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bio_enc.c

/* crypto/evp/bio_enc.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 <openssl/buffer.h>
#include <openssl/evp.h>

static int enc_write(BIO *h, const char *buf, int num);
static int enc_read(BIO *h, char *buf, int size);
/*static int enc_puts(BIO *h, const char *str); */
/*static int enc_gets(BIO *h, char *str, int size); */
static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2);
static int enc_new(BIO *h);
static int enc_free(BIO *data);
static long enc_callback_ctrl(BIO *h, int cmd, bio_info_cb *fps);
#define ENC_BLOCK_SIZE  (1024*4)
#define BUF_OFFSET      (EVP_MAX_BLOCK_LENGTH*2)

00076 typedef struct enc_struct
      {
      int buf_len;
      int buf_off;
      int cont;         /* <= 0 when finished */
      int finished;
      int ok;                 /* bad decrypt */
      EVP_CIPHER_CTX cipher;
      /* buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate
       * can return up to a block more data than is presented to it
       */
      char buf[ENC_BLOCK_SIZE+BUF_OFFSET+2];
      } BIO_ENC_CTX;

static BIO_METHOD methods_enc=
      {
      BIO_TYPE_CIPHER,"cipher",
      enc_write,
      enc_read,
      NULL, /* enc_puts, */
      NULL, /* enc_gets, */
      enc_ctrl,
      enc_new,
      enc_free,
      enc_callback_ctrl,
      };

BIO_METHOD *BIO_f_cipher(void)
      {
      return(&methods_enc);
      }

static int enc_new(BIO *bi)
      {
      BIO_ENC_CTX *ctx;

      ctx=(BIO_ENC_CTX *)OPENSSL_malloc(sizeof(BIO_ENC_CTX));
      if (ctx == NULL) return(0);
      EVP_CIPHER_CTX_init(&ctx->cipher);

      ctx->buf_len=0;
      ctx->buf_off=0;
      ctx->cont=1;
      ctx->finished=0;
      ctx->ok=1;

      bi->init=0;
      bi->ptr=(char *)ctx;
      bi->flags=0;
      return(1);
      }

static int enc_free(BIO *a)
      {
      BIO_ENC_CTX *b;

      if (a == NULL) return(0);
      b=(BIO_ENC_CTX *)a->ptr;
      EVP_CIPHER_CTX_cleanup(&(b->cipher));
      OPENSSL_cleanse(a->ptr,sizeof(BIO_ENC_CTX));
      OPENSSL_free(a->ptr);
      a->ptr=NULL;
      a->init=0;
      a->flags=0;
      return(1);
      }
      
static int enc_read(BIO *b, char *out, int outl)
      {
      int ret=0,i;
      BIO_ENC_CTX *ctx;

      if (out == NULL) return(0);
      ctx=(BIO_ENC_CTX *)b->ptr;

      if ((ctx == NULL) || (b->next_bio == NULL)) return(0);

      /* First check if there are bytes decoded/encoded */
      if (ctx->buf_len > 0)
            {
            i=ctx->buf_len-ctx->buf_off;
            if (i > outl) i=outl;
            memcpy(out,&(ctx->buf[ctx->buf_off]),i);
            ret=i;
            out+=i;
            outl-=i;
            ctx->buf_off+=i;
            if (ctx->buf_len == ctx->buf_off)
                  {
                  ctx->buf_len=0;
                  ctx->buf_off=0;
                  }
            }

      /* At this point, we have room of outl bytes and an empty
       * buffer, so we should read in some more. */

      while (outl > 0)
            {
            if (ctx->cont <= 0) break;

            /* read in at IV offset, read the EVP_Cipher
             * documentation about why */
            i=BIO_read(b->next_bio,&(ctx->buf[BUF_OFFSET]),ENC_BLOCK_SIZE);

            if (i <= 0)
                  {
                  /* Should be continue next time we are called? */
                  if (!BIO_should_retry(b->next_bio))
                        {
                        ctx->cont=i;
                        i=EVP_CipherFinal_ex(&(ctx->cipher),
                              (unsigned char *)ctx->buf,
                              &(ctx->buf_len));
                        ctx->ok=i;
                        ctx->buf_off=0;
                        }
                  else 
                        {
                        ret=(ret == 0)?i:ret;
                        break;
                        }
                  }
            else
                  {
                  EVP_CipherUpdate(&(ctx->cipher),
                        (unsigned char *)ctx->buf,&ctx->buf_len,
                        (unsigned char *)&(ctx->buf[BUF_OFFSET]),i);
                  ctx->cont=1;
                  /* Note: it is possible for EVP_CipherUpdate to
                   * decrypt zero bytes because this is or looks like
                   * the final block: if this happens we should retry
                   * and either read more data or decrypt the final
                   * block
                   */
                  if(ctx->buf_len == 0) continue;
                  }

            if (ctx->buf_len <= outl)
                  i=ctx->buf_len;
            else
                  i=outl;
            if (i <= 0) break;
            memcpy(out,ctx->buf,i);
            ret+=i;
            ctx->buf_off=i;
            outl-=i;
            out+=i;
            }

      BIO_clear_retry_flags(b);
      BIO_copy_next_retry(b);
      return((ret == 0)?ctx->cont:ret);
      }

static int enc_write(BIO *b, const char *in, int inl)
      {
      int ret=0,n,i;
      BIO_ENC_CTX *ctx;

      ctx=(BIO_ENC_CTX *)b->ptr;
      ret=inl;

      BIO_clear_retry_flags(b);
      n=ctx->buf_len-ctx->buf_off;
      while (n > 0)
            {
            i=BIO_write(b->next_bio,&(ctx->buf[ctx->buf_off]),n);
            if (i <= 0)
                  {
                  BIO_copy_next_retry(b);
                  return(i);
                  }
            ctx->buf_off+=i;
            n-=i;
            }
      /* at this point all pending data has been written */

      if ((in == NULL) || (inl <= 0)) return(0);

      ctx->buf_off=0;
      while (inl > 0)
            {
            n=(inl > ENC_BLOCK_SIZE)?ENC_BLOCK_SIZE:inl;
            EVP_CipherUpdate(&(ctx->cipher),
                  (unsigned char *)ctx->buf,&ctx->buf_len,
                  (unsigned char *)in,n);
            inl-=n;
            in+=n;

            ctx->buf_off=0;
            n=ctx->buf_len;
            while (n > 0)
                  {
                  i=BIO_write(b->next_bio,&(ctx->buf[ctx->buf_off]),n);
                  if (i <= 0)
                        {
                        BIO_copy_next_retry(b);
                        return (ret == inl) ? i : ret - inl;
                        }
                  n-=i;
                  ctx->buf_off+=i;
                  }
            ctx->buf_len=0;
            ctx->buf_off=0;
            }
      BIO_copy_next_retry(b);
      return(ret);
      }

static long enc_ctrl(BIO *b, int cmd, long num, void *ptr)
      {
      BIO *dbio;
      BIO_ENC_CTX *ctx,*dctx;
      long ret=1;
      int i;
      EVP_CIPHER_CTX **c_ctx;

      ctx=(BIO_ENC_CTX *)b->ptr;

      switch (cmd)
            {
      case BIO_CTRL_RESET:
            ctx->ok=1;
            ctx->finished=0;
            EVP_CipherInit_ex(&(ctx->cipher),NULL,NULL,NULL,NULL,
                  ctx->cipher.encrypt);
            ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
            break;
      case BIO_CTRL_EOF:      /* More to read */
            if (ctx->cont <= 0)
                  ret=1;
            else
                  ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
            break;
      case BIO_CTRL_WPENDING:
            ret=ctx->buf_len-ctx->buf_off;
            if (ret <= 0)
                  ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
            break;
      case BIO_CTRL_PENDING: /* More to read in buffer */
            ret=ctx->buf_len-ctx->buf_off;
            if (ret <= 0)
                  ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
            break;
      case BIO_CTRL_FLUSH:
            /* do a final write */
again:
            while (ctx->buf_len != ctx->buf_off)
                  {
                  i=enc_write(b,NULL,0);
                  if (i < 0)
                        return i;
                  }

            if (!ctx->finished)
                  {
                  ctx->finished=1;
                  ctx->buf_off=0;
                  ret=EVP_CipherFinal_ex(&(ctx->cipher),
                        (unsigned char *)ctx->buf,
                        &(ctx->buf_len));
                  ctx->ok=(int)ret;
                  if (ret <= 0) break;

                  /* push out the bytes */
                  goto again;
                  }
            
            /* Finally flush the underlying BIO */
            ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
            break;
      case BIO_C_GET_CIPHER_STATUS:
            ret=(long)ctx->ok;
            break;
      case BIO_C_DO_STATE_MACHINE:
            BIO_clear_retry_flags(b);
            ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
            BIO_copy_next_retry(b);
            break;
      case BIO_C_GET_CIPHER_CTX:
            c_ctx=(EVP_CIPHER_CTX **)ptr;
            (*c_ctx)= &(ctx->cipher);
            b->init=1;
            break;
      case BIO_CTRL_DUP:
            dbio=(BIO *)ptr;
            dctx=(BIO_ENC_CTX *)dbio->ptr;
            EVP_CIPHER_CTX_init(&dctx->cipher);
            ret = EVP_CIPHER_CTX_copy(&dctx->cipher,&ctx->cipher);
            if (ret)
                  dbio->init=1;
            break;
      default:
            ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
            break;
            }
      return(ret);
      }

static long enc_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
      {
      long ret=1;

      if (b->next_bio == NULL) return(0);
      switch (cmd)
            {
      default:
            ret=BIO_callback_ctrl(b->next_bio,cmd,fp);
            break;
            }
      return(ret);
      }

/*
void BIO_set_cipher_ctx(b,c)
BIO *b;
EVP_CIPHER_ctx *c;
      {
      if (b == NULL) return;

      if ((b->callback != NULL) &&
            (b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,0L) <= 0))
            return;

      b->init=1;
      ctx=(BIO_ENC_CTX *)b->ptr;
      memcpy(ctx->cipher,c,sizeof(EVP_CIPHER_CTX));
      
      if (b->callback != NULL)
            b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,1L);
      }
*/

void BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k,
           const unsigned char *i, int e)
      {
      BIO_ENC_CTX *ctx;

      if (b == NULL) return;

      if ((b->callback != NULL) &&
            (b->callback(b,BIO_CB_CTRL,(const char *)c,BIO_CTRL_SET,e,0L) <= 0))
            return;

      b->init=1;
      ctx=(BIO_ENC_CTX *)b->ptr;
      EVP_CipherInit_ex(&(ctx->cipher),c,NULL, k,i,e);
      
      if (b->callback != NULL)
            b->callback(b,BIO_CB_CTRL,(const char *)c,BIO_CTRL_SET,e,1L);
      }


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