idpf: sprinkle __counted_by{,_le}() in the virtchnl2 header

Both virtchnl2.h and its consumer idpf_virtchnl.c are very error-prone.
There are 10 structures with flexible arrays at the end, but 9 of them
has flex member counter in Little Endian.
Make the code a bit more robust by applying __counted_by_le() to those
9. LE platforms is the main target for this driver, so they would
receive additional protection.
While we're here, add __counted_by() to virtchnl2_ptype::proto_id, as
its counter is `u8` regardless of the Endianness.
Compile test on x86_64 (LE) didn't reveal any new issues after applying
the attributes.

Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://lore.kernel.org/r/20240327142241.1745989-4-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/intel/idpf/virtchnl2.h

@@ -555,7 +555,7 @@ VIRTCHNL2_CHECK_STRUCT_LEN(32, virtchnl2_queue_reg_chunk);
 struct virtchnl2_queue_reg_chunks {
 	__le16 num_chunks;
 	u8 pad[6];
-	struct virtchnl2_queue_reg_chunk chunks[];
+	struct virtchnl2_queue_reg_chunk chunks[] __counted_by_le(num_chunks);
 };
 VIRTCHNL2_CHECK_STRUCT_LEN(8, virtchnl2_queue_reg_chunks);
 
@@ -703,7 +703,7 @@ struct virtchnl2_config_tx_queues {
 	__le32 vport_id;
 	__le16 num_qinfo;
 	u8 pad[10];
-	struct virtchnl2_txq_info qinfo[];
+	struct virtchnl2_txq_info qinfo[] __counted_by_le(num_qinfo);
 };
 VIRTCHNL2_CHECK_STRUCT_LEN(16, virtchnl2_config_tx_queues);
 
@@ -782,7 +782,7 @@ struct virtchnl2_config_rx_queues {
 	__le32 vport_id;
 	__le16 num_qinfo;
 	u8 pad[18];
-	struct virtchnl2_rxq_info qinfo[];
+	struct virtchnl2_rxq_info qinfo[] __counted_by_le(num_qinfo);
 };
 VIRTCHNL2_CHECK_STRUCT_LEN(24, virtchnl2_config_rx_queues);
 
@@ -868,7 +868,7 @@ VIRTCHNL2_CHECK_STRUCT_LEN(32, virtchnl2_vector_chunk);
 struct virtchnl2_vector_chunks {
 	__le16 num_vchunks;
 	u8 pad[14];
-	struct virtchnl2_vector_chunk vchunks[];
+	struct virtchnl2_vector_chunk vchunks[] __counted_by_le(num_vchunks);
 };
 VIRTCHNL2_CHECK_STRUCT_LEN(16, virtchnl2_vector_chunks);
 
@@ -912,7 +912,7 @@ struct virtchnl2_rss_lut {
 	__le16 lut_entries_start;
 	__le16 lut_entries;
 	u8 pad[4];
-	__le32 lut[];
+	__le32 lut[] __counted_by_le(lut_entries);
 };
 VIRTCHNL2_CHECK_STRUCT_LEN(12, virtchnl2_rss_lut);
 
@@ -977,7 +977,7 @@ struct virtchnl2_ptype {
 	u8 ptype_id_8;
 	u8 proto_id_count;
 	__le16 pad;
-	__le16 proto_id[];
+	__le16 proto_id[] __counted_by(proto_id_count);
 } __packed __aligned(2);
 VIRTCHNL2_CHECK_STRUCT_LEN(6, virtchnl2_ptype);
 
@@ -1104,7 +1104,7 @@ struct virtchnl2_rss_key {
 	__le32 vport_id;
 	__le16 key_len;
 	u8 pad;
-	u8 key_flex[];
+	u8 key_flex[] __counted_by_le(key_len);
 } __packed;
 VIRTCHNL2_CHECK_STRUCT_LEN(7, virtchnl2_rss_key);
 
@@ -1131,7 +1131,7 @@ VIRTCHNL2_CHECK_STRUCT_LEN(16, virtchnl2_queue_chunk);
 struct virtchnl2_queue_chunks {
 	__le16 num_chunks;
 	u8 pad[6];
-	struct virtchnl2_queue_chunk chunks[];
+	struct virtchnl2_queue_chunk chunks[] __counted_by_le(num_chunks);
 };
 VIRTCHNL2_CHECK_STRUCT_LEN(8, virtchnl2_queue_chunks);
 
@@ -1195,7 +1195,7 @@ struct virtchnl2_queue_vector_maps {
 	__le32 vport_id;
 	__le16 num_qv_maps;
 	u8 pad[10];
-	struct virtchnl2_queue_vector qv_maps[];
+	struct virtchnl2_queue_vector qv_maps[] __counted_by_le(num_qv_maps);
 };
 VIRTCHNL2_CHECK_STRUCT_LEN(16, virtchnl2_queue_vector_maps);
 
@@ -1247,7 +1247,7 @@ struct virtchnl2_mac_addr_list {
 	__le32 vport_id;
 	__le16 num_mac_addr;
 	u8 pad[2];
-	struct virtchnl2_mac_addr mac_addr_list[];
+	struct virtchnl2_mac_addr mac_addr_list[] __counted_by_le(num_mac_addr);
 };
 VIRTCHNL2_CHECK_STRUCT_LEN(8, virtchnl2_mac_addr_list);