| From foo@baz Wed 22 May 2019 08:37:51 AM CEST |
| From: Sabrina Dubroca <sd@queasysnail.net> |
| Date: Tue, 14 May 2019 15:12:19 +0200 |
| Subject: rtnetlink: always put IFLA_LINK for links with a link-netnsid |
| |
| From: Sabrina Dubroca <sd@queasysnail.net> |
| |
| [ Upstream commit feadc4b6cf42a53a8a93c918a569a0b7e62bd350 ] |
| |
| Currently, nla_put_iflink() doesn't put the IFLA_LINK attribute when |
| iflink == ifindex. |
| |
| In some cases, a device can be created in a different netns with the |
| same ifindex as its parent. That device will not dump its IFLA_LINK |
| attribute, which can confuse some userspace software that expects it. |
| For example, if the last ifindex created in init_net and foo are both |
| 8, these commands will trigger the issue: |
| |
| ip link add parent type dummy # ifindex 9 |
| ip link add link parent netns foo type macvlan # ifindex 9 in ns foo |
| |
| So, in case a device puts the IFLA_LINK_NETNSID attribute in a dump, |
| always put the IFLA_LINK attribute as well. |
| |
| Thanks to Dan Winship for analyzing the original OpenShift bug down to |
| the missing netlink attribute. |
| |
| v2: change Fixes tag, it's been here forever, as Nicolas Dichtel said |
| add Nicolas' ack |
| v3: change Fixes tag |
| fix subject typo, spotted by Edward Cree |
| |
| Analyzed-by: Dan Winship <danw@redhat.com> |
| Fixes: d8a5ec672768 ("[NET]: netlink support for moving devices between network namespaces.") |
| Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> |
| Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/core/rtnetlink.c | 16 ++++++++++------ |
| 1 file changed, 10 insertions(+), 6 deletions(-) |
| |
| --- a/net/core/rtnetlink.c |
| +++ b/net/core/rtnetlink.c |
| @@ -1496,14 +1496,15 @@ static int put_master_ifindex(struct sk_ |
| return ret; |
| } |
| |
| -static int nla_put_iflink(struct sk_buff *skb, const struct net_device *dev) |
| +static int nla_put_iflink(struct sk_buff *skb, const struct net_device *dev, |
| + bool force) |
| { |
| int ifindex = dev_get_iflink(dev); |
| |
| - if (dev->ifindex == ifindex) |
| - return 0; |
| + if (force || dev->ifindex != ifindex) |
| + return nla_put_u32(skb, IFLA_LINK, ifindex); |
| |
| - return nla_put_u32(skb, IFLA_LINK, ifindex); |
| + return 0; |
| } |
| |
| static noinline_for_stack int nla_put_ifalias(struct sk_buff *skb, |
| @@ -1520,6 +1521,8 @@ static int rtnl_fill_link_netnsid(struct |
| const struct net_device *dev, |
| struct net *src_net) |
| { |
| + bool put_iflink = false; |
| + |
| if (dev->rtnl_link_ops && dev->rtnl_link_ops->get_link_net) { |
| struct net *link_net = dev->rtnl_link_ops->get_link_net(dev); |
| |
| @@ -1528,10 +1531,12 @@ static int rtnl_fill_link_netnsid(struct |
| |
| if (nla_put_s32(skb, IFLA_LINK_NETNSID, id)) |
| return -EMSGSIZE; |
| + |
| + put_iflink = true; |
| } |
| } |
| |
| - return 0; |
| + return nla_put_iflink(skb, dev, put_iflink); |
| } |
| |
| static int rtnl_fill_link_af(struct sk_buff *skb, |
| @@ -1617,7 +1622,6 @@ static int rtnl_fill_ifinfo(struct sk_bu |
| #ifdef CONFIG_RPS |
| nla_put_u32(skb, IFLA_NUM_RX_QUEUES, dev->num_rx_queues) || |
| #endif |
| - nla_put_iflink(skb, dev) || |
| put_master_ifindex(skb, dev) || |
| nla_put_u8(skb, IFLA_CARRIER, netif_carrier_ok(dev)) || |
| (dev->qdisc && |