[PATCH v3 net-next] xfrm: Add check to prevent un-complete key manager

[PATCH v3 net-next] xfrm: Add check to prevent un-complete key manager

[baker.kernel]

From: Baker Zhang <Baker.kernel@gmail.com>

"acquire" and "compile_policy" callbacks are necessary for a key manager.

Signed-off-by: Baker Zhang <Baker.kernel@gmail.com>
---
Thanks for all reply.

V1:
For current kernel source, there is no problem.

In our vpn product, we need a xfrm_km in kernel module
to monitor the xfrm state change.
thus, the 'acquire' and 'compile_policy' may be NULL.

So I think we should do the check before use it. 

V2:
Align the continuation line according the networking coding style.

V3:
Add check to prevent un-complete key manager at register time.

 net/xfrm/xfrm_state.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index b9c3f9e..178283e 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1806,6 +1806,9 @@ static DEFINE_SPINLOCK(xfrm_km_lock);
 
 int xfrm_register_km(struct xfrm_mgr *km)
 {
+	if (km->acquire == NULL || km->compile_policy == NULL)
+		return -EINVAL;
+
 	spin_lock_bh(&xfrm_km_lock);
 	list_add_tail_rcu(&km->list, &xfrm_km_list);
 	spin_unlock_bh(&xfrm_km_lock);
-- 
1.8.3.2

Re: [PATCH v3 net-next] xfrm: Add check to prevent un-complete key manager

[Fan Du]

On 2013年11月11日 14:39, baker.kernel@gmail.com wrote:
> From: Baker Zhang<Baker.kernel@gmail.com>
>
> "acquire" and "compile_policy" callbacks are necessary for a key manager.
>
> Signed-off-by: Baker Zhang<Baker.kernel@gmail.com>
> ---
> Thanks for all reply.
>
> V1:
> For current kernel source, there is no problem.
>
> In our vpn product, we need a xfrm_km in kernel module
> to monitor the xfrm state change.
> thus, the 'acquire' and 'compile_policy' may be NULL.
>
> So I think we should do the check before use it.
>
> V2:
> Align the continuation line according the networking coding style.
>
> V3:
> Add check to prevent un-complete key manager at register time.
>
>   net/xfrm/xfrm_state.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
> index b9c3f9e..178283e 100644
> --- a/net/xfrm/xfrm_state.c
> +++ b/net/xfrm/xfrm_state.c
> @@ -1806,6 +1806,9 @@ static DEFINE_SPINLOCK(xfrm_km_lock);
>
>   int xfrm_register_km(struct xfrm_mgr *km)
>   {
> +	if (km->acquire == NULL || km->compile_policy == NULL)

"acquire" is a MUST, "compile_policy" is not a necessity.

 From  the fist commit log, you probably add functionality providing SA state changes
in your private key manager, which current implementation does not. Maybe it's worthwhile
to elaborate the missing functionality than add those checking, because both key manage
(pfkeyv2/netlink) in use has "acquire" and "compile_policy" at the same time.



-- 
浮沉随浪只记今朝笑

--fan

Re: [PATCH v3 net-next] xfrm: Add check to prevent un-complete key manager

[David Miller]

From: baker.kernel@gmail.com
Date: Mon, 11 Nov 2013 14:39:11 +0800

> +	if (km->acquire == NULL || km->compile_policy == NULL)
> +		return -EINVAL;

There are 7 function pointer methods that must be fully implemented
in an xfrm_mgr object, not just two.

And really we absolutely do not care at all about your out-of-tree
product, it has no bearing upon what should happen here.