IB/core: Encorce MR access rights rules on kernel consumers

Enforce the rule that when requesting remote write or atomic permissions, local
write must be indicated as well. See IB spec 11.2.8.2.

Spotted by: Hagay Abramovsky <hagaya@mellanox.com>
Signed-off-by: NEli Cohen <eli@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

drivers/infiniband/core/uverbs_cmd.c

@@ -939,13 +939,9 @@ ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
 	if ((cmd.start & ~PAGE_MASK) != (cmd.hca_va & ~PAGE_MASK))
 		return -EINVAL;
 
-	/*
-	 * Local write permission is required if remote write or
-	 * remote atomic permission is also requested.
-	 */
-	if (cmd.access_flags & (IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_REMOTE_WRITE) &&
-	    !(cmd.access_flags & IB_ACCESS_LOCAL_WRITE))
-		return -EINVAL;
+	ret = ib_check_mr_access(cmd.access_flags);
+	if (ret)
+		return ret;
 
 	uobj = kmalloc(sizeof *uobj, GFP_KERNEL);
 	if (!uobj)

drivers/infiniband/core/verbs.c

@@ -961,6 +961,11 @@ EXPORT_SYMBOL(ib_resize_cq);
 struct ib_mr *ib_get_dma_mr(struct ib_pd *pd, int mr_access_flags)
 {
 	struct ib_mr *mr;
+	int err;
+
+	err = ib_check_mr_access(mr_access_flags);
+	if (err)
+		return ERR_PTR(err);
 
 	mr = pd->device->get_dma_mr(pd, mr_access_flags);
 
@@ -983,6 +988,11 @@ struct ib_mr *ib_reg_phys_mr(struct ib_pd *pd,
 			     u64 *iova_start)
 {
 	struct ib_mr *mr;
+	int err;
+
+	err = ib_check_mr_access(mr_access_flags);
+	if (err)
+		return ERR_PTR(err);
 
 	if (!pd->device->reg_phys_mr)
 		return ERR_PTR(-ENOSYS);
@@ -1013,6 +1023,10 @@ int ib_rereg_phys_mr(struct ib_mr *mr,
 	struct ib_pd *old_pd;
 	int ret;
 
+	ret = ib_check_mr_access(mr_access_flags);
+	if (ret)
+		return ret;
+
 	if (!mr->device->rereg_phys_mr)
 		return -ENOSYS;
 

include/rdma/ib_verbs.h

@@ -2386,4 +2386,17 @@ struct ib_flow *ib_create_flow(struct ib_qp *qp,
 			       struct ib_flow_attr *flow_attr, int domain);
 int ib_destroy_flow(struct ib_flow *flow_id);
 
+static inline int ib_check_mr_access(int flags)
+{
+	/*
+	 * Local write permission is required if remote write or
+	 * remote atomic permission is also requested.
+	 */
+	if (flags & (IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_REMOTE_WRITE) &&
+	    !(flags & IB_ACCESS_LOCAL_WRITE))
+		return -EINVAL;
+
+	return 0;
+}
+
 #endif /* IB_VERBS_H */