crypt.c

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/***************************************************************************
                          crypt.c  -  description
                             -------------------
    begin                : Mon Jul  7 14:16:22 EEST 2003
    copyright            : (C) 2003 by Petri Turunen
    email                : [e-mail]
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#include <stdio.h>
#include <string.h>

#include <evp.h> //openssl
#include <err.h> //openssl

#include <stdarg.h> //va_end


#include <fcntl.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>


#include "linux_mond.h"


extern unsigned char CRYPTIV[];

 /* T鋒鋘 encrypt aliohjelman kutsu */
// outlen = encrypt_stuff(key, &outbuf, "%s", intext);
// outlen = decrypt_stuff(key, &outbuf2, outbuf, outlen); 
// free(outbuf);
// free(outbuf2);


int encrypt_stuff(char *key, unsigned char **outbuf, char *fmt, ...)
{
 //unsigned char outbuf[1024];
 int outlen, tmplen;
 unsigned long error;

 char message[1024];
 va_list ap;

 EVP_CIPHER_CTX ctx;
 EVP_CIPHER_CTX_init(&ctx);

 ERR_load_crypto_strings();

 va_start (ap, fmt);

 vsnprintf(message, 1024, fmt, ap);
 EVP_EncryptInit(&ctx, EVP_bf_cfb (), key, CRYPTIV);
 EVP_CIPHER_CTX_set_key_length(&ctx,strlen(key));

 outlen = strlen(message);

 message[outlen]='\0';

 if((*outbuf=(unsigned char*)malloc(outlen + EVP_CIPHER_CTX_block_size(&ctx) + 1))==NULL){
   slog(1,"crypt.c:encrypt: Out of memory."); //DEBUG
   return 0;
 }
 memset(*outbuf,'0',outlen);

  if(!EVP_EncryptUpdate(&ctx, *outbuf, &outlen, message, strlen(message)))
  {
   error = ERR_get_error();
   slog(1,"crypt.c: %s:%s\n",ERR_func_error_string(error),ERR_reason_error_string(error));
   return 0;
  }
  /* Buffer passed to EVP_EncryptFinal() must be after data just
   * encrypted to avoid overwriting it.
   */
  if(!EVP_EncryptFinal(&ctx, *outbuf + outlen, &tmplen))
  {
   error = ERR_get_error();
   slog(2,"crypt.c: %s:%s\n",ERR_func_error_string(error),ERR_reason_error_string(error));
   return 0;
  }
  outlen += tmplen;

  EVP_CIPHER_CTX_cleanup(&ctx);
        /* Need binary mode for fopen because encrypted data is
         * binary data. Also cannot use strlen() on it because
         * it wont be null terminated and may contain embedded
         * nulls.
         */

 va_end(ap);
 ERR_free_strings();
 return outlen;
}

int decrypt_stuff(char *key, unsigned char **outbuf, unsigned char *inbuf, int inlen)
{
 int outlen, tmplen;
 unsigned long error;

 EVP_CIPHER_CTX ctx2;
 EVP_CIPHER_CTX_init(&ctx2);


 ERR_load_crypto_strings();
 EVP_DecryptInit(&ctx2, EVP_bf_cfb (), key, CRYPTIV);
 EVP_CIPHER_CTX_set_key_length(&ctx2,strlen(key));

 if((*outbuf=(unsigned char*)malloc(inlen + EVP_CIPHER_CTX_block_size(&ctx2) + 1))==NULL){
   slog(2,"crypt.c:decrypt: Out of memory."); //DEBUG
   return 0;
 }

 if(!EVP_DecryptUpdate(&ctx2, *outbuf, &outlen, inbuf, inlen))
 {
  error = ERR_get_error();
  slog(1,"crypt.c: %s:%s\n",ERR_func_error_string(error),ERR_reason_error_string(error));
  return 0;
 }

 tmplen=0;

 if(!EVP_DecryptFinal(&ctx2, *outbuf+outlen, &tmplen))
 {
  error = ERR_get_error();
  slog(1,"crypt.c: %s:%s\n",ERR_func_error_string(error),ERR_reason_error_string(error));
  //Fix for bug in openssl
  for(;;) {
   if(isalnum(*(*outbuf+outlen))==0) {
    outlen--;
   } else {
    outlen++;
    *(*outbuf+outlen)='\0';
     break;
   }
  }
  return 0;
 }
  outlen += tmplen;
 
  EVP_CIPHER_CTX_cleanup(&ctx2);
  ERR_free_strings();
 
  *(*outbuf+outlen)='\0';
 
 return outlen;
}