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enc_writ.c

/* crypto/des/enc_writ.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 <errno.h>
#include <time.h>
#include <stdio.h>
#include "cryptlib.h"
#include "des_locl.h"
#include <openssl/rand.h>

/*
 * 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.
 */

int DES_enc_write(int fd, const void *_buf, int len,
              DES_key_schedule *sched, DES_cblock *iv)
      {
#if defined(OPENSSL_NO_POSIX_IO)
      return (-1);
#else
#ifdef _LIBC
      extern unsigned long time();
      extern int write();
#endif
      const unsigned char *buf=_buf;
      long rnum;
      int i,j,k,outnum;
      static unsigned char *outbuf=NULL;
      unsigned char shortbuf[8];
      unsigned char *p;
      const unsigned char *cp;
      static int start=1;

      if (outbuf == NULL)
            {
            outbuf=OPENSSL_malloc(BSIZE+HDRSIZE);
            if (outbuf == NULL) return(-1);
            }
      /* If we are sending less than 8 bytes, the same char will look
       * the same if we don't pad it out with random bytes */
      if (start)
            {
            start=0;
            }

      /* lets recurse if we want to send the data in small chunks */
      if (len > MAXWRITE)
            {
            j=0;
            for (i=0; i<len; i+=k)
                  {
                  k=DES_enc_write(fd,&(buf[i]),
                        ((len-i) > MAXWRITE)?MAXWRITE:(len-i),sched,iv);
                  if (k < 0)
                        return(k);
                  else
                        j+=k;
                  }
            return(j);
            }

      /* write length first */
      p=outbuf;
      l2n(len,p);

      /* pad short strings */
      if (len < 8)
            {
            cp=shortbuf;
            memcpy(shortbuf,buf,len);
            RAND_pseudo_bytes(shortbuf+len, 8-len);
            rnum=8;
            }
      else
            {
            cp=buf;
            rnum=((len+7)/8*8); /* round up to nearest eight */
            }

      if (DES_rw_mode & DES_PCBC_MODE)
            DES_pcbc_encrypt(cp,&(outbuf[HDRSIZE]),(len<8)?8:len,sched,iv,
                         DES_ENCRYPT); 
      else
            DES_cbc_encrypt(cp,&(outbuf[HDRSIZE]),(len<8)?8:len,sched,iv,
                        DES_ENCRYPT); 

      /* output */
      outnum=rnum+HDRSIZE;

      for (j=0; j<outnum; j+=i)
            {
            /* eay 26/08/92 I was not doing writing from where we
             * got up to. */
#ifndef _WIN32
            i=write(fd,(void *)&(outbuf[j]),outnum-j);
#else
            i=_write(fd,(void *)&(outbuf[j]),outnum-j);
#endif
            if (i == -1)
                  {
#ifdef EINTR
                  if (errno == EINTR)
                        i=0;
                  else
#endif
                          /* This is really a bad error - very bad
                         * It will stuff-up both ends. */
                        return(-1);
                  }
            }

      return(len);
#endif /* OPENSSL_NO_POSIX_IO */
      }

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