Re: Patched Programs - Yet another spin

Googling for "Uehling" and "V5R4" indicates he's from IBM and gave a
presentation at Common on "What's New in Security."

The trick of putting PowerPC instructions in a user space won't work
anymore because there's a new bit in the hardware page tables (new in
V5R3) called "Nex," which I think stands for "No execute."  The bit is 1
for user spaces, meaning that code in a user space can't be executed.

(Of course, the bit is 0 for the pages in a program containing the
instructions.)

--Dave

Steve Richter wrote:
> 
> -----Original Message-----
> From: mi400-bounces-Zwy7GipZuJhWk0Htik3J/[email protected] [mailto:mi400-bounces-Zwy7GipZuJhWk0Htik3J/[email protected]]On
> Behalf Of Ted Slate
> Sent: Wednesday, February 15, 2006 8:17 AM
> To: mi400-Zwy7GipZuJhWk0Htik3J/[email protected]
> Subject: [MI400] Patched Programs - Yet another spin
> 
> 
>> <<"In V5R4," Uehling says, "we've enhanced the protection capabilities on
>> our objects that make it much, much stronger from the protection capability
>> standpoint. A program that's written by a user and then hacked or patched
>> cannot get access to our objects. That's the bottom line.">>
> 
> who is Uehling?
> 
> Does this mean an RPG program that has its PPC patched to branch to PPC code
> in a user space will no longer run?  That is, when the patched RPG program
> calls another RPG program, will that call fail because a patched program
> cannot use system functions like database I/O and program calls?
> 
> -Steve
> 


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