[PATCH nf-next] netfilter: nft_socket: fix erroneous socket assignment

[PATCH nf-next] netfilter: nft_socket: fix erroneous socket assignment

[Fernando Fernandez Mancera]

This socket assignment was unnecessary and also added a missing sock_gen_put().

Fixes: 554ced0a6e29 ("netfilter: nf_tables: add support for native socket matching")
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
---
 net/netfilter/nft_socket.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
index d7f3776dfd71..637ce3e8c575 100644
--- a/net/netfilter/nft_socket.c
+++ b/net/netfilter/nft_socket.c
@@ -47,9 +47,6 @@ static void nft_socket_eval(const struct nft_expr *expr,
 		return;
 	}
 
-	/* So that subsequent socket matching not to require other lookups. */
-	skb->sk = sk;
-
 	switch(priv->key) {
 	case NFT_SOCKET_TRANSPARENT:
 		nft_reg_store8(dest, inet_sk_transparent(sk));
@@ -66,6 +63,9 @@ static void nft_socket_eval(const struct nft_expr *expr,
 		WARN_ON(1);
 		regs->verdict.code = NFT_BREAK;
 	}
+
+	if (sk != skb->sk)
+		sock_gen_put(sk);
 }
 
 static const struct nla_policy nft_socket_policy[NFTA_SOCKET_MAX + 1] = {
-- 
2.20.1

Re: [PATCH nf-next] netfilter: nft_socket: fix erroneous socket assignment

[Fernando Fernandez Mancera]

This patch fixes https://bugzilla.redhat.com/show_bug.cgi?id=1651813. I
didn't include this link into the commit message because I don't know if
it is appropiate. Thanks! :-)

On 8/31/19 12:14 PM, Fernando Fernandez Mancera wrote:
> This socket assignment was unnecessary and also added a missing sock_gen_put().
> 
> Fixes: 554ced0a6e29 ("netfilter: nf_tables: add support for native socket matching")
> Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
> ---
>  net/netfilter/nft_socket.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
> index d7f3776dfd71..637ce3e8c575 100644
> --- a/net/netfilter/nft_socket.c
> +++ b/net/netfilter/nft_socket.c
> @@ -47,9 +47,6 @@ static void nft_socket_eval(const struct nft_expr *expr,
>  		return;
>  	}
>  
> -	/* So that subsequent socket matching not to require other lookups. */
> -	skb->sk = sk;
> -
>  	switch(priv->key) {
>  	case NFT_SOCKET_TRANSPARENT:
>  		nft_reg_store8(dest, inet_sk_transparent(sk));
> @@ -66,6 +63,9 @@ static void nft_socket_eval(const struct nft_expr *expr,
>  		WARN_ON(1);
>  		regs->verdict.code = NFT_BREAK;
>  	}
> +
> +	if (sk != skb->sk)
> +		sock_gen_put(sk);
>  }
>  
>  static const struct nla_policy nft_socket_policy[NFTA_SOCKET_MAX + 1] = {
> 

Re: [PATCH nf-next] netfilter: nft_socket: fix erroneous socket assignment

[Florian Westphal]

Fernando Fernandez Mancera <ffmancera@riseup.net> wrote:
> This socket assignment was unnecessary and also added a missing sock_gen_put().

The socket assignment is wrong, see skb_orphan():
When skb->destructor callback is not set, but skb->sk is set, this hits BUG().

You could add a 'Link: ' to the bugzilla ticket if you like.
Patch looks good, thanks for fixing this Fernando!