Me too.
On approximately Sat, Jul 14, 2001 at 05:00:21PM -0500, J Troy Piper wrote:
>
> > 2.4.5-ac17
> > o First set of ipt_unclean fixes (Rusty Russell)
>
> Alan,
>
> I apologise for having taken so long to write this (I have known about
> this problem since 2.4.5ac17 and have not had a chance to document til
> today) but there seems to be a problem with the ipt_unclean fixes by Rusty
> Russell. ANY incoming packets from any interface (ppp0 and eth0) are
> marked as 'unclean' with some variation on the following syslog entry:
>
> Jul 8 23:16:04 paranoia kernel: ipt_unclean: TCP option 3 at 37 too long
> Jul 8 23:16:05 paranoia kernel: ipt_unclean: TCP option 3 at 37 too long
> Jul 8 23:16:16 paranoia kernel: ipt_unclean: TCP option 3 at 37 too long
> Jul 8 23:16:18 paranoia kernel: ipt_unclean: TCP option 3 at 37 too long
>
> and thus are blocked by my 'unclean packet dropping' firewall (iptables).
>
> I haven't seen any mention of this on the list, nor have I seen any more
> ipt_unclean patches to address this problem, so here's your heads-up
> (albeit a bit late).
>
> Thanks,
>
> J Troy Piper
> [email protected]
> -
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In message <[email protected]> you write:
> today) but there seems to be a problem with the ipt_unclean fixes by Rusty
> Russell. ANY incoming packets from any interface (ppp0 and eth0) are
> marked as 'unclean' with some variation on the following syslog entry:
>
> Jul 8 23:16:04 paranoia kernel: ipt_unclean: TCP option 3 at 37 too long
Please try this patch which fixes this as well, which is in Linus'
pre-patches.
Rusty.
--
Premature optmztion is rt of all evl. --DK
diff -urN linux-2.4.6/net/ipv4/netfilter/ipt_unclean.c linux-2.4.6-f1/net/ipv4/netfilter/ipt_unclean.c
--- linux-2.4.6/net/ipv4/netfilter/ipt_unclean.c Wed Jul 4 21:27:32 2001
+++ linux-2.4.6-f1/net/ipv4/netfilter/ipt_unclean.c Thu Jul 5 19:16:00 2001
@@ -268,6 +268,7 @@
int embedded)
{
u_int8_t *opt = (u_int8_t *)tcph;
+ u_int8_t *endhdr = (u_int8_t *)tcph + tcph->doff * 4;
u_int8_t tcpflags;
int end_of_options = 0;
size_t i;
@@ -373,7 +374,7 @@
return 0;
}
/* CHECK: oversize options. */
- else if (opt[i+1] + i >= tcph->doff * 4) {
+ else if (&opt[i] + opt[i+1] > endhdr) {
limpk("TCP option %u at %Zu too long\n",
(unsigned int) opt[i], i);
return 0;
@@ -392,6 +393,7 @@
check_ip(struct iphdr *iph, size_t length, int embedded)
{
u_int8_t *opt = (u_int8_t *)iph;
+ u_int8_t *endhdr = (u_int8_t *)iph + iph->ihl * 4;
int end_of_options = 0;
void *protoh;
size_t datalen;
@@ -444,7 +446,7 @@
return 0;
}
/* CHECK: oversize options. */
- else if (opt[i+1] + i > iph->ihl * 4) {
+ else if (&opt[i] + opt[i+1] > endhdr) {
limpk("IP option %u at %u too long\n",
opt[i], i);
return 0;
Indeed, the patches work and I see that they have made it into 2.4.5-ac3
with the rest of the Linux -pre merge. Thanks.
Troy.
On Mon, Jul 16, 2001 at 08:28:45PM +1000, Rusty Russell wrote:
> In message <[email protected]> you write:
> > today) but there seems to be a problem with the ipt_unclean fixes by Rusty
> > Russell. ANY incoming packets from any interface (ppp0 and eth0) are
> > marked as 'unclean' with some variation on the following syslog entry:
> >
> > Jul 8 23:16:04 paranoia kernel: ipt_unclean: TCP option 3 at 37 too long
>
> Please try this patch which fixes this as well, which is in Linus'
> pre-patches.
>
> Rusty.
> --
> Premature optmztion is rt of all evl. --DK
>