235 lines
8.2 KiB
C
235 lines
8.2 KiB
C
/* crypto/des/enc_read.c */
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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* All rights reserved.
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*
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* This package is an SSL implementation written
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* by Eric Young (eay@cryptsoft.com).
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* The implementation was written so as to conform with Netscapes SSL.
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*
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* This library is free for commercial and non-commercial use as long as
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* the following conditions are aheared to. The following conditions
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* apply to all code found in this distribution, be it the RC4, RSA,
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation
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* included with this distribution is covered by the same copyright terms
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* except that the holder is Tim Hudson (tjh@cryptsoft.com).
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*
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* Copyright remains Eric Young's, and as such any Copyright notices in
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* the code are not to be removed.
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* If this package is used in a product, Eric Young should be given attribution
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* as the author of the parts of the library used.
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* This can be in the form of a textual message at program startup or
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* in documentation (online or textual) provided with the package.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* "This product includes cryptographic software written by
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* Eric Young (eay@cryptsoft.com)"
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* The word 'cryptographic' can be left out if the rouines from the library
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* being used are not cryptographic related :-).
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* 4. If you include any Windows specific code (or a derivative thereof) from
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* the apps directory (application code) you must include an acknowledgement:
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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*
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The licence and distribution terms for any publically available version or
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* derivative of this code cannot be changed. i.e. this code cannot simply be
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* copied and put under another distribution licence
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* [including the GNU Public Licence.]
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*/
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#include <stdio.h>
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#include <errno.h>
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#include "cryptlib.h"
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#include "des_locl.h"
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/* This has some uglies in it but it works - even over sockets. */
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/*
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* extern int errno;
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*/
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OPENSSL_IMPLEMENT_GLOBAL(int, DES_rw_mode, DES_PCBC_MODE)
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/*-
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* WARNINGS:
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*
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* - The data format used by DES_enc_write() and DES_enc_read()
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* has a cryptographic weakness: When asked to write more
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* than MAXWRITE bytes, DES_enc_write will split the data
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* into several chunks that are all encrypted
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* using the same IV. So don't use these functions unless you
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* are sure you know what you do (in which case you might
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* not want to use them anyway).
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*
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* - This code cannot handle non-blocking sockets.
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*
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* - This function uses an internal state and thus cannot be
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* used on multiple files.
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*/
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int DES_enc_read(int fd, void *buf, int len, DES_key_schedule *sched,
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DES_cblock *iv)
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{
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#if defined(OPENSSL_NO_POSIX_IO)
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return (0);
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#else
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/* data to be unencrypted */
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int net_num = 0;
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static unsigned char *net = NULL;
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/*
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* extra unencrypted data for when a block of 100 comes in but is
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* des_read one byte at a time.
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*/
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static unsigned char *unnet = NULL;
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static int unnet_start = 0;
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static int unnet_left = 0;
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static unsigned char *tmpbuf = NULL;
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int i;
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long num = 0, rnum;
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unsigned char *p;
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if (tmpbuf == NULL) {
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tmpbuf = OPENSSL_malloc(BSIZE);
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if (tmpbuf == NULL)
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return (-1);
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}
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if (net == NULL) {
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net = OPENSSL_malloc(BSIZE);
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if (net == NULL)
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return (-1);
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}
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if (unnet == NULL) {
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unnet = OPENSSL_malloc(BSIZE);
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if (unnet == NULL)
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return (-1);
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}
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/* left over data from last decrypt */
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if (unnet_left != 0) {
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if (unnet_left < len) {
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/*
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* we still still need more data but will return with the number
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* of bytes we have - should always check the return value
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*/
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memcpy(buf, &(unnet[unnet_start]), unnet_left);
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/*
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* eay 26/08/92 I had the next 2 lines reversed :-(
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*/
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i = unnet_left;
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unnet_start = unnet_left = 0;
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} else {
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memcpy(buf, &(unnet[unnet_start]), len);
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unnet_start += len;
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unnet_left -= len;
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i = len;
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}
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return (i);
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}
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/* We need to get more data. */
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if (len > MAXWRITE)
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len = MAXWRITE;
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/* first - get the length */
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while (net_num < HDRSIZE) {
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# ifndef OPENSSL_SYS_WIN32
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i = read(fd, (void *)&(net[net_num]), HDRSIZE - net_num);
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# else
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i = _read(fd, (void *)&(net[net_num]), HDRSIZE - net_num);
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# endif
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# ifdef EINTR
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if ((i == -1) && (errno == EINTR))
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continue;
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# endif
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if (i <= 0)
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return (0);
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net_num += i;
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}
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/* we now have at net_num bytes in net */
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p = net;
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/* num=0; */
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n2l(p, num);
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/*
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* num should be rounded up to the next group of eight we make sure that
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* we have read a multiple of 8 bytes from the net.
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*/
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if ((num > MAXWRITE) || (num < 0)) /* error */
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return (-1);
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rnum = (num < 8) ? 8 : ((num + 7) / 8 * 8);
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net_num = 0;
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while (net_num < rnum) {
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# ifndef OPENSSL_SYS_WIN32
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i = read(fd, (void *)&(net[net_num]), rnum - net_num);
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# else
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i = _read(fd, (void *)&(net[net_num]), rnum - net_num);
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# endif
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# ifdef EINTR
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if ((i == -1) && (errno == EINTR))
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continue;
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# endif
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if (i <= 0)
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return (0);
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net_num += i;
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}
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/* Check if there will be data left over. */
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if (len < num) {
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if (DES_rw_mode & DES_PCBC_MODE)
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DES_pcbc_encrypt(net, unnet, num, sched, iv, DES_DECRYPT);
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else
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DES_cbc_encrypt(net, unnet, num, sched, iv, DES_DECRYPT);
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memcpy(buf, unnet, len);
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unnet_start = len;
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unnet_left = num - len;
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/*
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* The following line is done because we return num as the number of
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* bytes read.
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*/
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num = len;
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} else {
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/*-
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* >output is a multiple of 8 byes, if len < rnum
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* >we must be careful. The user must be aware that this
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* >routine will write more bytes than he asked for.
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* >The length of the buffer must be correct.
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* FIXED - Should be ok now 18-9-90 - eay */
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if (len < rnum) {
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if (DES_rw_mode & DES_PCBC_MODE)
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DES_pcbc_encrypt(net, tmpbuf, num, sched, iv, DES_DECRYPT);
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else
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DES_cbc_encrypt(net, tmpbuf, num, sched, iv, DES_DECRYPT);
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/*
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* eay 26/08/92 fix a bug that returned more bytes than you asked
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* for (returned len bytes :-(
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*/
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memcpy(buf, tmpbuf, num);
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} else {
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if (DES_rw_mode & DES_PCBC_MODE)
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DES_pcbc_encrypt(net, buf, num, sched, iv, DES_DECRYPT);
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else
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DES_cbc_encrypt(net, buf, num, sched, iv, DES_DECRYPT);
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}
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}
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return num;
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#endif /* OPENSSL_NO_POSIX_IO */
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}
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