[delphizip] Re: Memory leak in Inflate.c in Unzip.dll
- From: "Roger Aelbrecht" <Roger.Aelbrecht@xxxxxxxxxx>
- To: <delphizip@xxxxxxxxxxxxx>
- Date: Sat, 10 May 2003 21:11:56 +0200
James Turner wrote:
> Roger,
>
> I don't have any reference code, but I have included the password
> checking code I use in Zipfusion.
> I arrived at this solution partially from code analysis and partially
> from experimentation using the debugger to watch variables.
>
> James Turner
> SKARO.NET
>
>
> procedure EnterPassword(WND:HWND; Attempts:integer);
> { The file pointer is assumed to be located at the start }
> { of the file data or the 12-byte encryption prefix. }
> { Failure will raise an exception. }
> type TCryptBlock = array [0..(SizeOf(TZipCryptKey) div 2) - 1] of
> Word;
>
> function Decrypt(CryptBlock:TCryptBlock):Boolean;
> { CryptBlock must be passed as a value parameter otherwise the }
> { password has to be entered correctly at the first attempt. }
> const InitKey : TZipCryptKey = (305419896,591751049,878082192);
> var i : integer;
> w : Word;
> begin
> Result := False; if Password = '' then exit;
> CryptKey := InitKey;
>
> for i := 1 to Length(Password) do
> UpdateCryptKey(byte(Password[i]));
>
> DecryptBuff(@CryptBlock,SizeOf(CryptBlock));
> w := CryptBlock[High(CryptBlock)];
>
> with Header do if Flags and 8 = 0 then result := w =
> HiWord(CRC32) else result :=
> w = LoWord(FileDate); end;
>
> var CryptBlock : TCryptBlock;
> begin { EnterPassword }
> if (Header.Flags and 1) = 0 then exit; { Not password protected }
>
> { If AutoRun is true, SkipFile should always be called }
> if not AutoRun then begin
> InfileRead(CryptBlock,SizeOf(CryptBlock));
>
> if Password <> '' then inc(Attempts);
>
> repeat
> if Decrypt(CryptBlock) then Exit;
>
> if (Attempts > 0) then begin
> dec(Attempts);
> case
> DialogBoxParam(HInstance,'DIALOG_Password',WND,@DP_Password,0) of
> ID_OK : Continue;
> ID_No : Break; { Skip button : return false }
> ID_Cancel : SkipFile('',sfAbort);
> else end;
> end
> else Break;
>
> until false;
> end;
>
> SkipFile(SourceFileName,sfWrongPassword);
> end;
>
>
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I got the impression that this is not the complete code
Missing -> DecryptBuff(@CryptBlock, SizeOf(CryptBlock);
I presume this is the replacement of decrypt_byte
probably the most important part
Missing->UpdateCryptKey( byte(Password[i]));
Maybe I did look gooed enough ?
Roger Aelbrecht
http://web.wanadoo.be/driehoeksw
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