Re: BUG: KASAN: global-out-of-bounds in strscpy+0x807/0x970

From: Simon Brewer
Date: Tue Oct 10 2017 - 22:37:20 EST


On 11 October 2017 at 12:46, Jakub Kicinski <kubakici@xxxxx> wrote:
> On Tue, 10 Oct 2017 21:44:01 -0400, Tyler Hicks wrote:
>> On 10/10/2017 09:28 PM, Jakub Kicinski wrote:
>> > I'm hitting this on sysctl -a with net-next (4.14-rc4).
>>
>> Hey Jakub - thanks for the bug report!
>>
>> >
>> > I saw that seccomp_actions_logged_handler was introduced
>> > not-so-long-ago by Tyler, is there a fix for this?
>>
>> No, this is the first I've heard of it. I'll have a look.
>
> Thanks! :)

Hint: start looking at this thread. https://lkml.org/lkml/2017/7/18/874

Summary: strscpy and KASAN are currently incompatible. strscpy does a
64 bit speculative fetch on a char pointer (for efficiency reasons).
KASAN spots this and flags an error.