Messages in this thread | | | Date | Sat, 3 May 2003 02:52:21 -0400 (EDT) | From | Ingo Molnar <> | Subject | Re: [Announcement] "Exec Shield", new Linux security feature |
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On Fri, 2 May 2003, Carl-Daniel Hailfinger wrote:
> Ingo Molnar wrote: > > > > Furthermore, the kernel also remaps all PROT_EXEC mappings to the > > so-called ASCII-armor area, which on x86 is the addresses 0-16MB. These > [snipped] > > In the above layout, the highest executable address is 0x01003fff, ie. > > every executable address is in the ASCII-armor. > > If my math is correct, > 0x01000000 is 16 MB boundary > 0x01003fff is outside the ASCII-armor.
the ASCII-armor, more precisely, is between addresses 0x00000000 and 0x0100ffff. Ie. 16 MB + 64K. [in the remaining 64K the \0 character is in the second byte of the address.] So the 0x01003fff address is still inside the ASCII-armor.
> Another question: Last time I checked, there were some problems with > binary only drivers (to name one, NVidia graphics) and a non-executable > stack. Has this been resolved?
i'm not using any binary-only drivers, so i have no idea. But as long as they use PROT_EXEC areas for code, they should be safe.
Ingo
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