/*
 * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * Copyright 2001 by the Massachusetts Institute of Technology.
 * Copyright 1993 by OpenVision Technologies, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appears in all copies and
 * that both that copyright notice and this permission notice appear in
 * supporting documentation, and that the name of OpenVision not be used
 * in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission. OpenVision makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * Copyright (C) 1998 by the FundsXpress, INC.
 *
 * All rights reserved.
 *
 * Export of this software from the United States of America may require
 * a specific license from the United States Government.  It is the
 * responsibility of any person or organization contemplating export to
 * obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of FundsXpress. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  FundsXpress makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include "gssapiP_krb5.h"
#include "k5-int.h"

/* message_buffer is an input if SIGN, output if SEAL, and ignored if DEL_CTX
   conf_state is only valid if SEAL. */

static OM_uint32
kg_unseal_v1(context, minor_status, ctx, ptr, bodysize, message_buffer,
             conf_state, qop_state, toktype)
    krb5_context context;
    OM_uint32 *minor_status;
    krb5_gss_ctx_id_rec *ctx;
    unsigned char *ptr;
    int bodysize;
    gss_buffer_t message_buffer;
    int *conf_state;
    int *qop_state;
    int toktype;
{
    krb5_error_code code;
    int conflen = 0;
    int signalg;
    int sealalg;
    gss_buffer_desc token;
    krb5_checksum cksum;
    krb5_checksum md5cksum;
    krb5_data plaind;
    char *data_ptr;
    krb5_timestamp now;
    unsigned char *plain;
    unsigned int cksum_len = 0;
    size_t plainlen;
    int direction;
    krb5_ui_4 seqnum;
    OM_uint32 retval;
    size_t sumlen, blocksize;
    int tmsglen;
    krb5_keyusage sign_usage = KG_USAGE_SIGN;

    KRB5_LOG0(KRB5_INFO, "kg_unseal_v1() start\n");

    /* Solaris Kerberos:  make sure this is initialized */
    *minor_status = 0;

    if (toktype == KG_TOK_SEAL_MSG) {
        message_buffer->length = 0;
        message_buffer->value = NULL;
    }

    /* get the sign and seal algorithms */

    signalg = ptr[0] + (ptr[1]<<8);
    sealalg = ptr[2] + (ptr[3]<<8);

    /* Sanity checks */

    if ((ptr[4] != 0xff) || (ptr[5] != 0xff)) {
        *minor_status = 0;
        KRB5_LOG0(KRB5_ERR, "kg_unseal_v1() end, error GSS_S_DEFECTIVE_TOKEN\n");
        return GSS_S_DEFECTIVE_TOKEN;
    }

    if ((toktype != KG_TOK_SEAL_MSG) &&
        (sealalg != 0xffff)) {
        *minor_status = 0;
        KRB5_LOG0(KRB5_ERR, "kg_unseal_v1() end, error2 GSS_S_DEFECTIVE_TOKEN\n");
        return GSS_S_DEFECTIVE_TOKEN;
    }

    /* in the current spec, there is only one valid seal algorithm per
       key type, so a simple comparison is ok */

    if ((toktype == KG_TOK_SEAL_MSG) &&
        !((sealalg == 0xffff) ||
          (sealalg == ctx->sealalg))) {
        *minor_status = 0;
        KRB5_LOG0(KRB5_ERR, "kg_unseal_v1() end, error3 GSS_S_DEFECTIVE_TOKEN\n");
        return GSS_S_DEFECTIVE_TOKEN;
    }

    /* there are several mappings of seal algorithms to sign algorithms,
       but few enough that we can try them all. */

    if ((ctx->sealalg == SEAL_ALG_NONE && signalg > 1) ||
        (ctx->sealalg == SEAL_ALG_1 && signalg != SGN_ALG_3) ||
        (ctx->sealalg == SEAL_ALG_DES3KD &&
         signalg != SGN_ALG_HMAC_SHA1_DES3_KD)||
        (ctx->sealalg == SEAL_ALG_MICROSOFT_RC4 &&
        signalg != SGN_ALG_HMAC_MD5)) {
        *minor_status = 0;
        KRB5_LOG0(KRB5_ERR, "kg_unseal_v1() end, error4 GSS_S_DEFECTIVE_TOKEN\n");
        return GSS_S_DEFECTIVE_TOKEN;
    }

    KRB5_LOG(KRB5_INFO, "kg_unseal_v1() signalg = %d\n", signalg);

    switch (signalg) {
    case SGN_ALG_DES_MAC_MD5:
    case SGN_ALG_MD2_5:
    case SGN_ALG_HMAC_MD5:
        cksum_len = 8;
        if (toktype != KG_TOK_SEAL_MSG)
          sign_usage = 15;
            break;
    case SGN_ALG_3:
        cksum_len = 16;
        break;
    case SGN_ALG_HMAC_SHA1_DES3_KD:
        cksum_len = 20;
        break;
    default:
        *minor_status = 0;
        KRB5_LOG(KRB5_ERR, "kg_unseal_v1() end, error signalg=%d\n", signalg);
        return GSS_S_DEFECTIVE_TOKEN;
    }

#ifdef _KERNEL
        /*
         * Because the ARCFOUR code bypasses the standard
         * crypto interfaces, we must make sure the kernel
         * crypto framework mechanism types are properly
         * initialized here.
         */
        context->kef_cipher_mt = get_cipher_mech_type(context,
                                        ctx->seq);
        context->kef_hash_mt = get_hash_mech_type(context,
                                        ctx->seq);
        if ((code = init_key_kef(context->kef_cipher_mt,
                                ctx->seq))) {
                *minor_status = code;
                return (GSS_S_FAILURE);
        }
        if ((code = init_key_kef(context->kef_cipher_mt,
                        ctx->enc))) {
                *minor_status = code;
                return (GSS_S_FAILURE);
        }
#endif /* _KERNEL */

    /* get the token parameters */

    if ((code = kg_get_seq_num(context, ctx->seq, ptr+14, ptr+6, &direction,
                               &seqnum))) {
        *minor_status = code;
        return(GSS_S_BAD_SIG);
    }

    /* decode the message, if SEAL */

    if (toktype == KG_TOK_SEAL_MSG) {
        tmsglen = bodysize-(14+cksum_len);
        KRB5_LOG1(KRB5_INFO, "kg_unseal_v1() tmsglen = %d cksum_len = %d",
                tmsglen, cksum_len);
        KRB5_LOG0(KRB5_INFO, "kg_unseal_v1() toktype == KG_TOK_SEAL_MSG\n");

        if (sealalg != 0xffff) {
            if ((plain = (unsigned char *) xmalloc(tmsglen)) == NULL) {
                *minor_status = ENOMEM;
                KRB5_LOG0(KRB5_ERR, "kg_unseal_v1() end, error ENOMEM\n");
                return(GSS_S_FAILURE);
            }
            if (ctx->enc->enctype == ENCTYPE_ARCFOUR_HMAC) {
              unsigned char bigend_seqnum[4];
              krb5_keyblock *enc_key;
              int i;
              bigend_seqnum[0] = (seqnum>>24) & 0xff;
              bigend_seqnum[1] = (seqnum>>16) & 0xff;
              bigend_seqnum[2] = (seqnum>>8) & 0xff;
              bigend_seqnum[3] = seqnum & 0xff;
              code = krb5_copy_keyblock (context, ctx->enc, &enc_key);
              if (code)
                {
                  xfree_wrap(plain, tmsglen);
                  *minor_status = code;
                  return(GSS_S_FAILURE);
                }

              for (i = 0; i <= 15; i++)
                ((char *) enc_key->contents)[i] ^=0xf0;

#ifndef _KERNEL
                /*
                 * The enc_key contents were modified, delete the
                 * key object so it doesn't get used later.
                 */
                if (enc_key->hKey != CK_INVALID_HANDLE) {
                        (void)C_DestroyObject(krb_ctx_hSession(context),
                                enc_key->hKey);
                        enc_key->hKey = CK_INVALID_HANDLE;
                }
#endif
                KRB5_LOG(KRB5_INFO, "kg_unseal_v1() enc_key->enctype = %d",
                        enc_key->enctype);

                code = kg_arcfour_docrypt (context,
                                enc_key, 0,
                                &bigend_seqnum[0], 4,
                                ptr+14+cksum_len, tmsglen,
                                plain);
                krb5_free_keyblock (context, enc_key);
            } else {
                code = kg_decrypt(context, ctx->enc, KG_USAGE_SEAL, NULL,
                        ptr+14+cksum_len, plain, tmsglen);
            }
            if (code) {
                xfree_wrap(plain, tmsglen);
                *minor_status = code;
                return(GSS_S_FAILURE);
            }
        } else {
            plain = ptr+14+cksum_len;
        }

        plainlen = tmsglen;

        if ((sealalg == 0xffff) && ctx->big_endian) {
            token.length = tmsglen;
        } else {
            conflen = kg_confounder_size(context, ctx->enc);
            /*
             * Solaris Kerberos: we want to perform a sanity check on the
             * pad length, so we know it can not be more than the blocksize.
             */
            code = krb5_c_block_size(context, ctx->enc->enctype, &blocksize);
            if (code != 0) {
                if (sealalg != 0xffff)
                    xfree_wrap(plain, tmsglen);
                *minor_status = code;
                return(GSS_S_FAILURE);
            }
            if (plain[tmsglen-1] > blocksize) {
                if (sealalg != 0xffff)
                    xfree_wrap(plain, tmsglen);
                *minor_status = KG_BAD_LENGTH;
                return(GSS_S_FAILURE);
            }
            token.length = tmsglen - conflen - plain[tmsglen-1];
        }

        if (token.length) {
            if ((token.value = (void *) xmalloc(token.length)) == NULL) {
                if (sealalg != 0xffff)
                    xfree_wrap(plain, tmsglen);
                *minor_status = ENOMEM;
                KRB5_LOG0(KRB5_ERR, "kg_unseal_v1() end, error2 ENOMEM\n");
                return(GSS_S_FAILURE);
            }
            (void) memcpy(token.value, plain+conflen, token.length);
        } else {
            token.value = NULL;
        }
    } else if (toktype == KG_TOK_SIGN_MSG) {
        KRB5_LOG0(KRB5_INFO, "kg_unseal_v1() toktype == KG_TOK_SIGN_MSG\n");
        token = *message_buffer;
        plain = token.value;
        plainlen = token.length;
    } else {
        KRB5_LOG0(KRB5_INFO, "kg_unseal_v1() toktype == NULL\n");
        token.length = 0;
        token.value = NULL;
        plain = token.value;
        plainlen = token.length;
    }

    /* compute the checksum of the message */

    /* initialize the the cksum */
    switch (signalg) {
    case SGN_ALG_DES_MAC_MD5:
    case SGN_ALG_MD2_5:
    case SGN_ALG_DES_MAC:
    case SGN_ALG_3:
        md5cksum.checksum_type = CKSUMTYPE_RSA_MD5;
        break;
    case SGN_ALG_HMAC_MD5:
      md5cksum.checksum_type = CKSUMTYPE_HMAC_MD5_ARCFOUR;
      break;
    case SGN_ALG_HMAC_SHA1_DES3_KD:
        md5cksum.checksum_type = CKSUMTYPE_HMAC_SHA1_DES3;
        break;
    default:
        KRB5_LOG(KRB5_ERR, "kg_unseal_v1() end, error2 signalg=%d\n", signalg);
#ifndef _KERNEL
        abort ();
#else
        *minor_status = 0;
        return(GSS_S_DEFECTIVE_TOKEN);
#endif /* _KERNEL */
    }

    code = krb5_c_checksum_length(context, md5cksum.checksum_type, &sumlen);
    if (code)
    {
        KRB5_LOG(KRB5_ERR, "kg_unseal_v1() end, krb5_c_checksum_length() error "
                "code=%d\n", code);
        return(code);
    }
    md5cksum.length = (size_t)sumlen;

    switch (signalg) {
    case SGN_ALG_DES_MAC_MD5:
    case SGN_ALG_3:
        /* compute the checksum of the message */

        /* 8 = bytes of token body to be checksummed according to spec */

        if (! (data_ptr = (void *)
               xmalloc(8 + (ctx->big_endian ? token.length : plainlen)))) {
            if (sealalg != 0xffff)
                xfree_wrap(plain, tmsglen);
            if (toktype == KG_TOK_SEAL_MSG) {
                xfree_wrap(token.value, token.length);
                /* Solaris Kerberos: just to be safe since token.value is an
                 * output parameter.
                 */
                token.value = NULL;
                token.length = 0;
            }
            *minor_status = ENOMEM;
            KRB5_LOG0(KRB5_ERR, "kg_unseal_v1() end, error3 ENOMEM\n");
            return(GSS_S_FAILURE);
        }

        (void) memcpy(data_ptr, ptr-2, 8);

        if (ctx->big_endian)
            (void) memcpy(data_ptr+8, token.value, token.length);
        else
            (void) memcpy(data_ptr+8, plain, plainlen);

        plaind.length = 8 + (ctx->big_endian ? token.length : plainlen);
        plaind.data = data_ptr;
        code = krb5_c_make_checksum(context, md5cksum.checksum_type,
                                    ctx->seq, sign_usage,
                                    &plaind, &md5cksum);
        xfree_wrap(data_ptr, 8 + (ctx->big_endian ? token.length : plainlen));

        if (code) {
            if (toktype == KG_TOK_SEAL_MSG) {
                xfree_wrap(token.value, token.length);
                /* Solaris Kerberos: just to be safe since token.value is an
                 * output parameter.
                 */
                token.value = NULL;
                token.length = 0;
            }
            *minor_status = code;
            KRB5_LOG(KRB5_ERR, "kg_unseal_v1() end, krb5_c_make_checksum() "
                    "error code = %d\n", code);
            return(GSS_S_FAILURE);
        }

        if ((code = kg_encrypt(context, ctx->seq, KG_USAGE_SEAL,
                               (g_OID_equal(ctx->mech_used, gss_mech_krb5_old) ?
                                ctx->seq->contents : NULL),
                               md5cksum.contents, md5cksum.contents, 16))) {
            xfree_wrap(md5cksum.contents, md5cksum.length);
            if (toktype == KG_TOK_SEAL_MSG) {
                xfree_wrap(token.value, token.length);
                /* Solaris Kerberos: just to be safe since token.value is an
                 * output parameter.
                 */
                token.value = NULL;
                token.length = 0;
            }
            *minor_status = code;
            KRB5_LOG(KRB5_ERR, "kg_unseal_v1() end, kg_encrypt() error"
                    "code = %d\n", code);
            return GSS_S_FAILURE;
        }

        if (signalg == 0)
            cksum.length = 8;
        else
            cksum.length = 16;
        cksum.contents = md5cksum.contents + 16 - cksum.length;

        code = memcmp(cksum.contents, ptr+14, cksum.length);
        break;

    case SGN_ALG_MD2_5:
        if (!ctx->seed_init &&
            (code = kg_make_seed(context, ctx->subkey, ctx->seed))) {
            xfree_wrap(md5cksum.contents, md5cksum.length);
            if (sealalg != 0xffff)
                xfree_wrap(plain, tmsglen);
            if (toktype == KG_TOK_SEAL_MSG) {
                xfree_wrap(token.value, token.length);
                /* Solaris Kerberos: just to be safe since token.value is an
                 * output parameter.
                 */
                token.value = NULL;
                token.length = 0;
            }
            *minor_status = code;
            return GSS_S_FAILURE;
        }

        if (! (data_ptr = (void *)
               xmalloc(sizeof(ctx->seed) + 8 +
                       (ctx->big_endian ? token.length : plainlen)))) {
            xfree_wrap(md5cksum.contents, md5cksum.length);
            if (sealalg == 0)
                xfree_wrap(plain, tmsglen);
            if (toktype == KG_TOK_SEAL_MSG) {
                xfree_wrap(token.value, token.length);
                /* Solaris Kerberos: just to be safe since token.value is an
                 * output parameter.
                 */
                token.value = NULL;
                token.length = 0;
            }
            *minor_status = ENOMEM;
            return(GSS_S_FAILURE);
        }
        (void) memcpy(data_ptr, ptr-2, 8);
        (void) memcpy(data_ptr+8, ctx->seed, sizeof(ctx->seed));
        if (ctx->big_endian)
            (void) memcpy(data_ptr+8+sizeof(ctx->seed),
                          token.value, token.length);
        else
            (void) memcpy(data_ptr+8+sizeof(ctx->seed),
                          plain, plainlen);
        plaind.length = 8 + sizeof(ctx->seed) +
            (ctx->big_endian ? token.length : plainlen);
        plaind.data = data_ptr;
        xfree_wrap(md5cksum.contents, md5cksum.length);
        code = krb5_c_make_checksum(context, md5cksum.checksum_type,
                                    ctx->seq, KG_USAGE_SIGN,
                                    &plaind, &md5cksum);
        xfree_wrap(data_ptr, 8 + sizeof(ctx->seed) +
            (ctx->big_endian ? token.length : plainlen));

        if (code) {
            if (sealalg == 0)
                xfree_wrap(plain, tmsglen);
            if (toktype == KG_TOK_SEAL_MSG) {
                xfree_wrap(token.value, token.length);
                /* Solaris Kerberos: just to be safe since token.value is an
                 * output parameter.
                 */
                token.value = NULL;
                token.length = 0;
            }
            *minor_status = code;
            return(GSS_S_FAILURE);
        }

        code = memcmp(md5cksum.contents, ptr+14, 8);
        /* Falls through to defective-token??  */
        /* FALLTHROUGH */

    default:
        *minor_status = 0;
        KRB5_LOG0(KRB5_ERR, "kg_unseal_v1() end, error SGN_ALG_MD2_5 "
                "GSS_S_DEFECTIVE_TOKEN\n");
        return(GSS_S_DEFECTIVE_TOKEN);

    case SGN_ALG_HMAC_SHA1_DES3_KD:
    case SGN_ALG_HMAC_MD5:
        /* compute the checksum of the message */

        /* 8 = bytes of token body to be checksummed according to spec */

        if (! (data_ptr = (void *)
               xmalloc(8 + (ctx->big_endian ? token.length : plainlen)))) {
            if (sealalg != 0xffff)
                xfree_wrap(plain, tmsglen);
            if (toktype == KG_TOK_SEAL_MSG) {
                xfree_wrap(token.value, token.length);
                /* Solaris Kerberos: just to be safe since token.value is an
                 * output parameter.
                 */
                token.value = NULL;
                token.length = 0;
            }
            *minor_status = ENOMEM;
            return(GSS_S_FAILURE);
        }

        (void) memcpy(data_ptr, ptr-2, 8);

        if (ctx->big_endian) {
            KRB5_LOG0(KRB5_INFO, "kg_unseal_v1() ctx->big_endian = 1\n");
            (void) memcpy(data_ptr+8, token.value, token.length);
        }
        else {
            KRB5_LOG0(KRB5_INFO, "kg_unseal_v1() ctx->big_endian = 0\n");
            (void) memcpy(data_ptr+8, plain, plainlen);
        }

        plaind.length = 8 + (ctx->big_endian ? token.length : plainlen);
        plaind.data = data_ptr;

        code = krb5_c_make_checksum(context, md5cksum.checksum_type,
                                    ctx->seq, sign_usage,
                                    &plaind, &md5cksum);

        xfree_wrap(data_ptr, 8 + (ctx->big_endian ? token.length : plainlen));

        if (code) {
            if (toktype == KG_TOK_SEAL_MSG) {
                xfree_wrap(token.value, token.length);
                /* Solaris Kerberos: just to be safe since token.value is an
                 * output parameter.
                 */
                token.value = NULL;
                token.length = 0;
            }
            *minor_status = code;
            KRB5_LOG0(KRB5_ERR, "kg_unseal_v1() end, error "
                    "SGN_ALG_HMAC_SHA1_DES3_KD GSS_S_FAILURE\n");
            return(GSS_S_FAILURE);
        }

        /* compare the computed checksum against the transmitted checksum */
        code = memcmp(md5cksum.contents, ptr+14, cksum_len);
        KRB5_LOG(KRB5_INFO, "kg_unseal_v1() memcmp %d bytes", cksum_len);
        break;
    }

    xfree_wrap(md5cksum.contents, md5cksum.length);
    if (sealalg != 0xffff)
        xfree_wrap(plain, tmsglen);

    if (code) {
        if (toktype == KG_TOK_SEAL_MSG) {
            xfree_wrap(token.value, token.length);
            /* Solaris Kerberos: just to be safe since token.value is an
             * output parameter.
             */
            token.value = NULL;
            token.length = 0;
        }
        *minor_status = 0;
        KRB5_LOG0(KRB5_ERR, "kg_unseal_v1() end, error GSS_S_BAD_SIG\n");
        return(GSS_S_BAD_SIG);
    }

    if (conf_state)
        *conf_state = (sealalg != 0xffff);

    if (qop_state)
        *qop_state = GSS_C_QOP_DEFAULT;

    if ((code = krb5_timeofday(context, &now))) {
        *minor_status = code;

        KRB5_LOG(KRB5_ERR, "kg_unseal_v1() end, krb5_timeofday()"
                "error code = %d\n", code);

        return(GSS_S_FAILURE);
    }

    if (now > ctx->endtime) {
        *minor_status = 0;

        KRB5_LOG1(KRB5_ERR, "kg_unseal_v1() end, error "
                "now %d > ctx->endtime %d\n", now, ctx->endtime);

        return(GSS_S_CONTEXT_EXPIRED);
    }

    /* do sequencing checks */
    if ((ctx->initiate && direction != 0xff) ||
        (!ctx->initiate && direction != 0)) {
        if (toktype == KG_TOK_SEAL_MSG) {
            xfree_wrap(token.value, token.length);
            /* Solaris Kerberos: just to be safe since token.value is an
             * output parameter.
             */
            token.value = NULL;
            token.length = 0;
        }
        *minor_status = (OM_uint32) G_BAD_DIRECTION;

        KRB5_LOG1(KRB5_ERR, "kg_unseal_v1() end, error GSS_S_BAD_SIG "
                "G_BAD_DIRECTION ctx->initiate = %d "
                "direction = %d\n", ctx->initiate, direction);

        return(GSS_S_BAD_SIG);
    }

    retval = g_order_check(&(ctx->seqstate), (gssint_uint64)seqnum);

    /* It got through unscathed, adjust the output message buffer. */
    if (retval == 0 && toktype == KG_TOK_SEAL_MSG)
        *message_buffer = token;

    *minor_status = 0;
    KRB5_LOG(KRB5_INFO, "kg_unseal_v1() end, retval = %d\n", retval);
    return(retval);
}

/* message_buffer is an input if SIGN, output if SEAL, and ignored if DEL_CTX
   conf_state is only valid if SEAL. */

OM_uint32
kg_unseal(minor_status, context_handle, input_token_buffer,
          message_buffer, conf_state, qop_state, toktype)
    OM_uint32 *minor_status;
    gss_ctx_id_t context_handle;
    gss_buffer_t input_token_buffer;
    gss_buffer_t message_buffer;
    int *conf_state;
    int *qop_state;
    int toktype;
{
    krb5_gss_ctx_id_rec *ctx;
    unsigned char *ptr;
    int bodysize;
    int err;
    int toktype2;

    KRB5_LOG0(KRB5_INFO, "kg_unseal() start \n");

    /* validate the context handle */
    if (! kg_validate_ctx_id(context_handle)) {
        *minor_status = (OM_uint32) G_VALIDATE_FAILED;

        KRB5_LOG0(KRB5_ERR, "kg_unseal() end, kg_validate_ctx_id() error "
                "G_VALIDATE_FAILED \n");

        return(GSS_S_NO_CONTEXT);
    }

    ctx = (krb5_gss_ctx_id_rec *) context_handle;

    if (! ctx->established) {
        *minor_status = KG_CTX_INCOMPLETE;
        KRB5_LOG0(KRB5_ERR, "kg_unseal() end, error ! ctx->established \n");
        return(GSS_S_NO_CONTEXT);
    }

    /* parse the token, leave the data in message_buffer, setting conf_state */

    /* verify the header */
    ptr = (unsigned char *) input_token_buffer->value;
    if (ctx->proto)
        switch (toktype) {
        case KG_TOK_SIGN_MSG:
            toktype2 = 0x0404;
            break;
        case KG_TOK_SEAL_MSG:
            toktype2 = 0x0504;
            break;
        case KG_TOK_DEL_CTX:
            toktype2 = 0x0405;
            break;
        default:
            toktype2 = toktype;
            break;
        }
    else
        toktype2 = toktype;
    err = g_verify_token_header(ctx->mech_used,
                                (uint32_t *)&bodysize, &ptr, toktype2,
                                input_token_buffer->length,
                                !ctx->proto);
    if (err) {
        *minor_status = err;
        return GSS_S_DEFECTIVE_TOKEN;
    }

    if (ctx->proto == 0) {
        err = kg_unseal_v1(ctx->k5_context, minor_status, ctx, ptr, bodysize,
                            message_buffer, conf_state, qop_state,
                            toktype);

    } else {
        err = gss_krb5int_unseal_token_v3(&ctx->k5_context, minor_status, ctx,
                                           ptr, bodysize, message_buffer,
                                           conf_state, qop_state, toktype);
    }

    *minor_status = err;

#ifndef _KERNEL
    if (err != 0)
        save_error_info (*minor_status, ctx->k5_context);
#endif

    KRB5_LOG(KRB5_INFO, "kg_unseal() end, err = %d", err);

    return(err);
}