Re: net/smc and the RDMA core

[Ursula Braun <ubraun@linux.vnet.ibm.com>]

On 05/04/2017 10:48 AM, hch@lst.de wrote:
> On Thu, May 04, 2017 at 11:43:50AM +0300, Sagi Grimberg wrote:
>> I would also suggest that you stop exposing the DMA MR for remote
>> access (at least by default) and use a proper reg_mr operations with a
>> limited lifetime on a properly sized buffer.
> 
> Yes, exposing the default DMA MR is a _major_ security risk.  As soon
> as SMC is enabled this will mean a remote system has full read/write
> access to the local systems memory.
> 
> There іs a reason why I removed the ib_get_dma_mr function and replaced
> it with the IB_PD_UNSAFE_GLOBAL_RKEY key that has _UNSAFE_ in the name
> and a very long comment explaining why, and I'm really disappointed that
> we got a driver merged that instead of asking on the relevant list on
> why a change unexpertong a function it needed happened and instead
> tried the hard way to keep a security vulnerarbility alive.
> 
Thanks for pointing out these problems. We will address them.