Re: usercopy whitelist woe in scsi_sense_cache

[Kees Cook]

On Tue, Apr 10, 2018 at 10:16 AM, Oleksandr Natalenko
<oleksandr@xxxxxxxxxxxxxx> wrote:
> Hi, Kees, Paolo et al.
>
> 10.04.2018 08:53, Kees Cook wrote:
>>
>> Unfortunately I only had a single hang with no dumps. I haven't been
>> able to reproduce it since. :(
>
>
> For your convenience I've prepared a VM that contains a reproducer.

Awesome. :)

> Under the /root folder there is a reproducer script (reproducer.sh). It does
> trivial things like enabling sysrq, opening LUKS device, mounting a volume,
> running a background I/O (this is an important part, actually, since I
> wasn't able to trigger the issue without the background I/O) and, finally,
> running the smartctl in a loop. If you are lucky, within a minute or two
> you'll get the first warning followed shortly by subsequent bugs and I/O
> stall (htop is pre-installed for your convenience too).

Yup!

[   27.729498] Bad or missing usercopy whitelist? Kernel memory
exposure attempt detected from SLUB object 'scsi_sense_cache' (offset
76, size 22)!

I'll see about booting with my own kernels, etc, and try to narrow this down. :)

-Kees

-- 
Kees Cook
Pixel Security