[PATCH] llc: fix skb size for test responses

[PATCH] llc: fix skb size for test responses

[Jim Westfall]

Hi

The llc test command is used for a layer2 ping and contains a variable 
length payload that we must include in the response.  Use the size of the 
received skb as the size of the skb we must allocate to hold the payload. 

This resolved an skb_over_panic(), when trying to copy the payload into 
what was a hard coded skb of size 128.

Signed-off-by: Jim Westfall <jwestfall@surrealistic.net>

diff -urp linux-2.6.24.2.org/net/llc/llc_s_ac.c linux-2.6.24.2/net/llc/llc_s_ac.c
--- linux-2.6.24.2.org/net/llc/llc_s_ac.c	2008-02-10 21:51:11.000000000 -0800
+++ linux-2.6.24.2/net/llc/llc_s_ac.c	2008-02-24 10:15:02.000000000 -0800
@@ -148,9 +148,18 @@ int llc_sap_action_send_test_r(struct ll
 	llc_pdu_decode_sa(skb, mac_da);
 	llc_pdu_decode_da(skb, mac_sa);
 	llc_pdu_decode_ssap(skb, &dsap);
-	nskb = llc_alloc_frame(NULL, skb->dev);
+	nskb = alloc_skb(skb->end - skb->head, GFP_ATOMIC);
+
 	if (!nskb)
 		goto out;
+
+	skb_reset_mac_header(nskb);
+	skb_reserve(nskb, 50);
+	skb_reset_network_header(nskb);
+	skb_reset_transport_header(nskb);
+	nskb->protocol = htons(ETH_P_802_2);
+	nskb->dev = skb->dev;
+
 	llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap, dsap,
 			    LLC_PDU_RSP);
 	llc_pdu_init_as_test_rsp(nskb, skb);
diff -urp linux-2.6.24.2.org/net/llc/llc_station.c linux-2.6.24.2/net/llc/llc_station.c
--- linux-2.6.24.2.org/net/llc/llc_station.c	2008-02-10 21:51:11.000000000 -0800
+++ linux-2.6.24.2/net/llc/llc_station.c	2008-02-24 10:10:01.000000000 -0800
@@ -298,10 +298,18 @@ static int llc_station_ac_send_test_r(st
 {
 	u8 mac_da[ETH_ALEN], dsap;
 	int rc = 1;
-	struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev);
+	struct sk_buff *nskb = alloc_skb(skb->end - skb->head, GFP_ATOMIC);
 
 	if (!nskb)
 		goto out;
+
+	skb_reset_mac_header(nskb);
+	skb_reserve(nskb, 50);
+	skb_reset_network_header(nskb);
+	skb_reset_transport_header(nskb);
+	nskb->protocol = htons(ETH_P_802_2);
+	nskb->dev = skb->dev;
+
 	rc = 0;
 	llc_pdu_decode_sa(skb, mac_da);
 	llc_pdu_decode_ssap(skb, &dsap);

Re: [PATCH] llc: fix skb size for test responses

[David Miller]

From: Jim Westfall <jwestfall@surrealistic.net>
Date: Sun, 24 Feb 2008 11:07:58 -0800

> Hi
> 
> The llc test command is used for a layer2 ping and contains a variable 
> length payload that we must include in the response.  Use the size of the 
> received skb as the size of the skb we must allocate to hold the payload. 
> 
> This resolved an skb_over_panic(), when trying to copy the payload into 
> what was a hard coded skb of size 128.
> 
> Signed-off-by: Jim Westfall <jwestfall@surrealistic.net>

Arnaldo, please review Jim's patch, thanks!

Re: [PATCH] llc: fix skb size for test responses

[Jim Westfall]

David Miller <davem@davemloft.net> wrote [02.24.08]:
> From: Jim Westfall <jwestfall@surrealistic.net>
> Date: Sun, 24 Feb 2008 11:07:58 -0800
> 
> > Hi
> > 
> > The llc test command is used for a layer2 ping and contains a variable 
> > length payload that we must include in the response.  Use the size of the 
> > received skb as the size of the skb we must allocate to hold the payload. 
> > 
> > This resolved an skb_over_panic(), when trying to copy the payload into 
> > what was a hard coded skb of size 128.
> > 
> > Signed-off-by: Jim Westfall <jwestfall@surrealistic.net>
> 
> Arnaldo, please review Jim's patch, thanks!

Our of curiosity did you all get my 2nd patch?  

Subject: [PATCH] llc: dont trust payload size on test cmd

I sent it a few minutes after this one, but seems like it never made it 
to the list.  My local smtp shows it was delivered sucussfully to 
vger.kernel.org.

thanks
jim

Re: [PATCH] llc: fix skb size for test responses

[Joonwoo Park]

2008/2/25, Jim Westfall <jwestfall@surrealistic.net>:
> David Miller <davem@davemloft.net> wrote [02.24.08]:
> > From: Jim Westfall <jwestfall@surrealistic.net>
> > Date: Sun, 24 Feb 2008 11:07:58 -0800
> >
> > > Hi
> > >
> > > The llc test command is used for a layer2 ping and contains a variable
> > > length payload that we must include in the response.  Use the size of the
> > > received skb as the size of the skb we must allocate to hold the payload.
> > >
> > > This resolved an skb_over_panic(), when trying to copy the payload into
> > > what was a hard coded skb of size 128.
> > >
> > > Signed-off-by: Jim Westfall <jwestfall@surrealistic.net>
> >
> > Arnaldo, please review Jim's patch, thanks!
>
> Our of curiosity did you all get my 2nd patch?
>
> Subject: [PATCH] llc: dont trust payload size on test cmd
>
> I sent it a few minutes after this one, but seems like it never made it
> to the list.  My local smtp shows it was delivered sucussfully to
> vger.kernel.org.
>

Jim,
Could you please send it again?
I cannot find your second patch on the list.
I have a pending patch for LLC as well, so I want to avoid conflict with yours.

Thanks,
Joonwoo

Re: [PATCH] llc: fix skb size for test responses

[Arnaldo Carvalho de Melo]

Em Sun, Feb 24, 2008 at 09:04:21PM -0800, Jim Westfall escreveu:
> David Miller <davem@davemloft.net> wrote [02.24.08]:
> > From: Jim Westfall <jwestfall@surrealistic.net>
> > Date: Sun, 24 Feb 2008 11:07:58 -0800
> > 
> > > Hi
> > > 
> > > The llc test command is used for a layer2 ping and contains a variable 
> > > length payload that we must include in the response.  Use the size of the 
> > > received skb as the size of the skb we must allocate to hold the payload. 
> > > 
> > > This resolved an skb_over_panic(), when trying to copy the payload into 
> > > what was a hard coded skb of size 128.
> > > 
> > > Signed-off-by: Jim Westfall <jwestfall@surrealistic.net>
> > 
> > Arnaldo, please review Jim's patch, thanks!
> 
> Our of curiosity did you all get my 2nd patch?  
> 
> Subject: [PATCH] llc: dont trust payload size on test cmd
> 
> I sent it a few minutes after this one, but seems like it never made it 
> to the list.  My local smtp shows it was delivered sucussfully to 
> vger.kernel.org.

I got it, but you made a mistake on the To: address:

From: Jim Westfall <jwestfall@surrealistic.net>
Subject: [PATCH] llc: dont trust payload size on test cmd
To: "To:netdev"@vger.kernel.org, acme@ghostprotocols.net

Re: [PATCH] llc: fix skb size for test responses

[David Miller]

From: Jim Westfall <jwestfall@surrealistic.net>
Date: Sun, 24 Feb 2008 21:04:21 -0800

> I sent it a few minutes after this one, but seems like it never made it 
> to the list.  My local smtp shows it was delivered sucussfully to 
> vger.kernel.org.

Usually this means some string in the email triggered our
Majordomo level regexp filters, they are listed at:

http://vger.kernel.org/majordomo-info.html#taboo

Re: [PATCH] llc: fix skb size for test responses

[Joonwoo Park]

On Sun, Feb 24, 2008 at 11:07:58AM -0800, Jim Westfall wrote:
> Hi
> 
> The llc test command is used for a layer2 ping and contains a variable 
> length payload that we must include in the response.  Use the size of the 
> received skb as the size of the skb we must allocate to hold the payload. 
> 
> This resolved an skb_over_panic(), when trying to copy the payload into 
> what was a hard coded skb of size 128.
> 
> Signed-off-by: Jim Westfall <jwestfall@surrealistic.net>
> 
> diff -urp linux-2.6.24.2.org/net/llc/llc_s_ac.c linux-2.6.24.2/net/llc/llc_s_ac.c
> --- linux-2.6.24.2.org/net/llc/llc_s_ac.c	2008-02-10 21:51:11.000000000 -0800
> +++ linux-2.6.24.2/net/llc/llc_s_ac.c	2008-02-24 10:15:02.000000000 -0800
> @@ -148,9 +148,18 @@ int llc_sap_action_send_test_r(struct ll
>  	llc_pdu_decode_sa(skb, mac_da);
>  	llc_pdu_decode_da(skb, mac_sa);
>  	llc_pdu_decode_ssap(skb, &dsap);
> -	nskb = llc_alloc_frame(NULL, skb->dev);
> +	nskb = alloc_skb(skb->end - skb->head, GFP_ATOMIC);

Jim,

Not enough.
Because of 'skb_reserve(nskb, 50)', we need additional 50bytes.

> +
>  	if (!nskb)
>  		goto out;
> +
> +	skb_reset_mac_header(nskb);
> +	skb_reserve(nskb, 50);
> +	skb_reset_network_header(nskb);
> +	skb_reset_transport_header(nskb);
> +	nskb->protocol = htons(ETH_P_802_2);
> +	nskb->dev = skb->dev;
> +
>  	llc_pdu_header_init(nskb, LLC_PDU_TYPE_U, sap->laddr.lsap, dsap,
>  			    LLC_PDU_RSP);
>  	llc_pdu_init_as_test_rsp(nskb, skb);
> diff -urp linux-2.6.24.2.org/net/llc/llc_station.c linux-2.6.24.2/net/llc/llc_station.c
> --- linux-2.6.24.2.org/net/llc/llc_station.c	2008-02-10 21:51:11.000000000 -0800
> +++ linux-2.6.24.2/net/llc/llc_station.c	2008-02-24 10:10:01.000000000 -0800
> @@ -298,10 +298,18 @@ static int llc_station_ac_send_test_r(st
>  {
>  	u8 mac_da[ETH_ALEN], dsap;
>  	int rc = 1;
> -	struct sk_buff *nskb = llc_alloc_frame(NULL, skb->dev);
> +	struct sk_buff *nskb = alloc_skb(skb->end - skb->head, GFP_ATOMIC);

Also here.

>  
>  	if (!nskb)
>  		goto out;
> +
> +	skb_reset_mac_header(nskb);
> +	skb_reserve(nskb, 50);
> +	skb_reset_network_header(nskb);
> +	skb_reset_transport_header(nskb);
> +	nskb->protocol = htons(ETH_P_802_2);
> +	nskb->dev = skb->dev;
> +
>  	rc = 0;
>  	llc_pdu_decode_sa(skb, mac_da);
>  	llc_pdu_decode_ssap(skb, &dsap);
> 

Thanks,
Joonwoo

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