Re: [patch] netfilter: nfnetlink: guard against undefined entries

[Patrick McHardy <kaber@trash.net>]

On 10.11.2010 02:50, Jan Engelhardt wrote:
> parent a391d495f6082f6348b9074214e81c7e2dc1151c (v2.6.37-rc1-184-ga391d49)
> commit 6e97eb121bc8e39c651645c3d937f468d2b3e7fe
> Author: Jan Engelhardt <jengelh@medozas.de>
> Date:   Sat Nov 6 21:19:16 2010 +0100
> 
> netfilter: nfnetlink: guard against undefined entries
> 
> Check for empty entries in struct nfnl_callback[] to avoid potential
> NULL deference. (Because I have run into one during development.)

It seems silly to add checks for easy to find bugs in users of
this code. Finding the cause of -EINVAL is much harder than
getting a nice oops.

> Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
> ---
>  net/netfilter/nfnetlink.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
> index b4a4532..7012882 100644
> --- a/net/netfilter/nfnetlink.c
> +++ b/net/netfilter/nfnetlink.c
> @@ -152,7 +152,7 @@ replay:
>  	}
>  
>  	nc = nfnetlink_find_client(type, ss);
> -	if (!nc)
> +	if (nc == NULL || nc->call == NULL)
>  		return -EINVAL;
>  
>  	{