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/* crypto/des/enc_read.c */
/* Copyright (C) 1995-1997 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 <errno.h>
#include "des_locl.h"
/* This has some uglies in it but it works - even over sockets. */
/*extern int errno;*/
int des_rw_mode=DES_PCBC_MODE;
int des_enc_read(fd, buf, len, sched, iv)
int fd;
char *buf;
int len;
des_key_schedule sched;
des_cblock (*iv);
{
/* data to be unencrypted */
int net_num=0;
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 char *unnet=NULL;
static int unnet_start=0;
static int unnet_left=0;
static char *tmpbuf=NULL;
int i;
long num=0,rnum;
unsigned char *p;
if (tmpbuf == NULL)
{
tmpbuf=(char *)malloc(BSIZE);
if (tmpbuf == NULL) return(-1);
}
if (net == NULL)
{
net=(unsigned char *)malloc(BSIZE);
if (net == NULL) return(-1);
}
if (unnet == NULL)
{
unnet=(char *)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]),
(unsigned int)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]),(unsigned int)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,&(net[net_num]),(unsigned int)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,&(net[net_num]),(unsigned int)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((des_cblock *)net,(des_cblock *)unnet,
num,sched,iv,DES_DECRYPT);
else
des_cbc_encrypt((des_cblock *)net,(des_cblock *)unnet,
num,sched,iv,DES_DECRYPT);
memcpy(buf,unnet,(unsigned int)len);
unnet_start=len;
unnet_left=(int)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((des_cblock *)net,
(des_cblock *)tmpbuf,
num,sched,iv,DES_DECRYPT);
else
des_cbc_encrypt((des_cblock *)net,
(des_cblock *)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,(unsigned int)num);
}
else
{
if (des_rw_mode & DES_PCBC_MODE)
des_pcbc_encrypt((des_cblock *)net,
(des_cblock *)buf,num,sched,iv,
DES_DECRYPT);
else
des_cbc_encrypt((des_cblock *)net,
(des_cblock *)buf,num,sched,iv,
DES_DECRYPT);
}
}
return((int)num);
}
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