virtchnl: fix fake 1-elem arrays in structures allocated as `nents + 1`

There are five virtchnl structures, which are allocated and checked in
the code as `nents + 1`, meaning that they always have memory for one
excessive element regardless of their actual number. This comes from
that their sizeof() includes space for 1 element and then they get
allocated via struct_size() or its open-coded equivalents, passing
the actual number of elements.
Expand virtchnl_struct_size() to handle such structures and replace
those 1-elem arrays with proper flex ones. Also fix several places
which open-code %IAVF_VIRTCHNL_VF_RESOURCE_SIZE. Finally, let the
virtchnl_ether_addr_list size be computed automatically when there's
no enough space for the whole list, otherwise we have to open-code
reverse struct_size() logics.

Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 35 insertions, 22 deletions

diff --git a/include/linux/avf/virtchnl.h b/include/linux/avf/virtchnl.h
index 3ab207c14809..c1a20b533fc0 100644
--- a/include/linux/avf/virtchnl.h
+++ b/include/linux/avf/virtchnl.h
@@ -268,10 +268,11 @@ struct virtchnl_vf_resource {
 	u32 rss_key_size;
 	u32 rss_lut_size;
 
-	struct virtchnl_vsi_resource vsi_res[1];
+	struct virtchnl_vsi_resource vsi_res[];
 };
 
-VIRTCHNL_CHECK_STRUCT_LEN(36, virtchnl_vf_resource);
+VIRTCHNL_CHECK_STRUCT_LEN(20, virtchnl_vf_resource);
+#define virtchnl_vf_resource_LEGACY_SIZEOF	36
 
 /* VIRTCHNL_OP_CONFIG_TX_QUEUE
  * VF sends this message to set up parameters for one TX queue.
@@ -340,10 +341,11 @@ struct virtchnl_vsi_queue_config_info {
 	u16 vsi_id;
 	u16 num_queue_pairs;
 	u32 pad;
-	struct virtchnl_queue_pair_info qpair[1];
+	struct virtchnl_queue_pair_info qpair[];
 };
 
-VIRTCHNL_CHECK_STRUCT_LEN(72, virtchnl_vsi_queue_config_info);
+VIRTCHNL_CHECK_STRUCT_LEN(8, virtchnl_vsi_queue_config_info);
+#define virtchnl_vsi_queue_config_info_LEGACY_SIZEOF	72
 
 /* VIRTCHNL_OP_REQUEST_QUEUES
  * VF sends this message to request the PF to allocate additional queues to
@@ -385,10 +387,11 @@ VIRTCHNL_CHECK_STRUCT_LEN(12, virtchnl_vector_map);
 
 struct virtchnl_irq_map_info {
 	u16 num_vectors;
-	struct virtchnl_vector_map vecmap[1];
+	struct virtchnl_vector_map vecmap[];
 };
 
-VIRTCHNL_CHECK_STRUCT_LEN(14, virtchnl_irq_map_info);
+VIRTCHNL_CHECK_STRUCT_LEN(2, virtchnl_irq_map_info);
+#define virtchnl_irq_map_info_LEGACY_SIZEOF	14
 
 /* VIRTCHNL_OP_ENABLE_QUEUES
  * VIRTCHNL_OP_DISABLE_QUEUES
@@ -459,10 +462,11 @@ VIRTCHNL_CHECK_STRUCT_LEN(8, virtchnl_ether_addr);
 struct virtchnl_ether_addr_list {
 	u16 vsi_id;
 	u16 num_elements;
-	struct virtchnl_ether_addr list[1];
+	struct virtchnl_ether_addr list[];
 };
 
-VIRTCHNL_CHECK_STRUCT_LEN(12, virtchnl_ether_addr_list);
+VIRTCHNL_CHECK_STRUCT_LEN(4, virtchnl_ether_addr_list);
+#define virtchnl_ether_addr_list_LEGACY_SIZEOF	12
 
 /* VIRTCHNL_OP_ADD_VLAN
  * VF sends this message to add one or more VLAN tag filters for receives.
@@ -481,10 +485,11 @@ VIRTCHNL_CHECK_STRUCT_LEN(12, virtchnl_ether_addr_list);
 struct virtchnl_vlan_filter_list {
 	u16 vsi_id;
 	u16 num_elements;
-	u16 vlan_id[1];
+	u16 vlan_id[];
 };
 
-VIRTCHNL_CHECK_STRUCT_LEN(6, virtchnl_vlan_filter_list);
+VIRTCHNL_CHECK_STRUCT_LEN(4, virtchnl_vlan_filter_list);
+#define virtchnl_vlan_filter_list_LEGACY_SIZEOF	6
 
 /* This enum is used for all of the VIRTCHNL_VF_OFFLOAD_VLAN_V2_CAPS related
  * structures and opcodes.
@@ -1372,11 +1377,19 @@ VIRTCHNL_CHECK_STRUCT_LEN(12, virtchnl_fdir_del);
 #define __vss_byone(p, member, count, old)				      \
 	(struct_size(p, member, count) + (old - 1 - struct_size(p, member, 0)))
 
+#define __vss_full(p, member, count, old)				      \
+	(struct_size(p, member, count) + (old - struct_size(p, member, 0)))
+
 #define __vss(type, func, p, member, count)		\
 	struct type: func(p, member, count, type##_LEGACY_SIZEOF)
 
 #define virtchnl_struct_size(p, m, c)					      \
 	_Generic(*p,							      \
+		 __vss(virtchnl_vf_resource, __vss_full, p, m, c),	      \
+		 __vss(virtchnl_vsi_queue_config_info, __vss_full, p, m, c),  \
+		 __vss(virtchnl_irq_map_info, __vss_full, p, m, c),	      \
+		 __vss(virtchnl_ether_addr_list, __vss_full, p, m, c),	      \
+		 __vss(virtchnl_vlan_filter_list, __vss_full, p, m, c),	      \
 		 __vss(virtchnl_rss_key, __vss_byone, p, m, c),		      \
 		 __vss(virtchnl_rss_lut, __vss_byone, p, m, c))
 
@@ -1414,24 +1427,23 @@ virtchnl_vc_validate_vf_msg(struct virtchnl_version_info *ver, u32 v_opcode,
 		valid_len = sizeof(struct virtchnl_rxq_info);
 		break;
 	case VIRTCHNL_OP_CONFIG_VSI_QUEUES:
-		valid_len = sizeof(struct virtchnl_vsi_queue_config_info);
+		valid_len = virtchnl_vsi_queue_config_info_LEGACY_SIZEOF;
 		if (msglen >= valid_len) {
 			struct virtchnl_vsi_queue_config_info *vqc =
 			    (struct virtchnl_vsi_queue_config_info *)msg;
-			valid_len += (vqc->num_queue_pairs *
-				      sizeof(struct
-					     virtchnl_queue_pair_info));
+			valid_len = virtchnl_struct_size(vqc, qpair,
+							 vqc->num_queue_pairs);
 			if (vqc->num_queue_pairs == 0)
 				err_msg_format = true;
 		}
 		break;
 	case VIRTCHNL_OP_CONFIG_IRQ_MAP:
-		valid_len = sizeof(struct virtchnl_irq_map_info);
+		valid_len = virtchnl_irq_map_info_LEGACY_SIZEOF;
 		if (msglen >= valid_len) {
 			struct virtchnl_irq_map_info *vimi =
 			    (struct virtchnl_irq_map_info *)msg;
-			valid_len += (vimi->num_vectors *
-				      sizeof(struct virtchnl_vector_map));
+			valid_len = virtchnl_struct_size(vimi, vecmap,
+							 vimi->num_vectors);
 			if (vimi->num_vectors == 0)
 				err_msg_format = true;
 		}
@@ -1442,23 +1454,24 @@ virtchnl_vc_validate_vf_msg(struct virtchnl_version_info *ver, u32 v_opcode,
 		break;
 	case VIRTCHNL_OP_ADD_ETH_ADDR:
 	case VIRTCHNL_OP_DEL_ETH_ADDR:
-		valid_len = sizeof(struct virtchnl_ether_addr_list);
+		valid_len = virtchnl_ether_addr_list_LEGACY_SIZEOF;
 		if (msglen >= valid_len) {
 			struct virtchnl_ether_addr_list *veal =
 			    (struct virtchnl_ether_addr_list *)msg;
-			valid_len += veal->num_elements *
-			    sizeof(struct virtchnl_ether_addr);
+			valid_len = virtchnl_struct_size(veal, list,
+							 veal->num_elements);
 			if (veal->num_elements == 0)
 				err_msg_format = true;
 		}
 		break;
 	case VIRTCHNL_OP_ADD_VLAN:
 	case VIRTCHNL_OP_DEL_VLAN:
-		valid_len = sizeof(struct virtchnl_vlan_filter_list);
+		valid_len = virtchnl_vlan_filter_list_LEGACY_SIZEOF;
 		if (msglen >= valid_len) {
 			struct virtchnl_vlan_filter_list *vfl =
 			    (struct virtchnl_vlan_filter_list *)msg;
-			valid_len += vfl->num_elements * sizeof(u16);
+			valid_len = virtchnl_struct_size(vfl, vlan_id,
+							 vfl->num_elements);
 			if (vfl->num_elements == 0)
 				err_msg_format = true;
 		}