Subject: Re: [PATCH 01/13] netfilter: fix problem with proto register

From: Pablo Neira Ayuso <[email-masked]>
Date: Mon, 25 Jun 2012 13:12:53 +0200

On Thu, Jun 21, 2012 at 10:36:38PM +0800, Gao feng wrote:
> before commit 2c352f444ccfa966a1aa4fd8e9ee29381c467448
> (netfilter: nf_conntrack: prepare namespace support for
> l4 protocol trackers), we register sysctl before register
> protos, so if sysctl is registered faild, the protos will
> not be registered.
> 
> but now, we register protos first, and when register
> sysctl failed, we can use protos too, it's different
> from before.

No, this has to be an all-or-nothing game. If one fails, everything
else that you've registered has to be unregistered.

> so change to register sysctl before register protos.
> 
> Signed-off-by: Gao feng <[email-masked]>
> ---
>  net/netfilter/nf_conntrack_proto.c |   36 +++++++++++++++++++++++-------------
>  1 files changed, 23 insertions(+), 13 deletions(-)
> 
> diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c
> index 1ea9194..9bd88aa 100644
> --- a/net/netfilter/nf_conntrack_proto.c
> +++ b/net/netfilter/nf_conntrack_proto.c
> @@ -253,18 +253,23 @@ int nf_conntrack_l3proto_register(struct net *net,
>  {
>  	int ret = 0;
>  
> -	if (net == &init_net)
> -		ret = nf_conntrack_l3proto_register_net(proto);
> +	if (proto->init_net) {
> +		ret = proto->init_net(net);
> +		if (ret < 0)
> +			return ret;
> +	}
>  
> +	ret = nf_ct_l3proto_register_sysctl(net, proto);
>  	if (ret < 0)
>  		return ret;

This is still wrong.

If nf_ct_l3proto_register_sysctl fails, we'll leak the memory that has
been reserved by proto->init_net.

> -	if (proto->init_net) {
> -		ret = proto->init_net(net);
> +	if (net == &init_net) {
> +		ret = nf_conntrack_l3proto_register_net(proto);
>  		if (ret < 0)
> -			return ret;
> +			nf_ct_l3proto_unregister_sysctl(net, proto);
>  	}
> -	return nf_ct_l3proto_register_sysctl(net, proto);
> +
> +	return ret;
>  }
>  EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);
>  
> @@ -454,19 +459,24 @@ int nf_conntrack_l4proto_register(struct net *net,
>  				  struct nf_conntrack_l4proto *l4proto)
>  {
>  	int ret = 0;
> -	if (net == &init_net)
> -		ret = nf_conntrack_l4proto_register_net(l4proto);
>  
> -	if (ret < 0)
> -		return ret;
> -
> -	if (l4proto->init_net)
> +	if (l4proto->init_net) {
>  		ret = l4proto->init_net(net);
> +		if (ret < 0)
> +			return ret;
> +	}
>  
> +	ret = nf_ct_l4proto_register_sysctl(net, l4proto);
>  	if (ret < 0)
>  		return ret;
>  
> -	return nf_ct_l4proto_register_sysctl(net, l4proto);
> +	if (net == &init_net) {
> +		ret = nf_conntrack_l4proto_register_net(l4proto);
> +		if (ret < 0)
> +			nf_ct_l4proto_unregister_sysctl(net, l4proto);
> +	}
> +
> +	return ret;
>  }
>  EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);
>  
> -- 
> 1.7.7.6
> 
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