Public bug reported: [Impact]
* update-rc.d, in sysv-rc-2.88dsf-41ubuntu6.3 is broken in trusty. * update-rc.d incorrectly modifies symlinks when enabling or disabling services which are started on the "S" runlevel. * This can lead to services being changed from S runlevel from where they would be started on boot, to "0" runlevel, and are run on halt, which is incorrect. * The bug is caused by trying to use the runlevel to index into an integer array of runlevels. When the runlevel in question is "S", an error is printed Argument "S" isn't numeric in array element at /usr/sbin/update-rc.d line 232. Perl then sets the index to default to 0, which changes the runlevel. * The fix is to check if the runlevel is "S", and if it is, set the index to 99 which conforms with other expected usages for the "S" runlevel in the script. See the "startstop" and "makelinks" subroutines. [Test Case] * You can reproduce this with any service that is started on the "S" runlevel. We will use open-iscsi for an example. 1) Install open-iscsi $ sudo apt install open-iscsi 2) Check to see symlinks for init.d scripts are set to defaults: root@trusty-openiscsi:/etc# ls -l /etc/rc[0123456S].d/*iscsi* /etc/rc0.d/K80umountiscsi.sh -> ../init.d/umountiscsi.sh /etc/rc0.d/K81open-iscsi -> ../init.d/open-iscsi /etc/rc1.d/K80umountiscsi.sh -> ../init.d/umountiscsi.sh /etc/rc1.d/K81open-iscsi -> ../init.d/open-iscsi /etc/rc6.d/K80umountiscsi.sh -> ../init.d/umountiscsi.sh /etc/rc6.d/K81open-iscsi -> ../init.d/open-iscsi /etc/rcS.d/S45open-iscsi -> ../init.d/open-iscsi 3) Use update-rc.d to enable open-iscsi service root@trusty-openiscsi:/etc# update-rc.d open-iscsi enable update-rc.d: warning: start runlevel arguments (none) do not match open-iscsi Default-Start values (S) update-rc.d: warning: stop runlevel arguments (none) do not match open-iscsi Default-Stop values (0 1 6) Argument "S" isn't numeric in array element at /usr/sbin/update-rc.d line 232. Enabling system startup links for /etc/init.d/open-iscsi ... Removing any system startup links for /etc/init.d/open-iscsi ... /etc/rc0.d/K81open-iscsi /etc/rc1.d/K81open-iscsi /etc/rc6.d/K81open-iscsi /etc/rcS.d/S45open-iscsi Adding system startup for /etc/init.d/open-iscsi ... /etc/rc0.d/K81open-iscsi -> ../init.d/open-iscsi /etc/rc1.d/K81open-iscsi -> ../init.d/open-iscsi /etc/rc6.d/K81open-iscsi -> ../init.d/open-iscsi /etc/rc0.d/S45open-iscsi -> ../init.d/open-iscsi * The problem is the "/etc/rcS.d/S45open-iscsi" symlink is incorrectly changed to "/etc/rc0.d/S45open-iscsi". * Instead, the correct behaviour is to keep the symlink in /etc/rcS.d/ intact: root@trusty-openiscsi:/etc# update-rc.d open-iscsi enable update-rc.d: warning: start runlevel arguments (none) do not match open-iscsi Default-Start values (S) update-rc.d: warning: stop runlevel arguments (none) do not match open-iscsi Default-Stop values (0 1 6) Enabling system startup links for /etc/init.d/open-iscsi ... Removing any system startup links for /etc/init.d/open-iscsi ... /etc/rc0.d/K81open-iscsi /etc/rc1.d/K81open-iscsi /etc/rc6.d/K81open-iscsi /etc/rcS.d/S45open-iscsi Adding system startup for /etc/init.d/open-iscsi ... /etc/rc0.d/K81open-iscsi -> ../init.d/open-iscsi /etc/rc1.d/K81open-iscsi -> ../init.d/open-iscsi /etc/rc6.d/K81open-iscsi -> ../init.d/open-iscsi /etc/rcS.d/S45open-iscsi -> ../init.d/open-iscsi [Regression Potential] * There is only one file modified, which is the update-rc.d perl script. Worst case scenario is that users cannot enable or disable their services, or a symlink is changed such that a service is started / stopped on an incorrect runlevel. * If a regression happens, any damage should be easily spotted by a sysadmin and can be manually repaired by making manual symlinks with "ln -s". [Other Info] * trusty is the last Ubuntu release to use sysvinit, and this bug is not present in newer versions since they use systemd, and the code in question is removed from update-rc.d. * The bug exists in debian squeeze, which is now unsupported, and the code in question is not in any newer versions. * The bug was introduced in 2009-06-29 and somehow evaded anyone noticing it. ** Affects: sysvinit (Ubuntu) Importance: Medium Assignee: Matthew Ruffell (mruffell) Status: New ** Affects: sysvinit (Ubuntu Trusty) Importance: Medium Assignee: Matthew Ruffell (mruffell) Status: New ** Tags: sts ** Also affects: sysvinit (Ubuntu Trusty) Importance: Undecided Status: New ** Changed in: sysvinit (Ubuntu Trusty) Importance: Undecided => Medium ** Changed in: sysvinit (Ubuntu Trusty) Assignee: (unassigned) => Matthew Ruffell (mruffell) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1827172 Title: update-rc.d: enabling or disabling S runlevel services incorrectly modifies runlevel To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/sysvinit/+bug/1827172/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs