af_key: fix netns ops ordering on module load/unload
diff mbox series

Message ID 20100130125327.GA4258@x200
State New, archived
Headers show
Series
  • af_key: fix netns ops ordering on module load/unload
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Commit Message

Alexey Dobriyan Jan. 30, 2010, 12:53 p.m. UTC
On Fri, Jan 29, 2010 at 05:33:26PM +0100, Eric Dumazet wrote:
> @@ -3807,21 +3807,24 @@ static int __init ipsec_pfkey_init(void)
>  	if (err != 0)
>  		goto out;
>  
> -	err = sock_register(&pfkey_family_ops);
> -	if (err != 0)
> -		goto out_unregister_key_proto;
>  	err = xfrm_register_km(&pfkeyv2_mgr);
>  	if (err != 0)
> -		goto out_sock_unregister;
> +		goto out_unregister_key_proto;
> +
>  	err = register_pernet_subsys(&pfkey_net_ops);
>  	if (err != 0)
>  		goto out_xfrm_unregister_km;
> +
> +	err = sock_register(&pfkey_family_ops);
> +	if (err != 0)
> +		goto out_unregister_pernet;
>  out:
>  	return err;
> +
> +out_unregister_pernet:
> +	unregister_pernet_subsys(&pfkey_net_ops);
>  out_xfrm_unregister_km:
>  	xfrm_unregister_km(&pfkeyv2_mgr);
> -out_sock_unregister:
> -	sock_unregister(PF_KEY);
>  out_unregister_key_proto:
>  	proto_unregister(&key_proto);
>  	goto out;

ACK analysis, except this is not enough.

Here is patch which survived netns start/stop/modprobe/rmmod cycles.

	Alexey, who still doesn't get why bug reproduces so easily for bug reporter.

Luca, please confirm.

Audit for the rest of the modules pending.

[PATCH] af_key: fix netns ops ordering on module load/unload

1. After sock_register() returns, it's possible to create sockets,
   even if module still not initialized fully (blame generic module code
   for that!)
2. Consequently, pfkey_create() can be called with pfkey_net_id still not
   initialized which will BUG_ON in net_generic():
	kernel BUG at include/net/netns/generic.h:43!
3. During netns shutdown, netns ops should be unregistered after
   key manager unregistered because key manager calls can be triggered
   from xfrm_user module:

   	general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
	pfkey_broadcast+0x111/0x210 [af_key]
	pfkey_send_notify+0x16a/0x300 [af_key]
	km_state_notify+0x41/0x70
	xfrm_flush_sa+0x75/0x90 [xfrm_user]
4. Unregister netns ops after socket ops just in case and for symmetry.

Reported by Luca Tettamanti.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 net/key/af_key.c |   15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

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Comments

Luca Tettamanti Feb. 1, 2010, 1:50 p.m. UTC | #1
On Sat, Jan 30, 2010 at 1:53 PM, Alexey Dobriyan <adobriyan@gmail.com> wrote:
> On Fri, Jan 29, 2010 at 05:33:26PM +0100, Eric Dumazet wrote:
>> @@ -3807,21 +3807,24 @@ static int __init ipsec_pfkey_init(void)
>>       if (err != 0)
>>               goto out;
>>
>> -     err = sock_register(&pfkey_family_ops);
>> -     if (err != 0)
>> -             goto out_unregister_key_proto;
>>       err = xfrm_register_km(&pfkeyv2_mgr);
>>       if (err != 0)
>> -             goto out_sock_unregister;
>> +             goto out_unregister_key_proto;
>> +
>>       err = register_pernet_subsys(&pfkey_net_ops);
>>       if (err != 0)
>>               goto out_xfrm_unregister_km;
>> +
>> +     err = sock_register(&pfkey_family_ops);
>> +     if (err != 0)
>> +             goto out_unregister_pernet;
>>  out:
>>       return err;
>> +
>> +out_unregister_pernet:
>> +     unregister_pernet_subsys(&pfkey_net_ops);
>>  out_xfrm_unregister_km:
>>       xfrm_unregister_km(&pfkeyv2_mgr);
>> -out_sock_unregister:
>> -     sock_unregister(PF_KEY);
>>  out_unregister_key_proto:
>>       proto_unregister(&key_proto);
>>       goto out;
>
> ACK analysis, except this is not enough.
>
> Here is patch which survived netns start/stop/modprobe/rmmod cycles.
>
>        Alexey, who still doesn't get why bug reproduces so easily for bug reporter.
>
> Luca, please confirm.

Seems to work fine.

> [PATCH] af_key: fix netns ops ordering on module load/unload
>
> 1. After sock_register() returns, it's possible to create sockets,
>   even if module still not initialized fully (blame generic module code
>   for that!)
> 2. Consequently, pfkey_create() can be called with pfkey_net_id still not
>   initialized which will BUG_ON in net_generic():
>        kernel BUG at include/net/netns/generic.h:43!
> 3. During netns shutdown, netns ops should be unregistered after
>   key manager unregistered because key manager calls can be triggered
>   from xfrm_user module:
>
>        general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
>        pfkey_broadcast+0x111/0x210 [af_key]
>        pfkey_send_notify+0x16a/0x300 [af_key]
>        km_state_notify+0x41/0x70
>        xfrm_flush_sa+0x75/0x90 [xfrm_user]
> 4. Unregister netns ops after socket ops just in case and for symmetry.
>
> Reported by Luca Tettamanti.
>
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

Tested-by: Luca Tettamanti <kronos.it@gmail.com>

thanks,
Luca
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Eric Dumazet Feb. 1, 2010, 1:56 p.m. UTC | #2
Le lundi 01 février 2010 à 14:50 +0100, Luca Tettamanti a écrit :
> On Sat, Jan 30, 2010 at 1:53 PM, Alexey Dobriyan <adobriyan@gmail.com> wrote:

> > [PATCH] af_key: fix netns ops ordering on module load/unload
> >
> > 1. After sock_register() returns, it's possible to create sockets,
> >   even if module still not initialized fully (blame generic module code
> >   for that!)
> > 2. Consequently, pfkey_create() can be called with pfkey_net_id still not
> >   initialized which will BUG_ON in net_generic():
> >        kernel BUG at include/net/netns/generic.h:43!
> > 3. During netns shutdown, netns ops should be unregistered after
> >   key manager unregistered because key manager calls can be triggered
> >   from xfrm_user module:
> >
> >        general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
> >        pfkey_broadcast+0x111/0x210 [af_key]
> >        pfkey_send_notify+0x16a/0x300 [af_key]
> >        km_state_notify+0x41/0x70
> >        xfrm_flush_sa+0x75/0x90 [xfrm_user]
> > 4. Unregister netns ops after socket ops just in case and for symmetry.
> >
> > Reported by Luca Tettamanti.
> >
> > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> 
> Tested-by: Luca Tettamanti <kronos.it@gmail.com>

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>



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David Miller Feb. 4, 2010, 2:11 a.m. UTC | #3
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Mon, 01 Feb 2010 14:56:30 +0100

> Le lundi 01 février 2010 à 14:50 +0100, Luca Tettamanti a écrit :
>> On Sat, Jan 30, 2010 at 1:53 PM, Alexey Dobriyan <adobriyan@gmail.com> wrote:
> 
>> > [PATCH] af_key: fix netns ops ordering on module load/unload
>> >
>> > 1. After sock_register() returns, it's possible to create sockets,
>> >   even if module still not initialized fully (blame generic module code
>> >   for that!)
>> > 2. Consequently, pfkey_create() can be called with pfkey_net_id still not
>> >   initialized which will BUG_ON in net_generic():
>> >        kernel BUG at include/net/netns/generic.h:43!
>> > 3. During netns shutdown, netns ops should be unregistered after
>> >   key manager unregistered because key manager calls can be triggered
>> >   from xfrm_user module:
>> >
>> >        general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
>> >        pfkey_broadcast+0x111/0x210 [af_key]
>> >        pfkey_send_notify+0x16a/0x300 [af_key]
>> >        km_state_notify+0x41/0x70
>> >        xfrm_flush_sa+0x75/0x90 [xfrm_user]
>> > 4. Unregister netns ops after socket ops just in case and for symmetry.
>> >
>> > Reported by Luca Tettamanti.
>> >
>> > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
>> 
>> Tested-by: Luca Tettamanti <kronos.it@gmail.com>
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Applied, thanks everyone!
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Patch
diff mbox series

--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -3794,9 +3794,9 @@  static struct pernet_operations pfkey_net_ops = {
 
 static void __exit ipsec_pfkey_exit(void)
 {
-	unregister_pernet_subsys(&pfkey_net_ops);
 	xfrm_unregister_km(&pfkeyv2_mgr);
 	sock_unregister(PF_KEY);
+	unregister_pernet_subsys(&pfkey_net_ops);
 	proto_unregister(&key_proto);
 }
 
@@ -3807,21 +3807,22 @@  static int __init ipsec_pfkey_init(void)
 	if (err != 0)
 		goto out;
 
-	err = sock_register(&pfkey_family_ops);
+	err = register_pernet_subsys(&pfkey_net_ops);
 	if (err != 0)
 		goto out_unregister_key_proto;
+	err = sock_register(&pfkey_family_ops);
+	if (err != 0)
+		goto out_unregister_pernet;
 	err = xfrm_register_km(&pfkeyv2_mgr);
 	if (err != 0)
 		goto out_sock_unregister;
-	err = register_pernet_subsys(&pfkey_net_ops);
-	if (err != 0)
-		goto out_xfrm_unregister_km;
 out:
 	return err;
-out_xfrm_unregister_km:
-	xfrm_unregister_km(&pfkeyv2_mgr);
+
 out_sock_unregister:
 	sock_unregister(PF_KEY);
+out_unregister_pernet:
+	unregister_pernet_subsys(&pfkey_net_ops);
 out_unregister_key_proto:
 	proto_unregister(&key_proto);
 	goto out;