On 11/13/20 10:47 AM, Jin Yan wrote:

Hi Michal,
I found this problem while performing migration, based on
     libvirt version: 6.2.0
     SELinux mode: permissive

Steps:
1. start a vm configured with pipe-type serial port.
     <serial type='pipe'>
       <source path='/tmp/test_pipe'/>
       <target type='system-serial' port='1'>
         <model name='pl011'/>
       </target>
     </serial>
2. migrate vm to Dst-side where no '/tmp/test_pipe' exits.
3. migration failed in Dst-side qemuProcessLaunch, and the path's label 
that
has been set is not restored ('/var/lib/libvirt/qemu/nvram/XXX.fd').

I have no idea why 2)rollback you mentioned didn't work.

I'm not sure. I could not reproduce with the current master. Is it 
possible for you to try the master?

Michal

I think we can reproduce it in a more easier way, that is, starting a VM whose XML is configured with a pipe file that does not exist on local host:
	<serial type='pipe'>
       <source path='/tmp/serial.pipe'/>
       <target port='0'/>
     </serial>

1. Though '/tmp/serial.pipe' does not exist, this secdriver (if I'm not mistaken about this concept) set SELinux-label return success, and the marked items (eg. XXX.fd, XXX.iso) will not be rollback.

[call trace]:
virSecuritySELinuxTransactionRun	   -- return 0
    virSecuritySELinuxSetFilecon           -- return 0
        virSecuritySELinuxSetFileconImpl   -- return 1, warned unable to ...

2. The next secdriver about setting DAC-label run in virSecurityDACTransactionRun() return false because above file does not exist.

virSecurityManagerTransactionCommit() return false, but where is the rollback performed for other secdrivers (here means setting SELinux-label in 1) ? I don't quite understand the second point you mentioned in your last reply:
    ---
    2) rollback for other secdrivers after one failed is handled in virSecurityStackSetAllLabel().
    ---

In addition, is there any wrong in virSecuritySELinuxTransactionRun return success while '/tmp/serial.pipe' does not exist?

Yan