Re: [PATCH rdma-next] IB/mthca: Check validity of output parameter pointer

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

[-- Attachment #1: Type: text/plain, Size: 2692 bytes --]

On Tue, Apr 18, 2017 at 04:48:56PM +0300, Yuval Shaia wrote:
> On Sat, Apr 15, 2017 at 06:47:25PM +0300, Leon Romanovsky wrote:
> > The mthca driver didn't check supplied pointer to functions
> > mthca_cmd_poll() and mthca_cmd_wait(). This caused to the following
> > smatch errors:
> >
> > drivers/infiniband/hw/mthca/mthca_cmd.c:371 mthca_cmd_poll() error: we previously assumed 'out_param' could be null (see line 353)
> > drivers/infiniband/hw/mthca/mthca_cmd.c:454 mthca_cmd_wait() error: we previously assumed 'out_param' could be null (see line 432)
> >
> > In reality all callers of these functions are setting out_is_imm
> > flag are providing pointer too. However it is better to check
> > again to remove smatch errors to achieve warning free subsystem.
> >
> > Signed-off-by: Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> > ---
> >  Based on k.o/for-4.12 branch.
> > ---
> >  drivers/infiniband/hw/mthca/mthca_cmd.c | 12 ++++++++++--
> >  1 file changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/infiniband/hw/mthca/mthca_cmd.c b/drivers/infiniband/hw/mthca/mthca_cmd.c
> > index c7f49bbb0c72..9d83a53c0c67 100644
> > --- a/drivers/infiniband/hw/mthca/mthca_cmd.c
> > +++ b/drivers/infiniband/hw/mthca/mthca_cmd.c
> > @@ -367,12 +367,16 @@ static int mthca_cmd_poll(struct mthca_dev *dev,
> >  		goto out;
> >  	}
> >
> > -	if (out_is_imm)
> > +	if (out_is_imm && out_param) {
> >  		*out_param =
> >  			(u64) be32_to_cpu((__force __be32)
> >  					  __raw_readl(dev->hcr + HCR_OUT_PARAM_OFFSET)) << 32 |
> >  			(u64) be32_to_cpu((__force __be32)
> >  					  __raw_readl(dev->hcr + HCR_OUT_PARAM_OFFSET + 4));
> > +	} else if (out_is_imm) {
> > +		err = -EINVAL;
> > +		goto out;
>
> So if this is a good reason to fail the function - how about doing this
> validation before triggering HW operation (mthca_cmd_post)?

It doesn't matter, it will give the same bytecode.

>
> > +	}
> >
> >  	status = be32_to_cpu((__force __be32) __raw_readl(dev->hcr + HCR_STATUS_OFFSET)) >> 24;
> >  	if (status) {
> > @@ -450,8 +454,12 @@ static int mthca_cmd_wait(struct mthca_dev *dev,
> >  		err = mthca_status_to_errno(context->status);
> >  	}
> >
> > -	if (out_is_imm)
> > +	if (out_is_imm && out_param) {
> >  		*out_param = context->out_param;
> > +	} else if (out_is_imm) {
> > +		err = -EINVAL;
>
> Ditto
>
> > +		goto out;
> > +	}
> >
> >  out:
> >  	spin_lock(&dev->cmd.context_lock);
> > --
> > 2.12.2
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]