Re: [Xen-devel] [PATCH] x86: polish __{get,put}_user_{,no}check()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 04/05/17 09:52, Julien Grall wrote:
> Hi,
>
> On 02/05/17 14:23, Jan Beulich wrote:
>> The primary purpose is correcting a latent bug in __get_user_check()
>> (the macro has no active user at present): The access_ok() check should
>> be before the actual access, or else any PV guest could initiate MMIO
>> reads with side effects.
>>
>> Clean up all four macros at once:
>> - all arguments evaluated exactly once
>> - build the "check" flavor using the "nocheck" ones, instead of open
>>   coding them
>> - "int" is wide enough for error codes
>> - name local variables without using underscores as prefixes
>> - avoid pointless parentheses
>> - add blanks after commas separating parameters or arguments
>> - consistently use tabs for indentation
>>
>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>> ---
>> This corrects the code which would have resulted in an XSA on Xen 4.2
>> and older, if those were still security supported. For that reason I at
>> least want to explore whether this is a change we want to take for 4.9.
>
> Andrew, do you have any opinion to get this patch in Xen 4.9?

It should go in.

~Andrew

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