Commit 834d9784 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Paolo Abeni
Browse files

ipv6: Protect fib6_link_table() with spinlock. 



We will get rid of RTNL from RTM_NEWROUTE and SIOCADDRT.

If the request specifies a new table ID, fib6_new_table() is
called to create a new routing table.

Two concurrent requests could specify the same table ID, so we
need a lock to protect net->ipv6.fib_table_hash[h].

Let's add a spinlock to protect the hash bucket linkage.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: default avatarPaolo Abeni <pabeni@redhat.com>
Link: https://patch.msgid.link/20250418000443.43734-13-kuniyu@amazon.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 71c0efb6

include/net/netns/ipv6.h

+1 −0
Original line number Diff line number Diff line
@@ -72,6 +72,7 @@ struct netns_ipv6 { 
	struct rt6_statistics   *rt6_stats;

	struct timer_list       ip6_fib_timer;

	struct hlist_head       *fib_table_hash;

	spinlock_t		fib_table_hash_lock;

	struct fib6_table       *fib6_main_tbl;

	struct list_head	fib6_walkers;

	rwlock_t		fib6_walker_lock;

net/ipv6/ip6_fib.c

+21 −5
Original line number Diff line number Diff line
@@ -249,20 +249,34 @@ static struct fib6_table *fib6_alloc_table(struct net *net, u32 id) 


struct fib6_table *fib6_new_table(struct net *net, u32 id)

{

	struct fib6_table *tb;

	struct fib6_table *tb, *new_tb;



	if (id == 0)

		id = RT6_TABLE_MAIN;



	tb = fib6_get_table(net, id);

	if (tb)

		return tb;



	tb = fib6_alloc_table(net, id);

	if (tb)

		fib6_link_table(net, tb);

	new_tb = fib6_alloc_table(net, id);

	if (!new_tb)

		return NULL;



	spin_lock_bh(&net->ipv6.fib_table_hash_lock);



	tb = fib6_get_table(net, id);

	if (unlikely(tb)) {

		spin_unlock_bh(&net->ipv6.fib_table_hash_lock);

		kfree(new_tb);

		return tb;

	}



	fib6_link_table(net, new_tb);



	spin_unlock_bh(&net->ipv6.fib_table_hash_lock);



	return new_tb;

}

EXPORT_SYMBOL_GPL(fib6_new_table);



struct fib6_table *fib6_get_table(struct net *net, u32 id)
@@ -2423,6 +2437,8 @@ static int __net_init fib6_net_init(struct net *net) 
	if (!net->ipv6.fib_table_hash)

		goto out_rt6_stats;



	spin_lock_init(&net->ipv6.fib_table_hash_lock);



	net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),

					  GFP_KERNEL);

	if (!net->ipv6.fib6_main_tbl)