From f74877a5457d34d604dba6dbbb13c4c05bac8b93 Mon Sep 17 00:00:00 2001 From: Michal Kubecek Date: Wed, 11 Dec 2019 10:58:14 +0100 Subject: [PATCH] rtnetlink: provide permanent hardware address in RTM_NEWLINK Permanent hardware address of a network device was traditionally provided via ethtool ioctl interface but as Jiri Pirko pointed out in a review of ethtool netlink interface, rtnetlink is much more suitable for it so let's add it to the RTM_NEWLINK message. Add IFLA_PERM_ADDRESS attribute to RTM_NEWLINK messages unless the permanent address is all zeros (i.e. device driver did not fill it). As permanent address is not modifiable, reject userspace requests containing IFLA_PERM_ADDRESS attribute. Note: we already provide permanent hardware address for bond slaves; unfortunately we cannot drop that attribute for backward compatibility reasons. v5 -> v6: only add the attribute if permanent address is not zero Signed-off-by: Michal Kubecek Acked-by: Jiri Pirko Acked-by: Stephen Hemminger Signed-off-by: David S. Miller --- include/uapi/linux/if_link.h | 1 + net/core/rtnetlink.c | 5 +++++ 2 files changed, 6 insertions(+) diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h index 8aec8769d944..1d69f637c5d6 100644 --- a/include/uapi/linux/if_link.h +++ b/include/uapi/linux/if_link.h @@ -169,6 +169,7 @@ enum { IFLA_MAX_MTU, IFLA_PROP_LIST, IFLA_ALT_IFNAME, /* Alternative ifname */ + IFLA_PERM_ADDRESS, __IFLA_MAX }; diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 02916f43bf63..20bc406f3871 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1041,6 +1041,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev, + nla_total_size(4) /* IFLA_MIN_MTU */ + nla_total_size(4) /* IFLA_MAX_MTU */ + rtnl_prop_list_size(dev) + + nla_total_size(MAX_ADDR_LEN) /* IFLA_PERM_ADDRESS */ + 0; } @@ -1757,6 +1758,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, nla_put_s32(skb, IFLA_NEW_IFINDEX, new_ifindex) < 0) goto nla_put_failure; + if (memchr_inv(dev->perm_addr, '\0', dev->addr_len) && + nla_put(skb, IFLA_PERM_ADDRESS, dev->addr_len, dev->perm_addr)) + goto nla_put_failure; rcu_read_lock(); if (rtnl_fill_link_af(skb, dev, ext_filter_mask)) @@ -1822,6 +1826,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = { [IFLA_PROP_LIST] = { .type = NLA_NESTED }, [IFLA_ALT_IFNAME] = { .type = NLA_STRING, .len = ALTIFNAMSIZ - 1 }, + [IFLA_PERM_ADDRESS] = { .type = NLA_REJECT }, }; static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = { -- 2.30.2