#include "stdafx.h"
#pragma hdrstop
#include "dz_errs.h"

#undef _DZ_FILE_
#define _DZ_FILE_ DZ_UNZCRYPT_CPP
/*
* crypt.c (full version) by Info-ZIP.      Last revised:  [see crypt.h]
*
* This code is not copyrighted and is put in the public domain.  The
* encryption/decryption parts (as opposed to the non-echoing password
* parts) were originally written in Europe; the whole file can there-
* fore be freely distributed from any country except the USA.  If this
* code is imported into the USA, it cannot be re-exported from from
* there to another country.  (This restriction might seem curious, but
* this is what US law requires.) */

/* This version modified by Chris Vleghert and Eric W. Engler
* for BCB/Delphi Zip, Sep 22, 2000. */

/* This encryption code is a direct transcription of the algorithm from
* Roger Schlafly, described by Phil Katz in the file appnote.txt.  This
* file (appnote.txt) is distributed with the PKZIP program (even in the
* version without encryption capabilities). *

  Copyright (c) 1990-2007 Info-ZIP.  All rights reserved.

  See the accompanying file LICENSE, version 2007-Mar-4 or later
  (the contents of which are also included in zip.h) for terms of use.
  If, for some reason, all these files are missing, the Info-ZIP license
  also may be found at:  ftp://ftp.info-zip.org/pub/infozip/license.html

  parts Copyright (C) 1997 Mike White, Eric W. Engler
************************************************************************
 Copyright (C) 2009, 2010  by Russell J. Peters, Roger Aelbrecht

   This file is part of TZipMaster Version 1.9.

    TZipMaster is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    TZipMaster is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with TZipMaster.  If not, see <http://www.gnu.org/licenses/>.

    contact: problems@delphizip.org (include ZipMaster in the subject).
    updates: http://www.delphizip.org
    DelphiZip maillist subscribe at http://www.freelists.org/list/delphizip 
************************************************************************/

#define ZCRYPT_INTERNAL

#include "UnzInf.h"

#include "crypt.h"
//#include "ucrypt.h"

//static int testp(UGlobals * pG, uch * h);
//static int testkey(UGlobals * pG, uch * h, char * key);

//#  define NEXTBYTE  (--fincnt >= 0 ? (int)(*finptr++) : readbyte())
/* ===========================================================================
* Get the password and set up keys for current zipfile member.  Return * PK_ class error. */
int UnzInf::decrypt(ulg crc)
{
  ush b;
  int n, n1;//, r;
  char h[RAND_HEAD_LEN];

  if (Verbose < 0)
    Notify(ITRACE,  _T("in crypt.c, [incnt = %d]: "), fincnt); //stout

  /* get header once (turn off "encrypted" flag temporarily so we don't * try to decrypt the same data twice) */
//  fpInfo->encrypted = false;
  Encrypted = false;
  defer_leftover_input();
  for (n = 0; n < RAND_HEAD_LEN; n++)
  {
    b = (ush)NEXTBYTE;
    /* RCV: ush added */
    h[n] = (uch)b;
    //Trace((pG, " (%02x)", h[n]));  //stdout
  }
  undefer_input();
  Encrypted = true;

  if (Verbose < 0)
    Notify(ITRACE, _T("EWE - in crypt.c, near fnewzip test"));

  if (!fPwdReqCount)
	return PK_WARN;
  if (fnewzip)
  {
    fnewzip = false;
    if (Verbose < 0)
      Notify(ITRACE, _T("newzip was set to false"));

    if (fP_flag == true)
    {
      /* user gave password on command line */
#ifdef ZDEBUG
      if (Verbose < 0)
        Notify(ITRACE, _T("user set password=%s"), fpwdarg.c_str());
#endif
    }
  }

  if (Verbose < 0)
    Notify(ITRACE, _T("EWE- near 'have key already' test"));
  /* if have key already, test it; else allocate memory for it */
  if (fkey)
  {
	if (!testkey(h, fkey, crc))
    {
      if (Verbose < 0)
        Notify(ITRACE, _T("existing pwd OK"));
      return PK_COOL; // existing password OK (else prompt for new)
    }
    else
      if (fnopwd)
        return PK_WARN; // user indicated no more prompting
  }
    else
      if (fnopwd)
		return PK_WARN; // user indicated no more prompting
  if (Verbose < 0)
    Notify(ITRACE, _T("EWE- near 'try a few keys' test"));

  /* try a few keys */
  n = fPwdReqCount;
  n1 = 15;
  do
  {
    // Call the component with a request for a password
    CB->Arg1 = n;
    CB->Msg = ffilename;
    int ucb = CB->UserCB(zacPassword);
    if (ucb == CALLBACK_TRUE)        // have password
    {
      fkey = DupStr(DZStrA(CB->Msg));
	  if (!testkey(h, fkey, crc))   // test local
        return PK_COOL;
    }
    if (ucb == CALLBACK_3)         // gave no password
    {
      fnopwd = true;
      n1 = 1;
    }
	n = MIN((int)CB->Arg1 & 0x0F, n1);
  }
  while (--n > 0 && --n1 > 0 && !Abort_Flag);

  return PK_WARN;
}
/* end function decrypt() */


/* ===========================================================================
*h   :: Decrypted header.
*key :: Decryption password to test. */
int UnzInf::testkey(const char *h, const char *key, ulg crc)
{
  ush b;

  int n;
  uch * p;
  uch hh[RAND_HEAD_LEN];
  /* decrypted header */

  /* set keys and save the encrypted header */
  init_keys(key, fkeys);
  memcpy(hh, h, RAND_HEAD_LEN);

  /* check password */
  for (n = 0; n < RAND_HEAD_LEN; n++)
  {
    hh[n] = (uch) zdecode(hh[n], fkeys);
  }

  b = hh[RAND_HEAD_LEN - 1];
  if (b != (ush)crc)
	return -1; // bad
//#endif
  /* password OK:  decrypt current buffer contents before leaving */
  for (n = (unsigned)fincnt > (unsigned) fcsize ? (int)fcsize : fincnt, p = finptr; n--; p++)
	*p = (uch) zdecode(*p, fkeys);
  return 0;  // OK
}
/* end function testkey() */