[IB] uverbs: reject invalid memory registration permission flags

Reject userspace memory registrations with invalid permission flags:
"local write" is required if "remote write" or "remote atomic" is also
requested.

Pointed out by Jack Morgenstein <jackm@mellanox.co.il>

Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index a0ceb1cbed52..2e959acf2ff1 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -396,6 +396,14 @@ 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;
+
         obj = kmalloc(sizeof *obj, GFP_KERNEL);
         if (!obj)
                 return -ENOMEM;