[PATCH rdma-next 08/23] RDMA/core: Suppress kverbs_provider for adversarial_mode devices

[Yishai Hadas <yishaih@nvidia.com>]

In adversarial mode the NIC is not trusted. Kernel ULPs such as MAD,
IB CM, rdma_cm, IPoIB, SRP, iSER and NVMe-oF trust what the device
reports, its completions and the data it writes, so they must not use
such a device.

Add an adversarial_mode field to struct ib_device and clear
kverbs_provider when it is set. add_client_context() then skips every
client but uverbs, the only one that sets no_kverbs_req, so the kernel
ULPs never bind to the device.

The driver still implements the kverbs ops, as the uverbs path shares
them, so kverbs_provider can't be cleared by the existing check of the
mandatory ops.

Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
---
 drivers/infiniband/core/device.c | 8 ++++++++
 include/rdma/ib_verbs.h          | 2 ++
 2 files changed, 10 insertions(+)

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 29af9fe860e2..eb6aa567d365 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -312,6 +312,14 @@ static void ib_device_check_mandatory(struct ib_device *device)
 			break;
 		}
 	}
+
+	/*
+	 * Kernel ULPs must not bind to an adversarial_mode device. Its kverbs
+	 * ops are still present, as uverbs uses them, so clear kverbs_provider
+	 * explicitly. uverbs sets no_kverbs_req, so it still binds.
+	 */
+	if (device->adversarial_mode)
+		device->kverbs_provider = false;
 }
 
 /*
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index d6eaa3fee66e..6209a5166f0d 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -3008,6 +3008,8 @@ struct ib_device {
 	u16                          use_cq_dim:1;
 	/* CoCo guest with DMA bounce buffering required */
 	u16                          cc_dma_bounce:1;
+	/* Untrusted-NIC, adversarial mode is required */
+	u8			     adversarial_mode;
 	u8                           node_type;
 	u32			     phys_port_cnt;
 	struct ib_device_attr        attrs;
-- 
2.18.1