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evp_enc.c

/* crypto/evp/evp_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 "cryptlib.h"
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/rand.h>
#ifndef OPENSSL_NO_ENGINE
#include <openssl/engine.h>
#endif
#include "evp_locl.h"

const char *EVP_version="EVP" OPENSSL_VERSION_PTEXT;

void EVP_CIPHER_CTX_init(EVP_CIPHER_CTX *ctx)
      {
      memset(ctx,0,sizeof(EVP_CIPHER_CTX));
      /* ctx->cipher=NULL; */
      }


int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
           const unsigned char *key, const unsigned char *iv, int enc)
      {
      if (cipher)
            EVP_CIPHER_CTX_init(ctx);
      return EVP_CipherInit_ex(ctx,cipher,NULL,key,iv,enc);
      }

int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher, ENGINE *impl,
           const unsigned char *key, const unsigned char *iv, int enc)
      {
      if (enc == -1)
            enc = ctx->encrypt;
      else
            {
            if (enc)
                  enc = 1;
            ctx->encrypt = enc;
            }
#ifndef OPENSSL_NO_ENGINE
      /* Whether it's nice or not, "Inits" can be used on "Final"'d contexts
       * so this context may already have an ENGINE! Try to avoid releasing
       * the previous handle, re-querying for an ENGINE, and having a
       * reinitialisation, when it may all be unecessary. */
      if (ctx->engine && ctx->cipher && (!cipher ||
                  (cipher && (cipher->nid == ctx->cipher->nid))))
            goto skip_to_init;
#endif
      if (cipher)
            {
            /* Ensure a context left lying around from last time is cleared
             * (the previous check attempted to avoid this if the same
             * ENGINE and EVP_CIPHER could be used). */
            EVP_CIPHER_CTX_cleanup(ctx);

            /* Restore encrypt field: it is zeroed by cleanup */
            ctx->encrypt = enc;
#ifndef OPENSSL_NO_ENGINE
            if(impl)
                  {
                  if (!ENGINE_init(impl))
                        {
                        EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
                        return 0;
                        }
                  }
            else
                  /* Ask if an ENGINE is reserved for this job */
                  impl = ENGINE_get_cipher_engine(cipher->nid);
            if(impl)
                  {
                  /* There's an ENGINE for this job ... (apparently) */
                  const EVP_CIPHER *c = ENGINE_get_cipher(impl, cipher->nid);
                  if(!c)
                        {
                        /* One positive side-effect of US's export
                         * control history, is that we should at least
                         * be able to avoid using US mispellings of
                         * "initialisation"? */
                        EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
                        return 0;
                        }
                  /* We'll use the ENGINE's private cipher definition */
                  cipher = c;
                  /* Store the ENGINE functional reference so we know
                   * 'cipher' came from an ENGINE and we need to release
                   * it when done. */
                  ctx->engine = impl;
                  }
            else
                  ctx->engine = NULL;
#endif

            ctx->cipher=cipher;
            if (ctx->cipher->ctx_size)
                  {
                  ctx->cipher_data=OPENSSL_malloc(ctx->cipher->ctx_size);
                  if (!ctx->cipher_data)
                        {
                        EVPerr(EVP_F_EVP_CIPHERINIT_EX, ERR_R_MALLOC_FAILURE);
                        return 0;
                        }
                  }
            else
                  {
                  ctx->cipher_data = NULL;
                  }
            ctx->key_len = cipher->key_len;
            ctx->flags = 0;
            if(ctx->cipher->flags & EVP_CIPH_CTRL_INIT)
                  {
                  if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_INIT, 0, NULL))
                        {
                        EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
                        return 0;
                        }
                  }
            }
      else if(!ctx->cipher)
            {
            EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_NO_CIPHER_SET);
            return 0;
            }
#ifndef OPENSSL_NO_ENGINE
skip_to_init:
#endif
      /* we assume block size is a power of 2 in *cryptUpdate */
      OPENSSL_assert(ctx->cipher->block_size == 1
          || ctx->cipher->block_size == 8
          || ctx->cipher->block_size == 16);

      if(!(EVP_CIPHER_CTX_flags(ctx) & EVP_CIPH_CUSTOM_IV)) {
            switch(EVP_CIPHER_CTX_mode(ctx)) {

                  case EVP_CIPH_STREAM_CIPHER:
                  case EVP_CIPH_ECB_MODE:
                  break;

                  case EVP_CIPH_CFB_MODE:
                  case EVP_CIPH_OFB_MODE:

                  ctx->num = 0;

                  case EVP_CIPH_CBC_MODE:

                  OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) <=
                              (int)sizeof(ctx->iv));
                  if(iv) memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
                  memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
                  break;

                  default:
                  return 0;
                  break;
            }
      }

      if(key || (ctx->cipher->flags & EVP_CIPH_ALWAYS_CALL_INIT)) {
            if(!ctx->cipher->init(ctx,key,iv,enc)) return 0;
      }
      ctx->buf_len=0;
      ctx->final_used=0;
      ctx->block_mask=ctx->cipher->block_size-1;
      return 1;
      }

int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
           const unsigned char *in, int inl)
      {
      if (ctx->encrypt)
            return EVP_EncryptUpdate(ctx,out,outl,in,inl);
      else  return EVP_DecryptUpdate(ctx,out,outl,in,inl);
      }

int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
      {
      if (ctx->encrypt)
            return EVP_EncryptFinal_ex(ctx,out,outl);
      else  return EVP_DecryptFinal_ex(ctx,out,outl);
      }

int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
      {
      if (ctx->encrypt)
            return EVP_EncryptFinal(ctx,out,outl);
      else  return EVP_DecryptFinal(ctx,out,outl);
      }

int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
           const unsigned char *key, const unsigned char *iv)
      {
      return EVP_CipherInit(ctx, cipher, key, iv, 1);
      }

int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx,const EVP_CIPHER *cipher, ENGINE *impl,
            const unsigned char *key, const unsigned char *iv)
      {
      return EVP_CipherInit_ex(ctx, cipher, impl, key, iv, 1);
      }

int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
           const unsigned char *key, const unsigned char *iv)
      {
      return EVP_CipherInit(ctx, cipher, key, iv, 0);
      }

int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher, ENGINE *impl,
           const unsigned char *key, const unsigned char *iv)
      {
      return EVP_CipherInit_ex(ctx, cipher, impl, key, iv, 0);
      }

int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
           const unsigned char *in, int inl)
      {
      int i,j,bl;

      OPENSSL_assert(inl > 0);
      if(ctx->buf_len == 0 && (inl&(ctx->block_mask)) == 0)
            {
            if(ctx->cipher->do_cipher(ctx,out,in,inl))
                  {
                  *outl=inl;
                  return 1;
                  }
            else
                  {
                  *outl=0;
                  return 0;
                  }
            }
      i=ctx->buf_len;
      bl=ctx->cipher->block_size;
      OPENSSL_assert(bl <= (int)sizeof(ctx->buf));
      if (i != 0)
            {
            if (i+inl < bl)
                  {
                  memcpy(&(ctx->buf[i]),in,inl);
                  ctx->buf_len+=inl;
                  *outl=0;
                  return 1;
                  }
            else
                  {
                  j=bl-i;
                  memcpy(&(ctx->buf[i]),in,j);
                  if(!ctx->cipher->do_cipher(ctx,out,ctx->buf,bl)) return 0;
                  inl-=j;
                  in+=j;
                  out+=bl;
                  *outl=bl;
                  }
            }
      else
            *outl = 0;
      i=inl&(bl-1);
      inl-=i;
      if (inl > 0)
            {
            if(!ctx->cipher->do_cipher(ctx,out,in,inl)) return 0;
            *outl+=inl;
            }

      if (i != 0)
            memcpy(ctx->buf,&(in[inl]),i);
      ctx->buf_len=i;
      return 1;
      }

int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
      {
      int ret;
      ret = EVP_EncryptFinal_ex(ctx, out, outl);
      return ret;
      }

int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
      {
      int n,ret;
      unsigned int i, b, bl;

      b=ctx->cipher->block_size;
      OPENSSL_assert(b <= sizeof ctx->buf);
      if (b == 1)
            {
            *outl=0;
            return 1;
            }
      bl=ctx->buf_len;
      if (ctx->flags & EVP_CIPH_NO_PADDING)
            {
            if(bl)
                  {
                  EVPerr(EVP_F_EVP_ENCRYPTFINAL_EX,EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH);
                  return 0;
                  }
            *outl = 0;
            return 1;
            }

      n=b-bl;
      for (i=bl; i<b; i++)
            ctx->buf[i]=n;
      ret=ctx->cipher->do_cipher(ctx,out,ctx->buf,b);


      if(ret)
            *outl=b;

      return ret;
      }

int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
           const unsigned char *in, int inl)
      {
      int fix_len;
      unsigned int b;

      if (inl == 0)
            {
            *outl=0;
            return 1;
            }

      if (ctx->flags & EVP_CIPH_NO_PADDING)
            return EVP_EncryptUpdate(ctx, out, outl, in, inl);

      b=ctx->cipher->block_size;
      OPENSSL_assert(b <= sizeof ctx->final);

      if(ctx->final_used)
            {
            memcpy(out,ctx->final,b);
            out+=b;
            fix_len = 1;
            }
      else
            fix_len = 0;


      if(!EVP_EncryptUpdate(ctx,out,outl,in,inl))
            return 0;

      /* if we have 'decrypted' a multiple of block size, make sure
       * we have a copy of this last block */
      if (b > 1 && !ctx->buf_len)
            {
            *outl-=b;
            ctx->final_used=1;
            memcpy(ctx->final,&out[*outl],b);
            }
      else
            ctx->final_used = 0;

      if (fix_len)
            *outl += b;
            
      return 1;
      }

int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
      {
      int ret;
      ret = EVP_DecryptFinal_ex(ctx, out, outl);
      return ret;
      }

int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
      {
      int i,n;
      unsigned int b;

      *outl=0;
      b=ctx->cipher->block_size;
      if (ctx->flags & EVP_CIPH_NO_PADDING)
            {
            if(ctx->buf_len)
                  {
                  EVPerr(EVP_F_EVP_DECRYPTFINAL_EX,EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH);
                  return 0;
                  }
            *outl = 0;
            return 1;
            }
      if (b > 1)
            {
            if (ctx->buf_len || !ctx->final_used)
                  {
                  EVPerr(EVP_F_EVP_DECRYPTFINAL_EX,EVP_R_WRONG_FINAL_BLOCK_LENGTH);
                  return(0);
                  }
            OPENSSL_assert(b <= sizeof ctx->final);
            n=ctx->final[b-1];
            if (n == 0 || n > (int)b)
                  {
                  EVPerr(EVP_F_EVP_DECRYPTFINAL_EX,EVP_R_BAD_DECRYPT);
                  return(0);
                  }
            for (i=0; i<n; i++)
                  {
                  if (ctx->final[--b] != n)
                        {
                        EVPerr(EVP_F_EVP_DECRYPTFINAL_EX,EVP_R_BAD_DECRYPT);
                        return(0);
                        }
                  }
            n=ctx->cipher->block_size-n;
            for (i=0; i<n; i++)
                  out[i]=ctx->final[i];
            *outl=n;
            }
      else
            *outl=0;
      return(1);
      }

int EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *c)
      {
      if (c->cipher != NULL)
            {
            if(c->cipher->cleanup && !c->cipher->cleanup(c))
                  return 0;
            /* Cleanse cipher context data */
            if (c->cipher_data)
                  OPENSSL_cleanse(c->cipher_data, c->cipher->ctx_size);
            }
      if (c->cipher_data)
            OPENSSL_free(c->cipher_data);
#ifndef OPENSSL_NO_ENGINE
      if (c->engine)
            /* The EVP_CIPHER we used belongs to an ENGINE, release the
             * functional reference we held for this reason. */
            ENGINE_finish(c->engine);
#endif
      memset(c,0,sizeof(EVP_CIPHER_CTX));
      return 1;
      }

int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *c, int keylen)
      {
      if(c->cipher->flags & EVP_CIPH_CUSTOM_KEY_LENGTH) 
            return EVP_CIPHER_CTX_ctrl(c, EVP_CTRL_SET_KEY_LENGTH, keylen, NULL);
      if(c->key_len == keylen) return 1;
      if((keylen > 0) && (c->cipher->flags & EVP_CIPH_VARIABLE_LENGTH))
            {
            c->key_len = keylen;
            return 1;
            }
      EVPerr(EVP_F_EVP_CIPHER_CTX_SET_KEY_LENGTH,EVP_R_INVALID_KEY_LENGTH);
      return 0;
      }

int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *ctx, int pad)
      {
      if (pad) ctx->flags &= ~EVP_CIPH_NO_PADDING;
      else ctx->flags |= EVP_CIPH_NO_PADDING;
      return 1;
      }

int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr)
{
      int ret;
      if(!ctx->cipher) {
            EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL, EVP_R_NO_CIPHER_SET);
            return 0;
      }

      if(!ctx->cipher->ctrl) {
            EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL, EVP_R_CTRL_NOT_IMPLEMENTED);
            return 0;
      }

      ret = ctx->cipher->ctrl(ctx, type, arg, ptr);
      if(ret == -1) {
            EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL, EVP_R_CTRL_OPERATION_NOT_IMPLEMENTED);
            return 0;
      }
      return ret;
}

int EVP_CIPHER_CTX_rand_key(EVP_CIPHER_CTX *ctx, unsigned char *key)
      {
      if (ctx->cipher->flags & EVP_CIPH_RAND_KEY)
            return EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_RAND_KEY, 0, key);
      if (RAND_bytes(key, ctx->key_len) <= 0)
            return 0;
      return 1;
      }


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