Re: Questions about the ownership of /var/cache/libvirt/qemu
On 8/22/21 11:49 AM, Peng Liang wrote:
Hi all,
When we change the user for QEMU process (change "user" and "group"
in
/etc/libvirt/qemu.conf) to a normal user, we found that libvirtd will
also change the ownership of /var/cache/libvirt/qemu but will keep the
ownership of /var/cache/libvirt/qemu/capabilities as root.
Is it secure to put files/directories owned by root in a directory
owned by a normal user? Could the normal user replace the root's file
with a new one?
No, the capabilities directory lacks write perms:
drwxr-xr-x 2 root root 234 Aug 20 17:11
/var/cache/libvirt/qemu/capabilities/
and caps files themselves are RW by root only:
-rw------- 1 root root 144215 Aug 20 15:38
926803a9278e445ec919c2b6cbd8c1c449c75b26dcb1686b774314180376c725.xml
Therefore, I don't think a regular user could spoof capabilities.
Does it need to set sticky bit on
/var/cache/libvirt/qemu or keep the ownership of /var/cache/libvirt/qemu
as root?
No, setting sticky bit would make caps files owned by root:group and I
don't think we want that (even though, not even group can write caps files).
I hope this answers your concern.
Michal