Thanks a lot Mindaugas, I'll include this in next commit.
Brgds,
Viktor
On 2010 Jan 14, at 14:28, Mindaugas Kavaliauskas wrote:
> Hi,
>
>
>> 2010-01-13 17:12 UTC+0100 Viktor Szakats (harbour.01 syenar.hu)
>> + src/rtl/strclear.c
>> + Added HB_STRCLEAR() function to safely clear the content of a
>> string variable.
>
> I suggest to change HB_STRCLEAR() code. Current implementation returns true,
> if hb_itemGetWriteCL() returns true, but it happens if pItem is string. It is
> already validated by hb_param( 1, HB_IT_STRING ), so, return value is not
> useful. If the purpose of the function is to clear memory containing
> sensitive information, the function should return if the memory was really
> cleared. I propose this code (self test included):
>
> PROC main()
> LOCAL cI, cJ
>
> cI := "abc"
> ? HB_STRCLEAR(cI)
>
> cI := "abc"
> ? HB_STRCLEAR(@cI)
>
> cI := REPLICATE("a", 5)
> cJ := cI
> ? HB_STRCLEAR(@cI)
>
> cI := REPLICATE("a", 5)
> cJ := cI
> cJ := NIL
> ? HB_STRCLEAR(@cI)
> RETURN
>
> #pragma begindump
> #include "hbapi.h"
> #include "hbapiitm.h"
>
> HB_FUNC( HB_STRCLEAR )
> {
> PHB_ITEM pItem = hb_param( 1, HB_IT_STRING );
>
> /* NOTE: clear RETURN value before calling hb_itemGetWriteCL(),
> it's possible that it contains copy of passed item [druzus] */
> hb_retl( HB_FALSE );
>
> if( pItem && HB_ISBYREF( 1 ) )
> {
> const char * szPtr;
> char * pBuffer;
> HB_SIZE nSize;
>
> szPtr = hb_itemGetCPtr( pItem );
> hb_itemGetWriteCL( pItem, &pBuffer, &nSize );
> memset( pBuffer, '\0', nSize + 1 );
> hb_retl( szPtr == pBuffer );
> }
> }
> #pragma enddump
>
>
> In this case HB_STRCLEAR() returns, if memory was cleared. It prints:
> .F. // Pass by reference is forgotten
> .F. // String data is static (part of PCODE) and can not be cleared
> .F. // Multiple strings exists
> .T. // OK!
>
>
> Regards,
> Mindaugas
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