netdev - gre interfaces copied to new namespace

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-next>] [day] [month] [year] [list]

Date:	Thu, 5 Feb 2015 15:37:33 -0800
From:	Steve Biggs <sbiggs@...cade.com>
To:	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: gre interfaces copied to new namespace

(My first post to this list. I forgot to change my settings and I sent the previous version of this post using HTML mail. Terribly sorry if this caused anybody any problems; won't happen again... it may be that it never got to the list at all?)

I am going under the assumption that a newly created network namespace should have the loopback (lo) device as its only contents, with it being an error to have any other already existing interfaces in the default namespace also copied in. If this assumption is wrong, please advise and then if so, sorry for the noise.

I was able to reproduce this on a vanilla Debian Wheezy installation with the following sequence of commands. Debian Wheezy is running an older kernel version, so this is a long-standing issue. I am also able to reproduce this on a 3.14.y based kernel.

# ip netns list
# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
# modprobe ip_gre
# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
12: gre0@...E: <NOARP> mtu 1476 qdisc noop state DOWN group default 
    link/gre 0.0.0.0 brd 0.0.0.0
13: gretap0@...E: <BROADCAST,MULTICAST> mtu 1462 qdisc noop state DOWN group default qlen 1000
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
# ip netns add foo
# ip netns list
foo
# ip netns exec foo ip a
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: gre0@...E: <NOARP> mtu 1476 qdisc noop state DOWN group default 
    link/gre 0.0.0.0 brd 0.0.0.0
3: gretap0@...E: <BROADCAST,MULTICAST> mtu 1462 qdisc noop state DOWN group default qlen 1000
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
# rmmod ip_gre
# ip netns exec foo ip a
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
# ip netns del foo
# ip netns list
#

--
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