that's not a bad idea, though the solution addresses a limited number of attacks. you can insert, for Intel and Athlon-based machines, NOPs (assembler for No Operation) to pad the code. To randomize the number/position of NOPs inserted one could use a perl script to identify begin and end-points in a c program and have it insert the NOPs randomly before compilation. In the case of optimizing compilers you may have to use dummy instructions such as SHL then SHR on some variable, or conditional jumps leading to a NOP, etc.
phillip

> -----Original Message-----
> From: owner-selinux@tycho.nsa.gov [mailto:owner-selinux@tycho.nsa.gov]On
> Behalf Of Justin R. Smith
> Sent: Tuesday, October 02, 2001 4:43 AM
> To: selinux@tycho.nsa.gov
> Subject: A notion
>
>
> It occurred to me that custom versions of software can be more secure
> than standard versions because various exploits (like stack smashing,
> etc.) require precise knowledge of certain sizes and distances in RAM
> (for instance, the distance from the end of a buffer to the return
> point...).
>
> Isn't it possible to develop a "randomizing C compiler" that randomly
> varies these distances every time it compiles a program? No two compiles
> of the same source code would be exactly the same (but they would
> execute the same way).
>
> This might involve inserting small random-sized blocks of dead code, or
> doing returns from subroutines through a level of indirection (i.e.,
> putting the actual return at some random location in the object code
> with a branch to it).
>
> Done right, this might not degrade performance significantly.
>
>
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>
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