[PATCH V1 rdma-next 23/24] RDMA/core: Report and enforce adversarial mode via GET_CONTEXT

[Yishai Hadas <yishaih@nvidia.com>]

Userspace must know when a device is in adversarial mode, and an
unaware rdma-core must not get a context on such a device, as it
doesn't harden itself against the NIC.

Report the mode with IB_UVERBS_CORE_SUPPORT_ADVERSARIAL in the
core_support of GET_CONTEXT and QUERY_CONTEXT. Add an optional
UVERBS_ATTR_GET_CONTEXT_FLAGS input, where userspace declares
UVERBS_ATTR_GET_CONTEXT_FLAG_ADVERSARIAL_SUPPORTED. In adversarial
mode, GET_CONTEXT without that flag fails with -EPERM, and so does the
legacy write() GET_CONTEXT, which has no way to pass it.

Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
---
 drivers/infiniband/core/uverbs_cmd.c             |  5 +++++
 .../infiniband/core/uverbs_std_types_device.c    | 16 ++++++++++++++++
 include/uapi/rdma/ib_user_ioctl_cmds.h           |  5 +++++
 include/uapi/rdma/ib_user_ioctl_verbs.h          |  1 +
 4 files changed, 27 insertions(+)

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index aca7c6ab55cd..b78207a81091 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -292,6 +292,11 @@ static int ib_uverbs_get_context(struct uverbs_attr_bundle *attrs)
 		goto err_ucontext;
 	}
 
+	if (ib_dev->adversarial_mode) {
+		ret = -EPERM;
+		goto err_uobj;
+	}
+
 	resp = (struct ib_uverbs_get_context_resp){
 		.num_comp_vectors = attrs->ufile->device->num_comp_vectors,
 		.async_fd = uobj->id,
diff --git a/drivers/infiniband/core/uverbs_std_types_device.c b/drivers/infiniband/core/uverbs_std_types_device.c
index db65032e80b4..72c67f09533e 100644
--- a/drivers/infiniband/core/uverbs_std_types_device.c
+++ b/drivers/infiniband/core/uverbs_std_types_device.c
@@ -248,6 +248,7 @@ static int UVERBS_HANDLER(UVERBS_METHOD_GET_CONTEXT)(
 	u32 num_comp = attrs->ufile->device->num_comp_vectors;
 	u64 core_support = IB_UVERBS_CORE_SUPPORT_OPTIONAL_MR_ACCESS;
 	struct ib_device *ib_dev;
+	u32 ctx_flags;
 	int ret;
 
 	ib_dev = srcu_dereference(attrs->ufile->device->ib_dev,
@@ -255,6 +256,15 @@ static int UVERBS_HANDLER(UVERBS_METHOD_GET_CONTEXT)(
 	if (!ib_dev)
 		return -EIO;
 
+	ret = uverbs_get_flags32(&ctx_flags, attrs, UVERBS_ATTR_GET_CONTEXT_FLAGS,
+				 UVERBS_ATTR_GET_CONTEXT_FLAG_ADVERSARIAL_SUPPORTED);
+	if (ret)
+		return ret;
+
+	if (ib_dev->adversarial_mode &&
+	    !(ctx_flags & UVERBS_ATTR_GET_CONTEXT_FLAG_ADVERSARIAL_SUPPORTED))
+		return -EPERM;
+
 	ret = uverbs_copy_to(attrs, UVERBS_ATTR_GET_CONTEXT_NUM_COMP_VECTORS,
 			     &num_comp, sizeof(num_comp));
 	if (IS_UVERBS_COPY_ERR(ret))
@@ -262,6 +272,8 @@ static int UVERBS_HANDLER(UVERBS_METHOD_GET_CONTEXT)(
 
 	if (ib_dev->ops.uverbs_robust_udata)
 		core_support |= IB_UVERBS_CORE_SUPPORT_ROBUST_UDATA;
+	if (ib_dev->adversarial_mode)
+		core_support |= IB_UVERBS_CORE_SUPPORT_ADVERSARIAL;
 	ret = uverbs_copy_to(attrs, UVERBS_ATTR_GET_CONTEXT_CORE_SUPPORT,
 			     &core_support, sizeof(core_support));
 	if (IS_UVERBS_COPY_ERR(ret))
@@ -303,6 +315,8 @@ static int UVERBS_HANDLER(UVERBS_METHOD_QUERY_CONTEXT)(
 	if (IS_UVERBS_COPY_ERR(ret))
 		return ret;
 
+	if (ib_dev->adversarial_mode)
+		core_support |= IB_UVERBS_CORE_SUPPORT_ADVERSARIAL;
 	ret = uverbs_copy_to(attrs, UVERBS_ATTR_QUERY_CONTEXT_CORE_SUPPORT,
 			     &core_support, sizeof(core_support));
 	if (IS_UVERBS_COPY_ERR(ret))
@@ -519,6 +533,8 @@ DECLARE_UVERBS_NAMED_METHOD(
 			   UVERBS_ATTR_MIN_SIZE(sizeof(int)),
 			   UA_OPTIONAL,
 			   UA_ALLOC_AND_COPY),
+	UVERBS_ATTR_FLAGS_IN(UVERBS_ATTR_GET_CONTEXT_FLAGS, u32,
+			     UA_OPTIONAL),
 	UVERBS_ATTR_UHW());
 
 DECLARE_UVERBS_NAMED_METHOD(
diff --git a/include/uapi/rdma/ib_user_ioctl_cmds.h b/include/uapi/rdma/ib_user_ioctl_cmds.h
index 816b3107464f..3e482a4338f9 100644
--- a/include/uapi/rdma/ib_user_ioctl_cmds.h
+++ b/include/uapi/rdma/ib_user_ioctl_cmds.h
@@ -101,10 +101,15 @@ enum uverbs_attrs_query_comp_cntr_caps_attr_ids {
 	UVERBS_ATTR_QUERY_COMP_CNTR_CAPS_SUPPORTED_QP_ATTACH_OPS,
 };
 
+enum uverbs_attrs_get_context_flags {
+	UVERBS_ATTR_GET_CONTEXT_FLAG_ADVERSARIAL_SUPPORTED = 1 << 0,
+};
+
 enum uverbs_attrs_get_context_attr_ids {
 	UVERBS_ATTR_GET_CONTEXT_NUM_COMP_VECTORS,
 	UVERBS_ATTR_GET_CONTEXT_CORE_SUPPORT,
 	UVERBS_ATTR_GET_CONTEXT_FD_ARR,
+	UVERBS_ATTR_GET_CONTEXT_FLAGS,
 };
 
 enum uverbs_attrs_query_context_attr_ids {
diff --git a/include/uapi/rdma/ib_user_ioctl_verbs.h b/include/uapi/rdma/ib_user_ioctl_verbs.h
index 21f86cc7bb1f..5861f34f8343 100644
--- a/include/uapi/rdma/ib_user_ioctl_verbs.h
+++ b/include/uapi/rdma/ib_user_ioctl_verbs.h
@@ -47,6 +47,7 @@
 enum ib_uverbs_core_support {
 	IB_UVERBS_CORE_SUPPORT_OPTIONAL_MR_ACCESS = 1 << 0,
 	IB_UVERBS_CORE_SUPPORT_ROBUST_UDATA = 1 << 1,
+	IB_UVERBS_CORE_SUPPORT_ADVERSARIAL = 1 << 2,
 };
 
 enum ib_uverbs_access_flags {
-- 
2.18.1