enc_read.c
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- /* 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.]
- */
- #include <stdio.h>
- #include <errno.h>
- #include "cryptlib.h"
- #include "des_locl.h"
- /* This has some uglies in it but it works - even over sockets. */
- /*extern int errno;*/
- OPENSSL_IMPLEMENT_GLOBAL(int,DES_rw_mode)=DES_PCBC_MODE;
- /*
- * 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.
- */
- 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;
- 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;
- 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;
- }