On Tue, 2013-01-15 at 10:10 -0500, Daniel J Walsh wrote: > On 01/15/2013 10:03 AM, Dominick Grift wrote: > > On Tue, 2013-01-15 at 09:58 -0500, Daniel J Walsh wrote: > >> On 01/15/2013 09:15 AM, Dominick Grift wrote: > >>> On Tue, 2013-01-15 at 14:11 +0100, Göran Uddeborg wrote: > >>>> I'm running a "restorecon -n -R -v /" from cron once a month, just to > >>>> be careful and know what is happening. Last night when it ran, I got > >>>> a lot of error messages like these: > >>>> > >>>> restorecon: Warning no default label for /dev/pts/3 > >>>> > >>>> and > >>>> > >>>> restorecon: Warning no default label for /tmp/efs0YYVa79.html > >>>> > >>>> There were a couple for things in /dev, and lots of them for things > >>>> in /tmp. > >>>> > >>>> I have lately been upgrading bit by bit to Fedora 18 (the beta, > >>>> strictly speaking, since the final release isn't officially out at > >>>> the time of this writing), so I assume the new message is related to > >>>> these upgrades. But why? When I list file contexts, I see rules like > >>>> this: > >>>> > >>>> /dev/pts(/.*)? all files > >>>> <<None>> > >>>> > >>>> So I guess it is not a simple mistake. But what is the reason? Why > >>>> don't some /dev entries, and almost the entire /tmp directory, have > >>>> any default context any more? > >>> > >>> It has to do with some optional security models like mcs, mls and ubac > >>> and the nature of their security attributes i believe > >>> > >>> For example if you create a file in /tmp with a compartment of s0:c23 > >>> then you do not want a relabel to reset it because that would > >>> declassify the file back to s0 > >>> > >>> SELinux cannot determine that the file should be labeled s0:c23 because > >>> a unprivileged user with access to the compartment decided that > >>> > >>> So by ignoring the context altogether you can be sure that the file > >>> will not get declassified by restorecon/fixfiles > >>> > >>> So you will see this in public places like /tmp etc. > >>> > >>> There is a similar issue with types. Users may have some discretion > >>> over select types to relabel to and from. SELinux cannot determine that > >>> a user decided to label from example file ~/bla type > >>> httpd_user_content_t. > >>> > >>> So with types there is a different approach: some types are declared > >>> customizable types. If a file has a customizable type then SELinux will > >>> not try to relabel it (so that it wont get unintentionally > >>> declassified) unless you use the -F flag. > >>> > >>> The identity field by default does not get reset unless one uses > >>> restorecon with the -F flag > >>> > >>> With MLS security models processes are forced to operate on specified > >>> security levels for the sake of enforcing confidentiality. Files that > >>> may be affected and are in public places are not flagged to be reset > >>> with the <<None>> > >>> > >>> Disclaimer: this is my understanding of the issue but i might be wrong > >>> > >>> > >>> > >>>> -- selinux mailing list selinux@xxxxxxxxxxxxxxxxxxxxxxx > >>>> https://admin.fedoraproject.org/mailman/listinfo/selinux > >>> > >>> > >>> -- selinux mailing list selinux@xxxxxxxxxxxxxxxxxxxxxxx > >>> https://admin.fedoraproject.org/mailman/listinfo/selinux > >>> > >> Yes the basic idea is in certain directories like mnt_t, tmp_t, tmpfs_t > >> we do not have a standard definition of content in these directories. So > >> <<none>> says any content could be here, so don't change the labels. For > >> example a user does cp -a ~/.ssh /tmp Would move ssh_home_t content to > >> /tmp, if you ran restorecon on it and we had default label of tmp_t or > >> user_tmp_t, then all apps could read tmp_t could not read the content. > >> > >> Modern restorecon in RHEL7 and Latest Fedoras does not change any > >> components of the security context other then the type field. unless you > >> specify force. This is something we want avoid as we move forward with > >> MCS labeling and MLS Labeling. If you use containers or static labeling > >> for virtual machines, you do not want restorecon changing the MLS/MCS > >> field. > >> > >> The reason you are noticing this is we added an error check to restorecon > >> to tell the user that restorecon /mnt/foobar did not do anything. > >> > >> restorecon -R /mnt > >> > >> Will not output the error, since we wanted to quiet the noise, but if you > >> get verbose, you will get the noise. I guess we could add a -vv for > >> realy verbose, if the message is aggravating. > > > > By the way, we probably want to not relabel content in > > /var/lib/libvirt/filesystems. > > > > I did a relabel and all my container contexts were reset > > > Really, I don't see that > > # restorecon -R -v /var/lib/libvirt/filesystems/ > # ls -lZ /var/lib/libvirt/filesystems/ > drwxr-xr-x. root root system_u:object_r:svirt_lxc_file_t:s0:c1,c2 apache1 > drwxr-xr-x. root root system_u:object_r:svirt_lxc_file_t:s0:c1,c2 container1 > drwxr-xr-x. root root system_u:object_r:svirt_lxc_file_t:s0:c0.c1023 dan > drwxr-xr-x. root root system_u:object_r:svirt_lxc_file_t:s0:c0.c1023 myapache > drwxr-xr-x. root root system_u:object_r:svirt_lxc_file_t:s0:c0.c1023 mymysql > I did see it but i did a fixfiles onboot -- selinux mailing list selinux@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/selinux
