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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: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://patch.msgid.link/20250418000443.43734-13-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Kuniyuki Iwashima 2025-04-17 17:03:53 -07:00 committed by Paolo Abeni
parent 71c0efb6d1
commit 834d97843e
2 changed files with 22 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/net/netns/ipv6.h
View File

@ -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;

26
net/ipv6/ip6_fib.c
View File

@ -249,19 +249,33 @@ 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;
return tb;
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);
@ -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)