net/mlx4_core: Add security check / enforcement for flow steering rules set for VMs

Since VFs may be mapped to VMs which aren't trusted entities,  flow
steering rules attached through the wrapper on behalf of VFs must be
checked to make sure that their L2 specification relate to MAC address
assigned to that VF, and add L2 specification if its missing.

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/resource_tracker.c

@@ -42,6 +42,7 @@
 #include <linux/mlx4/cmd.h>
 #include <linux/mlx4/qp.h>
 #include <linux/if_ether.h>
+#include <linux/etherdevice.h>
 
 #include "mlx4.h"
 #include "fw.h"
@@ -2776,18 +2777,133 @@ ex_put:
 	return err;
 }
 
+/*
+ * MAC validation for Flow Steering rules.
+ * VF can attach rules only with a mac address which is assigned to it.
+ */
+static int validate_eth_header_mac(int slave, struct _rule_hw *eth_header,
+				   struct list_head *rlist)
+{
+	struct mac_res *res, *tmp;
+	__be64 be_mac;
+
+	/* make sure it isn't multicast or broadcast mac*/
+	if (!is_multicast_ether_addr(eth_header->eth.dst_mac) &&
+	    !is_broadcast_ether_addr(eth_header->eth.dst_mac)) {
+		list_for_each_entry_safe(res, tmp, rlist, list) {
+			be_mac = cpu_to_be64(res->mac << 16);
+			if (!memcmp(&be_mac, eth_header->eth.dst_mac, ETH_ALEN))
+				return 0;
+		}
+		pr_err("MAC %pM doesn't belong to VF %d, Steering rule rejected\n",
+		       eth_header->eth.dst_mac, slave);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/*
+ * In case of missing eth header, append eth header with a MAC address
+ * assigned to the VF.
+ */
+static int add_eth_header(struct mlx4_dev *dev, int slave,
+			  struct mlx4_cmd_mailbox *inbox,
+			  struct list_head *rlist, int header_id)
+{
+	struct mac_res *res, *tmp;
+	u8 port;
+	struct mlx4_net_trans_rule_hw_ctrl *ctrl;
+	struct mlx4_net_trans_rule_hw_eth *eth_header;
+	struct mlx4_net_trans_rule_hw_ipv4 *ip_header;
+	struct mlx4_net_trans_rule_hw_tcp_udp *l4_header;
+	__be64 be_mac = 0;
+	__be64 mac_msk = cpu_to_be64(MLX4_MAC_MASK << 16);
+
+	ctrl = (struct mlx4_net_trans_rule_hw_ctrl *)inbox->buf;
+	port = be32_to_cpu(ctrl->vf_vep_port) & 0xff;
+	eth_header = (struct mlx4_net_trans_rule_hw_eth *)(ctrl + 1);
+
+	/* Clear a space in the inbox for eth header */
+	switch (header_id) {
+	case MLX4_NET_TRANS_RULE_ID_IPV4:
+		ip_header =
+			(struct mlx4_net_trans_rule_hw_ipv4 *)(eth_header + 1);
+		memmove(ip_header, eth_header,
+			sizeof(*ip_header) + sizeof(*l4_header));
+		break;
+	case MLX4_NET_TRANS_RULE_ID_TCP:
+	case MLX4_NET_TRANS_RULE_ID_UDP:
+		l4_header = (struct mlx4_net_trans_rule_hw_tcp_udp *)
+			    (eth_header + 1);
+		memmove(l4_header, eth_header, sizeof(*l4_header));
+		break;
+	default:
+		return -EINVAL;
+	}
+	list_for_each_entry_safe(res, tmp, rlist, list) {
+		if (port == res->port) {
+			be_mac = cpu_to_be64(res->mac << 16);
+			break;
+		}
+	}
+	if (!be_mac) {
+		pr_err("Failed adding eth header to FS rule, Can't find matching MAC for port %d .\n",
+		       port);
+		return -EINVAL;
+	}
+
+	memset(eth_header, 0, sizeof(*eth_header));
+	eth_header->size = sizeof(*eth_header) >> 2;
+	eth_header->id = cpu_to_be16(__sw_id_hw[MLX4_NET_TRANS_RULE_ID_ETH]);
+	memcpy(eth_header->dst_mac, &be_mac, ETH_ALEN);
+	memcpy(eth_header->dst_mac_msk, &mac_msk, ETH_ALEN);
+
+	return 0;
+
+}
+
 int mlx4_QP_FLOW_STEERING_ATTACH_wrapper(struct mlx4_dev *dev, int slave,
 					 struct mlx4_vhcr *vhcr,
 					 struct mlx4_cmd_mailbox *inbox,
 					 struct mlx4_cmd_mailbox *outbox,
 					 struct mlx4_cmd_info *cmd)
 {
+
+	struct mlx4_priv *priv = mlx4_priv(dev);
+	struct mlx4_resource_tracker *tracker = &priv->mfunc.master.res_tracker;
+	struct list_head *rlist = &tracker->slave_list[slave].res_list[RES_MAC];
 	int err;
+	struct mlx4_net_trans_rule_hw_ctrl *ctrl;
+	struct _rule_hw  *rule_header;
+	int header_id;
 
 	if (dev->caps.steering_mode !=
 	    MLX4_STEERING_MODE_DEVICE_MANAGED)
 		return -EOPNOTSUPP;
 
+	ctrl = (struct mlx4_net_trans_rule_hw_ctrl *)inbox->buf;
+	rule_header = (struct _rule_hw *)(ctrl + 1);
+	header_id = map_hw_to_sw_id(be16_to_cpu(rule_header->id));
+
+	switch (header_id) {
+	case MLX4_NET_TRANS_RULE_ID_ETH:
+		if (validate_eth_header_mac(slave, rule_header, rlist))
+			return -EINVAL;
+		break;
+	case MLX4_NET_TRANS_RULE_ID_IPV4:
+	case MLX4_NET_TRANS_RULE_ID_TCP:
+	case MLX4_NET_TRANS_RULE_ID_UDP:
+		pr_warn("Can't attach FS rule without L2 headers, adding L2 header.\n");
+		if (add_eth_header(dev, slave, inbox, rlist, header_id))
+			return -EINVAL;
+		vhcr->in_modifier +=
+			sizeof(struct mlx4_net_trans_rule_hw_eth) >> 2;
+		break;
+	default:
+		pr_err("Corrupted mailbox.\n");
+		return -EINVAL;
+	}
+
 	err = mlx4_cmd_imm(dev, inbox->dma, &vhcr->out_param,
 			   vhcr->in_modifier, 0,
 			   MLX4_QP_FLOW_STEERING_ATTACH, MLX4_CMD_TIME_CLASS_A,

include/linux/mlx4/device.h

@@ -798,6 +798,17 @@ enum mlx4_net_trans_rule_id {
 
 extern const u16 __sw_id_hw[];
 
+static inline int map_hw_to_sw_id(u16 header_id)
+{
+
+	int i;
+	for (i = 0; i < MLX4_NET_TRANS_RULE_NUM; i++) {
+		if (header_id == __sw_id_hw[i])
+			return i;
+	}
+	return -EINVAL;
+}
+
 enum mlx4_net_trans_promisc_mode {
 	MLX4_FS_PROMISC_NONE = 0,
 	MLX4_FS_PROMISC_UPLINK,