From mboxrd@z Thu Jan  1 00:00:00 1970
From: davem@davemloft.net (David Miller)
Date: Wed, 13 Jan 2016 00:00:16 -0500 (EST)
Subject: [PATCHv2] net: bpf: reject invalid shifts
In-Reply-To: <1452658064.1223.58.camel@edumazet-glaptop2.roam.corp.google.com>
References: <1452651098.1223.41.camel@edumazet-glaptop2.roam.corp.google.com>
 <20160112.214315.2135966842775837844.davem@davemloft.net>
 <1452658064.1223.58.camel@edumazet-glaptop2.roam.corp.google.com>
Message-ID: <20160113.000016.2304166666171388740.davem@davemloft.net>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 12 Jan 2016 20:07:44 -0800

> On Tue, 2016-01-12 at 21:43 -0500, David Miller wrote:
>> From: Eric Dumazet <eric.dumazet@gmail.com>
>> Date: Tue, 12 Jan 2016 18:11:38 -0800
>> 
>> > As I said, it is possible some guys never noticed their BPF program
>> > were 'broken' because this invalid shift was hidden in a dead code
>> > part.
>> 
>> We should not hide bugs and unintended uses of operations with
>> undefined behavior.
> 
>    JUMP 2:
>    SHR  45
> 2: RET  10
> 
> 
> was a valid program.
> 
> But a dumb loader decided to know better.

I guess you are uninterested in knowing your programs contains such
garbage.