lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 11 Aug 2011 08:33:07 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	therbert@...gle.com, netdev@...r.kernel.org
Subject: Re: [RFC PATCH] tcp: Replace possible syn attack msg by counters

Le mercredi 10 août 2011 à 23:13 -0700, David Miller a écrit :
> From: Tom Herbert <therbert@...gle.com>
> Date: Wed, 10 Aug 2011 22:38:02 -0700 (PDT)
> 
> > Rather than printing the message to the log, use a mib counter to keep
> > track of the count of occurences of syn cookies being used or syn
> > being dropped when request queue is full.
> > 
> > Rationale is these messages can fill up /var/log/messages on server
> > which is simply under heavy load... I'm not sure how much more useful
> > they would be in identifying a server DOS attack (compared to
> > counters).
> > 
> > Signed-off-by: Tom Herbert <therbert@...gle.com>
> 
> Print the message once, and also do the counters.
> 
> Say something like "Possible SYN flooding, see SNMP counters." or
> similar.
> 
> Because if people are grepping for that message in their logs, they
> will now have a false sense of confidence seeing it not being there
> any more.

An alternative would be to guard the message by net_msg_warn
(/proc/sys/net/core/warnings)

LIMIT_NETDEBUG(KERN_INFO "TCP: Possible SYN flooding on port %d. %s.\n" 
	...)



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists