Commit fc9c273d authored by Paolo Abeni's avatar Paolo Abeni
Browse files

ipmr: fix tables suspicious RCU usage 



Similar to the previous patch, plumb the RCU lock inside
the ipmr_get_table(), provided a lockless variant and apply
the latter in the few spots were the lock is already held.

Fixes: 709b46e8 ("net: Add compat ioctl support for the ipv4 multicast ioctl SIOCGETSGCNT")
Fixes: f0ad0860 ("ipv4: ipmr: support multiple tables")
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent f1553c98

net/ipv4/ipmr.c

+29 −13
Original line number Diff line number Diff line
@@ -142,7 +142,7 @@ static struct mr_table *ipmr_mr_table_iter(struct net *net, 
	return ret;

}



static struct mr_table *ipmr_get_table(struct net *net, u32 id)

static struct mr_table *__ipmr_get_table(struct net *net, u32 id)

{

	struct mr_table *mrt;
@@ -153,6 +153,16 @@ static struct mr_table *ipmr_get_table(struct net *net, u32 id) 
	return NULL;

}



static struct mr_table *ipmr_get_table(struct net *net, u32 id)

{

	struct mr_table *mrt;



	rcu_read_lock();

	mrt = __ipmr_get_table(net, id);

	rcu_read_unlock();

	return mrt;

}



static int ipmr_fib_lookup(struct net *net, struct flowi4 *flp4,

			   struct mr_table **mrt)

{
@@ -194,7 +204,7 @@ static int ipmr_rule_action(struct fib_rule *rule, struct flowi *flp, 


	arg->table = fib_rule_get_table(rule, arg);



	mrt = ipmr_get_table(rule->fr_net, arg->table);

	mrt = __ipmr_get_table(rule->fr_net, arg->table);

	if (!mrt)

		return -EAGAIN;

	res->mrt = mrt;
@@ -325,6 +335,8 @@ static struct mr_table *ipmr_get_table(struct net *net, u32 id) 
	return net->ipv4.mrt;

}



#define __ipmr_get_table ipmr_get_table



static int ipmr_fib_lookup(struct net *net, struct flowi4 *flp4,

			   struct mr_table **mrt)

{
@@ -413,7 +425,7 @@ static struct mr_table *ipmr_new_table(struct net *net, u32 id) 
	if (id != RT_TABLE_DEFAULT && id >= 1000000000)

		return ERR_PTR(-EINVAL);



	mrt = ipmr_get_table(net, id);

	mrt = __ipmr_get_table(net, id);

	if (mrt)

		return mrt;
@@ -1388,7 +1400,7 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, sockptr_t optval, 
		goto out_unlock;

	}



	mrt = ipmr_get_table(net, raw_sk(sk)->ipmr_table ? : RT_TABLE_DEFAULT);

	mrt = __ipmr_get_table(net, raw_sk(sk)->ipmr_table ? : RT_TABLE_DEFAULT);

	if (!mrt) {

		ret = -ENOENT;

		goto out_unlock;
@@ -2276,11 +2288,13 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb, 
	struct mr_table *mrt;

	int err;



	mrt = ipmr_get_table(net, RT_TABLE_DEFAULT);

	if (!mrt)

	rcu_read_lock();

	mrt = __ipmr_get_table(net, RT_TABLE_DEFAULT);

	if (!mrt) {

		rcu_read_unlock();

		return -ENOENT;

	}



	rcu_read_lock();

	cache = ipmr_cache_find(mrt, saddr, daddr);

	if (!cache && skb->dev) {

		int vif = ipmr_find_vif(mrt, skb->dev);
@@ -2564,7 +2578,7 @@ static int ipmr_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
	grp = nla_get_in_addr_default(tb[RTA_DST], 0);

	tableid = nla_get_u32_default(tb[RTA_TABLE], 0);



	mrt = ipmr_get_table(net, tableid ? tableid : RT_TABLE_DEFAULT);

	mrt = __ipmr_get_table(net, tableid ? tableid : RT_TABLE_DEFAULT);

	if (!mrt) {

		err = -ENOENT;

		goto errout_free;
@@ -2618,7 +2632,7 @@ static int ipmr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb) 
	if (filter.table_id) {

		struct mr_table *mrt;



		mrt = ipmr_get_table(sock_net(skb->sk), filter.table_id);

		mrt = __ipmr_get_table(sock_net(skb->sk), filter.table_id);

		if (!mrt) {

			if (rtnl_msg_family(cb->nlh) != RTNL_FAMILY_IPMR)

				return skb->len;
@@ -2726,7 +2740,7 @@ static int rtm_to_ipmr_mfcc(struct net *net, struct nlmsghdr *nlh, 
			break;

		}

	}

	mrt = ipmr_get_table(net, tblid);

	mrt = __ipmr_get_table(net, tblid);

	if (!mrt) {

		ret = -ENOENT;

		goto out;
@@ -2934,13 +2948,15 @@ static void *ipmr_vif_seq_start(struct seq_file *seq, loff_t *pos) 
	struct net *net = seq_file_net(seq);

	struct mr_table *mrt;



	mrt = ipmr_get_table(net, RT_TABLE_DEFAULT);

	if (!mrt)

	rcu_read_lock();

	mrt = __ipmr_get_table(net, RT_TABLE_DEFAULT);

	if (!mrt) {

		rcu_read_unlock();

		return ERR_PTR(-ENOENT);

	}



	iter->mrt = mrt;



	rcu_read_lock();

	return mr_vif_seq_start(seq, pos);

}