RDMA/irdma: Prevent rereg_mr for non-mem regions

[ Upstream commit a846aec ]

When a QP/CQ/SRQ is created, a two step process is used
where the buffer is allocated in userspace and explicitly
registered with the normal reg_mr mechanism prior to creating
the actual QP/CQ/SRQ object.

These special registrations are indicated via an ABI field
so the driver knows that they do not have a valid mkey and
to skip the actual CQP command submission.

Since these are real MR objects from the core's perspective,
it is possible for a user application to invoke rereg_mr on them
and cause a real CQP op to be emitted with the zero-initialized
mkey value of 0.

Fix this by preventing rereg_mr on these special regions.

Fixes: 5ac388d ("RDMA/irdma: Add support to re-register a memory region")
Signed-off-by: Jacob Moroni <jmoroni@google.com>
Reviewed-by: David Hu <xuehaohu@google.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: jakemoroni

drivers/infiniband/hw/irdma/verbs.c

@@ -3251,6 +3251,9 @@ static struct ib_mr *irdma_rereg_user_mr(struct ib_mr *ib_mr, int flags,
 	if (flags & ~(IB_MR_REREG_TRANS | IB_MR_REREG_PD | IB_MR_REREG_ACCESS))
 		return ERR_PTR(-EOPNOTSUPP);
 
+	if (iwmr->type != IRDMA_MEMREG_TYPE_MEM)
+	     return ERR_PTR(-EINVAL);
+
 	ret = ib_umem_check_rereg(iwmr->region, flags, new_access);
 	if (ret)
 		return ERR_PTR(ret);