/*
 * lib/krb5/krb/ser_eblk.c
 *
 * Copyright 1995 by the Massachusetts Institute of Technology.
 * 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 M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 *
 */

/*
 * ser_eblk.c - Serialize a krb5_encblock structure.
 */
#include "k5-int.h"

/*
 * Routines to deal with externalizing the krb5_encrypt_block:
 *	krb5_encrypt_block_size();
 *	krb5_encrypt_block_externalize();
 *	krb5_encrypt_block_internalize();
 */
static krb5_error_code krb5_encrypt_block_size
	KRB5_PROTOTYPE((krb5_context, krb5_pointer, size_t *));
static krb5_error_code krb5_encrypt_block_externalize
	KRB5_PROTOTYPE((krb5_context, krb5_pointer, krb5_octet **, size_t *));
static krb5_error_code krb5_encrypt_block_internalize
	KRB5_PROTOTYPE((krb5_context,krb5_pointer *, krb5_octet **, size_t *));

/* Local data */
static const krb5_ser_entry krb5_encrypt_block_ser_entry = {
    KV5M_ENCRYPT_BLOCK,			/* Type			*/
    krb5_encrypt_block_size,		/* Sizer routine	*/
    krb5_encrypt_block_externalize,	/* Externalize routine	*/
    krb5_encrypt_block_internalize	/* Internalize routine	*/
};

/*
 * krb5_encrypt_block_size()	- Determine the size required to externalize
 *				  the krb5_encrypt_block.
 */
static krb5_error_code
krb5_encrypt_block_size(kcontext, arg, sizep)
    krb5_context	kcontext;
    krb5_pointer	arg;
    size_t		*sizep;
{
    krb5_error_code	kret;
    krb5_encrypt_block	*encrypt_block;
    size_t		required;

    /*
     * NOTE: This ASSuMES that enctype are sufficient to recreate
     * the _krb5_cryptosystem_entry.  If this is not true, then something else
     * had better be encoded here.
     * 
     * krb5_encrypt_block base requirements:
     *	krb5_int32			for KV5M_ENCRYPT_BLOCK
     *	krb5_int32			for enctype
     *	krb5_int32			for private length
     *	encrypt_block->priv_size	for private contents
     *	krb5_int32			for KV5M_ENCRYPT_BLOCK
     */
    kret = EINVAL;
    if ((encrypt_block = (krb5_encrypt_block *) arg)) {
	required = (sizeof(krb5_int32) +
		    sizeof(krb5_int32) +
		    sizeof(krb5_int32) +
		    sizeof(krb5_int32) +
		    sizeof(krb5_int32) +
		    (size_t) encrypt_block->priv_size);
	if (encrypt_block->key)
	    kret = krb5_size_opaque(kcontext,
				    KV5M_KEYBLOCK,
				    (krb5_pointer) encrypt_block->key,
				    &required);
	else
	    kret = 0;
	if (!kret)
	    *sizep += required;
    }
    return(kret);
}

/*
 * krb5_encrypt_block_externalize()	- Externalize the krb5_encrypt_block.
 */
static krb5_error_code
krb5_encrypt_block_externalize(kcontext, arg, buffer, lenremain)
    krb5_context	kcontext;
    krb5_pointer	arg;
    krb5_octet		**buffer;
    size_t		*lenremain;
{
    krb5_error_code	kret;
    krb5_encrypt_block	*encrypt_block;
    size_t		required;
    krb5_octet		*bp;
    size_t		remain;

    required = 0;
    bp = *buffer;
    remain = *lenremain;
    kret = EINVAL;
    if ((encrypt_block = (krb5_encrypt_block *) arg)) {
	kret = ENOMEM;
	if (!krb5_encrypt_block_size(kcontext, arg, &required) &&
	    (required <= remain)) {
	    /* Our identifier */
	    (void) krb5_ser_pack_int32(KV5M_ENCRYPT_BLOCK, &bp, &remain);
		
	    /* Our enctype */
	    (void) krb5_ser_pack_int32((krb5_int32) encrypt_block->
				       crypto_entry->proto_enctype,
				       &bp, &remain);

	    /* Our length */
	    (void) krb5_ser_pack_int32((krb5_int32) encrypt_block->priv_size,
				       &bp, &remain);

	    /* Our private data */
	    (void) krb5_ser_pack_bytes(encrypt_block->priv,
				       (size_t) encrypt_block->priv_size,
				       &bp, &remain);

	    /* Finally, the key data */
	    if (encrypt_block->key)
		kret = krb5_externalize_opaque(kcontext,
					       KV5M_KEYBLOCK,
					       (krb5_pointer)
					       encrypt_block->key,
					       &bp,
					       &remain);
	    else
		kret = 0;

	    if (!kret) {
		/* Write trailer */
		(void) krb5_ser_pack_int32(KV5M_ENCRYPT_BLOCK, &bp, &remain);
		*buffer = bp;
		*lenremain = remain;
	    }
	}
    }
    return(kret);
}

/*
 * krb5_encrypt_block_internalize()	- Internalize the krb5_encrypt_block.
 */
static krb5_error_code
krb5_encrypt_block_internalize(kcontext, argp, buffer, lenremain)
    krb5_context	kcontext;
    krb5_pointer	*argp;
    krb5_octet		**buffer;
    size_t		*lenremain;
{
    krb5_error_code	kret;
    krb5_encrypt_block	*encrypt_block;
    krb5_int32		ibuf;
    krb5_enctype	ktype;
    krb5_octet		*bp;
    size_t		remain;

    bp = *buffer;
    remain = *lenremain;
    kret = EINVAL;
    /* Read our magic number */
    if (krb5_ser_unpack_int32(&ibuf, &bp, &remain))
	ibuf = 0;
    if (ibuf == KV5M_ENCRYPT_BLOCK) {
	kret = ENOMEM;

	/* Get an encrypt_block */
	if ((remain >= (3*sizeof(krb5_int32))) &&
	    (encrypt_block = (krb5_encrypt_block *)
	     malloc(sizeof(krb5_encrypt_block)))) {
	    memset(encrypt_block, 0, sizeof(krb5_encrypt_block));

	    /* Get the enctype */
	    (void) krb5_ser_unpack_int32(&ibuf, &bp, &remain);
	    ktype = (krb5_enctype) ibuf;

	    /* Use the ktype to determine the crypto_system entry. */
	    krb5_use_enctype(kcontext, encrypt_block, ktype);

	    /* Get the length */
	    (void) krb5_ser_unpack_int32(&ibuf, &bp, &remain);
	    encrypt_block->priv_size = (int) ibuf;

	    /* Get the string */
	    if (!ibuf ||
		((encrypt_block->priv = (void *) malloc((size_t) (ibuf))) &&
		 !(kret = krb5_ser_unpack_bytes((krb5_octet *)
						encrypt_block->priv,
						(size_t)
						encrypt_block->priv_size,
						&bp, &remain)))) {
		kret = krb5_internalize_opaque(kcontext,
					       KV5M_KEYBLOCK,
					       (krb5_pointer *)
					       &encrypt_block->key,
					       &bp,
					       &remain);
		if (kret == EINVAL)
		    kret = 0;

		if (!kret) {
		    kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain);
		    if (!kret && (ibuf == KV5M_ENCRYPT_BLOCK)) {
			*buffer = bp;
			*lenremain = remain;
			encrypt_block->magic = KV5M_ENCRYPT_BLOCK;
			*argp = (krb5_pointer) encrypt_block;
		    }
		    else
			kret = EINVAL;
		}
	    }
	    if (kret) {
		if (encrypt_block->priv)
		    free(encrypt_block->priv);
		free(encrypt_block);
	    }
	}
    }
    return(kret);
}

/*
 * Register the encblock serializer.
 */
krb5_error_code
krb5_ser_encrypt_block_init(kcontext)
    krb5_context	kcontext;
{
    return(krb5_register_serializer(kcontext, &krb5_encrypt_block_ser_entry));
}
