Re: [tip:x86/mpx] x86/insn-eval: Add utility function to get segment descriptor

Borislav Petkov
2017-12-07T08:03:24Z

On Wed, Dec 06, 2017 at 11:23:59PM -0800, Ricardo Neri wrote:
> In UMIP emulation we can potentially access the LDT twice. Once when
> determining the base address of the code segment and again when determining
> the base address and limit of the segment in which the result of the
> emulation is written. I guess that mm->context.ldt_seq needs to not change
> not only while decoding a particular linear address but across these two
> linear address decodings.

Yap, stuff which needs to see an *unchanged* LDT should use the cookie
to verify that and the LDT code should change the cookie when the LDT
is modified.

> Sure, I will look into implementing this idea and post patches for it.

Thanks!

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Regards/Gruss,
Boris.

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