net: ethtool: reject unsupported RSS input xfrm values

RXFH input_xfrm currently has three supported values: 0 (clear all),
symmetric_xor and NO_CHANGE.

Reject any other value sent from user-space.

Fixes: 13e59344 ("net: ethtool: add support for symmetric-xor RSS hash")
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
Link: https://lore.kernel.org/r/20240104212653.394424-1-ahmed.zaki@intel.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/ethtool/ioctl.c

@@ -1302,6 +1302,9 @@ static noinline_for_stack int ethtool_set_rxfh(struct net_device *dev,
 	if (rxfh.rss_context && !ops->cap_rss_ctx_supported)
 		return -EOPNOTSUPP;
 	/* Check input data transformation capabilities */
+	if (rxfh.input_xfrm && rxfh.input_xfrm != RXH_XFRM_SYM_XOR &&
+	    rxfh.input_xfrm != RXH_XFRM_NO_CHANGE)
+		return -EINVAL;
 	if ((rxfh.input_xfrm & RXH_XFRM_SYM_XOR) &&
 	    !ops->cap_rss_sym_xor_supported)
 		return -EOPNOTSUPP;