How to fuzz testing infiniband/uverb driver

How to fuzz testing infiniband/uverb driver

[Changming Liu]

Hi Jason,
Greetings, I'm a PhD student interested in linux, I found a bug in 
drivers/infiniband/core/uverbs_cmd.c via static analysis.

As a follow-up, I planned to fuzz testing this driver using syzkaller
to confirm this.
However, according to the doc in Documentation/infiniband/user_verbs.rst,
(it's a bit out-dated BTW, as CONFIG_INFINIBAND_USER_VERBS is not used anymore).
I built the kernel with all related options set to y, installed libibverbs-dev,
and added KERNEL="uverbs*", NAME="infiniband/%k" to my udev rule.

there is no 'uverbs0' file created under /sys/class/infiniband or 
/dev/infiniband/. So may I ask how to properly set up my testing 
environment so that I can fuzzi testing this driver? Is a physical
device required?

Any information is greatly appreciated.

Best,
Changming Liu

Re: How to fuzz testing infiniband/uverb driver

[Ira Weiny]

On Sun, Nov 01, 2020 at 09:00:13PM +0000, Changming Liu wrote:
> 
> there is no 'uverbs0' file created under /sys/class/infiniband or 
> /dev/infiniband/. So may I ask how to properly set up my testing 
> environment so that I can fuzzi testing this driver? Is a physical
> device required?

A physical device is not required.  Look at one of the software drivers like
rxe.

Ira

RE: How to fuzz testing infiniband/uverb driver

[Changming Liu]

> -----Original Message-----
> From: Ira Weiny <ira.weiny@intel.com>
> Sent: Monday, November 2, 2020 11:16 AM
> To: Changming Liu <liu.changm@northeastern.edu>
> Cc: jgg@ziepe.ca; linux-rdma@vger.kernel.org; yaohway
> <yaohway@gmail.com>
> Subject: Re: How to fuzz testing infiniband/uverb driver
> 
> On Sun, Nov 01, 2020 at 09:00:13PM +0000, Changming Liu wrote:
> >
> > there is no 'uverbs0' file created under /sys/class/infiniband or
> > /dev/infiniband/. So may I ask how to properly set up my testing
> > environment so that I can fuzzi testing this driver? Is a physical
> > device required?
> 
> A physical device is not required.  Look at one of the software drivers like rxe.
> 

Thank you so much for your guidance, 
now uverb0 has appeared and syzkaller works!

Best,
Changming

Re: How to fuzz testing infiniband/uverb driver

[Ira Weiny]

On Mon, Nov 02, 2020 at 10:26:22PM +0000, Changming Liu wrote:
> 
> 
> > -----Original Message-----
> > From: Ira Weiny <ira.weiny@intel.com>
> > Sent: Monday, November 2, 2020 11:16 AM
> > To: Changming Liu <liu.changm@northeastern.edu>
> > Cc: jgg@ziepe.ca; linux-rdma@vger.kernel.org; yaohway
> > <yaohway@gmail.com>
> > Subject: Re: How to fuzz testing infiniband/uverb driver
> > 
> > On Sun, Nov 01, 2020 at 09:00:13PM +0000, Changming Liu wrote:
> > >
> > > there is no 'uverbs0' file created under /sys/class/infiniband or
> > > /dev/infiniband/. So may I ask how to properly set up my testing
> > > environment so that I can fuzzi testing this driver? Is a physical
> > > device required?
> > 
> > A physical device is not required.  Look at one of the software drivers like rxe.
> > 
> 
> Thank you so much for your guidance, 
> now uverb0 has appeared and syzkaller works!

Awesome!  More testing is never a bad thing!  :-D

Ira