From d4e4fdf9e4a27c87edb79b1478955075be141f67 Mon Sep 17 00:00:00 2001 From: Guillaume Nault Date: Wed, 23 Oct 2019 18:39:04 +0200 Subject: netns: fix GFP flags in rtnl_net_notifyid() In rtnl_net_notifyid(), we certainly can't pass a null GFP flag to rtnl_notify(). A GFP_KERNEL flag would be fine in most circumstances, but there are a few paths calling rtnl_net_notifyid() from atomic context or from RCU critical sections. The later also precludes the use of gfp_any() as it wouldn't detect the RCU case. Also, the nlmsg_new() call is wrong too, as it uses GFP_KERNEL unconditionally. Therefore, we need to pass the GFP flags as parameter and propagate it through function calls until the proper flags can be determined. In most cases, GFP_KERNEL is fine. The exceptions are: * openvswitch: ovs_vport_cmd_get() and ovs_vport_cmd_dump() indirectly call rtnl_net_notifyid() from RCU critical section, * rtnetlink: rtmsg_ifinfo_build_skb() already receives GFP flags as parameter. Also, in ovs_vport_cmd_build_info(), let's change the GFP flags used by nlmsg_new(). The function is allowed to sleep, so better make the flags consistent with the ones used in the following ovs_vport_cmd_fill_info() call. Found by code inspection. Fixes: 9a9634545c70 ("netns: notify netns id events") Signed-off-by: Guillaume Nault Acked-by: Nicolas Dichtel Acked-by: Pravin B Shelar Signed-off-by: David S. Miller --- net/core/net_namespace.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'net/core/net_namespace.c') diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 5a4ae0845bac..39402840025e 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -246,11 +246,11 @@ static int __peernet2id(struct net *net, struct net *peer) } static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid, - struct nlmsghdr *nlh); + struct nlmsghdr *nlh, gfp_t gfp); /* This function returns the id of a peer netns. If no id is assigned, one will * be allocated and returned. */ -int peernet2id_alloc(struct net *net, struct net *peer) +int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp) { bool alloc = false, alive = false; int id; @@ -269,7 +269,7 @@ int peernet2id_alloc(struct net *net, struct net *peer) id = __peernet2id_alloc(net, peer, &alloc); spin_unlock_bh(&net->nsid_lock); if (alloc && id >= 0) - rtnl_net_notifyid(net, RTM_NEWNSID, id, 0, NULL); + rtnl_net_notifyid(net, RTM_NEWNSID, id, 0, NULL, gfp); if (alive) put_net(peer); return id; @@ -534,7 +534,8 @@ static void unhash_nsid(struct net *net, struct net *last) idr_remove(&tmp->netns_ids, id); spin_unlock_bh(&tmp->nsid_lock); if (id >= 0) - rtnl_net_notifyid(tmp, RTM_DELNSID, id, 0, NULL); + rtnl_net_notifyid(tmp, RTM_DELNSID, id, 0, NULL, + GFP_KERNEL); if (tmp == last) break; } @@ -767,7 +768,7 @@ static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh, spin_unlock_bh(&net->nsid_lock); if (err >= 0) { rtnl_net_notifyid(net, RTM_NEWNSID, err, NETLINK_CB(skb).portid, - nlh); + nlh, GFP_KERNEL); err = 0; } else if (err == -ENOSPC && nsid >= 0) { err = -EEXIST; @@ -1055,7 +1056,7 @@ end: } static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid, - struct nlmsghdr *nlh) + struct nlmsghdr *nlh, gfp_t gfp) { struct net_fill_args fillargs = { .portid = portid, @@ -1066,7 +1067,7 @@ static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid, struct sk_buff *msg; int err = -ENOMEM; - msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); + msg = nlmsg_new(rtnl_net_get_size(), gfp); if (!msg) goto out; @@ -1074,7 +1075,7 @@ static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid, if (err < 0) goto err_out; - rtnl_notify(msg, net, portid, RTNLGRP_NSID, nlh, 0); + rtnl_notify(msg, net, portid, RTNLGRP_NSID, nlh, gfp); return; err_out: -- cgit v1.2.3