/* ssl/d1_enc.c */

/* 

 * DTLS implementation written by Nagendra Modadugu

 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.  

 */

/* ====================================================================

 * Copyright (c) 1998-2005 The OpenSSL Project.  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. All advertising materials mentioning features or use of this

 *    software must display the following acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"

 *

 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to

 *    endorse or promote products derived from this software without

 *    prior written permission. For written permission, please contact

 *    openssl-core@openssl.org.

 *

 * 5. Products derived from this software may not be called "OpenSSL"

 *    nor may "OpenSSL" appear in their names without prior written

 *    permission of the OpenSSL Project.

 *

 * 6. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"

 *

 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY

 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT 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.

 * ====================================================================

 *

 * This product includes cryptographic software written by Eric Young

 * (eay@cryptsoft.com).  This product includes software written by Tim

 * Hudson (tjh@cryptsoft.com).

 *

 */

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

 * All rights reserved.

 *

 * This package is an SSL implementation written

 * by Eric Young (eay@cryptsoft.com).

 * The implementation was written so as to conform with Netscapes SSL.

 * 

 * This library is free for commercial and non-commercial use as long as

 * the following conditions are aheared to.  The following conditions

 * apply to all code found in this distribution, be it the RC4, RSA,

 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

 * included with this distribution is covered by the same copyright terms

 * except that the holder is Tim Hudson (tjh@cryptsoft.com).

 * 

 * Copyright remains Eric Young's, and as such any Copyright notices in

 * the code are not to be removed.

 * If this package is used in a product, Eric Young should be given attribution

 * as the author of the parts of the library used.

 * This can be in the form of a textual message at program startup or

 * in documentation (online or textual) provided with the package.

 * 

 * 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 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. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *    "This product includes cryptographic software written by

 *     Eric Young (eay@cryptsoft.com)"

 *    The word 'cryptographic' can be left out if the rouines from the library

 *    being used are not cryptographic related :-).

 * 4. If you include any Windows specific code (or a derivative thereof) from 

 *    the apps directory (application code) you must include an acknowledgement:

 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

 * 

 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 * 

 * The licence and distribution terms for any publically available version or

 * derivative of this code cannot be changed.  i.e. this code cannot simply be

 * copied and put under another distribution licence

 * [including the GNU Public Licence.]

 */

#include <stdio.h>

#include "ssl_locl.h"

#include <openssl/comp.h>

#include <openssl/evp.h>

#include <openssl/hmac.h>

#include <openssl/md5.h>

#include <openssl/rand.h>

int dtls1_enc(SSL *s, int send)

	{

	SSL3_RECORD *rec;

	EVP_CIPHER_CTX *ds;

	unsigned long l;

	int bs,i,ii,j,k,n=0;

	const EVP_CIPHER *enc;

	if (send)

		{

		if (s->write_hash != NULL)

			n=EVP_MD_size(s->write_hash);

		ds=s->enc_write_ctx;

		rec= &(s->s3->wrec);

		if (s->enc_write_ctx == NULL)

			enc=NULL;

		else

			{

			enc=EVP_CIPHER_CTX_cipher(s->enc_write_ctx);

			if ( rec->data != rec->input)

				/* we can't write into the input stream */

				fprintf(stderr, "%s:%d: rec->data != rec->input\n",

					__FILE__, __LINE__);

			else if ( EVP_CIPHER_block_size(ds->cipher) > 1)

				{

				if (!RAND_bytes(rec->input, EVP_CIPHER_block_size(ds->cipher)))

					return -1;

				}

			}

		}

	else

		{

		if (s->read_hash != NULL)

			n=EVP_MD_size(s->read_hash);

		ds=s->enc_read_ctx;

		rec= &(s->s3->rrec);

		if (s->enc_read_ctx == NULL)

			enc=NULL;

		else

			enc=EVP_CIPHER_CTX_cipher(s->enc_read_ctx);

		}

#ifdef KSSL_DEBUG

	printf("dtls1_enc(%d)\n", send);

#endif    /* KSSL_DEBUG */

	if ((s->session == NULL) || (ds == NULL) ||

		(enc == NULL))

		{

		memmove(rec->data,rec->input,rec->length);

		rec->input=rec->data;

		}

	else

		{

		l=rec->length;

		bs=EVP_CIPHER_block_size(ds->cipher);

		if ((bs != 1) && send)

			{

			i=bs-((int)l%bs);

			/* Add weird padding of upto 256 bytes */

			/* we need to add 'i' padding bytes of value j */

			j=i-1;

			if (s->options & SSL_OP_TLS_BLOCK_PADDING_BUG)

				{

				if (s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG)

					j++;

				}

			for (k=(int)l; k<(int)(l+i); k++)

				rec->input[k]=j;

			l+=i;

			rec->length+=i;

			}

#ifdef KSSL_DEBUG

		{

                unsigned long ui;

		printf("EVP_Cipher(ds=%p,rec->data=%p,rec->input=%p,l=%ld) ==>\n",

                        ds,rec->data,rec->input,l);

		printf("\tEVP_CIPHER_CTX: %d buf_len, %d key_len [%d %d], %d iv_len\n",

                        ds->buf_len, ds->cipher->key_len,

                        DES_KEY_SZ, DES_SCHEDULE_SZ,

                        ds->cipher->iv_len);

		printf("\t\tIV: ");

		for (i=0; i<ds->cipher->iv_len; i++) printf("%02X", ds->iv[i]);

		printf("\n");

		printf("\trec->input=");

		for (ui=0; ui<l; ui++) printf(" %02x", rec->input[ui]);

		printf("\n");

		}

#endif	/* KSSL_DEBUG */

		if (!send)

			{

			if (l == 0 || l%bs != 0)

				{

				SSLerr(SSL_F_DTLS1_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);

				ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);

				return 0;

				}

			}

		EVP_Cipher(ds,rec->data,rec->input,l);

#ifdef KSSL_DEBUG

		{

                unsigned long i;

                printf("\trec->data=");

		for (i=0; i<l; i++)

                        printf(" %02x", rec->data[i]);  printf("\n");

                }

#endif	/* KSSL_DEBUG */

		if ((bs != 1) && !send)

			{

			ii=i=rec->data[l-1]; /* padding_length */

			i++;

			if (s->options&SSL_OP_TLS_BLOCK_PADDING_BUG)

				{

				/* First packet is even in size, so check */

				if ((memcmp(s->s3->read_sequence,

					"\0\0\0\0\0\0\0\0",8) == 0) && !(ii & 1))

					s->s3->flags|=TLS1_FLAGS_TLS_PADDING_BUG;

				if (s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG)

					i--;

				}

			/* TLS 1.0 does not bound the number of padding bytes by the block size.

			 * All of them must have value 'padding_length'. */

			if (i > (int)rec->length)

				{

				/* Incorrect padding. SSLerr() and ssl3_alert are done

				 * by caller: we don't want to reveal whether this is

				 * a decryption error or a MAC verification failure

				 * (see http://www.openssl.org/~bodo/tls-cbc.txt) 

				 */

				return -1;

				}

			for (j=(int)(l-i); j<(int)l; j++)

				{

				if (rec->data[j] != ii)

					{

					/* Incorrect padding */

					return -1;

					}

				}

			rec->length-=i;

			rec->data += bs;    /* skip the implicit IV */

			rec->input += bs;

			rec->length -= bs;

			}

		}

	return(1);

	}