Re: [PATCH Bugfix v2 2/4] x86/xsaves: Define and use user_xstate_size for xstate size in signal context

[Dave Hansen]

On 04/23/2015 10:09 AM, Yu, Fenghua wrote:
>> > If those untouched fields of the xsave buffer are in the "init state", then
>> > we've got no problem.  But, are those "untouched since (1)" fields in the
>> > kernel xsave buf *GUARANTEED* to be in the init state?
> In fact, those untouched fields in kernel xsave buf "IS GUARANTEED" to be in
> the init state.
> 
> Please check __sanitize_i387_state() called just before copy_to_user_xstate().
> That functions GUARANTEES the untouched fields in kernel xsave buf to be in
> init state.

OK, that makes sense.  Other than the horribly-named
sanitize_i387_state(). :)
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