/* 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;

 	}