From: Sven Eckelmann sven@narfation.org
stable inclusion from stable-v5.10.104 commit 3dae11d21fc8aa57f389fd32ab884b638a04aff2 bugzilla: https://gitee.com/openeuler/kernel/issues/I56XAC
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 6116ba09423f7d140f0460be6a1644dceaad00da upstream.
There is no need to call dev_get_iflink multiple times for the same net_device in batadv_get_real_netdevice. And since some of the ndo_get_iflink callbacks are dynamic (for example via RCUs like in vxcan_get_iflink), it could easily happen that the returned values are not stable. The pre-checks before __dev_get_by_index are then of course bogus.
Fixes: 5ed4a460a1d3 ("batman-adv: additional checks for virtual interfaces on top of WiFi") Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yu Liao liaoyu15@huawei.com Reviewed-by: Wei Li liwei391@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- net/batman-adv/hard-interface.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index 20f7c397817c..a82ab29aef33 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -217,14 +217,16 @@ static struct net_device *batadv_get_real_netdevice(struct net_device *netdev) struct net_device *real_netdev = NULL; struct net *real_net; struct net *net; - int ifindex; + int iflink;
ASSERT_RTNL();
if (!netdev) return NULL;
- if (netdev->ifindex == dev_get_iflink(netdev)) { + iflink = dev_get_iflink(netdev); + + if (netdev->ifindex == iflink) { dev_hold(netdev); return netdev; } @@ -234,9 +236,8 @@ static struct net_device *batadv_get_real_netdevice(struct net_device *netdev) goto out;
net = dev_net(hard_iface->soft_iface); - ifindex = dev_get_iflink(netdev); real_net = batadv_getlink_net(netdev, net); - real_netdev = dev_get_by_index(real_net, ifindex); + real_netdev = dev_get_by_index(real_net, iflink);
out: if (hard_iface)