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From: Dan Williams <dan.j.williams@intel.com>
Date: Tue, 9 Jan 2018 11:44:05 -0800
Message-ID: <CAPcyv4gccDQYx9urpagnBo-TqNLoQ00gEoE7kp+JXNKsmFxcHw@mail.gmail.com> (sfid-20180109_204449_177698_2538E001)
Subject: Re: [PATCH 00/18] prevent bounds-check bypass via speculative execution
To: Jiri Kosina <jikos@kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
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On Tue, Jan 9, 2018 at 11:34 AM, Jiri Kosina <jikos@kernel.org> wrote:
> On Fri, 5 Jan 2018, Dan Williams wrote:
>
> [ ... snip ... ]
>> Andi Kleen (1):
>>       x86, barrier: stop speculation for failed access_ok
>>
>> Dan Williams (13):
>>       x86: implement nospec_barrier()
>>       [media] uvcvideo: prevent bounds-check bypass via speculative execution
>>       carl9170: prevent bounds-check bypass via speculative execution
>>       p54: prevent bounds-check bypass via speculative execution
>>       qla2xxx: prevent bounds-check bypass via speculative execution
>>       cw1200: prevent bounds-check bypass via speculative execution
>>       Thermal/int340x: prevent bounds-check bypass via speculative execution
>>       ipv6: prevent bounds-check bypass via speculative execution
>>       ipv4: prevent bounds-check bypass via speculative execution
>>       vfs, fdtable: prevent bounds-check bypass via speculative execution
>>       net: mpls: prevent bounds-check bypass via speculative execution
>>       udf: prevent bounds-check bypass via speculative execution
>>       userns: prevent bounds-check bypass via speculative execution
>>
>> Mark Rutland (4):
>>       asm-generic/barrier: add generic nospec helpers
>>       Documentation: document nospec helpers
>>       arm64: implement nospec_ptr()
>>       arm: implement nospec_ptr()
>
> So considering the recent publication of [1], how come we all of a sudden
> don't need the barriers in ___bpf_prog_run(), namely for LD_IMM_DW and
> LDX_MEM_##SIZEOP, and something comparable for eBPF JIT?
>
> Is this going to be handled in eBPF in some other way?
>
> Without that in place, and considering Jann Horn's paper, it would seem
> like PTI doesn't really lock it down fully, right?

Here is the latest (v3) bpf fix:

https://patchwork.ozlabs.org/patch/856645/

I currently have v2 on my 'nospec' branch and will move that to v3 for
the next update, unless it goes upstream before then.