genetlink: limit the use of validation workarounds to old ops

During review of previous change another thing came up - we should
limit the use of validation workarounds to old commands.
Don't list the workarounds one by one, as we're rejecting all existing
ones. We can deal with the masking in the unlikely event that new flag
is added.

Link: https://lore.kernel.org/all/6ba9f727e555fd376623a298d5d305ad408c3d47.camel@sipsolutions.net/
Link: https://lore.kernel.org/r/20221026001524.1892202-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index b1fd059c99928569c97258dbb8d13855b6db1d96..3e16527beb9148b5da97baf7d193f1da9af445a9 100644 (file)
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -380,6 +380,8 @@ static int genl_validate_ops(const struct genl_family *family)
                genl_get_cmd_by_index(i, family, &op);
                if (op.dumpit == NULL && op.doit == NULL)
                        return -EINVAL;
+               if (WARN_ON(op.cmd >= family->resv_start_op && op.validate))
+                       return -EINVAL;
                for (j = i + 1; j < genl_get_cmd_cnt(family); j++) {
                        struct genl_ops op2;