[libvirt] This patch adds the label to lxc-enter-namespace
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 lxc-enter-namespace allows a process from outside a container to start a process inside a container. One problem with the current code is the process running within the container would run with the label of the process that created it. For example if the admin process is running as unconfined_t and executes the following command # virsh -c lxc:/// lxc-enter-namespace --nolabel dan -- /bin/ps -eZ LABEL PID TTY TIME CMD system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 1 pts/0 00:00:00 systemd system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 3 pts/1 00:00:00 sh system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 24 ? 00:00:00 systemd-journal system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 29 ? 00:00:00 dhclient staff_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 47 ? 00:00:00 ps Note the ps command is running as unconfined_t, After this patch, virsh -c lxc:/// lxc-enter-namespace dan -- /bin/ps -eZ LABEL PID TTY TIME CMD system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 1 pts/0 00:00:00 systemd system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 3 pts/1 00:00:00 sh system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 24 ? 00:00:00 systemd-journal system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 32 ? 00:00:00 dhclient system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 38 ? 00:00:00 ps I also add a --nolabel command to virsh, which can go back to the original behaviour. virsh -c lxc:/// lxc-enter-namespace --nolabel dan -- /bin/ps -eZ LABEL PID TTY TIME CMD system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 1 pts/0 00:00:00 systemd system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 3 pts/1 00:00:00 sh system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 24 ? 00:00:00 systemd-journal system_u:system_r:svirt_lxc_net_t:s0:c0.c1023 32 ? 00:00:00 dhclient staff_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 37 ? 00:00:00 ps One problem I had when I originally did the patch is lxcDomainGetSecurityLabel was returning the incorrect label, I needed the label of the initpid within the container not its parent process, so I changed this function to match OpenNamespaces function. One last strangeness, about half the time I run this, virsh hangs and never returns. Seems like if (conn->driver->domainGetSecurityLabel(domain, seclabel) == 0) { Gets hung up. I have attached the strace in out1.gz -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlE476kACgkQrlYvE4MpobMW8QCeMwkx5uzMgQdJbNqnyiOa62+Y JNIAnA8ZZRhjlqMIRAy5/RbMc1g3Wxv1 =cSsv -----END PGP SIGNATURE-----
On Thu, Mar 07, 2013 at 02:51:05PM -0500, Daniel J Walsh wrote:
One last strangeness, about half the time I run this, virsh hangs and never returns. Seems like
if (conn->driver->domainGetSecurityLabel(domain, seclabel) == 0) {
Gets hung up. I have attached the strace in out1.gz
This is because you are trying to invoke libvirt RPC calls in the fork()d child process. Now you have both the child & parent trying to use the same libvirt socket FD, which means it is random which will see the incoming I/O.
+static int +virDomainSetDefaultSecurityLabel(virDomainPtr domain) +{ + int rc = 0; + virSecurityLabelPtr seclabel; + if (VIR_ALLOC(seclabel) < 0) + return -1; + + if (virDomainGetSecurityLabel(domain, seclabel)) + return -1;
This causes libvirt todo RPC calls
@@ -135,7 +168,12 @@ virDomainLxcEnterNamespace(virDomainPtr domain, { int i;
- virCheckFlags(0, -1); + virCheckFlags(SECURITY_LABEL, -1); + + if (flags & SECURITY_LABEL) { + if (virDomainSetDefaultSecurityLabel(domain) < 0) + goto error; + }
And this is running in the child process. As with the enter namespace code, we need to split the functionality. virsh needs to call virDomainGetSecurityLabel before fork, and then invoke an API to apply the security label after fork. I've CC'd you on a patch which takes that approach. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
participants (2)
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Daniel J Walsh -
Daniel P. Berrange