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Description of problem: Save a running guest, the context of the save file is different with the expect result. The actual result is: system_u:object_r:virt_tmp_t:s0 The expect result is: system_u:object_r:svirt_image_t:s0 BTW, after downgrade libvirt from libvirt-0.9.10-1 to libvirt-0.9.10-0rc2, the result is correct. Not sure if this is a regression bug or new design result. Version-Release number of selected component (if applicable): libvirt-0.9.10-1.el6.x86_64 qemu-kvm-0.12.1.2-2.225.el6.x86_64 kernel-2.6.32-220.el6.x86_64 How reproducible: 100% Steps to Reproduce: 1. Start a normal guest and save it. # virsh save test /tmp/test.save Domain test saved to /tmp/test.save 2.Check the context of the save file. # ll -Z /tmp/test.save -rw-------. root root system_u:object_r:virt_tmp_t:s0 /tmp/test.save 3. Downgrade libvirt to libvirt-0.9.10-0rc2 and do step1 & step2 again. # virsh save test /tmp/test3.save Domain test saved to /tmp/test3.save # ll -Z /tmp/test3.save -rw-------. root root system_u:object_r:svirt_image_t:s0:c506,c657 /tmp/test3.save Actual results: the context of the save file is system_u:object_r:virt_tmp_t:s0 Expected results: the context of the save file should be system_u:object_r:svirt_image_t:s0 Additional info: SELinux is Enforcing. After upgrade libvirt back to libvirt-0.9.10-1, then save the guest, will get a different result: # virsh save test /tmp/test5.save Domain test saved to /tmp/test5.save # ll -Z /tmp/test5.save -rw-------. root root unconfined_u:object_r:virt_tmp_t:s0 /tmp/test5.save The security labels is added automatically, and default type is 'dynamic', following is the XML content after start the guest: ----new libvirt version---- <seclabel type='dynamic' model='selinux' relabel='yes'> <label>system_u:system_r:svirt_t:s0:c422,c458</label> <imagelabel>system_u:object_r:svirt_image_t:s0:c422,c458</imagelabel> </seclabel> ---- ----old libvirt version---- <seclabel type='dynamic' model='selinux' relabel='yes'> <label>system_u:system_r:svirt_t:s0:c570,c773</label> <imagelabel>system_u:object_r:svirt_image_t:s0:c570,c773</imagelabel> </seclabel> ----
I think this is an unintentional change, probably a side-effect of: commit c8683f231dd227da8540f3249d7e332ec7a75ad7 Author: Jiri Denemark <jdenemar> Date: Mon Feb 6 14:53:24 2012 +0100 qemu: Always use iohelper for dumping domain core Qemu uses non-blocking I/O which doesn't play nice with regular file descriptors. We need to pass a pipe to qemu instead, which can easily be done using iohelper.
It was indeed unintentional but it was actually a bug fix :-) The "system_u:object_r:svirt_image_t:s0:c506,c657" context was actually an undesired side effect of relabeling file descriptor in a way that qemu can write to it. Since we now pass a pipe instead, the file's context is not affected. Also the old context didn't make sense at all with dynamic labeling once the domain shuts down.