);
        size_t ksize = 8 * dklen;
        size_t nblocks = (ksize + 8 * blocksize - 1) / (8 * blocksize);
        uint8_t *dkptr;
        uint8_t block[blocksize];

        MALLOC(*dkey, void *, nblocks * blocksize, M_TEMP, M_WAITOK | M_ZERO);
        dkptr = *dkey;

        krb5_n_fold(cons, conslen, block, blocksize);
        cccbc_init(ctx->enc_mode, enc_ctx, ctx->keylen, ctx->key);
        for (size_t i = 0; i < nblocks; i++) {
                cccbc_set_iv(ctx->enc_mode, iv, NULL);
                cccbc_update(ctx->enc_mode, enc_ctx, iv, 1, block, block);
                memcpy(dkptr, block, blocksize);
                dkptr += blocksize;
        }
}

static void
des_make_key(const uint8_t rawkey[7], uint8_t deskey[8])
{
        uint8_t val = 0;

        memcpy(deskey, rawkey, 7);
        for (int i = 0; i < 7; i++) {
                val |= ((deskey[i] & 1) << (i + 1));
        }
        deskey[7] = val;
        ccdes_key_set_odd_parity(deskey, 8);
}

static void
krb5_3des_key_derivation(crypto_ctx_t ctx, const void *cons, size_t conslen, void **des3key)
{
        const struct ccmode_cbc *cbcmode = ctx->enc_mode;
        void *rawkey;
        uint8_t *kptr, *rptr;

        MALLOC(*des3key, void *, 3 * cbcmode->block_size, M_TEMP, M_WAITOK | M_ZERO);
        krb5_key_derivation(ctx, cons, conslen, &rawkey, 3 * (cbcmode->block_size - 1));
        kptr = (uint8_t *)*des3key;
        rptr = (uint8_t *)rawkey;

        for (int i = 0; i < 3; i++) {
                des_make_key(rptr, kptr);
                rptr += cbcmode->block_size - 1;
                kptr += cbcmode->block_size;
        }

        cc_clear(3 * (cbcmode->block_size - 1), rawkey);
        FREE(rawkey, M_TEMP);
}

/*
 * Create a key schecule
 *
 */
void
cc_key_schedule_create(crypto_ctx_t ctx)
{
        uint8_t usage_string[KRB5_USAGE_LEN];
        lucid_context_t lctx = ctx->gss_ctx;
        void *ekey;

        switch (lctx->key_data.proto) {
        case 0: {
                if (ctx->ks.enc == NULL) {
                        MALLOC(ctx->ks.enc, cccbc_ctx *, ctx->enc_mode->size, M_TEMP, M_WAITOK | M_ZERO);
                        cccbc_init(ctx->enc_mode, ctx->ks.enc, ctx->keylen, ctx->key);
                }
                if (ctx->ks.dec == NULL) {
                        MALLOC(ctx->ks.dec, cccbc_ctx *, ctx->dec_mode->size, M_TEMP, M_WAITOK | M_ZERO);
                        cccbc_init(ctx->dec_mode, ctx->ks.dec, ctx->keylen, ctx->key);
                }
        }
                OS_FALLTHROUGH;
        case 1: {
                if (ctx->ks.enc == NULL) {
                        krb5_make_usage(lctx->initiate ?
                            KRB5_USAGE_INITIATOR_SEAL : KRB5_USAGE_ACCEPTOR_SEAL,
                            0xAA, usage_string);
                        krb5_key_derivation(ctx, usage_string, KRB5_USAGE_LEN, &ekey, ctx->keylen);
                        MALLOC(ctx->ks.enc, cccbc_ctx *, ctx->enc_mode->size, M_TEMP, M_WAITOK | M_ZERO);
                        cccbc_init(ctx->enc_mode, ctx->ks.enc, ctx->keylen, ekey);
                        FREE(ekey, M_TEMP);
                }
                if (ctx->ks.dec == NULL) {
                        krb5_make_usage(lctx->initiate ?
                            KRB5_USAGE_ACCEPTOR_SEAL : KRB5_USAGE_INITIATOR_SEAL,
                            0xAA, usage_string);
                        krb5_key_derivation(ctx, usage_string, KRB5_USAGE_LEN, &ekey, ctx->keylen);
                        MALLOC(ctx->ks.dec, cccbc_ctx *, ctx->dec_mode->size, M_TEMP, M_WAITOK | M_ZERO);
                        cccbc_init(ctx->dec_mode, ctx->ks.dec, ctx->keylen, ekey);
                        FREE(ekey, M_TEMP);
                }
                if (ctx->ks.ikey[GSS_SND] == NULL) {
                        krb5_make_usage(lctx->initiate ?
                            KRB5_USAGE_INITIATOR_SEAL : KRB5_USAGE_ACCEPTOR_SEAL,
                            0x55, usage_string);
                        krb5_key_derivation(ctx, usage_string, KRB5_USAGE_LEN, &ctx->ks.ikey[GSS_SND], ctx->keylen);
                }
                if (ctx->ks.ikey[GSS_RCV] == NULL) {
                        krb5_make_usage(lctx->initiate ?
                            KRB5_USAGE_ACCEPTOR_SEAL : KRB5_USAGE_INITIATOR_SEAL,
                            0x55, usage_string);
                        krb5_key_derivation(ctx, usage_string, KRB5_USAGE_LEN, &ctx->ks.ikey[GSS_RCV], ctx->keylen);
                }
        }
        }
}

void
gss_crypto_ctx_free(crypto_ctx_t ctx)
{
        ctx->ks.ikey[GSS_SND] = NULL;
        if (ctx->ks.ikey[GSS_RCV] && ctx->key != ctx->ks.ikey[GSS_RCV]) {
                cc_clear(ctx->keylen, ctx->ks.ikey[GSS_RCV]);
                FREE(ctx->ks.ikey[GSS_RCV], M_TEMP);
        }
        ctx->ks.ikey[GSS_RCV] = NULL;
        if (ctx->ks.enc) {
                cccbc_ctx_clear(ctx->enc_mode->size, ctx->ks.enc);
                FREE(ctx->ks.enc, M_TEMP);
                ctx->ks.enc = NULL;
        }
        if (ctx->ks.dec) {
                cccbc_ctx_clear(ctx->dec_mode->size, ctx->ks.dec);
                FREE(ctx->ks.dec, M_TEMP);
                ctx->ks.dec = NULL;
        }
        if (ctx->ckey[GSS_SND] && ctx->ckey[GSS_SND] != ctx->key) {
                cc_clear(ctx->keylen, ctx->ckey[GSS_SND]);
                FREE(ctx->ckey[GSS_SND], M_TEMP);
        }
        ctx->ckey[GSS_SND] = NULL;
        if (ctx->ckey[GSS_RCV] && ctx->ckey[GSS_RCV] != ctx->key) {
                cc_clear(ctx->keylen, ctx->ckey[GSS_RCV]);
                FREE(ctx->ckey[GSS_RCV], M_TEMP);
        }
        ctx->ckey[GSS_RCV] = NULL;
        ctx->key = NULL;
        ctx->keylen = 0;
}

int
gss_crypto_ctx_init(struct crypto_ctx *ctx, lucid_context_t lucid)
{
        ctx->gss_ctx = lucid;
        void *key;
        uint8_t usage_string[KRB5_USAGE_LEN];

        ctx->keylen = ctx->gss_ctx->ctx_key.key.key_len;
        key = ctx->gss_ctx->ctx_key.key.key_val;
        ctx->etype = ctx->gss_ctx->ctx_key.etype;
        ctx->key = key;

        switch (ctx->etype) {
        case AES128_CTS_HMAC_SHA1_96:
        case AES256_CTS_HMAC_SHA1_96:
                ctx->enc_mode = ccaes_cbc_encrypt_mode();
                assert(ctx->enc_mode);
                ctx->dec_mode = ccaes_cbc_decrypt_mode();
                assert(ctx->dec_mode);
                ctx->ks.enc = NULL;
                ctx->ks.dec = NULL;
                ctx->di = ccsha1_di();
                assert(ctx->di);
                ctx->flags = CRYPTO_CTS_ENABLE;
                ctx->mpad = 1;
                ctx->digest_size = 12; /* 96 bits */
                krb5_make_usage(ctx->gss_ctx->initiate ?
                    KRB5_USAGE_INITIATOR_SIGN : KRB5_USAGE_ACCEPTOR_SIGN,
                    0x99, usage_string);
                krb5_key_derivation(ctx, usage_string, KRB5_USAGE_LEN, &ctx->ckey[GSS_SND], ctx->keylen);
                krb5_make_usage(ctx->gss_ctx->initiate ?
                    KRB5_USAGE_ACCEPTOR_SIGN : KRB5_USAGE_INITIATOR_SIGN,
                    0x99, usage_string);
                krb5_key_derivation(ctx, usage_string, KRB5_USAGE_LEN, &ctx->ckey[GSS_RCV], ctx->keylen);
                break;
        case DES3_CBC_SHA1_KD:
                ctx->enc_mode = ccdes3_cbc_encrypt_mode();
                assert(ctx->enc_mode);
                ctx->dec_mode = ccdes3_cbc_decrypt_mode();
                assert(ctx->dec_mode);
                ctx->ks.ikey[GSS_SND]  = ctx->key;
                ctx->ks.ikey[GSS_RCV]  = ctx->key;
                ctx->di = ccsha1_di();
                assert(ctx->di);
                ctx->flags = 0;
                ctx->mpad = ctx->enc_mode->block_size;
                ctx->digest_size = 20; /* 160 bits */
                krb5_make_usage(KRB5_USAGE_ACCEPTOR_SIGN, 0x99, usage_string);
                krb5_3des_key_derivation(ctx, usage_string, KRB5_USAGE_LEN, &ctx->ckey[GSS_SND]);
                krb5_3des_key_derivation(ctx, usage_string, KRB5_USAGE_LEN, &ctx->ckey[GSS_RCV]);
                break;
        default:
                return ENOTSUP;
        }

        ctx->lock = lck_mtx_alloc_init(gss_krb5_mech_grp, LCK_ATTR_NULL);

        return 0;
}

/*
 * CFX gss support routines
 */
/* From Heimdal cfx.h file RFC 4121 Cryptoo framework extensions */
typedef struct gss_cfx_mic_token_desc_struct {
        uint8_t TOK_ID[2];      /* 04 04 */
        uint8_t Flags;
        uint8_t Filler[5];
        uint8_t SND_SEQ[8];
} gss_cfx_mic_token_desc, *gss_cfx_mic_token;

typedef struct gss_cfx_wrap_token_desc_struct {
        uint8_t TOK_ID[2];      /* 05 04 */
        uint8_t Flags;
        uint8_t Filler;
        uint8_t EC[2];
        uint8_t RRC[2];
        uint8_t SND_SEQ[8];
} gss_cfx_wrap_token_desc, *gss_cfx_wrap_token;

/* End of cfx.h file */

#define CFXSentByAcceptor       (1 << 0)
#define CFXSealed               (1 << 1)
#define CFXAcceptorSubkey       (1 << 2)

const gss_cfx_mic_token_desc mic_cfx_token = {
        .TOK_ID = "\x04\x04",
        .Flags = 0,
        .Filler = "\xff\xff\xff\xff\xff",
        .SND_SEQ = "\x00\x00\x00\x00\x00\x00\x00\x00"
};

const gss_cfx_wrap_token_desc wrap_cfx_token = {
        .TOK_ID = "\x05\04",
        .Flags = 0,
        .Filler = '\xff',
        .EC = "\x00\x00",
        .RRC = "\x00\x00",
        .SND_SEQ = "\x00\x00\x00\x00\x00\x00\x00\x00"
};

static int
gss_krb5_cfx_verify_mic_token(gss_ctx_id_t ctx, gss_cfx_mic_token token)
{
        int i;
        lucid_context_t lctx = &ctx->gss_lucid_ctx;
        uint8_t flags = 0;

        if (token->TOK_ID[0] != mic_cfx_token.TOK_ID[0] || token->TOK_ID[1] != mic_cfx_token.TOK_ID[1]) {
                printf("Bad mic TOK_ID %x %x\n", token->TOK_ID[0], token->TOK_ID[1]);
                return EBADRPC;
        }
        if (lctx->initiate) {
                flags |= CFXSentByAcceptor;
        }
        if (lctx->key_data.lucid_protocol_u.data_4121.acceptor_subkey) {
                flags |= CFXAcceptorSubkey;
        }
        if (token->Flags != flags) {
                printf("Bad flags received %x exptect %x\n", token->Flags, flags);
                return EBADRPC;
        }
        for (i = 0; i < 5; i++) {
                if (token->Filler[i] != mic_cfx_token.Filler[i]) {
                        break;
                }
        }

        if (i != 5) {
                printf("Bad mic filler %x @ %d\n", token->Filler[i], i);
                return EBADRPC;
        }

        return 0;
}

uint32_t
gss_krb5_cfx_get_mic(uint32_t *minor,           /* minor_status */
    gss_ctx_id_t ctx,                           /* context_handle */
    gss_qop_t qop __unused,                     /* qop_req (ignored) */
    gss_buffer_t mbp,                           /* message mbuf */
    gss_buffer_t mic /* message_token */)
{
        gss_cfx_mic_token_desc token;
        lucid_context_t lctx = &ctx->gss_lucid_ctx;
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        gss_buffer_desc header;
        uint32_t rv;
        uint64_t seq = htonll(lctx->send_seq);

        if (minor == NULL) {
                minor = &rv;
        }
        *minor = 0;
        token = mic_cfx_token;
        mic->length = sizeof(token) + cctx->digest_size;
        MALLOC(mic->value, void *, mic->length, M_TEMP, M_WAITOK | M_ZERO);
        if (!lctx->initiate) {
                token.Flags |= CFXSentByAcceptor;
        }
        if (lctx->key_data.lucid_protocol_u.data_4121.acceptor_subkey) {
                token.Flags |= CFXAcceptorSubkey;
        }
        memcpy(&token.SND_SEQ, &seq, sizeof(lctx->send_seq));
        lctx->send_seq++; //XXX should only update this below on success? Heimdal seems to do it this way
        header.value = &token;
        header.length = sizeof(gss_cfx_mic_token_desc);

        *minor = krb5_mic(cctx, NULL, mbp, &header, (uint8_t *)mic->value + sizeof(token), NULL, 0, 0);

        if (*minor) {
                mic->length = 0;
                FREE(mic->value, M_TEMP);
                mic->value = NULL;
        } else {
                memcpy(mic->value, &token, sizeof(token));
        }

        return *minor ? GSS_S_FAILURE : GSS_S_COMPLETE;
}

uint32_t
gss_krb5_cfx_verify_mic(uint32_t *minor,        /* minor_status */
    gss_ctx_id_t ctx,                           /* context_handle */
    gss_buffer_t mbp,                           /* message_buffer */
    gss_buffer_t mic,                           /* message_token */
    gss_qop_t *qop /* qop_state */)
{
        gss_cfx_mic_token token = mic->value;
        lucid_context_t lctx = &ctx->gss_lucid_ctx;
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        uint8_t *digest = (uint8_t *)mic->value + sizeof(gss_cfx_mic_token_desc);
        int verified = 0;
        uint64_t seq;
        uint32_t rv;
        gss_buffer_desc header;

        if (qop) {
                *qop = GSS_C_QOP_DEFAULT;
        }
        if (minor == NULL) {
                minor = &rv;
        }

        if (mic->length != sizeof(gss_cfx_mic_token_desc) + cctx->digest_size) {
                printf("mic token wrong length\n");
                *minor = EBADRPC;
                goto out;
        }
        *minor = gss_krb5_cfx_verify_mic_token(ctx, token);
        if (*minor) {
                return GSS_S_FAILURE;
        }
        header.value = token;
        header.length = sizeof(gss_cfx_mic_token_desc);
        *minor = krb5_mic(cctx, NULL, mbp, &header, digest, &verified, 0, 0);

        if (verified) {
                //XXX  errors and such? Sequencing and replay? Not supported in RPCSEC_GSS
                memcpy(&seq, token->SND_SEQ, sizeof(uint64_t));
                seq = ntohll(seq);
                lctx->recv_seq = seq;
        }

out:
        return verified ? GSS_S_COMPLETE : GSS_S_BAD_SIG;
}

uint32_t
gss_krb5_cfx_get_mic_mbuf(uint32_t *minor,      /* minor_status */
    gss_ctx_id_t ctx,                           /* context_handle */
    gss_qop_t qop __unused,                       /* qop_req (ignored) */
    mbuf_t mbp,                         /* message mbuf */
    size_t offset,                              /* offest */
    size_t len,                         /* length */
    gss_buffer_t mic /* message_token */)
{
        gss_cfx_mic_token_desc token;
        lucid_context_t lctx = &ctx->gss_lucid_ctx;
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        uint32_t rv;
        uint64_t seq = htonll(lctx->send_seq);
        gss_buffer_desc header;

        if (minor == NULL) {
                minor = &rv;
        }
        *minor = 0;

        token = mic_cfx_token;
        mic->length = sizeof(token) + cctx->digest_size;
        MALLOC(mic->value, void *, mic->length, M_TEMP, M_WAITOK | M_ZERO);
        if (!lctx->initiate) {
                token.Flags |= CFXSentByAcceptor;
        }
        if (lctx->key_data.lucid_protocol_u.data_4121.acceptor_subkey) {
                token.Flags |= CFXAcceptorSubkey;
        }

        memcpy(&token.SND_SEQ, &seq, sizeof(lctx->send_seq));
        lctx->send_seq++; //XXX should only update this below on success? Heimdal seems to do it this way

        header.length = sizeof(token);
        header.value = &token;

        len = len ? len : gss_mbuf_len(mbp, offset);
        *minor = krb5_mic_mbuf(cctx, NULL, mbp, offset, len, &header, (uint8_t *)mic->value + sizeof(token), NULL, 0, 0);

        if (*minor) {
                mic->length = 0;
                FREE(mic->value, M_TEMP);
                mic->value = NULL;
        } else {
                memcpy(mic->value, &token, sizeof(token));
        }

        return *minor ? GSS_S_FAILURE : GSS_S_COMPLETE;
}


uint32_t
gss_krb5_cfx_verify_mic_mbuf(uint32_t *minor,   /* minor_status */
    gss_ctx_id_t ctx,                           /* context_handle */
    mbuf_t mbp,                                         /* message_buffer */
    size_t offset,                                      /* offset */
    size_t len,                                         /* length */
    gss_buffer_t mic,                           /* message_token */
    gss_qop_t *qop /* qop_state */)
{
        gss_cfx_mic_token token = mic->value;
        lucid_context_t lctx = &ctx->gss_lucid_ctx;
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        uint8_t *digest = (uint8_t *)mic->value + sizeof(gss_cfx_mic_token_desc);
        int verified;
        uint64_t seq;
        uint32_t rv;
        gss_buffer_desc header;

        if (qop) {
                *qop = GSS_C_QOP_DEFAULT;
        }

        if (minor == NULL) {
                minor = &rv;
        }

        *minor = gss_krb5_cfx_verify_mic_token(ctx, token);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        header.length = sizeof(gss_cfx_mic_token_desc);
        header.value = mic->value;

        *minor = krb5_mic_mbuf(cctx, NULL, mbp, offset, len, &header, digest, &verified, 0, 0);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        //XXX  errors and such? Sequencing and replay? Not Supported RPCSEC_GSS
        memcpy(&seq, token->SND_SEQ, sizeof(uint64_t));
        seq = ntohll(seq);
        lctx->recv_seq = seq;

        return verified ? GSS_S_COMPLETE : GSS_S_BAD_SIG;
}

errno_t
krb5_cfx_crypt_mbuf(crypto_ctx_t ctx, mbuf_t *mbp, size_t *len, int encrypt, int reverse)
{
        const struct ccmode_cbc *ccmode = encrypt ? ctx->enc_mode : ctx->dec_mode;
        uint8_t confounder[ccmode->block_size];
        uint8_t digest[ctx->digest_size];
        size_t tlen, r = 0;
        errno_t error;

        if (encrypt) {
                assert(ccmode->block_size <= UINT_MAX);
                read_random(confounder, (u_int)ccmode->block_size);
                error = gss_prepend_mbuf(mbp, confounder, ccmode->block_size);
                if (error) {
                        return error;
                }
                tlen = *len + ccmode->block_size;
                if (ctx->mpad > 1) {
                        r = ctx->mpad - (tlen % ctx->mpad);
                }
                /* We expect that r == 0 from krb5_cfx_wrap */
                if (r != 0) {
                        uint8_t mpad[r];
                        memset(mpad, 0, r);
                        error = gss_append_mbuf(*mbp, mpad, r);
                        if (error) {
                                return error;
                        }
                }
                tlen += r;
                error = krb5_mic_mbuf(ctx, NULL, *mbp, 0, tlen, NULL, digest, NULL, 1, 0);
                if (error) {
                        return error;
                }
                error = krb5_crypt_mbuf(ctx, mbp, tlen, 1, NULL);
                if (error) {
                        return error;
                }
                error = gss_append_mbuf(*mbp, digest, ctx->digest_size);
                if (error) {
                        return error;
                }
                *len = tlen + ctx->digest_size;
                return 0;
        } else {
                int verf;
                cccbc_ctx *ks = NULL;

                if (*len < ctx->digest_size + sizeof(confounder)) {
                        return EBADRPC;
                }
                tlen = *len - ctx->digest_size;
                /* get the digest */
                error = mbuf_copydata(*mbp, tlen, ctx->digest_size, digest);
                /* Remove the digest from the mbuffer */
                error = gss_strip_mbuf(*mbp, -ctx->digest_size);
                if (error) {
                        return error;
                }

                if (reverse) {
                        /*
                         * Derive a key schedule that the sender can unwrap with. This
                         * is so that RPCSEC_GSS can restore encrypted arguments for
                         * resending. We do that because the RPCSEC_GSS sequence number in
                         * the rpc header is prepended to the body of the message before wrapping.
                         */
                        void *ekey;
                        uint8_t usage_string[KRB5_USAGE_LEN];
                        lucid_context_t lctx = ctx->gss_ctx;

                        krb5_make_usage(lctx->initiate ?
                            KRB5_USAGE_INITIATOR_SEAL : KRB5_USAGE_ACCEPTOR_SEAL,
                            0xAA, usage_string);
                        krb5_key_derivation(ctx, usage_string, KRB5_USAGE_LEN, &ekey, ctx->keylen);
                        MALLOC(ks, cccbc_ctx *, ctx->dec_mode->size, M_TEMP, M_WAITOK | M_ZERO);
                        cccbc_init(ctx->dec_mode, ks, ctx->keylen, ekey);
                        FREE(ekey, M_TEMP);
                }
                error = krb5_crypt_mbuf(ctx, mbp, tlen, 0, ks);
                FREE(ks, M_TEMP);
                if (error) {
                        return error;
                }
                error = krb5_mic_mbuf(ctx, NULL, *mbp, 0, tlen, NULL, digest, &verf, 1, reverse);
                if (error) {
                        return error;
                }
                if (!verf) {
                        return EBADRPC;
                }
                /* strip off the confounder */
                assert(ccmode->block_size <= INT_MAX);
                error = gss_strip_mbuf(*mbp, (int)ccmode->block_size);
                if (error) {
                        return error;
                }
                *len = tlen - ccmode->block_size;
        }
        return 0;
}

uint32_t
gss_krb5_cfx_wrap_mbuf(uint32_t *minor,         /* minor_status */
    gss_ctx_id_t ctx,                           /* context_handle */
    int conf_flag,                              /* conf_req_flag */
    gss_qop_t qop __unused,                     /* qop_req */
    mbuf_t *mbp,                                /* input/output message_buffer */
    size_t len,                                 /* mbuf chain length */
    int *conf /* conf_state */)
{
        gss_cfx_wrap_token_desc token;
        lucid_context_t lctx = &ctx->gss_lucid_ctx;
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        int error = 0;
        uint32_t mv;
        uint64_t seq = htonll(lctx->send_seq);

        if (minor == NULL) {
                minor = &mv;
        }
        if (conf) {
                *conf = conf_flag;
        }

        *minor = 0;
        token = wrap_cfx_token;
        if (!lctx->initiate) {
                token.Flags |= CFXSentByAcceptor;
        }
        if (lctx->key_data.lucid_protocol_u.data_4121.acceptor_subkey) {
                token.Flags |= CFXAcceptorSubkey;
        }
        memcpy(&token.SND_SEQ, &seq, sizeof(uint64_t));
        lctx->send_seq++;
        if (conf_flag) {
                uint8_t pad[cctx->mpad];
                size_t plen = 0;

                token.Flags |= CFXSealed;
                memset(pad, 0, cctx->mpad);
                if (cctx->mpad > 1) {
                        size_t val = cctx->mpad - ((len + sizeof(gss_cfx_wrap_token_desc)) % cctx->mpad);
                        plen = sizeof(val) > sizeof(uint32_t) ? htonll(val) : htonl(val);
                        token.EC[0] = ((plen >> 8) & 0xff);
                        token.EC[1] = (plen & 0xff);
                }
                if (plen) {
                        error = gss_append_mbuf(*mbp, pad, plen);
                        len += plen;
                }
                if (error == 0) {
                        error = gss_append_mbuf(*mbp, (uint8_t *)&token, sizeof(gss_cfx_wrap_token_desc));
                        len += sizeof(gss_cfx_wrap_token_desc);
                }
                if (error == 0) {
                        error = krb5_cfx_crypt_mbuf(cctx, mbp, &len, 1, 0);
                }
                if (error == 0) {
                        error = gss_prepend_mbuf(mbp, (uint8_t *)&token, sizeof(gss_cfx_wrap_token_desc));
                }
        } else {
                uint8_t digest[cctx->digest_size];
                gss_buffer_desc header;

                header.length = sizeof(token);
                header.value = &token;

                error = krb5_mic_mbuf(cctx, NULL, *mbp, 0, len, &header, digest, NULL, 1, 0);
                if (error == 0) {
                        error = gss_append_mbuf(*mbp, digest, cctx->digest_size);
                        if (error == 0) {
                                uint32_t plen = htonl(cctx->digest_size);
                                memcpy(token.EC, &plen, 2);
                                error = gss_prepend_mbuf(mbp, (uint8_t *)&token, sizeof(gss_cfx_wrap_token_desc));
                        }
                }
        }
        if (error) {
                *minor = error;
                return GSS_S_FAILURE;
        }

        return GSS_S_COMPLETE;
}

/*
 * Given a wrap token the has a rrc, move the trailer back to the end.
 */
static void
gss_krb5_cfx_unwrap_rrc_mbuf(mbuf_t header, size_t rrc)
{
        mbuf_t body, trailer;

        gss_normalize_mbuf(header, sizeof(gss_cfx_wrap_token_desc), &rrc, &trailer, &body, 0);
        gss_join_mbuf(header, body, trailer);
}

uint32_t
gss_krb5_cfx_unwrap_mbuf(uint32_t * minor,      /* minor_status */
    gss_ctx_id_t ctx,                           /* context_handle */
    mbuf_t *mbp,                                /* input/output message_buffer */
    size_t len,                                 /* mbuf chain length */
    int *conf_flag,                             /* conf_state */
    gss_qop_t *qop /* qop state */)
{
        gss_cfx_wrap_token_desc token;
        lucid_context_t lctx = &ctx->gss_lucid_ctx;
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        int error, conf;
        uint32_t ec = 0, rrc = 0;
        uint64_t seq;
        int reverse = (*qop == GSS_C_QOP_REVERSE);
        int initiate = lctx->initiate ? (reverse ? 0 : 1) : (reverse ? 1 : 0);

        error = mbuf_copydata(*mbp, 0, sizeof(gss_cfx_wrap_token_desc), &token);
        gss_strip_mbuf(*mbp, sizeof(gss_cfx_wrap_token_desc));
        len -= sizeof(gss_cfx_wrap_token_desc);

        /* Check for valid token */
        if (token.TOK_ID[0] != wrap_cfx_token.TOK_ID[0] ||
            token.TOK_ID[1] != wrap_cfx_token.TOK_ID[1] ||
            token.Filler != wrap_cfx_token.Filler) {
                printf("Token id does not match\n");
                goto badrpc;
        }
        if ((initiate && !(token.Flags & CFXSentByAcceptor)) ||
            (lctx->key_data.lucid_protocol_u.data_4121.acceptor_subkey && !(token.Flags & CFXAcceptorSubkey))) {
                printf("Bad flags %x\n", token.Flags);
                goto badrpc;
        }

        /* XXX Sequence replay detection */
        memcpy(&seq, token.SND_SEQ, sizeof(seq));
        seq = ntohll(seq);
        lctx->recv_seq = seq;

        ec = (token.EC[0] << 8) | token.EC[1];
        rrc = (token.RRC[0] << 8) | token.RRC[1];
        *qop = GSS_C_QOP_DEFAULT;
        conf = ((token.Flags & CFXSealed) == CFXSealed);
        if (conf_flag) {
                *conf_flag = conf;
        }
        if (conf) {
                gss_cfx_wrap_token_desc etoken;

                if (rrc) { /* Handle Right rotation count */
                        gss_krb5_cfx_unwrap_rrc_mbuf(*mbp, rrc);
                }
                error = krb5_cfx_crypt_mbuf(cctx, mbp, &len, 0, reverse);
                if (error) {
                        printf("krb5_cfx_crypt_mbuf %d\n", error);
                        *minor = error;
                        return GSS_S_FAILURE;
                }
                if (len >= sizeof(gss_cfx_wrap_token_desc)) {
                        len -= sizeof(gss_cfx_wrap_token_desc);
                } else {
                        goto badrpc;
                }
                mbuf_copydata(*mbp, len, sizeof(gss_cfx_wrap_token_desc), &etoken);
                /* Verify etoken with the token wich should be the same, except the rc field is always zero */
                token.RRC[0] = token.RRC[1] = 0;
                if (memcmp(&token, &etoken, sizeof(gss_cfx_wrap_token_desc)) != 0) {
                        printf("Encrypted token mismach\n");
                        goto badrpc;
                }
                /* strip the encrypted token and any pad bytes */
                gss_strip_mbuf(*mbp, -(sizeof(gss_cfx_wrap_token_desc) + ec));
                len -= (sizeof(gss_cfx_wrap_token_desc) + ec);
        } else {
                uint8_t digest[cctx->digest_size];
                int verf;
                gss_buffer_desc header;

                if (ec != cctx->digest_size || len >= cctx->digest_size) {
                        goto badrpc;
                }
                len -= cctx->digest_size;
                mbuf_copydata(*mbp, len, cctx->digest_size, digest);
                gss_strip_mbuf(*mbp, -cctx->digest_size);
                /* When calculating the mic header fields ec and rcc must be zero */
                token.EC[0] = token.EC[1] = token.RRC[0] = token.RRC[1] = 0;
                header.value = &token;
                header.length = sizeof(gss_cfx_wrap_token_desc);
                error = krb5_mic_mbuf(cctx, NULL, *mbp, 0, len, &header, digest, &verf, 1, reverse);
                if (error) {
                        goto badrpc;
                }
        }
        return GSS_S_COMPLETE;

badrpc:
        *minor = EBADRPC;
        return GSS_S_FAILURE;
}

/*
 * RFC 1964 3DES support
 */

typedef struct gss_1964_mic_token_desc_struct {
        uint8_t TOK_ID[2];      /* 01 01 */
        uint8_t Sign_Alg[2];
        uint8_t Filler[4];      /* ff ff ff ff */
} gss_1964_mic_token_desc, *gss_1964_mic_token;

typedef struct gss_1964_wrap_token_desc_struct {
        uint8_t TOK_ID[2];      /* 02 01 */
        uint8_t Sign_Alg[2];
        uint8_t Seal_Alg[2];
        uint8_t Filler[2];      /* ff ff */
} gss_1964_wrap_token_desc, *gss_1964_wrap_token;

typedef struct gss_1964_delete_token_desc_struct {
        uint8_t TOK_ID[2];      /* 01 02 */
        uint8_t Sign_Alg[2];
        uint8_t Filler[4];      /* ff ff ff ff */
} gss_1964_delete_token_desc, *gss_1964_delete_token;

typedef struct gss_1964_header_desc_struct {
        uint8_t App0;           /* 0x60 Application 0 constructed */
        uint8_t AppLen[];       /* Variable Der length */
} gss_1964_header_desc, *gss_1964_header;

typedef union {
        gss_1964_mic_token_desc         mic_tok;
        gss_1964_wrap_token_desc        wrap_tok;
        gss_1964_delete_token_desc      del_tok;
} gss_1964_tok_type __attribute__((transparent_union));

typedef struct gss_1964_token_body_struct {
        uint8_t OIDType;        /* 0x06 */
        uint8_t OIDLen;         /* 0x09 */
        uint8_t kerb_mech[9];   /* Der Encode kerberos mech 1.2.840.113554.1.2.2
                                 *  0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x01, 0x02, 0x02 */
        gss_1964_tok_type body;
        uint8_t SND_SEQ[8];
        uint8_t Hash[];         /* Mic */
} gss_1964_token_body_desc, *gss_1964_token_body;


gss_1964_header_desc tok_1964_header = {
        .App0 = 0x60
};

gss_1964_mic_token_desc mic_1964_token = {
        .TOK_ID = "\x01\x01",
        .Filler = "\xff\xff\xff\xff"
};

gss_1964_wrap_token_desc wrap_1964_token = {
        .TOK_ID = "\x02\x01",
        .Filler = "\xff\xff"
};

gss_1964_delete_token_desc del_1964_token = {
        .TOK_ID = "\x01\x01",
        .Filler = "\xff\xff\xff\xff"
};

gss_1964_token_body_desc body_1964_token = {
        .OIDType = 0x06,
        .OIDLen = 0x09,
        .kerb_mech = "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02",
};

#define GSS_KRB5_3DES_MAXTOKSZ (sizeof(gss_1964_header_desc) + 5 /* max der length supported */ + sizeof(gss_1964_token_body_desc))

uint32_t gss_krb5_3des_get_mic(uint32_t *, gss_ctx_id_t, gss_qop_t, gss_buffer_t, gss_buffer_t);
uint32_t gss_krb5_3des_verify_mic(uint32_t *, gss_ctx_id_t, gss_buffer_t, gss_buffer_t, gss_qop_t *);
uint32_t gss_krb5_3des_get_mic_mbuf(uint32_t *, gss_ctx_id_t, gss_qop_t, mbuf_t, size_t, size_t, gss_buffer_t);
uint32_t gss_krb5_3des_verify_mic_mbuf(uint32_t *, gss_ctx_id_t, mbuf_t, size_t, size_t, gss_buffer_t, gss_qop_t *);
uint32_t gss_krb5_3des_wrap_mbuf(uint32_t *, gss_ctx_id_t, int, gss_qop_t, mbuf_t *, size_t, int *);
uint32_t gss_krb5_3des_unwrap_mbuf(uint32_t *, gss_ctx_id_t, mbuf_t *, size_t, int *, gss_qop_t *);

/*
 * Decode an ASN.1 DER length field
 */
static ssize_t
gss_krb5_der_length_get(uint8_t **pp)
{
        uint8_t *p = *pp;
        uint32_t flen, len = 0;

        flen = *p & 0x7f;

        if (*p++ & 0x80) {
                if (flen > sizeof(uint32_t)) {
                        return -1;
                }
                while (flen--) {
                        len = (len << 8) + *p++;
                }
        } else {
                len = flen;
        }
        *pp = p;
        return len;
}

/*
 * Determine size of ASN.1 DER length
 */
static int
gss_krb5_der_length_size(size_t len)
{
        return
                len < (1 <<  7) ? 1 :
                len < (1 <<  8) ? 2 :
                len < (1 << 16) ? 3 :
                len < (1 << 24) ? 4 : 5;
}

/*
 * Encode an ASN.1 DER length field
 */
static void
gss_krb5_der_length_put(uint8_t **pp, size_t len)
{
        int sz = gss_krb5_der_length_size(len);
        uint8_t *p = *pp;

        if (sz == 1) {
                *p++ = (uint8_t) len;
        } else {
                *p++ = (uint8_t) ((sz - 1) | 0x80);
                sz -= 1;
                while (sz--) {
                        *p++ = (uint8_t) ((len >> (sz * 8)) & 0xff);
                }
        }

        *pp = p;
}

static void
gss_krb5_3des_token_put(gss_ctx_id_t ctx, gss_1964_tok_type body, gss_buffer_t hash, size_t datalen, gss_buffer_t des3_token)
{
        gss_1964_header token;
        gss_1964_token_body tokbody;
        lucid_context_t lctx = &ctx->gss_lucid_ctx;
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        uint32_t seq = (uint32_t) (lctx->send_seq++ & 0xffff);
        size_t toklen = sizeof(gss_1964_token_body_desc)  + cctx->digest_size;
        size_t alloclen = toklen + sizeof(gss_1964_header_desc) + gss_krb5_der_length_size(toklen + datalen);
        uint8_t *tokptr;

        MALLOC(token, gss_1964_header, alloclen, M_TEMP, M_WAITOK | M_ZERO);
        *token = tok_1964_header;
        tokptr = token->AppLen;
        gss_krb5_der_length_put(&tokptr, toklen + datalen);
        tokbody = (gss_1964_token_body)tokptr;
        *tokbody = body_1964_token;  /* Initalize the token body */
        tokbody->body = body;  /* and now set the body to the token type passed in */
        seq = htonl(seq);
        for (int i = 0; i < 4; i++) {
                tokbody->SND_SEQ[i] = (uint8_t)((seq >> (i * 8)) & 0xff);
        }
        for (int i = 4; i < 8; i++) {
                tokbody->SND_SEQ[i] = lctx->initiate ? 0x00 : 0xff;
        }

        size_t blocksize = cctx->enc_mode->block_size;
        cccbc_iv_decl(blocksize, iv);
        cccbc_ctx_decl(cctx->enc_mode->size, enc_ctx);
        cccbc_set_iv(cctx->enc_mode, iv, hash->value);
        cccbc_init(cctx->enc_mode, enc_ctx, cctx->keylen, cctx->key);
        cccbc_update(cctx->enc_mode, enc_ctx, iv, 1, tokbody->SND_SEQ, tokbody->SND_SEQ);

        assert(hash->length == cctx->digest_size);
        memcpy(tokbody->Hash, hash->value, hash->length);
        des3_token->length = alloclen;
        des3_token->value = token;
}

static int
gss_krb5_3des_token_get(gss_ctx_id_t ctx, gss_buffer_t intok,
    gss_1964_tok_type body, gss_buffer_t hash, size_t *offset, size_t *len, int reverse)
{
        gss_1964_header token = intok->value;
        gss_1964_token_body tokbody;
        lucid_context_t lctx = &ctx->gss_lucid_ctx;
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        ssize_t length;
        size_t toklen;
        uint8_t *tokptr;
        uint32_t seq;
        int initiate;

        if (token->App0 != tok_1964_header.App0) {
                printf("%s: bad framing\n", __func__);
                printgbuf(__func__, intok);
                return EBADRPC;
        }
        tokptr = token->AppLen;
        length = gss_krb5_der_length_get(&tokptr);
        if (length < 0) {
                printf("%s: invalid length\n", __func__);
                printgbuf(__func__, intok);
                return EBADRPC;
        }
        toklen = sizeof(gss_1964_header_desc) + gss_krb5_der_length_size(length)
            + sizeof(gss_1964_token_body_desc);

        if (intok->length < toklen + cctx->digest_size) {
                printf("%s: token to short", __func__);
                printf("toklen = %d, length = %d\n", (int)toklen, (int)length);
                printgbuf(__func__, intok);
                return EBADRPC;
        }

        if (offset) {
                *offset = toklen + cctx->digest_size;
        }

        if (len) {
                *len = length - sizeof(gss_1964_token_body_desc) - cctx->digest_size;
        }

        tokbody = (gss_1964_token_body)tokptr;
        if (tokbody->OIDType != body_1964_token.OIDType ||
            tokbody->OIDLen != body_1964_token.OIDLen ||
            memcmp(tokbody->kerb_mech, body_1964_token.kerb_mech, tokbody->OIDLen) != 0) {
                printf("%s: Invalid mechanism\n", __func__);
                printgbuf(__func__, intok);
                return EBADRPC;
        }
        if (memcmp(&tokbody->body, &body, sizeof(gss_1964_tok_type)) != 0) {
                printf("%s: Invalid body\n", __func__);
                printgbuf(__func__, intok);
                return EBADRPC;
        }
        size_t blocksize = cctx->enc_mode->block_size;
        uint8_t *block = tokbody->SND_SEQ;

        assert(blocksize == sizeof(tokbody->SND_SEQ));
        cccbc_iv_decl(blocksize, iv);
        cccbc_ctx_decl(cctx->dec_mode->size, dec_ctx);
        cccbc_set_iv(cctx->dec_mode, iv, tokbody->Hash);
        cccbc_init(cctx->dec_mode, dec_ctx, cctx->keylen, cctx->key);
        cccbc_update(cctx->dec_mode, dec_ctx, iv, 1, block, block);

        initiate = lctx->initiate ? (reverse ? 0 : 1) : (reverse ? 1 : 0);
        for (int i = 4; i < 8; i++) {
                if (tokbody->SND_SEQ[i] != (initiate ? 0xff : 0x00)) {
                        printf("%s: Invalid des mac\n", __func__);
                        printgbuf(__func__, intok);
                        return EAUTH;
                }
        }

        memcpy(&seq, tokbody->SND_SEQ, sizeof(uint32_t));

        lctx->recv_seq = ntohl(seq);

        assert(hash->length >= cctx->digest_size);
        memcpy(hash->value, tokbody->Hash, cctx->digest_size);

        return 0;
}

uint32_t
gss_krb5_3des_get_mic(uint32_t *minor,          /* minor status */
    gss_ctx_id_t ctx,                           /* krb5 context id */
    gss_qop_t qop __unused,                     /* qop_req (ignored) */
    gss_buffer_t mbp,                           /* message buffer in */
    gss_buffer_t mic)                           /* mic token out */
{
        gss_1964_mic_token_desc tokbody = mic_1964_token;
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        gss_buffer_desc hash;
        gss_buffer_desc header;
        uint8_t hashval[cctx->digest_size];

        hash.length = cctx->digest_size;
        hash.value = hashval;
        tokbody.Sign_Alg[0] = 0x04; /* lctx->keydata.lucid_protocol_u.data_1964.sign_alg */
        tokbody.Sign_Alg[1] = 0x00;
        header.length = sizeof(gss_1964_mic_token_desc);
        header.value = &tokbody;

        /* Hash the data */
        *minor = krb5_mic(cctx, &header, mbp, NULL, hashval, NULL, 0, 0);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        /* Make the token */
        gss_krb5_3des_token_put(ctx, tokbody, &hash, 0, mic);

        return GSS_S_COMPLETE;
}

uint32_t
gss_krb5_3des_verify_mic(uint32_t *minor,
    gss_ctx_id_t ctx,
    gss_buffer_t mbp,
    gss_buffer_t mic,
    gss_qop_t *qop)
{
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        uint8_t hashval[cctx->digest_size];
        gss_buffer_desc hash;
        gss_1964_mic_token_desc mtok = mic_1964_token;
        gss_buffer_desc header;
        int verf;

        mtok.Sign_Alg[0] = 0x04; /* lctx->key_data.lucid_protocol_u.data_1964.sign_alg */
        mtok.Sign_Alg[1] = 0x00;
        hash.length = cctx->digest_size;
        hash.value = hashval;
        header.length = sizeof(gss_1964_mic_token_desc);
        header.value = &mtok;

        if (qop) {
                *qop = GSS_C_QOP_DEFAULT;
        }

        *minor = gss_krb5_3des_token_get(ctx, mic, mtok, &hash, NULL, NULL, 0);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        *minor = krb5_mic(cctx, &header, mbp, NULL, hashval, &verf, 0, 0);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        return verf ? GSS_S_COMPLETE : GSS_S_BAD_SIG;
}

uint32_t
gss_krb5_3des_get_mic_mbuf(uint32_t *minor,
    gss_ctx_id_t ctx,
    gss_qop_t qop __unused,
    mbuf_t mbp,
    size_t offset,
    size_t len,
    gss_buffer_t mic)
{
        gss_1964_mic_token_desc tokbody = mic_1964_token;
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        gss_buffer_desc header;
        gss_buffer_desc hash;
        uint8_t hashval[cctx->digest_size];

        hash.length = cctx->digest_size;
        hash.value = hashval;
        tokbody.Sign_Alg[0] = 0x04; /* lctx->key_data.lucid_protocol_u.data_4121.sign_alg */
        tokbody.Sign_Alg[1] = 0x00;
        header.length = sizeof(gss_1964_mic_token_desc);
        header.value = &tokbody;

        /* Hash the data */
        *minor = krb5_mic_mbuf(cctx, &header, mbp, offset, len, NULL, hashval, NULL, 0, 0);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        /* Make the token */
        gss_krb5_3des_token_put(ctx, tokbody, &hash, 0, mic);

        return GSS_S_COMPLETE;
}

uint32_t
gss_krb5_3des_verify_mic_mbuf(uint32_t *minor,
    gss_ctx_id_t ctx,
    mbuf_t mbp,
    size_t offset,
    size_t len,
    gss_buffer_t mic,
    gss_qop_t *qop)
{
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        uint8_t hashval[cctx->digest_size];
        gss_buffer_desc header;
        gss_buffer_desc hash;
        gss_1964_mic_token_desc mtok = mic_1964_token;
        int verf;

        mtok.Sign_Alg[0] = 0x04; /* lctx->key_data.lucic_protocol_u.data1964.sign_alg */
        mtok.Sign_Alg[1] = 0x00;
        hash.length = cctx->digest_size;
        hash.value = hashval;
        header.length = sizeof(gss_1964_mic_token_desc);
        header.value = &mtok;

        if (qop) {
                *qop = GSS_C_QOP_DEFAULT;
        }

        *minor = gss_krb5_3des_token_get(ctx, mic, mtok, &hash, NULL, NULL, 0);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        *minor = krb5_mic_mbuf(cctx, &header, mbp, offset, len, NULL, hashval, &verf, 0, 0);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        return verf ? GSS_S_COMPLETE : GSS_S_BAD_SIG;
}

uint32_t
gss_krb5_3des_wrap_mbuf(uint32_t *minor,
    gss_ctx_id_t ctx,
    int conf_flag,
    gss_qop_t qop __unused,
    mbuf_t *mbp,
    size_t len,
    int *conf_state)
{
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        const struct ccmode_cbc *ccmode = cctx->enc_mode;
        uint8_t padlen;
        uint8_t pad[8];
        uint8_t confounder[ccmode->block_size];
        gss_1964_wrap_token_desc tokbody = wrap_1964_token;
        gss_buffer_desc header;
        gss_buffer_desc mic;
        gss_buffer_desc hash;
        uint8_t hashval[cctx->digest_size];

        if (conf_state) {
                *conf_state = conf_flag;
        }

        hash.length = cctx->digest_size;
        hash.value = hashval;
        tokbody.Sign_Alg[0] = 0x04; /* lctx->key_data.lucid_protocol_u.data_1964.sign_alg */
        tokbody.Sign_Alg[1] = 0x00;
        /* conf_flag ? lctx->key_data.lucid_protocol_u.data_1964.seal_alg : 0xffff */
        tokbody.Seal_Alg[0] = conf_flag ? 0x02 : 0xff;
        tokbody.Seal_Alg[1] = conf_flag ? 0x00 : 0xff;
        header.length = sizeof(gss_1964_wrap_token_desc);
        header.value = &tokbody;

        /* Prepend confounder */
        assert(ccmode->block_size <= UINT_MAX);
        read_random(confounder, (u_int)ccmode->block_size);
        *minor = gss_prepend_mbuf(mbp, confounder, ccmode->block_size);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        /* Append trailer of up to 8 bytes and set pad length in each trailer byte */
        padlen = 8 - len % 8;
        for (int i = 0; i < padlen; i++) {
                pad[i] = padlen;
        }
        *minor = gss_append_mbuf(*mbp, pad, padlen);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        len += ccmode->block_size + padlen;

        /* Hash the data */
        *minor = krb5_mic_mbuf(cctx, &header, *mbp, 0, len, NULL, hashval, NULL, 0, 0);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        /* Make the token */
        gss_krb5_3des_token_put(ctx, tokbody, &hash, len, &mic);

        if (conf_flag) {
                *minor = krb5_crypt_mbuf(cctx, mbp, len, 1, 0);
                if (*minor) {
                        return GSS_S_FAILURE;
                }
        }

        *minor = gss_prepend_mbuf(mbp, mic.value, mic.length);

        return *minor ? GSS_S_FAILURE : GSS_S_COMPLETE;
}

uint32_t
gss_krb5_3des_unwrap_mbuf(uint32_t *minor,
    gss_ctx_id_t ctx,
    mbuf_t *mbp,
    size_t len,
    int *conf_state,
    gss_qop_t *qop)
{
        crypto_ctx_t cctx = &ctx->gss_cryptor;
        const struct ccmode_cbc *ccmode = cctx->dec_mode;
        size_t length = 0, offset = 0;
        gss_buffer_desc hash;
        uint8_t hashval[cctx->digest_size];
        gss_buffer_desc itoken;
        uint8_t tbuffer[GSS_KRB5_3DES_MAXTOKSZ + cctx->digest_size];
        itoken.length = GSS_KRB5_3DES_MAXTOKSZ + cctx->digest_size;
        itoken.value = tbuffer;
        gss_1964_wrap_token_desc wrap = wrap_1964_token;
        gss_buffer_desc header;
        uint8_t padlen;
        mbuf_t smb, tmb;
        int cflag, verified, reverse = 0;

        if (len < GSS_KRB5_3DES_MAXTOKSZ) {
                *minor = EBADRPC;
                return GSS_S_FAILURE;
        }

        if (*qop == GSS_C_QOP_REVERSE) {
                reverse = 1;
        }
        *qop = GSS_C_QOP_DEFAULT;

        *minor = mbuf_copydata(*mbp, 0, itoken.length, itoken.value);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        hash.length = cctx->digest_size;
        hash.value = hashval;
        wrap.Sign_Alg[0] = 0x04;
        wrap.Sign_Alg[1] = 0x00;
        wrap.Seal_Alg[0] = 0x02;
        wrap.Seal_Alg[1] = 0x00;

        for (cflag = 1; cflag >= 0; cflag--) {
                *minor = gss_krb5_3des_token_get(ctx, &itoken, wrap, &hash, &offset, &length, reverse);
                if (*minor == 0) {
                        break;
                }
                wrap.Seal_Alg[0] = 0xff;
                wrap.Seal_Alg[1] = 0xff;
        }
        if (*minor) {
                return GSS_S_FAILURE;
        }

        if (conf_state) {
                *conf_state = cflag;
        }

        /*
         * Seperate off the header
         */
        *minor = gss_normalize_mbuf(*mbp, offset, &length, &smb, &tmb, 0);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        assert(tmb == NULL);

        /* Decrypt the chain if needed */
        if (cflag) {
                *minor = krb5_crypt_mbuf(cctx, &smb, length, 0, NULL);
                if (*minor) {
                        return GSS_S_FAILURE;
                }
        }

        /* Verify the mic */
        header.length = sizeof(gss_1964_wrap_token_desc);
        header.value = &wrap;

        *minor = krb5_mic_mbuf(cctx, &header, smb, 0, length, NULL, hashval, &verified, 0, 0);
        if (*minor) {
                return GSS_S_FAILURE;
        }
        if (!verified) {
                return GSS_S_BAD_SIG;
        }

        /* Get the pad bytes */
        *minor = mbuf_copydata(smb, length - 1, 1, &padlen);
        if (*minor) {
                return GSS_S_FAILURE;
        }

        /* Strip the confounder and trailing pad bytes */
        gss_strip_mbuf(smb, -padlen);
        assert(ccmode->block_size <= INT_MAX);
        gss_strip_mbuf(smb, (int)ccmode->block_size);

        if (*mbp != smb) {
                mbuf_freem(*mbp);
                *mbp = smb;
        }

        return GSS_S_COMPLETE;
}

static const char *
etype_name(etypes etype)
{
        switch (etype) {
        case DES3_CBC_SHA1_KD:
                return "des3-cbc-sha1";
        case AES128_CTS_HMAC_SHA1_96:
                return "aes128-cts-hmac-sha1-96";
        case AES256_CTS_HMAC_SHA1_96:
                return "aes-cts-hmac-sha1-96";
        default:
                return "unknown enctype";
        }
}

static int
supported_etype(uint32_t proto, etypes etype)
{
        const char *proto_name;

        switch (proto) {
        case 0:
                /* RFC 1964 */
                proto_name = "RFC 1964 krb5 gss mech";
                switch (etype) {
                case DES3_CBC_SHA1_KD:
                        return 1;
                default:
                        break;
                }
                break;
        case 1:
                /* RFC 4121 */
                proto_name = "RFC 4121 krb5 gss mech";
                switch (etype) {
                case AES256_CTS_HMAC_SHA1_96:
                case AES128_CTS_HMAC_SHA1_96:
                        return 1;
                default:
                        break;
                }
                break;
        default:
                proto_name = "Unknown krb5 gss mech";
                break;
        }
        printf("%s: Non supported encryption %s (%d) type for protocol %s (%d)\n",
            __func__, etype_name(etype), etype, proto_name, proto);
        return 0;
}

/*
 * Kerberos gss mech entry points
 */
uint32_t
gss_krb5_get_mic(uint32_t *minor,       /* minor_status */
    gss_ctx_id_t ctx,                   /* context_handle */
    gss_qop_t qop,                      /* qop_req */
    gss_buffer_t mbp,                   /* message buffer */
    gss_buffer_t mic /* message_token */)
{
        uint32_t minor_stat = 0;

        if (minor == NULL) {
                minor = &minor_stat;
        }
        *minor = 0;

        /* Validate context */
        if (ctx == NULL || ((lucid_context_version_t)ctx)->version != 1) {
                return GSS_S_NO_CONTEXT;
        }

        if (!supported_etype(ctx->gss_lucid_ctx.key_data.proto, ctx->gss_cryptor.etype)) {
                *minor = ENOTSUP;
                return GSS_S_FAILURE;
        }

        switch (ctx->gss_lucid_ctx.key_data.proto) {
        case 0:
                /* RFC 1964 DES3 case */
                return gss_krb5_3des_get_mic(minor, ctx, qop, mbp, mic);
        case 1:
                /* RFC 4121 CFX case */
                return gss_krb5_cfx_get_mic(minor, ctx, qop, mbp, mic);
        }

        return GSS_S_COMPLETE;
}

uint32_t
gss_krb5_verify_mic(uint32_t *minor,            /* minor_status */
    gss_ctx_id_t ctx,                           /* context_handle */
    gss_buffer_t mbp,                           /* message_buffer */
    gss_buffer_t mic,                           /* message_token */
    gss_qop_t *qop /* qop_state */)
{
        uint32_t minor_stat = 0;
        gss_qop_t qop_val = GSS_C_QOP_DEFAULT;

        if (minor == NULL) {
                minor = &minor_stat;
        }
        if (qop == NULL) {
                qop = &qop_val;
        }

        *minor = 0;

        /* Validate context */
        if (ctx == NULL || ((lucid_context_version_t)ctx)->version != 1) {
                return GSS_S_NO_CONTEXT;
        }

        if (!supported_etype(ctx->gss_lucid_ctx.key_data.proto, ctx->gss_cryptor.etype)) {
                *minor = ENOTSUP;
                return GSS_S_FAILURE;
        }

        switch (ctx->gss_lucid_ctx.key_data.proto) {
        case 0:
                /* RFC 1964 DES3 case */
                return gss_krb5_3des_verify_mic(minor, ctx, mbp, mic, qop);
        case 1:
                /* RFC 4121 CFX case */
                return gss_krb5_cfx_verify_mic(minor, ctx, mbp, mic, qop);
        }
        return GSS_S_COMPLETE;
}

uint32_t
gss_krb5_get_mic_mbuf(uint32_t *minor,  /* minor_status */
    gss_ctx_id_t ctx,                   /* context_handle */
    gss_qop_t qop,                      /* qop_req */
    mbuf_t mbp,                         /* message mbuf */
    size_t offset,                      /* offest */
    size_t len,                         /* length */
    gss_buffer_t mic /* message_token */)
{
        uint32_t minor_stat = 0;

        if (minor == NULL) {
                minor = &minor_stat;
        }
        *minor = 0;

        if (len == 0) {
                len = ~(size_t)0;
        }

        /* Validate context */
        if (ctx == NULL || ((lucid_context_version_t)ctx)->version != 1) {
                return GSS_S_NO_CONTEXT;
        }

        if (!supported_etype(ctx->gss_lucid_ctx.key_data.proto, ctx->gss_cryptor.etype)) {
                *minor = ENOTSUP;
                return GSS_S_FAILURE;
        }

        switch (ctx->gss_lucid_ctx.key_data.proto) {
        case 0:
                /* RFC 1964 DES3 case */
                return gss_krb5_3des_get_mic_mbuf(minor, ctx, qop, mbp, offset, len, mic);
        case 1:
                /* RFC 4121 CFX case */
                return gss_krb5_cfx_get_mic_mbuf(minor, ctx, qop, mbp, offset, len, mic);
        }

        return GSS_S_COMPLETE;
}

uint32_t
gss_krb5_verify_mic_mbuf(uint32_t *minor,               /* minor_status */
    gss_ctx_id_t ctx,                                   /* context_handle */
    mbuf_t mbp,                                         /* message_buffer */
    size_t offset,                              /* offset */
    size_t len,                                         /* length */
    gss_buffer_t mic,                                   /* message_token */
    gss_qop_t *qop /* qop_state */)
{
        uint32_t minor_stat = 0;
        gss_qop_t qop_val = GSS_C_QOP_DEFAULT;

        if (minor == NULL) {
                minor = &minor_stat;
        }
        if (qop == NULL) {
                qop = &qop_val;
        }

        *minor = 0;

        if (len == 0) {
                len = ~(size_t)0;
        }

        /* Validate context */
        if (ctx == NULL || ((lucid_context_version_t)ctx)->version != 1) {
                return GSS_S_NO_CONTEXT;
        }

        if (!supported_etype(ctx->gss_lucid_ctx.key_data.proto, ctx->gss_cryptor.etype)) {
                *minor = ENOTSUP;
                return GSS_S_FAILURE;
        }

        switch (ctx->gss_lucid_ctx.key_data.proto) {
        case 0:
                /* RFC 1964 DES3 case */
                return gss_krb5_3des_verify_mic_mbuf(minor, ctx, mbp, offset, len, mic, qop);
        case 1:
                /* RFC 4121 CFX case */
                return gss_krb5_cfx_verify_mic_mbuf(minor, ctx, mbp, offset, len, mic, qop);
        }

        return GSS_S_COMPLETE;
}

uint32_t
gss_krb5_wrap_mbuf(uint32_t *minor,     /* minor_status */
    gss_ctx_id_t ctx,                   /* context_handle */
    int conf_flag,                      /* conf_req_flag */
    gss_qop_t qop,                      /* qop_req */
    mbuf_t *mbp,                        /* input/output message_buffer */
    size_t offset,                      /* offset */
    size_t len,                         /* length */
    int *conf_state /* conf state */)
{
        uint32_t major = GSS_S_FAILURE, minor_stat = 0;
        mbuf_t smb, tmb;
        int conf_val = 0;

        if (minor == NULL) {
                minor = &minor_stat;
        }
        if (conf_state == NULL) {
                conf_state = &conf_val;
        }

        *minor = 0;

        /* Validate context */
        if (ctx == NULL || ((lucid_context_version_t)ctx)->version != 1) {
                return GSS_S_NO_CONTEXT;
        }

        if (!supported_etype(ctx->gss_lucid_ctx.key_data.proto, ctx->gss_cryptor.etype)) {
                *minor = ENOTSUP;
                return GSS_S_FAILURE;
        }

        gss_normalize_mbuf(*mbp, offset, &len, &smb, &tmb, 0);

        switch (ctx->gss_lucid_ctx.key_data.proto) {
        case 0:
                /* RFC 1964 DES3 case */
                major = gss_krb5_3des_wrap_mbuf(minor, ctx, conf_flag, qop, &smb, len, conf_state);
                break;
        case 1:
                /* RFC 4121 CFX case */
                major = gss_krb5_cfx_wrap_mbuf(minor, ctx, conf_flag, qop, &smb, len, conf_state);
                break;
        }

        if (offset) {
                gss_join_mbuf(*mbp, smb, tmb);
        } else {
                *mbp = smb;
                gss_join_mbuf(smb, tmb, NULL);
        }

        return major;
}

uint32_t
gss_krb5_unwrap_mbuf(uint32_t * minor,          /* minor_status */
    gss_ctx_id_t ctx,                           /* context_handle */
    mbuf_t *mbp,                                /* input/output message_buffer */
    size_t offset,                              /* offset */
    size_t len,                                 /* length */
    int *conf_flag,                             /* conf_state */
    gss_qop_t *qop /* qop state */)
{
        uint32_t major = GSS_S_FAILURE, minor_stat = 0;
        gss_qop_t qop_val = GSS_C_QOP_DEFAULT;
        int conf_val = 0;
        mbuf_t smb, tmb;

        if (minor == NULL) {
                minor = &minor_stat;
        }
        if (qop == NULL) {
                qop = &qop_val;
        }
        if (conf_flag == NULL) {
                conf_flag = &conf_val;
        }

        /* Validate context */
        if (ctx == NULL || ((lucid_context_version_t)ctx)->version != 1) {
                return GSS_S_NO_CONTEXT;
        }

        if (!supported_etype(ctx->gss_lucid_ctx.key_data.proto, ctx->gss_cryptor.etype)) {
                *minor = ENOTSUP;
                return GSS_S_FAILURE;
        }

        gss_normalize_mbuf(*mbp, offset, &len, &smb, &tmb, 0);

        switch (ctx->gss_lucid_ctx.key_data.proto) {
        case 0:
                /* RFC 1964 DES3 case */
                major = gss_krb5_3des_unwrap_mbuf(minor, ctx, &smb, len, conf_flag, qop);
                break;
        case 1:
                /* RFC 4121 CFX case */
                major = gss_krb5_cfx_unwrap_mbuf(minor, ctx, &smb, len, conf_flag, qop);
                break;
        }

        if (offset) {
                gss_join_mbuf(*mbp, smb, tmb);
        } else {
                *mbp = smb;
                gss_join_mbuf(smb, tmb, NULL);
        }

        return major;
}

#include <nfs/xdr_subs.h>

static int
xdr_lucid_context(void *data, uint32_t length, lucid_context_t lctx)
{
        struct xdrbuf xb;
        int error = 0;
        uint32_t keylen = 0;

        xb_init_buffer(&xb, data, length);
        xb_get_32(error, &xb, lctx->vers);
        if (!error && lctx->vers != 1) {
                error = EINVAL;
                printf("%s: invalid version %d\n", __func__, (int)lctx->vers);
                goto out;
        }
        xb_get_32(error, &xb, lctx->initiate);
        if (error) {
                printf("%s: Could not decode initiate\n", __func__);
                goto out;
        }
        xb_get_32(error, &xb, lctx->endtime);
        if (error) {
                printf("%s: Could not decode endtime\n", __func__);
                goto out;
        }
        xb_get_64(error, &xb, lctx->send_seq);
        if (error) {
                printf("%s: Could not decode send_seq\n", __func__);
                goto out;
        }
        xb_get_64(error, &xb, lctx->recv_seq);
        if (error) {
                printf("%s: Could not decode recv_seq\n", __func__);
                goto out;
        }
        xb_get_32(error, &xb, lctx->key_data.proto);
        if (error) {
                printf("%s: Could not decode mech protocol\n", __func__);
                goto out;
        }
        switch (lctx->key_data.proto) {
        case 0:
                xb_get_32(error, &xb, lctx->key_data.lucid_protocol_u.data_1964.sign_alg);
                xb_get_32(error, &xb, lctx->key_data.lucid_protocol_u.data_1964.seal_alg);
                if (error) {
                        printf("%s: Could not decode rfc1964 sign and seal\n", __func__);
                }
                break;
        case 1:
                xb_get_32(error, &xb, lctx->key_data.lucid_protocol_u.data_4121.acceptor_subkey);
                if (error) {
                        printf("%s: Could not decode rfc4121 acceptor_subkey", __func__);
                }
                break;
        default:
                printf("%s: Invalid mech protocol %d\n", __func__, (int)lctx->key_data.proto);
                error = EINVAL;
        }
        if (error) {
                goto out;
        }
        xb_get_32(error, &xb, lctx->ctx_key.etype);
        if (error) {
                printf("%s: Could not decode key enctype\n", __func__);
                goto out;
        }
        switch (lctx->ctx_key.etype) {
        case DES3_CBC_SHA1_KD:
                keylen = 24;
                break;
        case AES128_CTS_HMAC_SHA1_96:
                keylen = 16;
                break;
        case AES256_CTS_HMAC_SHA1_96:
                keylen = 32;
                break;
        default:
                error = ENOTSUP;
                goto out;
        }
        xb_get_32(error, &xb, lctx->ctx_key.key.key_len);
        if (error) {
                printf("%s: could not decode key length\n", __func__);
                goto out;
        }
        if (lctx->ctx_key.key.key_len != keylen) {
                error = EINVAL;
                printf("%s: etype = %d keylen = %d expected keylen = %d\n", __func__,
                    lctx->ctx_key.etype, lctx->ctx_key.key.key_len, keylen);
                goto out;
        }

        lctx->ctx_key.key.key_val = xb_malloc(keylen);
        if (lctx->ctx_key.key.key_val == NULL) {
                printf("%s: could not get memory for key\n", __func__);
                error = ENOMEM;
                goto out;
        }
        error = xb_get_bytes(&xb, (char *)lctx->ctx_key.key.key_val, keylen, 1);
        if (error) {
                printf("%s: could get key value\n", __func__);
                xb_free(lctx->ctx_key.key.key_val);
        }
out:
        return error;
}

gss_ctx_id_t
gss_krb5_make_context(void *data, uint32_t datalen)
{
        gss_ctx_id_t ctx;

        if (!corecrypto_available()) {
                return NULL;
        }

        gss_krb5_mech_init();
        MALLOC(ctx, gss_ctx_id_t, sizeof(struct gss_ctx_id_desc), M_TEMP, M_WAITOK | M_ZERO);
        if (xdr_lucid_context(data, datalen, &ctx->gss_lucid_ctx) ||
            !supported_etype(ctx->gss_lucid_ctx.key_data.proto, ctx->gss_lucid_ctx.ctx_key.etype)) {
                FREE(ctx, M_TEMP);
                FREE(data, M_TEMP);
                return NULL;
        }

        /* Set up crypto context */
        gss_crypto_ctx_init(&ctx->gss_cryptor, &ctx->gss_lucid_ctx);
        FREE(data, M_TEMP);

        return ctx;
}

void
gss_krb5_destroy_context(gss_ctx_id_t ctx)
{
        if (ctx == NULL) {
                return;
        }
        gss_crypto_ctx_free(&ctx->gss_cryptor);
        FREE(ctx->gss_lucid_ctx.ctx_key.key.key_val, M_TEMP);
        cc_clear(sizeof(lucid_context_t), &ctx->gss_lucid_ctx);
        FREE(ctx, M_TEMP);
}