Re: [PATCH 14/18] ipv4: prevent bounds-check bypass via speculative execution

Dan Williams
2018-01-06T16:29:23Z

On Sat, Jan 6, 2018 at 7:14 AM, Greg KH <gregkh@linuxfoundation.org> wrote:
> On Sat, Jan 06, 2018 at 12:23:47PM +0000, Alan Cox wrote:
>> On Sat, 6 Jan 2018 10:01:54 +0100
>> Greg KH <gregkh@linuxfoundation.org> wrote:
>>
>> > On Fri, Jan 05, 2018 at 05:11:10PM -0800, Dan Williams wrote:
>> > > Static analysis reports that 'offset' may be a user controlled value
>> >
>> > Can I see the rule that determined that? It does not feel like that is
>> > correct, given the 3+ levels deep that this function gets this value
>> > from...
>>
>> On a current x86 you can execute something upwards of 150 instructions in
>> a speculation window.
>
> Yeah, I agree, it's deep :(
>
> But for this patch, I thought the prior review determined that it was
> not a problem. Was that somehow proven incorrect?

I kept it in the series to get a re-review with the wider netdev
because I missed the discussion leading up to that 'drop the patch'
decision. Sorry, I should have noted that in the changelog or cover
letter.