Messages in this thread | | | Date | Mon, 15 Oct 2007 14:00:25 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] ipv4: kernel panic when only one unsecured port available |
| |
On Mon, 15 Oct 2007 13:06:14 -0700 (PDT) David Miller <davem@davemloft.net> wrote:
> From: Andrew Morton <akpm@linux-foundation.org> > Date: Mon, 15 Oct 2007 12:49:19 -0700 > > > This code has recently been reworked, but from my reading, that > > divide-by-zero can still occur. And given that the numbers in > > /proc/sys/net/ipv4/ip_local_port_range are inclusive, the arithmetic in > > inet_csk_get_port() seems to just be wrong? > > > > So we have this, against David's current devel tree: > > I'm pretty sure we took care of this, but maybe not :-)
<looks>
OK, in ipv4_local_port_range() we have
if (range[1] <= range[0]) ret = -EINVAL;
which will prevent the crashes.
But is it good to disallow high=low? This disallows a port range of one single port. Unless "high" is exclusive. But Documentation/filesystems/proc.txt says
: ip_local_port_range : ------------------- : : Range of ports used by TCP and UDP to choose the local port. Contains two : numbers, the first number is the lowest port, the second number the highest : local port. Default is 1024-4999. Should be changed to 32768-61000 for : high-usage systems.
ie: inclusive.
Documentation/networking/ip-sysctl.txt says
: ip_local_port_range - 2 INTEGERS : Defines the local port range that is used by TCP and UDP to : choose the local port. The first number is the first, the : second the last local port number. Default value depends on : amount of memory available on the system: : > 128Mb 32768-61000 : < 128Mb 1024-4999 or even less. : This number defines number of active connections, which this : system can issue simultaneously to systems not supporting : TCP extensions (timestamps). With tcp_tw_recycle enabled : (i.e. by default) range 1024-4999 is enough to issue up to : 2000 connections per second to systems supporting timestamps.
also inclusive.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |