[PATCH net] xfrm: Fix ignored return value in xfrm6_init()

[PATCH net] xfrm: Fix ignored return value in xfrm6_init()

[Chen Zhongjin]

When IPv6 module initializing in xfrm6_init(), register_pernet_subsys()
is possible to fail but its return value is ignored.

If IPv6 initialization fails later and xfrm6_fini() is called,
removing uninitialized list in xfrm6_net_ops will cause null-ptr-deref:

KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 330 Comm: insmod
RIP: 0010:unregister_pernet_operations+0xc9/0x450
Call Trace:
 <TASK>
 unregister_pernet_subsys+0x31/0x3e
 xfrm6_fini+0x16/0x30 [ipv6]
 ip6_route_init+0xcd/0x128 [ipv6]
 inet6_init+0x29c/0x602 [ipv6]
 ...

Fix it by catching the error return value of register_pernet_subsys().

Fixes: 8d068875caca ("xfrm: make gc_thresh configurable in all namespaces")
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
---
 net/ipv6/xfrm6_policy.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 4a4b0e49ec92..ea435eba3053 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -287,9 +287,13 @@ int __init xfrm6_init(void)
 	if (ret)
 		goto out_state;
 
-	register_pernet_subsys(&xfrm6_net_ops);
+	ret = register_pernet_subsys(&xfrm6_net_ops);
+	if (ret)
+		goto out_protocol;
 out:
 	return ret;
+out_protocol:
+	xfrm6_protocol_fini();
 out_state:
 	xfrm6_state_fini();
 out_policy:
-- 
2.17.1

Re: [PATCH net] xfrm: Fix ignored return value in xfrm6_init()

[Leon Romanovsky]

On Thu, Nov 03, 2022 at 05:07:13PM +0800, Chen Zhongjin wrote:
> When IPv6 module initializing in xfrm6_init(), register_pernet_subsys()
> is possible to fail but its return value is ignored.
> 
> If IPv6 initialization fails later and xfrm6_fini() is called,
> removing uninitialized list in xfrm6_net_ops will cause null-ptr-deref:
> 
> KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
> CPU: 1 PID: 330 Comm: insmod
> RIP: 0010:unregister_pernet_operations+0xc9/0x450
> Call Trace:
>  <TASK>
>  unregister_pernet_subsys+0x31/0x3e
>  xfrm6_fini+0x16/0x30 [ipv6]
>  ip6_route_init+0xcd/0x128 [ipv6]
>  inet6_init+0x29c/0x602 [ipv6]
>  ...
> 
> Fix it by catching the error return value of register_pernet_subsys().
> 
> Fixes: 8d068875caca ("xfrm: make gc_thresh configurable in all namespaces")
> Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
> ---
>  net/ipv6/xfrm6_policy.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)

I see same error in net/ipv4/xfrm4_policy.c which introduced by same
commit mentioned in Fixes line.

Thanks

> 
> diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
> index 4a4b0e49ec92..ea435eba3053 100644
> --- a/net/ipv6/xfrm6_policy.c
> +++ b/net/ipv6/xfrm6_policy.c
> @@ -287,9 +287,13 @@ int __init xfrm6_init(void)
>  	if (ret)
>  		goto out_state;
>  
> -	register_pernet_subsys(&xfrm6_net_ops);
> +	ret = register_pernet_subsys(&xfrm6_net_ops);
> +	if (ret)
> +		goto out_protocol;
>  out:
>  	return ret;
> +out_protocol:
> +	xfrm6_protocol_fini();
>  out_state:
>  	xfrm6_state_fini();
>  out_policy:
> -- 
> 2.17.1
> 

Re: [PATCH net] xfrm: Fix ignored return value in xfrm6_init()

[Chen Zhongjin]

Hi,

On 2022/11/7 3:08, Leon Romanovsky wrote:
> On Thu, Nov 03, 2022 at 05:07:13PM +0800, Chen Zhongjin wrote:
>> When IPv6 module initializing in xfrm6_init(), register_pernet_subsys()
>> is possible to fail but its return value is ignored.
>>
>> If IPv6 initialization fails later and xfrm6_fini() is called,
>> removing uninitialized list in xfrm6_net_ops will cause null-ptr-deref:
>>
>> KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
>> CPU: 1 PID: 330 Comm: insmod
>> RIP: 0010:unregister_pernet_operations+0xc9/0x450
>> Call Trace:
>>   <TASK>
>>   unregister_pernet_subsys+0x31/0x3e
>>   xfrm6_fini+0x16/0x30 [ipv6]
>>   ip6_route_init+0xcd/0x128 [ipv6]
>>   inet6_init+0x29c/0x602 [ipv6]
>>   ...
>>
>> Fix it by catching the error return value of register_pernet_subsys().
>>
>> Fixes: 8d068875caca ("xfrm: make gc_thresh configurable in all namespaces")
>> Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
>> ---
>>   net/ipv6/xfrm6_policy.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
> I see same error in net/ipv4/xfrm4_policy.c which introduced by same
> commit mentioned in Fixes line.

It's true that in xfrm4_init() the ops->init is possible to fail as well.

However there is no error handling or exit path for ipv4, so IIUC the 
ops won't be unregistered anyway.

Considering that ipv4 don't handle most of error in initialization, 
maybe it's better to keep it as it is?


Best,

Chen

> Thanks
>

Re: [PATCH net] xfrm: Fix ignored return value in xfrm6_init()

[Leon Romanovsky]

On Mon, Nov 07, 2022 at 11:22:40AM +0800, Chen Zhongjin wrote:
> Hi,
> 
> On 2022/11/7 3:08, Leon Romanovsky wrote:
> > On Thu, Nov 03, 2022 at 05:07:13PM +0800, Chen Zhongjin wrote:
> > > When IPv6 module initializing in xfrm6_init(), register_pernet_subsys()
> > > is possible to fail but its return value is ignored.
> > > 
> > > If IPv6 initialization fails later and xfrm6_fini() is called,
> > > removing uninitialized list in xfrm6_net_ops will cause null-ptr-deref:
> > > 
> > > KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
> > > CPU: 1 PID: 330 Comm: insmod
> > > RIP: 0010:unregister_pernet_operations+0xc9/0x450
> > > Call Trace:
> > >   <TASK>
> > >   unregister_pernet_subsys+0x31/0x3e
> > >   xfrm6_fini+0x16/0x30 [ipv6]
> > >   ip6_route_init+0xcd/0x128 [ipv6]
> > >   inet6_init+0x29c/0x602 [ipv6]
> > >   ...
> > > 
> > > Fix it by catching the error return value of register_pernet_subsys().
> > > 
> > > Fixes: 8d068875caca ("xfrm: make gc_thresh configurable in all namespaces")
> > > Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
> > > ---
> > >   net/ipv6/xfrm6_policy.c | 6 +++++-
> > >   1 file changed, 5 insertions(+), 1 deletion(-)
> > I see same error in net/ipv4/xfrm4_policy.c which introduced by same
> > commit mentioned in Fixes line.
> 
> It's true that in xfrm4_init() the ops->init is possible to fail as well.
> 
> However there is no error handling or exit path for ipv4, so IIUC the ops
> won't be unregistered anyway.
> 
> Considering that ipv4 don't handle most of error in initialization, maybe
> it's better to keep it as it is?

Yeah, makes sense.

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>

Re: [PATCH net] xfrm: Fix ignored return value in xfrm6_init()

[Steffen Klassert]

On Mon, Nov 07, 2022 at 10:06:48AM +0200, Leon Romanovsky wrote:
> On Mon, Nov 07, 2022 at 11:22:40AM +0800, Chen Zhongjin wrote:
> > Hi,
> > 
> > On 2022/11/7 3:08, Leon Romanovsky wrote:
> > > On Thu, Nov 03, 2022 at 05:07:13PM +0800, Chen Zhongjin wrote:
> > > > When IPv6 module initializing in xfrm6_init(), register_pernet_subsys()
> > > > is possible to fail but its return value is ignored.
> > > > 
> > > > If IPv6 initialization fails later and xfrm6_fini() is called,
> > > > removing uninitialized list in xfrm6_net_ops will cause null-ptr-deref:
> > > > 
> > > > KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
> > > > CPU: 1 PID: 330 Comm: insmod
> > > > RIP: 0010:unregister_pernet_operations+0xc9/0x450
> > > > Call Trace:
> > > >   <TASK>
> > > >   unregister_pernet_subsys+0x31/0x3e
> > > >   xfrm6_fini+0x16/0x30 [ipv6]
> > > >   ip6_route_init+0xcd/0x128 [ipv6]
> > > >   inet6_init+0x29c/0x602 [ipv6]
> > > >   ...
> > > > 
> > > > Fix it by catching the error return value of register_pernet_subsys().
> > > > 
> > > > Fixes: 8d068875caca ("xfrm: make gc_thresh configurable in all namespaces")
> > > > Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
> > > > ---
> > > >   net/ipv6/xfrm6_policy.c | 6 +++++-
> > > >   1 file changed, 5 insertions(+), 1 deletion(-)
> > > I see same error in net/ipv4/xfrm4_policy.c which introduced by same
> > > commit mentioned in Fixes line.
> > 
> > It's true that in xfrm4_init() the ops->init is possible to fail as well.
> > 
> > However there is no error handling or exit path for ipv4, so IIUC the ops
> > won't be unregistered anyway.
> > 
> > Considering that ipv4 don't handle most of error in initialization, maybe
> > it's better to keep it as it is?
> 
> Yeah, makes sense.
> 
> Thanks,
> Reviewed-by: Leon Romanovsky <leonro@nvidia.com>

Applied, thanks a lot!