Re: [PATCH V2] posix-timers: Protect posix clock array access against speculation

From: Dan Williams
Date: Wed Mar 07 2018 - 13:13:57 EST


On Thu, Feb 15, 2018 at 9:01 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Thu, Feb 15, 2018 at 05:21:55PM +0100, Thomas Gleixner wrote:
>> The clockid argument of clockid_to_kclock() comes straight from user space
>> via various syscalls and is used as index into the posix_clocks array.
>>
>> Protect it against spectre v1 array out of bounds speculation. Remove the
>> redundant check for !posix_clock[id] as this is another source for
>> speculation and does not provide any advantage over the return
>> posix_clock[id] path which returns NULL in that case anyway.
>>
>> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: stable@xxxxxxxxxxxxxxx
>
> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
>

Curious where this ended up, I don't see it on tip/master. In any event:

Acked-by: Dan Williams <dan.j.williams@xxxxxxxxx>