[PATCHv2] net: bpf: reject invalid shifts

[Eric Dumazet]

On Tue, 2016-01-12 at 21:43 -0500, David Miller wrote:
> From: Eric Dumazet <eric.dumazet at 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.