Re: [PATCH nf-next] netfilter: nf_tables: Expose socket mark

2018-07-12 Thread Máté Eckl
On Thu, Jul 12, 2018 at 04:26:54PM +0200, Pablo Neira Ayuso wrote:
> On Thu, Jul 12, 2018 at 12:52:16AM +0200, Máté Eckl wrote:
> > Signed-off-by: Máté Eckl 
> > ---
> >  include/uapi/linux/netfilter/nf_tables.h |  4 +++-
> >  net/netfilter/nft_socket.c   | 11 ++-
> >  2 files changed, 13 insertions(+), 2 deletions(-)
> > 
> > diff --git a/include/uapi/linux/netfilter/nf_tables.h 
> > b/include/uapi/linux/netfilter/nf_tables.h
> > index 89438e68dc03..f466860bcf75 100644
> > --- a/include/uapi/linux/netfilter/nf_tables.h
> > +++ b/include/uapi/linux/netfilter/nf_tables.h
> > @@ -921,10 +921,12 @@ enum nft_socket_attributes {
> >  /*
> >   * enum nft_socket_keys - nf_tables socket expression keys
> >   *
> > - * @NFT_SOCKET_TRANSPARENT: Value of the IP(V6)_TRANSPARENT socket option_
> > + * @NFT_SOCKET_TRANSPARENT: Value of the IP(V6)_TRANSPARENT socket option
> > + * @NFT_SOCKET_MARK: Value of the socket mark
> >   */
> >  enum nft_socket_keys {
> > NFT_SOCKET_TRANSPARENT,
> > +   NFT_SOCKET_MARK,
> > __NFT_SOCKET_MAX
> >  };
> >  #define NFT_SOCKET_MAX (__NFT_SOCKET_MAX - 1)
> > diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
> > index 74e1b3bd6954..3f46b2013e26 100644
> > --- a/net/netfilter/nft_socket.c
> > +++ b/net/netfilter/nft_socket.c
> > @@ -40,7 +40,7 @@ static void nft_socket_eval(const struct nft_expr *expr,
> > }
> >  
> > if(!sk) {
> > -   nft_reg_store8(dest, 0);
> > +   *dest = 0;
> > return;
> 
> I think this should be:
> 
> if (!sk)
> regs->verdict.code = NFT_BREAK;
> 
> So we make sure we skip further evaluation, because zero may be a
> valid mark.
> 
> or better:
> 
> if (!sk)
> goto out:
> ...
> out:
> regs->verdict.code = NFT_BREAK;
> 
> so you consolidate this evaluation break path.
> 
> An initial patch to fix what we have would be good to have.
> 
> > }
> >  
> > @@ -51,6 +51,12 @@ static void nft_socket_eval(const struct nft_expr *expr,
> > case NFT_SOCKET_TRANSPARENT:
> > nft_reg_store8(dest, inet_sk_transparent(sk));
> > break;
> > +   case NFT_SOCKET_MARK:
> > +   if (sk_fullsock(sk))
> > +   *dest = inet_request_mark(sk, skb);
> > +   else
> > +   *dest = 0;
> 
> Again, better break evaluation here, so I would do:
> 
> if (!sk_fullsock(sk))
> goto out;
> 
> ...
> out:
> regs->verdict.code = NFT_BREAK;
> 
> Thanks.

Thanks for the observation, you are right, it should break evaluation. I'll fix
this too.
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Re: [PATCH nf-next] netfilter: nf_tables: Expose socket mark

2018-07-12 Thread Pablo Neira Ayuso
On Thu, Jul 12, 2018 at 12:52:16AM +0200, Máté Eckl wrote:
> Signed-off-by: Máté Eckl 
> ---
>  include/uapi/linux/netfilter/nf_tables.h |  4 +++-
>  net/netfilter/nft_socket.c   | 11 ++-
>  2 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/include/uapi/linux/netfilter/nf_tables.h 
> b/include/uapi/linux/netfilter/nf_tables.h
> index 89438e68dc03..f466860bcf75 100644
> --- a/include/uapi/linux/netfilter/nf_tables.h
> +++ b/include/uapi/linux/netfilter/nf_tables.h
> @@ -921,10 +921,12 @@ enum nft_socket_attributes {
>  /*
>   * enum nft_socket_keys - nf_tables socket expression keys
>   *
> - * @NFT_SOCKET_TRANSPARENT: Value of the IP(V6)_TRANSPARENT socket option_
> + * @NFT_SOCKET_TRANSPARENT: Value of the IP(V6)_TRANSPARENT socket option
> + * @NFT_SOCKET_MARK: Value of the socket mark
>   */
>  enum nft_socket_keys {
>   NFT_SOCKET_TRANSPARENT,
> + NFT_SOCKET_MARK,
>   __NFT_SOCKET_MAX
>  };
>  #define NFT_SOCKET_MAX   (__NFT_SOCKET_MAX - 1)
> diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
> index 74e1b3bd6954..3f46b2013e26 100644
> --- a/net/netfilter/nft_socket.c
> +++ b/net/netfilter/nft_socket.c
> @@ -40,7 +40,7 @@ static void nft_socket_eval(const struct nft_expr *expr,
>   }
>  
>   if(!sk) {
> - nft_reg_store8(dest, 0);
> + *dest = 0;
>   return;

I think this should be:

if (!sk)
regs->verdict.code = NFT_BREAK;

So we make sure we skip further evaluation, because zero may be a
valid mark.

or better:

if (!sk)
goto out:
...
out:
regs->verdict.code = NFT_BREAK;

so you consolidate this evaluation break path.

An initial patch to fix what we have would be good to have.

>   }
>  
> @@ -51,6 +51,12 @@ static void nft_socket_eval(const struct nft_expr *expr,
>   case NFT_SOCKET_TRANSPARENT:
>   nft_reg_store8(dest, inet_sk_transparent(sk));
>   break;
> + case NFT_SOCKET_MARK:
> + if (sk_fullsock(sk))
> + *dest = inet_request_mark(sk, skb);
> + else
> + *dest = 0;

Again, better break evaluation here, so I would do:

if (!sk_fullsock(sk))
goto out;

...
out:
regs->verdict.code = NFT_BREAK;

Thanks.
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Re: [PATCH nf-next] netfilter: nf_tables: Expose socket mark

2018-07-12 Thread Máté Eckl
On Thu, Jul 12, 2018 at 01:11:33PM +0200, Florian Westphal wrote:
> Máté Eckl  wrote:
> > Signed-off-by: Máté Eckl 
> > ---
> >  include/uapi/linux/netfilter/nf_tables.h |  4 +++-
> >  net/netfilter/nft_socket.c   | 11 ++-
> >  2 files changed, 13 insertions(+), 2 deletions(-)
> > 
> > diff --git a/include/uapi/linux/netfilter/nf_tables.h 
> > b/include/uapi/linux/netfilter/nf_tables.h
> > index 89438e68dc03..f466860bcf75 100644
> > --- a/include/uapi/linux/netfilter/nf_tables.h
> > +++ b/include/uapi/linux/netfilter/nf_tables.h
> > @@ -921,10 +921,12 @@ enum nft_socket_attributes {
> >  /*
> >   * enum nft_socket_keys - nf_tables socket expression keys
> >   *
> > - * @NFT_SOCKET_TRANSPARENT: Value of the IP(V6)_TRANSPARENT socket option_
> > + * @NFT_SOCKET_TRANSPARENT: Value of the IP(V6)_TRANSPARENT socket option
> > + * @NFT_SOCKET_MARK: Value of the socket mark
> >   */
> >  enum nft_socket_keys {
> > NFT_SOCKET_TRANSPARENT,
> > +   NFT_SOCKET_MARK,
> > __NFT_SOCKET_MAX
> >  };
> >  #define NFT_SOCKET_MAX (__NFT_SOCKET_MAX - 1)
> > diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
> > index 74e1b3bd6954..3f46b2013e26 100644
> > --- a/net/netfilter/nft_socket.c
> > +++ b/net/netfilter/nft_socket.c
> > @@ -40,7 +40,7 @@ static void nft_socket_eval(const struct nft_expr *expr,
> > }
> >  
> > if(!sk) {
> > -   nft_reg_store8(dest, 0);
> > +   *dest = 0;
> > return;
> > }
> >  
> > @@ -51,6 +51,12 @@ static void nft_socket_eval(const struct nft_expr *expr,
> > case NFT_SOCKET_TRANSPARENT:
> > nft_reg_store8(dest, inet_sk_transparent(sk));
> > break;
> > +   case NFT_SOCKET_MARK:
> > +   if (sk_fullsock(sk))
> > +   *dest = inet_request_mark(sk, skb);
> 
> I wonder if it wouldn't be better to use sk->sk_mark directly.
> If user wants to fallback to skb->mark they could do
> 
> socket mark 0 meta mark 42
> 
> rather than
> 
> socket mark 42
> 
> ... matching when skb->mark is 42 and sk_mark is 0, it seems
> unexpected to me.

Yes that will be better. I'll wait some time in case other comments come up and
then I resubmit with this modification.

> Rest looks great.
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Re: [PATCH nf-next] netfilter: nf_tables: Expose socket mark

2018-07-12 Thread Florian Westphal
Máté Eckl  wrote:
> Signed-off-by: Máté Eckl 
> ---
>  include/uapi/linux/netfilter/nf_tables.h |  4 +++-
>  net/netfilter/nft_socket.c   | 11 ++-
>  2 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/include/uapi/linux/netfilter/nf_tables.h 
> b/include/uapi/linux/netfilter/nf_tables.h
> index 89438e68dc03..f466860bcf75 100644
> --- a/include/uapi/linux/netfilter/nf_tables.h
> +++ b/include/uapi/linux/netfilter/nf_tables.h
> @@ -921,10 +921,12 @@ enum nft_socket_attributes {
>  /*
>   * enum nft_socket_keys - nf_tables socket expression keys
>   *
> - * @NFT_SOCKET_TRANSPARENT: Value of the IP(V6)_TRANSPARENT socket option_
> + * @NFT_SOCKET_TRANSPARENT: Value of the IP(V6)_TRANSPARENT socket option
> + * @NFT_SOCKET_MARK: Value of the socket mark
>   */
>  enum nft_socket_keys {
>   NFT_SOCKET_TRANSPARENT,
> + NFT_SOCKET_MARK,
>   __NFT_SOCKET_MAX
>  };
>  #define NFT_SOCKET_MAX   (__NFT_SOCKET_MAX - 1)
> diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
> index 74e1b3bd6954..3f46b2013e26 100644
> --- a/net/netfilter/nft_socket.c
> +++ b/net/netfilter/nft_socket.c
> @@ -40,7 +40,7 @@ static void nft_socket_eval(const struct nft_expr *expr,
>   }
>  
>   if(!sk) {
> - nft_reg_store8(dest, 0);
> + *dest = 0;
>   return;
>   }
>  
> @@ -51,6 +51,12 @@ static void nft_socket_eval(const struct nft_expr *expr,
>   case NFT_SOCKET_TRANSPARENT:
>   nft_reg_store8(dest, inet_sk_transparent(sk));
>   break;
> + case NFT_SOCKET_MARK:
> + if (sk_fullsock(sk))
> + *dest = inet_request_mark(sk, skb);

I wonder if it wouldn't be better to use sk->sk_mark directly.
If user wants to fallback to skb->mark they could do

socket mark 0 meta mark 42

rather than

socket mark 42

... matching when skb->mark is 42 and sk_mark is 0, it seems
unexpected to me.

Rest looks great.
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