[net] ipv6: fix memory leak with multiple tables during netns destruction

Message ID 204659713af1979c26b8defb2b52e1668b4e5aad.1504859062.git.sd@queasysnail.net
State Accepted
Delegated to: David Miller
Headers show
Series
  • [net] ipv6: fix memory leak with multiple tables during netns destruction
Related show

Commit Message

Sabrina Dubroca Sept. 8, 2017, 8:26 a.m.
fib6_net_exit only frees the main and local tables. If another table was
created with fib6_alloc_table, we leak it when the netns is destroyed.

Fix this in the same way ip_fib_net_exit cleans up tables, by walking
through the whole hashtable of fib6_table's. We can get rid of the
special cases for local and main, since they're also part of the
hashtable.

Reproducer:
    ip netns add x
    ip -net x -6 rule add from 6003:1::/64 table 100
    ip netns del x

Reported-by: Jianlin Shi <jishi@redhat.com>
Fixes: 58f09b78b730 ("[NETNS][IPV6] ip6_fib - make it per network namespace")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
---
 net/ipv6/ip6_fib.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

Comments

David Miller Sept. 8, 2017, 4:49 p.m. | #1
From: Sabrina Dubroca <sd@queasysnail.net>
Date: Fri,  8 Sep 2017 10:26:19 +0200

> fib6_net_exit only frees the main and local tables. If another table was
> created with fib6_alloc_table, we leak it when the netns is destroyed.
> 
> Fix this in the same way ip_fib_net_exit cleans up tables, by walking
> through the whole hashtable of fib6_table's. We can get rid of the
> special cases for local and main, since they're also part of the
> hashtable.
> 
> Reproducer:
>     ip netns add x
>     ip -net x -6 rule add from 6003:1::/64 table 100
>     ip netns del x
> 
> Reported-by: Jianlin Shi <jishi@redhat.com>
> Fixes: 58f09b78b730 ("[NETNS][IPV6] ip6_fib - make it per network namespace")
> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>

Applied and queued up for -stable, thanks.
Eric Dumazet Sept. 8, 2017, 5:59 p.m. | #2
On Fri, 2017-09-08 at 10:26 +0200, Sabrina Dubroca wrote:
> fib6_net_exit only frees the main and local tables. If another table was
> created with fib6_alloc_table, we leak it when the netns is destroyed.
> 
> Fix this in the same way ip_fib_net_exit cleans up tables, by walking
> through the whole hashtable of fib6_table's. We can get rid of the
> special cases for local and main, since they're also part of the
> hashtable.
> 
> Reproducer:
>     ip netns add x
>     ip -net x -6 rule add from 6003:1::/64 table 100
>     ip netns del x
> 
> Reported-by: Jianlin Shi <jishi@redhat.com>
> Fixes: 58f09b78b730 ("[NETNS][IPV6] ip6_fib - make it per network namespace")
> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
> ---
>  net/ipv6/ip6_fib.c | 25 +++++++++++++++++++------
>  1 file changed, 19 insertions(+), 6 deletions(-)
> 
> diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
> index a3b5c163325f..8280172c806c 100644
> --- a/net/ipv6/ip6_fib.c
> +++ b/net/ipv6/ip6_fib.c
> @@ -191,6 +191,12 @@ void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
>  }
>  EXPORT_SYMBOL_GPL(rt6_free_pcpu);
>  
> +static void fib6_free_table(struct fib6_table *table)
> +{
> +	inetpeer_invalidate_tree(&table->tb6_peers);
> +	kfree(table);
> +}
> +
>  static void fib6_link_table(struct net *net, struct fib6_table *tb)
>  {
>  	unsigned int h;
> @@ -2022,15 +2028,22 @@ static int __net_init fib6_net_init(struct net *net)
>  
>  static void fib6_net_exit(struct net *net)
>  {
> +	unsigned int i;
> +
>  	rt6_ifdown(net, NULL);
>  	del_timer_sync(&net->ipv6.ip6_fib_timer);
>  
> -#ifdef CONFIG_IPV6_MULTIPLE_TABLES
> -	inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
> -	kfree(net->ipv6.fib6_local_tbl);
> -#endif
> -	inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
> -	kfree(net->ipv6.fib6_main_tbl);
> +	for (i = 0; i < FIB_TABLE_HASHSZ; i++) {

should not this be FIB6_TABLE_HASHSZ ?

> +		struct hlist_head *head = &net->ipv6.fib_table_hash[i];
> +		struct hlist_node *tmp;
> +		struct fib6_table *tb;
> +
> +		hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) {
> +			hlist_del(&tb->tb6_hlist);
> +			fib6_free_table(tb);
> +		}
> +	}
> +
>  	kfree(net->ipv6.fib_table_hash);
>  	kfree(net->ipv6.rt6_stats);
>  	fib6_notifier_exit(net);
Cong Wang Sept. 8, 2017, 6:24 p.m. | #3
On Fri, Sep 8, 2017 at 1:26 AM, Sabrina Dubroca <sd@queasysnail.net> wrote:
> fib6_net_exit only frees the main and local tables. If another table was
> created with fib6_alloc_table, we leak it when the netns is destroyed.
>
> Fix this in the same way ip_fib_net_exit cleans up tables, by walking
> through the whole hashtable of fib6_table's. We can get rid of the
> special cases for local and main, since they're also part of the
> hashtable.
>
> Reproducer:
>     ip netns add x
>     ip -net x -6 rule add from 6003:1::/64 table 100
>     ip netns del x
>
> Reported-by: Jianlin Shi <jishi@redhat.com>
> Fixes: 58f09b78b730 ("[NETNS][IPV6] ip6_fib - make it per network namespace")
> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
> ---
>  net/ipv6/ip6_fib.c | 25 +++++++++++++++++++------
>  1 file changed, 19 insertions(+), 6 deletions(-)
>
> diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
> index a3b5c163325f..8280172c806c 100644
> --- a/net/ipv6/ip6_fib.c
> +++ b/net/ipv6/ip6_fib.c
> @@ -191,6 +191,12 @@ void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
>  }
>  EXPORT_SYMBOL_GPL(rt6_free_pcpu);
>
> +static void fib6_free_table(struct fib6_table *table)
> +{
> +       inetpeer_invalidate_tree(&table->tb6_peers);
> +       kfree(table);
> +}
> +
>  static void fib6_link_table(struct net *net, struct fib6_table *tb)
>  {
>         unsigned int h;
> @@ -2022,15 +2028,22 @@ static int __net_init fib6_net_init(struct net *net)
>
>  static void fib6_net_exit(struct net *net)
>  {
> +       unsigned int i;
> +
>         rt6_ifdown(net, NULL);
>         del_timer_sync(&net->ipv6.ip6_fib_timer);
>
> -#ifdef CONFIG_IPV6_MULTIPLE_TABLES
> -       inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
> -       kfree(net->ipv6.fib6_local_tbl);
> -#endif
> -       inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
> -       kfree(net->ipv6.fib6_main_tbl);
> +       for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
> +               struct hlist_head *head = &net->ipv6.fib_table_hash[i];
> +               struct hlist_node *tmp;
> +               struct fib6_table *tb;
> +
> +               hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) {
> +                       hlist_del(&tb->tb6_hlist);

hlist_del_rcu() ?


> +                       fib6_free_table(tb);

kfree_rcu() in fib6_free_table()?


> +               }
> +       }
> +
>         kfree(net->ipv6.fib_table_hash);
>         kfree(net->ipv6.rt6_stats);
>         fib6_notifier_exit(net);
> --
> 2.14.1
>

Patch

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index a3b5c163325f..8280172c806c 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -191,6 +191,12 @@  void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
 }
 EXPORT_SYMBOL_GPL(rt6_free_pcpu);
 
+static void fib6_free_table(struct fib6_table *table)
+{
+	inetpeer_invalidate_tree(&table->tb6_peers);
+	kfree(table);
+}
+
 static void fib6_link_table(struct net *net, struct fib6_table *tb)
 {
 	unsigned int h;
@@ -2022,15 +2028,22 @@  static int __net_init fib6_net_init(struct net *net)
 
 static void fib6_net_exit(struct net *net)
 {
+	unsigned int i;
+
 	rt6_ifdown(net, NULL);
 	del_timer_sync(&net->ipv6.ip6_fib_timer);
 
-#ifdef CONFIG_IPV6_MULTIPLE_TABLES
-	inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
-	kfree(net->ipv6.fib6_local_tbl);
-#endif
-	inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
-	kfree(net->ipv6.fib6_main_tbl);
+	for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
+		struct hlist_head *head = &net->ipv6.fib_table_hash[i];
+		struct hlist_node *tmp;
+		struct fib6_table *tb;
+
+		hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) {
+			hlist_del(&tb->tb6_hlist);
+			fib6_free_table(tb);
+		}
+	}
+
 	kfree(net->ipv6.fib_table_hash);
 	kfree(net->ipv6.rt6_stats);
 	fib6_notifier_exit(net);