stack smashing Was: Re: Scanning Formats (TIFF vs. JPEG) - test-drb@ccmp.vtda.org

19 Aug 2006

 --- Chuck Guzis <cclist at sydex.com> wrote: 
...
  On 8/19/2006 at 12:49 AM Alexey Toptygin wrote:

 >This is computationally expensive and complicated .
...
  Every time you have to 
 cross a privilege boundary you have to switch
 context, validate any data 
 >going across and verify permissions. You also nee d
...
  an exact specification 
 >of the interface for every such interface - if th e
...
  system doesn't know 
 >what your DLL is allowed to do, how can it stop i t
...
  from doing what it 
 >shouldn't? This is why this sort of pain is usual ly
...
  reserved for the 
 user-kernel interface.  
 I don't think so.  There is a subset of all DLLs
 that can be classified as
 "trusted"--they know to check arguments and the
 operation is well-defined.
 One might classify these as "friendly" DLLs and om it
...
  any sort of checking.
 For all others, the calling program can specify a
 tighter degree of control
 at the expense of more overhead.

 Cheers,
 Chuck

How is the checking done? If it's purely by
name then it can easily be switched for
something much nastier without the user
finding out.

There used to be a fake "datatypes.library"
for Workbench 3 on the Amiga. Instead of
containing various datatypes functions/data
(say for JPEG's, GIF's and IFF's etc.) it was
a nasty virus.

Personally I prefer Workbench 2 and have
mine set up with my own custom icons and
mouse pointers :)

NB: For those that don't know, Workbench is
the Amiga version of Windows - or should that
be Windows is the PC version of Workbench :) 

Regards,
Andrew B
aliensrcooluk at yahoo.co.uk