/* crypto/des/enc_read.c */

/* 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.]

 */

/*

 © Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.

 */

#include <stdio.h>

#include <errno.h>

#include "cryptlib.h"

#include "des_locl.h"

#if (defined(SYMBIAN) && (defined(__WINSCW__) || defined(__WINS__)))

#include "libcrypto_wsd_macros.h"

#include "libcrypto_wsd.h"

#endif

/* This has some uglies in it but it works - even over sockets. */

/*extern int errno;*/

#ifndef EMULATOR

OPENSSL_IMPLEMENT_GLOBAL(int,DES_rw_mode)=DES_PCBC_MODE;

#else

#define DES_rw_mode libcrypto_ImpurePtr()->_shadow_DES_rw_mode

#endif

/*

 * WARNINGS:

 *

 *  -  The data format used by DES_enc_write() and DES_enc_read()

 *     has a cryptographic weakness: When asked to write more

 *     than MAXWRITE bytes, DES_enc_write will split the data

 *     into several chunks that are all encrypted

 *     using the same IV.  So don't use these functions unless you

 *     are sure you know what you do (in which case you might

 *     not want to use them anyway).

 *

 *  -  This code cannot handle non-blocking sockets.

 *

 *  -  This function uses an internal state and thus cannot be

 *     used on multiple files.

 */

#ifdef EMULATOR

  GET_STATIC_VAR_FROM_TLS(net,enc_read,unsigned char *)

  #define net (*GET_WSD_VAR_NAME(net,enc_read, s)())

  GET_STATIC_VAR_FROM_TLS(unnet,enc_read,unsigned char *)

  #define unnet (*GET_WSD_VAR_NAME(unnet,enc_read, s)())

  GET_STATIC_VAR_FROM_TLS(unnet_start,enc_read,int)

  #define unnet_start (*GET_WSD_VAR_NAME(unnet_start,enc_read, s)())

  GET_STATIC_VAR_FROM_TLS(unnet_left,enc_read,int)

  #define unnet_left (*GET_WSD_VAR_NAME(unnet_left,enc_read, s)())

  GET_STATIC_VAR_FROM_TLS(tmpbuf,enc_read,unsigned char *)

  #define tmpbuf (*GET_WSD_VAR_NAME(tmpbuf,enc_read, s)())

#endif

EXPORT_C int DES_enc_read(int fd, void *buf, int len, DES_key_schedule *sched,

		 DES_cblock *iv)

	{

	/* data to be unencrypted */

	int net_num=0;

#ifndef EMULATOR	

	static unsigned char *net=NULL;

	/* extra unencrypted data 

	 * for when a block of 100 comes in but is des_read one byte at

	 * a time. */

	static unsigned char *unnet=NULL;

	static int unnet_start=0;

	static int unnet_left=0;

	static unsigned char *tmpbuf=NULL;

#endif		

	int i;

	long num=0,rnum;

	unsigned char *p;

	if (tmpbuf == NULL)

		{

		tmpbuf=OPENSSL_malloc(BSIZE);

		if (tmpbuf == NULL) return(-1);

		}

	if (net == NULL)

		{

		net=OPENSSL_malloc(BSIZE);

		if (net == NULL) return(-1);

		}

	if (unnet == NULL)

		{

		unnet=OPENSSL_malloc(BSIZE);

		if (unnet == NULL) return(-1);

		}

	/* left over data from last decrypt */

	if (unnet_left != 0)

		{

		if (unnet_left < len)

			{

			/* we still still need more data but will return

			 * with the number of bytes we have - should always

			 * check the return value */

			memcpy(buf,&(unnet[unnet_start]),

			       unnet_left);

			/* eay 26/08/92 I had the next 2 lines

			 * reversed :-( */

			i=unnet_left;

			unnet_start=unnet_left=0;

			}

		else

			{

			memcpy(buf,&(unnet[unnet_start]),len);

			unnet_start+=len;

			unnet_left-=len;

			i=len;

			}

		return(i);

		}

	/* We need to get more data. */

	if (len > MAXWRITE) len=MAXWRITE;

	/* first - get the length */

	while (net_num < HDRSIZE) 

		{

		i=read(fd,(void *)&(net[net_num]),HDRSIZE-net_num);

#ifdef EINTR

		if ((i == -1) && (errno == EINTR)) continue;

#endif

		if (i <= 0) return(0);

		net_num+=i;

		}

	/* we now have at net_num bytes in net */

	p=net;

	/* num=0;  */

	n2l(p,num);

	/* num should be rounded up to the next group of eight

	 * we make sure that we have read a multiple of 8 bytes from the net.

	 */

	if ((num > MAXWRITE) || (num < 0)) /* error */

		return(-1);

	rnum=(num < 8)?8:((num+7)/8*8);

	net_num=0;

	while (net_num < rnum)

		{

		i=read(fd,(void *)&(net[net_num]),rnum-net_num);

#ifdef EINTR

		if ((i == -1) && (errno == EINTR)) continue;

#endif

		if (i <= 0) return(0);

		net_num+=i;

		}

	/* Check if there will be data left over. */

	if (len < num)

		{

		if (DES_rw_mode & DES_PCBC_MODE)

			DES_pcbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);

		else

			DES_cbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);

		memcpy(buf,unnet,len);

		unnet_start=len;

		unnet_left=num-len;

		/* The following line is done because we return num

		 * as the number of bytes read. */

		num=len;

		}

	else

		{

		/* >output is a multiple of 8 byes, if len < rnum

		 * >we must be careful.  The user must be aware that this

		 * >routine will write more bytes than he asked for.

		 * >The length of the buffer must be correct.

		 * FIXED - Should be ok now 18-9-90 - eay */

		if (len < rnum)

			{

			if (DES_rw_mode & DES_PCBC_MODE)

				DES_pcbc_encrypt(net,tmpbuf,num,sched,iv,

						 DES_DECRYPT);

			else

				DES_cbc_encrypt(net,tmpbuf,num,sched,iv,

						DES_DECRYPT);

			/* eay 26/08/92 fix a bug that returned more

			 * bytes than you asked for (returned len bytes :-( */

			memcpy(buf,tmpbuf,num);

			}

		else

			{

			if (DES_rw_mode & DES_PCBC_MODE)

				DES_pcbc_encrypt(net,buf,num,sched,iv,

						 DES_DECRYPT);

			else

				DES_cbc_encrypt(net,buf,num,sched,iv,

						DES_DECRYPT);

			}

		}

	return num;

	}