path: root/net/core
diff options
authorSabrina Dubroca <sd@queasysnail.net>2019-05-14 15:12:19 +0200
committerDavid S. Miller <davem@davemloft.net>2019-05-14 15:40:01 -0700
commitfeadc4b6cf42a53a8a93c918a569a0b7e62bd350 (patch)
tree45440a7927d2c1506ca6bd752288bcfc09ac8773 /net/core
parentnet/mlx4_core: Change the error print to info print (diff)
rtnetlink: always put IFLA_LINK for links with a link-netnsid
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>
Diffstat (limited to 'net/core')
1 files changed, 10 insertions, 6 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 2bd12afb9297..adcc045952c2 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1496,14 +1496,15 @@ static int put_master_ifindex(struct sk_buff *skb, struct net_device *dev)
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 sk_buff *skb,
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 sk_buff *skb,
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_buff *skb,
nla_put_u32(skb, IFLA_NUM_RX_QUEUES, dev->num_rx_queues) ||
- nla_put_iflink(skb, dev) ||
put_master_ifindex(skb, dev) ||
nla_put_u8(skb, IFLA_CARRIER, netif_carrier_ok(dev)) ||
(dev->qdisc &&