Ubuntu
libvirt package

dnsmasq cannot read /var/lib/libvirt/dnsmasq/default.hostsfile: Permission denied

Asked by David Tio

I am currently using Ubuntu 24.04, upgraded from Ubuntu 22.04

I notice that my DHCP IP assignment was not working recently and when I check the status of libvirtd.service I see the message:
Jun 01 07:07:50 dttp dnsmasq[2921]: failed to load names from /var/lib/libvirt/dnsmasq/default.addnhosts: Permission denied
Jun 01 07:07:50 dttp dnsmasq[2921]: cannot read /var/lib/libvirt/dnsmasq/default.hostsfile: Permission denied

Both files seems to be recreated by libvirtd upton starting.

The permission of the files are:
-rw-r--r-- 1 root root 0 Jun 1 07:07 default.hostsfile
-rw-r--r-- 1 root root 0 Jun 1 07:07 default.addnhosts

The file should still be world readable. I can't figure out what seems to be the issue.

Anyone encounter this issue ? Any advice ?

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actionparsnip (andrew-woodhead666) said : 		#1

https://forum.level1techs.com/t/solved-virtual-network-issue-virsh-net-start-default/136141

Seems to be selinux related (pretty standard)

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David Tio (dtio) said : 		#2

Hi actionparnsnip,

I don't even have selinux installed.
root@hostname:~# getenforce
Command 'getenforce' not found, but can be installed with:
apt install selinux-utils

root@hostname:~# ls -ld /var/lib/libvirt/dnsmasq/default*
-rw-r--r-- 1 root root 0 Jun 1 07:07 /var/lib/libvirt/dnsmasq/default.addnhosts
-rw-rw---- 1 root root 619 May 31 22:26 /var/lib/libvirt/dnsmasq/default.conf
-rw-r--r-- 1 root root 0 Jun 1 07:07 /var/lib/libvirt/dnsmasq/default.hostsfile

It was able to read default.conf, only default.addnhosts and default.hostsfile encounter permission denied.

I have tried to manually change the permission of the two files to 660 but it always revert back to 644.

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actionparsnip (andrew-woodhead666) said : 		#3

Are there any bugs reported? Could be a mount issue. What is the output of:

mount

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David Tio (dtio) said : 		#4

I am not aware of any bugs reported on this issue.

I assume we are looking at /var/lib/libvirt mount point ?

/dev/nvme1n1 on /var/lib/libvirt type xfs (rw,relatime,attr2,inode64,logbufs=8,logbsize=32k,noquota)

I don't see any mount issues reported by mount command too

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David Tio (dtio) said : 		#5

I am not aware of any bugs reported on this issue.

I assume we are looking at /var/lib/libvirt mount point ?

/dev/nvme1n1 on /var/lib/libvirt type xfs (rw,relatime,attr2,inode64,logbufs=8,logbsize=32k,noquota)

I don't see any mount issues reported by mount command too

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actionparsnip (andrew-woodhead666) said : 		#6

If you fsck the file system (will need to be offline so may need to be done in Live Ubuntu USB boot) is it complete and consistent?

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David Tio (dtio) said : 		#7

Yes, the filesystem is complete and consistent.

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Manfred Hampl (m-hampl) said : 		#8

Does "lsattr /var/lib/libvirt/dnsmasq/default*" list anything?
Is there anything in the system logs when the access attempt fails (e.g. a message from apparmor)?

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