Hi.
I just reported the following bug to linux-audit@xxxxxxxxxx under a slightly different subject line. I am forwarding it to containers@xxxxxxxxxxxxxxxxxxxxxxxxxx so you can be aware the possible cause of this problem that apparently effects Linux Containers.
Adam Richter
My bug report to linux-audit@xxxxxxxxxx:
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On Friday, February 14, 2014 2:56 PM, Adam Richter <adam_richter2004@xxxxxxxxx> wrote:
Hi.
If I take an Ubuntu 13.10-amd64 system and install an Ubuntu 13.04-i386 Linux Container, it works fine with kernel.org kernel releases through Linux-3.13, but, for Linux-13.14-rc1 and beyond, I cannot login with "lxc-console". In that case, if I try to log in as "ubuntu" with the correct password, it quickly tell me the login was incorrect, and prompts me with a new "login:" prompt, but without the delay that occurs if I type in the wrong password. I haven't bothered breaking into the "linux container", but, looking at its log files from the outside as it runs, I see some PAM errors about "operation not permitted."
I have reproduced this problem with the following container configurations, all on an
Ubuntu 13.10-amd64 hosts ("amd64" is Ubuntu's terminology, not my jibing Intel):
Ubuntu 13.04-i386
Ubuntu 13.10-i386
Ubuntu 13.10-amd64
I have also reproduced this with a kernel built from git://git.infradead.org/users/eparis/audit.git yesterday (Ubuntu 13.10-amd64 hosting an Ubuntu
13.04-i386 container).
I have also tried disabling CONFIG_AUDIT{SYSCALL,_WATCH,_TREE} and CONFIG_KVM_MMU_AUDIT from linux-3.14-rc2-x86_64 and still observed the same problem.
Doing a "git bisect" on Linus's public tree brought me to the following change (Ubuntu 13.10-x86_64 hosting an Ubuntu 13.04-i386
container):
33faba7fa7f2288d2f8aaea95958b2c97bf9ebfb is the first bad commit
commit 33faba7fa7f2288d2f8aaea95958b2c97bf9ebfb
Author: Richard Guy Briggs <rgb@xxxxxxxxxx>
Date: Tue Jul 16 13:18:45 2013 -0400
audit: listen in all network namespaces
Convert audit from only
listening in init_net to use register_pernet_subsys()
to dynamically manage the netlink socket list.
Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
:040000 040000 3c5f63118d5fe9b5a4f0a6dd828249979a10ffa0 c8feaa4fd9bc260cde3bb703ff20ae6938fabe6a M kernel
For those of you who are not used to using Linux Containers, here are some commands that should reproduce the bug, although I am going from memory rather than copying from my command history.
% sudo lxc-create -t ubuntu -n myubuntu13.04 -- --release raring --arch i386
# ^^ This takes a while. It installs a Linux distribution in a directory.
% sudo lxc-start -n myubuntu13.04 -d
% sudo lxc-console
-n myubuntu13.04
...Try to log in as "ubuntu" with password "ubuntu". When you'd done, do <ctrl-A>q to disconnect the session.
% sudo lxc-stop -n myubuntu13.04
# This next command basically does "rm -rf" on the container's directory tree.
% sudo lxc-destroy -n myubuntu13.04
In the above example, change "raring" to "saucy" if you want Ubuntu 13.10. You can change i386 to amd64 to try 64-bit. "myubuntu13.04" is just a name, which you can change to whatever you want. The Fedora container template shipped with Ubuntu 13.10 does not install for me, otherwise I would have tested that too.
I am not yet sure if this is really a kernel bug or if this is a case of a valid change in Linux kernel behavior exposing a bug elsewhere (for example, Ubuntu's PAM configuration). I am not a Linux Audit developer. I am hoping that, if this is a Linux Audit bug, you folks will be able to take it from here,
but I'm happy to try to help as best I
can.
Thanks in advance for any help with this.
Adam
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