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Subject: Re: [PATCH] [XFRM]: Don't dereference error pointer dst1
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Roel Kluin <roel.kluin@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>
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Date: Wed, 29 Sep 2010 22:45:13 +0200
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Le jeudi 30 septembre 2010 à 00:37 +0200, Roel Kluin a écrit :
> Don't dereference dst1 when it's an error pointer.
> 
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
> ---
>  net/xfrm/xfrm_policy.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> I just noticed this by code analysis. It wasn't tested in any way.
> 
> diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
> index cbab6e1..b186c3d 100644
> --- a/net/xfrm/xfrm_policy.c
> +++ b/net/xfrm/xfrm_policy.c
> @@ -1414,13 +1414,14 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
>  
>  	for (; i < nx; i++) {
>  		struct xfrm_dst *xdst = xfrm_alloc_dst(net, family);
> -		struct dst_entry *dst1 = &xdst->u.dst;
> +		struct dst_entry *dst1;
>  
>  		err = PTR_ERR(xdst);
>  		if (IS_ERR(xdst)) {
>  			dst_release(dst);
>  			goto put_states;
>  		}
> +		dst1 = &xdst->u.dst;
>  
>  		if (!dst_prev)
>  			dst0 = dst1;
> 

This is not a dereference, but a cast from "struct xfrm_dst *" to
"struct dst_entry *"