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@xxxxxxxxxxxx [mailto:mi400-bounces@xxxxxxxxxxxx]On
Behalf Of Ted Slate
Sent: Wednesday, February 15, 2006 8:17 AM
To: mi400@xxxxxxxxxxxx
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