RE: ZLib double free bug: Windows NT potentially unaffected

From: Robert Collins (robert.collinsat_private)
Date: Thu Mar 14 2002 - 15:49:11 PST

  • Next message: Dragos Ruiu: "Re: ZLib double free bug: Windows NT potentially unaffected"

    > -----Original Message-----
    > From: KJK::Hyperion [mailto:noogat_private] 
    > Sent: Friday, March 15, 2002 4:52 AM
    > To: bugtraqat_private
    > Subject: ZLib double free bug: Windows NT potentially unaffected
    
    
    > I allocate 4 kb of memory, then I free the block twice. Under 
    > debugging, 
    > this program will emit the following diagnostic message:
    > 
    > HEAP[testheap.exe]: Invalid Address specified to RtlFreeHeap( 
    > 130000, 1357f0 )
    > 
    > immediately after this, a breakpoint exception (code 
    > 0x80000003) is raised. 
    > So, apparently, the second free operation degrades 
    > gracefully, apparently 
    > without any corruption of in-memory structures, since the subsequent 
    > allocation/deallocation runs fine
    
    Can I suggest you try it with a non-debug build. I've seen heap
    corruption occur in winNT software, that in debug-builds was trapped,
    but in non-debug builds was not.
    
    Cheers,
    Rob
    



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