Please queue up:
commit c2ed1880fd61a998e3ce40254a99a2ad000f1a7d
Author: Mantas M [off-list ref]
Date: Fri Dec 16 10:30:59 2016 +0200
net: ipv6: check route protocol when deleting routes
for stable.
Ben.
On Tue, 2017-02-14 at 19:52 +0100, Pascal Mathis wrote:
Package: src:linux
Version: 4.9.6-3
Severity: important
Tags: ipv6
Dear Debian Kernel Maintainers,
when trying to delete an IPv6 route with a specific route protocol field
in a kernel 4.9, the kernel does not actually check the protocol of the
route and just deletes all the routes that match the other attributes.
This leads to various issues with routing daemons, for example BIRD.
E.g. when a BGP withdraw update is being received with a prefix matching
a kernel route, both "proto bird" and "proto kernel" get deleted.
The only workaround is currently to maintain a manual blacklist in the
routing daemon, however a proper fix at kernel level would be definitely
appreciated. As a patch was already committed to the Linux Kernel Git
Repository, I recommend backporting into the Debian Stretch kernel, as
the patch is both overseeable and easy to implement.
The bug itself can be easily reproduced on any Linux running kernel
version 4.9 or lower by executing these commands:
~$ ip -6 route add ff::/64 dev eth0 proto kernel
~$ ip -6 route
(check the routing table, the newly added route is visible)
~$ ip -6 route del ff::/64 proto boot
~$ ip -6 route
(the route is gone, although it should still be there!)
A link to the Git commit fixing this specific issue can be found at the
following URL and was already merged into kernel 4.10 since rc1:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c2ed1880fd61a998e3ce40254a99a2ad000f1a7d
[...]
--
Ben Hutchings
Reality is just a crutch for people who can't handle science fiction.