Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-15 Thread Willy Tarreau
Hi Eric, On Fri, Feb 15, 2013 at 02:31:27AM -0800, Eric W. Biederman wrote: > > I'm not saying this will > > not eventually happen, but there are significant risks associated with > > this feature. Netfilter had this in the window tracking patches around > > 2002-2003 and this had to be reverted

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-15 Thread Eric W. Biederman
Willy Tarreau writes: > Hi Eric, > > On Thu, Feb 14, 2013 at 11:10:46PM -0800, Eric W. Biederman wrote: >> Kees Cook writes: >> >> > On Thu, Feb 14, 2013 at 9:30 PM, Eric W. Biederman >> > wrote: >> >> Kees Cook writes: >> >> >> >>> The patch would not break it -- it defaults the sysctl to

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-15 Thread Eric W. Biederman
Willy Tarreau w...@1wt.eu writes: Hi Eric, On Thu, Feb 14, 2013 at 11:10:46PM -0800, Eric W. Biederman wrote: Kees Cook keesc...@chromium.org writes: On Thu, Feb 14, 2013 at 9:30 PM, Eric W. Biederman ebied...@xmission.com wrote: Kees Cook keesc...@chromium.org writes: The patch

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-14 Thread Willy Tarreau
Hi Eric, On Thu, Feb 14, 2013 at 11:10:46PM -0800, Eric W. Biederman wrote: > Kees Cook writes: > > > On Thu, Feb 14, 2013 at 9:30 PM, Eric W. Biederman > > wrote: > >> Kees Cook writes: > >> > >>> The patch would not break it -- it defaults the sysctl to staying enabled. > >>> > >>> If you

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-14 Thread Eric W. Biederman
Kees Cook writes: > On Thu, Feb 14, 2013 at 9:30 PM, Eric W. Biederman > wrote: >> Kees Cook writes: >> >>> The patch would not break it -- it defaults the sysctl to staying enabled. >>> >>> If you mean the documentation should be updated, sure, that's easy to do. >>> >>> David: I know you

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-14 Thread Kees Cook
On Thu, Feb 14, 2013 at 9:30 PM, Eric W. Biederman wrote: > Kees Cook writes: > >> The patch would not break it -- it defaults the sysctl to staying enabled. >> >> If you mean the documentation should be updated, sure, that's easy to do. >> >> David: I know you aren't a fan of this patch, but

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-14 Thread Eric W. Biederman
Kees Cook writes: > The patch would not break it -- it defaults the sysctl to staying enabled. > > If you mean the documentation should be updated, sure, that's easy to do. > > David: I know you aren't a fan of this patch, but I'd like to try to > convince you. :) This leaves the feature enabled

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-14 Thread Eric W. Biederman
Kees Cook keesc...@chromium.org writes: The patch would not break it -- it defaults the sysctl to staying enabled. If you mean the documentation should be updated, sure, that's easy to do. David: I know you aren't a fan of this patch, but I'd like to try to convince you. :) This leaves the

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-14 Thread Kees Cook
On Thu, Feb 14, 2013 at 9:30 PM, Eric W. Biederman ebied...@xmission.com wrote: Kees Cook keesc...@chromium.org writes: The patch would not break it -- it defaults the sysctl to staying enabled. If you mean the documentation should be updated, sure, that's easy to do. David: I know you

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-14 Thread Eric W. Biederman
Kees Cook keesc...@chromium.org writes: On Thu, Feb 14, 2013 at 9:30 PM, Eric W. Biederman ebied...@xmission.com wrote: Kees Cook keesc...@chromium.org writes: The patch would not break it -- it defaults the sysctl to staying enabled. If you mean the documentation should be updated, sure,

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-14 Thread Willy Tarreau
Hi Eric, On Thu, Feb 14, 2013 at 11:10:46PM -0800, Eric W. Biederman wrote: Kees Cook keesc...@chromium.org writes: On Thu, Feb 14, 2013 at 9:30 PM, Eric W. Biederman ebied...@xmission.com wrote: Kees Cook keesc...@chromium.org writes: The patch would not break it -- it defaults the

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread H. Peter Anvin
On 02/07/2013 10:44 AM, Kees Cook wrote: >> >> This patch probably also breaks TCP STUNT that is used by some applications >> for NAT >> traversal. > > The patch would not break it -- it defaults the sysctl to staying enabled. > > If you mean the documentation should be updated, sure, that's

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread David Miller
From: Kees Cook Date: Thu, 7 Feb 2013 10:44:02 -0800 > David: I know you aren't a fan of this patch, but I'd like to try to > convince you. :) This leaves the feature enabled and add a toggle for > systems (like Chrome OS) that don't want to risk this DoS at all. > There are so very many other

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread Kees Cook
On Thu, Feb 7, 2013 at 10:39 AM, Stephen Hemminger wrote: > On Thu, 7 Feb 2013 09:52:40 -0800 > Kees Cook wrote: > >> This is based on Willy Tarreau's patch from 2008[1]. The goal is to >> close a corner-case of TCP that isn't used and poses a small DoS risk. >> For systems that do not want to

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread Stephen Hemminger
On Thu, 7 Feb 2013 09:52:40 -0800 Kees Cook wrote: > This is based on Willy Tarreau's patch from 2008[1]. The goal is to > close a corner-case of TCP that isn't used and poses a small DoS risk. > For systems that do not want to take any risk at all, this is a desirable > configuration knob. > >

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread David Miller
Sorry I'm not applying this. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/

[PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread Kees Cook
This is based on Willy Tarreau's patch from 2008[1]. The goal is to close a corner-case of TCP that isn't used and poses a small DoS risk. For systems that do not want to take any risk at all, this is a desirable configuration knob. It is possible for two clients to connect with crossed SYNs

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread David Miller
Sorry I'm not applying this. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread Stephen Hemminger
On Thu, 7 Feb 2013 09:52:40 -0800 Kees Cook keesc...@chromium.org wrote: This is based on Willy Tarreau's patch from 2008[1]. The goal is to close a corner-case of TCP that isn't used and poses a small DoS risk. For systems that do not want to take any risk at all, this is a desirable

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread Kees Cook
On Thu, Feb 7, 2013 at 10:39 AM, Stephen Hemminger step...@networkplumber.org wrote: On Thu, 7 Feb 2013 09:52:40 -0800 Kees Cook keesc...@chromium.org wrote: This is based on Willy Tarreau's patch from 2008[1]. The goal is to close a corner-case of TCP that isn't used and poses a small DoS

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread David Miller
From: Kees Cook keesc...@chromium.org Date: Thu, 7 Feb 2013 10:44:02 -0800 David: I know you aren't a fan of this patch, but I'd like to try to convince you. :) This leaves the feature enabled and add a toggle for systems (like Chrome OS) that don't want to risk this DoS at all. There are so

Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread H. Peter Anvin
On 02/07/2013 10:44 AM, Kees Cook wrote: This patch probably also breaks TCP STUNT that is used by some applications for NAT traversal. The patch would not break it -- it defaults the sysctl to staying enabled. If you mean the documentation should be updated, sure, that's easy to do.

[PATCH] tcp: sysctl to disable TCP simultaneous connect

2013-02-07 Thread Kees Cook
This is based on Willy Tarreau's patch from 2008[1]. The goal is to close a corner-case of TCP that isn't used and poses a small DoS risk. For systems that do not want to take any risk at all, this is a desirable configuration knob. It is possible for two clients to connect with crossed SYNs