sl@0: /* ssl/d1_enc.c */
sl@0: /* 
sl@0:  * DTLS implementation written by Nagendra Modadugu
sl@0:  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.  
sl@0:  */
sl@0: /* ====================================================================
sl@0:  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
sl@0:  *
sl@0:  * Redistribution and use in source and binary forms, with or without
sl@0:  * modification, are permitted provided that the following conditions
sl@0:  * are met:
sl@0:  *
sl@0:  * 1. Redistributions of source code must retain the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer. 
sl@0:  *
sl@0:  * 2. Redistributions in binary form must reproduce the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer in
sl@0:  *    the documentation and/or other materials provided with the
sl@0:  *    distribution.
sl@0:  *
sl@0:  * 3. All advertising materials mentioning features or use of this
sl@0:  *    software must display the following acknowledgment:
sl@0:  *    "This product includes software developed by the OpenSSL Project
sl@0:  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
sl@0:  *
sl@0:  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
sl@0:  *    endorse or promote products derived from this software without
sl@0:  *    prior written permission. For written permission, please contact
sl@0:  *    openssl-core@openssl.org.
sl@0:  *
sl@0:  * 5. Products derived from this software may not be called "OpenSSL"
sl@0:  *    nor may "OpenSSL" appear in their names without prior written
sl@0:  *    permission of the OpenSSL Project.
sl@0:  *
sl@0:  * 6. Redistributions of any form whatsoever must retain the following
sl@0:  *    acknowledgment:
sl@0:  *    "This product includes software developed by the OpenSSL Project
sl@0:  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
sl@0:  *
sl@0:  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
sl@0:  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
sl@0:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
sl@0:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
sl@0:  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
sl@0:  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
sl@0:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
sl@0:  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
sl@0:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
sl@0:  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
sl@0:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
sl@0:  * OF THE POSSIBILITY OF SUCH DAMAGE.
sl@0:  * ====================================================================
sl@0:  *
sl@0:  * This product includes cryptographic software written by Eric Young
sl@0:  * (eay@cryptsoft.com).  This product includes software written by Tim
sl@0:  * Hudson (tjh@cryptsoft.com).
sl@0:  *
sl@0:  */
sl@0: /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
sl@0:  * All rights reserved.
sl@0:  *
sl@0:  * This package is an SSL implementation written
sl@0:  * by Eric Young (eay@cryptsoft.com).
sl@0:  * The implementation was written so as to conform with Netscapes SSL.
sl@0:  * 
sl@0:  * This library is free for commercial and non-commercial use as long as
sl@0:  * the following conditions are aheared to.  The following conditions
sl@0:  * apply to all code found in this distribution, be it the RC4, RSA,
sl@0:  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
sl@0:  * included with this distribution is covered by the same copyright terms
sl@0:  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
sl@0:  * 
sl@0:  * Copyright remains Eric Young's, and as such any Copyright notices in
sl@0:  * the code are not to be removed.
sl@0:  * If this package is used in a product, Eric Young should be given attribution
sl@0:  * as the author of the parts of the library used.
sl@0:  * This can be in the form of a textual message at program startup or
sl@0:  * in documentation (online or textual) provided with the package.
sl@0:  * 
sl@0:  * Redistribution and use in source and binary forms, with or without
sl@0:  * modification, are permitted provided that the following conditions
sl@0:  * are met:
sl@0:  * 1. Redistributions of source code must retain the copyright
sl@0:  *    notice, this list of conditions and the following disclaimer.
sl@0:  * 2. Redistributions in binary form must reproduce the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer in the
sl@0:  *    documentation and/or other materials provided with the distribution.
sl@0:  * 3. All advertising materials mentioning features or use of this software
sl@0:  *    must display the following acknowledgement:
sl@0:  *    "This product includes cryptographic software written by
sl@0:  *     Eric Young (eay@cryptsoft.com)"
sl@0:  *    The word 'cryptographic' can be left out if the rouines from the library
sl@0:  *    being used are not cryptographic related :-).
sl@0:  * 4. If you include any Windows specific code (or a derivative thereof) from 
sl@0:  *    the apps directory (application code) you must include an acknowledgement:
sl@0:  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
sl@0:  * 
sl@0:  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
sl@0:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
sl@0:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
sl@0:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
sl@0:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
sl@0:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
sl@0:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
sl@0:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
sl@0:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
sl@0:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
sl@0:  * SUCH DAMAGE.
sl@0:  * 
sl@0:  * The licence and distribution terms for any publically available version or
sl@0:  * derivative of this code cannot be changed.  i.e. this code cannot simply be
sl@0:  * copied and put under another distribution licence
sl@0:  * [including the GNU Public Licence.]
sl@0:  */
sl@0: 
sl@0: #include <stdio.h>
sl@0: #include "ssl_locl.h"
sl@0: #include <openssl/comp.h>
sl@0: #include <openssl/evp.h>
sl@0: #include <openssl/hmac.h>
sl@0: #include <openssl/md5.h>
sl@0: #include <openssl/rand.h>
sl@0: 
sl@0: 
sl@0: int dtls1_enc(SSL *s, int send)
sl@0: 	{
sl@0: 	SSL3_RECORD *rec;
sl@0: 	EVP_CIPHER_CTX *ds;
sl@0: 	unsigned long l;
sl@0: 	int bs,i,ii,j,k,n=0;
sl@0: 	const EVP_CIPHER *enc;
sl@0: 
sl@0: 	if (send)
sl@0: 		{
sl@0: 		if (s->write_hash != NULL)
sl@0: 			n=EVP_MD_size(s->write_hash);
sl@0: 		ds=s->enc_write_ctx;
sl@0: 		rec= &(s->s3->wrec);
sl@0: 		if (s->enc_write_ctx == NULL)
sl@0: 			enc=NULL;
sl@0: 		else
sl@0: 			{
sl@0: 			enc=EVP_CIPHER_CTX_cipher(s->enc_write_ctx);
sl@0: 			if ( rec->data != rec->input)
sl@0: 				/* we can't write into the input stream */
sl@0: 				fprintf(stderr, "%s:%d: rec->data != rec->input\n",
sl@0: 					__FILE__, __LINE__);
sl@0: 			else if ( EVP_CIPHER_block_size(ds->cipher) > 1)
sl@0: 				{
sl@0: 				if (!RAND_bytes(rec->input, EVP_CIPHER_block_size(ds->cipher)))
sl@0: 					return -1;
sl@0: 				}
sl@0: 			}
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		if (s->read_hash != NULL)
sl@0: 			n=EVP_MD_size(s->read_hash);
sl@0: 		ds=s->enc_read_ctx;
sl@0: 		rec= &(s->s3->rrec);
sl@0: 		if (s->enc_read_ctx == NULL)
sl@0: 			enc=NULL;
sl@0: 		else
sl@0: 			enc=EVP_CIPHER_CTX_cipher(s->enc_read_ctx);
sl@0: 		}
sl@0: 
sl@0: #ifdef KSSL_DEBUG
sl@0: 	printf("dtls1_enc(%d)\n", send);
sl@0: #endif    /* KSSL_DEBUG */
sl@0: 
sl@0: 	if ((s->session == NULL) || (ds == NULL) ||
sl@0: 		(enc == NULL))
sl@0: 		{
sl@0: 		memmove(rec->data,rec->input,rec->length);
sl@0: 		rec->input=rec->data;
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		l=rec->length;
sl@0: 		bs=EVP_CIPHER_block_size(ds->cipher);
sl@0: 
sl@0: 		if ((bs != 1) && send)
sl@0: 			{
sl@0: 			i=bs-((int)l%bs);
sl@0: 
sl@0: 			/* Add weird padding of upto 256 bytes */
sl@0: 
sl@0: 			/* we need to add 'i' padding bytes of value j */
sl@0: 			j=i-1;
sl@0: 			if (s->options & SSL_OP_TLS_BLOCK_PADDING_BUG)
sl@0: 				{
sl@0: 				if (s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG)
sl@0: 					j++;
sl@0: 				}
sl@0: 			for (k=(int)l; k<(int)(l+i); k++)
sl@0: 				rec->input[k]=j;
sl@0: 			l+=i;
sl@0: 			rec->length+=i;
sl@0: 			}
sl@0: 
sl@0: #ifdef KSSL_DEBUG
sl@0: 		{
sl@0:                 unsigned long ui;
sl@0: 		printf("EVP_Cipher(ds=%p,rec->data=%p,rec->input=%p,l=%ld) ==>\n",
sl@0:                         ds,rec->data,rec->input,l);
sl@0: 		printf("\tEVP_CIPHER_CTX: %d buf_len, %d key_len [%d %d], %d iv_len\n",
sl@0:                         ds->buf_len, ds->cipher->key_len,
sl@0:                         DES_KEY_SZ, DES_SCHEDULE_SZ,
sl@0:                         ds->cipher->iv_len);
sl@0: 		printf("\t\tIV: ");
sl@0: 		for (i=0; i<ds->cipher->iv_len; i++) printf("%02X", ds->iv[i]);
sl@0: 		printf("\n");
sl@0: 		printf("\trec->input=");
sl@0: 		for (ui=0; ui<l; ui++) printf(" %02x", rec->input[ui]);
sl@0: 		printf("\n");
sl@0: 		}
sl@0: #endif	/* KSSL_DEBUG */
sl@0: 
sl@0: 		if (!send)
sl@0: 			{
sl@0: 			if (l == 0 || l%bs != 0)
sl@0: 				{
sl@0: 				SSLerr(SSL_F_DTLS1_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
sl@0: 				ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);
sl@0: 				return 0;
sl@0: 				}
sl@0: 			}
sl@0: 		
sl@0: 		EVP_Cipher(ds,rec->data,rec->input,l);
sl@0: 
sl@0: #ifdef KSSL_DEBUG
sl@0: 		{
sl@0:                 unsigned long i;
sl@0:                 printf("\trec->data=");
sl@0: 		for (i=0; i<l; i++)
sl@0:                         printf(" %02x", rec->data[i]);  printf("\n");
sl@0:                 }
sl@0: #endif	/* KSSL_DEBUG */
sl@0: 
sl@0: 		if ((bs != 1) && !send)
sl@0: 			{
sl@0: 			ii=i=rec->data[l-1]; /* padding_length */
sl@0: 			i++;
sl@0: 			if (s->options&SSL_OP_TLS_BLOCK_PADDING_BUG)
sl@0: 				{
sl@0: 				/* First packet is even in size, so check */
sl@0: 				if ((memcmp(s->s3->read_sequence,
sl@0: 					"\0\0\0\0\0\0\0\0",8) == 0) && !(ii & 1))
sl@0: 					s->s3->flags|=TLS1_FLAGS_TLS_PADDING_BUG;
sl@0: 				if (s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG)
sl@0: 					i--;
sl@0: 				}
sl@0: 			/* TLS 1.0 does not bound the number of padding bytes by the block size.
sl@0: 			 * All of them must have value 'padding_length'. */
sl@0: 			if (i > (int)rec->length)
sl@0: 				{
sl@0: 				/* Incorrect padding. SSLerr() and ssl3_alert are done
sl@0: 				 * by caller: we don't want to reveal whether this is
sl@0: 				 * a decryption error or a MAC verification failure
sl@0: 				 * (see http://www.openssl.org/~bodo/tls-cbc.txt) 
sl@0: 				 */
sl@0: 				return -1;
sl@0: 				}
sl@0: 			for (j=(int)(l-i); j<(int)l; j++)
sl@0: 				{
sl@0: 				if (rec->data[j] != ii)
sl@0: 					{
sl@0: 					/* Incorrect padding */
sl@0: 					return -1;
sl@0: 					}
sl@0: 				}
sl@0: 			rec->length-=i;
sl@0: 
sl@0: 			rec->data += bs;    /* skip the implicit IV */
sl@0: 			rec->input += bs;
sl@0: 			rec->length -= bs;
sl@0: 			}
sl@0: 		}
sl@0: 	return(1);
sl@0: 	}
sl@0: