[PATCH] tcp: fix tcp header size miscalculation when window scale is unused

[PATCH] tcp: fix tcp header size miscalculation when window scale is unused

[Philip Love]

tcp: fix tcp header size miscalculation when window scale is unused

The size of the TCP header is miscalculated when the window scale ends  
up being
0. Additionally, this can be induced by sending a SYN to a passive  
open port
with a window scale option with value 0.

Signed-off-by: Philip Love <love_phil@emc.com>

---

net/ipv4/tcp_output.c |    6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index a00532d..71eea00 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -468,7 +468,8 @@ static unsigned tcp_syn_options(struct sock *sk,  
struct sk_buff *skb,
	}
	if (likely(sysctl_tcp_window_scaling)) {
		opts->ws = tp->rx_opt.rcv_wscale;
-		size += TCPOLEN_WSCALE_ALIGNED;
+		if (likely(opts->ws))
+			size += TCPOLEN_WSCALE_ALIGNED;
	}
	if (likely(sysctl_tcp_sack)) {
		opts->options |= OPTION_SACK_ADVERTISE;
@@ -509,7 +510,8 @@ static unsigned tcp_synack_options(struct sock *sk,

	if (likely(ireq->wscale_ok)) {
		opts->ws = ireq->rcv_wscale;
-		size += TCPOLEN_WSCALE_ALIGNED;
+		if (likely(opts->ws))
+			size += TCPOLEN_WSCALE_ALIGNED;
	}
	if (likely(doing_ts)) {
		opts->options |= OPTION_TS;

Re: [PATCH] tcp: fix tcp header size miscalculation when window scale is unused

[Adam Langley]

On Sat, Aug 23, 2008 at 10:18 AM, Philip Love <love_phil@emc.com> wrote:
> tcp: fix tcp header size miscalculation when window scale is unused

Reviewed-by: Adam Langley <agl@imperialviolet.org>



AGL

-- 
Adam Langley agl@imperialviolet.org http://www.imperialviolet.org

Re: [PATCH] tcp: fix tcp header size miscalculation when window scale is unused

[David Miller]

From: Philip Love <love_phil@emc.com>
Date: Sat, 23 Aug 2008 10:18:27 -0700

> tcp: fix tcp header size miscalculation when window scale is unused
> 
> The size of the TCP header is miscalculated when the window scale ends  
> up being
> 0. Additionally, this can be induced by sending a SYN to a passive  
> open port
> with a window scale option with value 0.
> 
> Signed-off-by: Philip Love <love_phil@emc.com>

This patch has been mangled by your email client, long lines have been
broken up, leading spaces and tabs have been converted to pure tab
characters, etc.

There I cannot apply the patch.

Please turn off all content modifications in your email client and
resubmit this, thank you.

Re: [PATCH] tcp: fix tcp header size miscalculation when window scale is unused

[Adam Langley]

From: Philip Love <love_phil@emc.com>

tcp: fix tcp header size miscalculation when window scale is unused

The size of the TCP header is miscalculated when the window scale ends up being
0. Additionally, this can be induced by sending a SYN to a passive open port
with a window scale option with value 0.

Signed-off-by: Philip Love <love_phil@emc.com>
Signed-off-by: Adam Langley <agl@imperialviolet.org>

---

 net/ipv4/tcp_output.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index a00532d..71eea00 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -468,7 +468,8 @@ static unsigned tcp_syn_options(struct sock *sk, struct sk_buff *skb,
 	}
 	if (likely(sysctl_tcp_window_scaling)) {
 		opts->ws = tp->rx_opt.rcv_wscale;
-		size += TCPOLEN_WSCALE_ALIGNED;
+		if (likely(opts->ws))
+			size += TCPOLEN_WSCALE_ALIGNED;
 	}
 	if (likely(sysctl_tcp_sack)) {
 		opts->options |= OPTION_SACK_ADVERTISE;
@@ -509,7 +510,8 @@ static unsigned tcp_synack_options(struct sock *sk,
 
 	if (likely(ireq->wscale_ok)) {
 		opts->ws = ireq->rcv_wscale;
-		size += TCPOLEN_WSCALE_ALIGNED;
+		if (likely(opts->ws))
+			size += TCPOLEN_WSCALE_ALIGNED;
 	}
 	if (likely(doing_ts)) {
 		opts->options |= OPTION_TS;

Re: [PATCH] tcp: fix tcp header size miscalculation when window scale is unused

[David Miller]

From: "Adam Langley" <agl@imperialviolet.org>
Date: Sun, 24 Aug 2008 10:40:23 -0700

> From: Philip Love <love_phil@emc.com>
> 
> tcp: fix tcp header size miscalculation when window scale is unused
> 
> The size of the TCP header is miscalculated when the window scale ends up being
> 0. Additionally, this can be induced by sending a SYN to a passive open port
> with a window scale option with value 0.
> 
> Signed-off-by: Philip Love <love_phil@emc.com>
> Signed-off-by: Adam Langley <agl@imperialviolet.org>

Adam I really appreciate you're fixing up the patch for Philip, but
how in the world is he ever going to learn how to submit a patch
properly if you just do it for him?

I could have fixed it up too, but I pushed it back so that he learns
how to submit a patch correctly, and this will help him and the rest
of us in the future when he wants to submit other patches.

Re: [PATCH] tcp: fix tcp header size miscalculation when window scale is unused

[Phil Love]

Here is the patch using Thunderbird, rather than Apple Mail. Hopefully 
it is not mangled this time.

Signed-off-by: Philip Love <love_phil@emc.com>

--- a/net/ipv4/tcp_output.c	2008-08-24 07:44:18.000000000 -0700
+++ b/net/ipv4/tcp_output.c	2008-08-24 07:43:05.000000000 -0700
@@ -468,7 +468,8 @@ static unsigned tcp_syn_options(struct s
  	}
  	if (likely(sysctl_tcp_window_scaling)) {
  		opts->ws = tp->rx_opt.rcv_wscale;
-		size += TCPOLEN_WSCALE_ALIGNED;
+		if(likely(opts->ws))
+			size += TCPOLEN_WSCALE_ALIGNED;
  	}
  	if (likely(sysctl_tcp_sack)) {
  		opts->options |= OPTION_SACK_ADVERTISE;
@@ -509,7 +510,8 @@ static unsigned tcp_synack_options(struc

  	if (likely(ireq->wscale_ok)) {
  		opts->ws = ireq->rcv_wscale;
-		size += TCPOLEN_WSCALE_ALIGNED;
+		if(likely(opts->ws))
+			size += TCPOLEN_WSCALE_ALIGNED;
  	}
  	if (likely(doing_ts)) {
  		opts->options |= OPTION_TS;

Re: [PATCH] tcp: fix tcp header size miscalculation when window scale is unused

[David Miller]

From: Phil Love <love_phil@emc.com>
Date: Mon, 25 Aug 2008 09:30:13 -0700

> Here is the patch using Thunderbird, rather than Apple Mail. Hopefully 
> it is not mangled this time.
> 
> Signed-off-by: Philip Love <love_phil@emc.com>

Unfortunately it is still mangled.

> --- a/net/ipv4/tcp_output.c	2008-08-24 07:44:18.000000000 -0700
> +++ b/net/ipv4/tcp_output.c	2008-08-24 07:43:05.000000000 -0700
> @@ -468,7 +468,8 @@ static unsigned tcp_syn_options(struct s
>   	}
>   	if (likely(sysctl_tcp_window_scaling)) {
>   		opts->ws = tp->rx_opt.rcv_wscale;
> -		size += TCPOLEN_WSCALE_ALIGNED;
> +		if(likely(opts->ws))
> +			size += TCPOLEN_WSCALE_ALIGNED;
>   	}
>   	if (likely(sysctl_tcp_sack)) {
>   		opts->options |= OPTION_SACK_ADVERTISE;

On those lines of the patch where no changes are occuring there
should be a single space then one or more tab characters.

There are instead two spaces then the tab characters.