| Message ID | 20180206134832.21136-1-nicolas.dichtel@6wind.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] netlink: ensure to loop over all netns in genlmsg_multicast_allns() | expand |
From: Nicolas Dichtel <nicolas.dichtel@6wind.com> Date: Tue, 6 Feb 2018 14:48:32 +0100 > Nowadays, nlmsg_multicast() returns only 0 or -ESRCH but this was not the > case when commit 134e63756d5f was pushed. > However, there was no reason to stop the loop if a netns does not have > listeners. > Returns -ESRCH only if there was no listeners in all netns. > > To avoid having the same problem in the future, I didn't take the > assumption that nlmsg_multicast() returns only 0 or -ESRCH. > > Fixes: 134e63756d5f ("genetlink: make netns aware") > CC: Johannes Berg <johannes.berg@intel.com> > Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Ok, that indeed preserves the original behavior. Given this has been this way since 2.6.32 I wonder if fixing this might break something. Regardless, applied and queued up for -stable, thanks.
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index d444daf1ac04..6f02499ef007 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -1081,6 +1081,7 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, { struct sk_buff *tmp; struct net *net, *prev = NULL; + bool delivered = false; int err; for_each_net_rcu(net) { @@ -1092,14 +1093,21 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, } err = nlmsg_multicast(prev->genl_sock, tmp, portid, group, flags); - if (err) + if (!err) + delivered = true; + else if (err != -ESRCH) goto error; } prev = net; } - return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); + err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags); + if (!err) + delivered = true; + else if (err != -ESRCH) + goto error; + return delivered ? 0 : -ESRCH; error: kfree_skb(skb); return err;
Nowadays, nlmsg_multicast() returns only 0 or -ESRCH but this was not the case when commit 134e63756d5f was pushed. However, there was no reason to stop the loop if a netns does not have listeners. Returns -ESRCH only if there was no listeners in all netns. To avoid having the same problem in the future, I didn't take the assumption that nlmsg_multicast() returns only 0 or -ESRCH. Fixes: 134e63756d5f ("genetlink: make netns aware") CC: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> --- net/netlink/genetlink.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)