Commit d4e4fdf9 authored by Guillaume Nault's avatar Guillaume Nault Committed by David S. Miller
Browse files

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: 9a963454 ("netns: notify netns id events")
Signed-off-by: default avatarGuillaume Nault <gnault@redhat.com>
Acked-by: default avatarNicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: default avatarPravin B Shelar <pshelar@ovn.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 16d65287

include/net/net_namespace.h

+1 −1
Original line number Diff line number Diff line
@@ -342,7 +342,7 @@ static inline struct net *read_pnet(const possible_net_t *pnet) 
#define __net_initconst	__initconst

#endif



int peernet2id_alloc(struct net *net, struct net *peer);

int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp);

int peernet2id(struct net *net, struct net *peer);

bool peernet_has_id(struct net *net, struct net *peer);

struct net *get_net_ns_by_id(struct net *net, int id);

net/core/dev.c

+1 −1
Original line number Diff line number Diff line
@@ -9770,7 +9770,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char 
	call_netdevice_notifiers(NETDEV_UNREGISTER, dev);

	rcu_barrier();



	new_nsid = peernet2id_alloc(dev_net(dev), net);

	new_nsid = peernet2id_alloc(dev_net(dev), net, GFP_KERNEL);

	/* If there is an ifindex conflict assign a new one */

	if (__dev_get_by_index(net, dev->ifindex))

		new_ifindex = dev_new_index(net);

net/core/net_namespace.c

+9 −8
Original line number Diff line number Diff line
@@ -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:

net/core/rtnetlink.c

+7 −7
Original line number Diff line number Diff line
@@ -1523,7 +1523,7 @@ static noinline_for_stack int nla_put_ifalias(struct sk_buff *skb, 


static int rtnl_fill_link_netnsid(struct sk_buff *skb,

				  const struct net_device *dev,

				  struct net *src_net)

				  struct net *src_net, gfp_t gfp)

{

	bool put_iflink = false;
@@ -1531,7 +1531,7 @@ static int rtnl_fill_link_netnsid(struct sk_buff *skb, 
		struct net *link_net = dev->rtnl_link_ops->get_link_net(dev);



		if (!net_eq(dev_net(dev), link_net)) {

			int id = peernet2id_alloc(src_net, link_net);

			int id = peernet2id_alloc(src_net, link_net, gfp);



			if (nla_put_s32(skb, IFLA_LINK_NETNSID, id))

				return -EMSGSIZE;
@@ -1589,7 +1589,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, 
			    int type, u32 pid, u32 seq, u32 change,

			    unsigned int flags, u32 ext_filter_mask,

			    u32 event, int *new_nsid, int new_ifindex,

			    int tgt_netnsid)

			    int tgt_netnsid, gfp_t gfp)

{

	struct ifinfomsg *ifm;

	struct nlmsghdr *nlh;
@@ -1681,7 +1681,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, 
			goto nla_put_failure;

	}



	if (rtnl_fill_link_netnsid(skb, dev, src_net))

	if (rtnl_fill_link_netnsid(skb, dev, src_net, gfp))

		goto nla_put_failure;



	if (new_nsid &&
@@ -2001,7 +2001,7 @@ walk_entries: 
					       NETLINK_CB(cb->skb).portid,

					       nlh->nlmsg_seq, 0, flags,

					       ext_filter_mask, 0, NULL, 0,

					       netnsid);

					       netnsid, GFP_KERNEL);



			if (err < 0) {

				if (likely(skb->len))
@@ -3360,7 +3360,7 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
	err = rtnl_fill_ifinfo(nskb, dev, net,

			       RTM_NEWLINK, NETLINK_CB(skb).portid,

			       nlh->nlmsg_seq, 0, 0, ext_filter_mask,

			       0, NULL, 0, netnsid);

			       0, NULL, 0, netnsid, GFP_KERNEL);

	if (err < 0) {

		/* -EMSGSIZE implies BUG in if_nlmsg_size */

		WARN_ON(err == -EMSGSIZE);
@@ -3472,7 +3472,7 @@ struct sk_buff *rtmsg_ifinfo_build_skb(int type, struct net_device *dev, 


	err = rtnl_fill_ifinfo(skb, dev, dev_net(dev),

			       type, 0, 0, change, 0, 0, event,

			       new_nsid, new_ifindex, -1);

			       new_nsid, new_ifindex, -1, flags);

	if (err < 0) {

		/* -EMSGSIZE implies BUG in if_nlmsg_size() */

		WARN_ON(err == -EMSGSIZE);

net/openvswitch/datapath.c

+11 −9
Original line number Diff line number Diff line
@@ -1881,7 +1881,7 @@ static struct genl_family dp_datapath_genl_family __ro_after_init = { 
/* Called with ovs_mutex or RCU read lock. */

static int ovs_vport_cmd_fill_info(struct vport *vport, struct sk_buff *skb,

				   struct net *net, u32 portid, u32 seq,

				   u32 flags, u8 cmd)

				   u32 flags, u8 cmd, gfp_t gfp)

{

	struct ovs_header *ovs_header;

	struct ovs_vport_stats vport_stats;
@@ -1902,7 +1902,7 @@ static int ovs_vport_cmd_fill_info(struct vport *vport, struct sk_buff *skb, 
		goto nla_put_failure;



	if (!net_eq(net, dev_net(vport->dev))) {

		int id = peernet2id_alloc(net, dev_net(vport->dev));

		int id = peernet2id_alloc(net, dev_net(vport->dev), gfp);



		if (nla_put_s32(skb, OVS_VPORT_ATTR_NETNSID, id))

			goto nla_put_failure;
@@ -1943,11 +1943,12 @@ struct sk_buff *ovs_vport_cmd_build_info(struct vport *vport, struct net *net, 
	struct sk_buff *skb;

	int retval;



	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);

	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);

	if (!skb)

		return ERR_PTR(-ENOMEM);



	retval = ovs_vport_cmd_fill_info(vport, skb, net, portid, seq, 0, cmd);

	retval = ovs_vport_cmd_fill_info(vport, skb, net, portid, seq, 0, cmd,

					 GFP_KERNEL);

	BUG_ON(retval < 0);



	return skb;
@@ -2089,7 +2090,7 @@ restart: 


	err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),

				      info->snd_portid, info->snd_seq, 0,

				      OVS_VPORT_CMD_NEW);

				      OVS_VPORT_CMD_NEW, GFP_KERNEL);



	new_headroom = netdev_get_fwd_headroom(vport->dev);
@@ -2150,7 +2151,7 @@ static int ovs_vport_cmd_set(struct sk_buff *skb, struct genl_info *info) 


	err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),

				      info->snd_portid, info->snd_seq, 0,

				      OVS_VPORT_CMD_SET);

				      OVS_VPORT_CMD_SET, GFP_KERNEL);

	BUG_ON(err < 0);



	ovs_unlock();
@@ -2190,7 +2191,7 @@ static int ovs_vport_cmd_del(struct sk_buff *skb, struct genl_info *info) 


	err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),

				      info->snd_portid, info->snd_seq, 0,

				      OVS_VPORT_CMD_DEL);

				      OVS_VPORT_CMD_DEL, GFP_KERNEL);

	BUG_ON(err < 0);



	/* the vport deletion may trigger dp headroom update */
@@ -2237,7 +2238,7 @@ static int ovs_vport_cmd_get(struct sk_buff *skb, struct genl_info *info) 
		goto exit_unlock_free;

	err = ovs_vport_cmd_fill_info(vport, reply, genl_info_net(info),

				      info->snd_portid, info->snd_seq, 0,

				      OVS_VPORT_CMD_GET);

				      OVS_VPORT_CMD_GET, GFP_ATOMIC);

	BUG_ON(err < 0);

	rcu_read_unlock();
@@ -2273,7 +2274,8 @@ static int ovs_vport_cmd_dump(struct sk_buff *skb, struct netlink_callback *cb) 
						    NETLINK_CB(cb->skb).portid,

						    cb->nlh->nlmsg_seq,

						    NLM_F_MULTI,

						    OVS_VPORT_CMD_GET) < 0)

						    OVS_VPORT_CMD_GET,

						    GFP_ATOMIC) < 0)

				goto out;



			j++;

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