Could you please check the permissions of your
ls -l /
If the group has write permissions over that directory you can try to add the user that is executing the plugin to that group, so will be able to write into the
To check the user that jenkins is using you can execute
ps | grep jenkins.
Once you know the user that is executing jenkins and the group of
/tmp, if the group has write permissions, you can execute:
sudo usermod -a -G <group> <name>