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Groups > linux.debian.user > #189609 > unrolled thread
| Started by | Urs Thuermann <urs@isnogud.escape.de> |
|---|---|
| First post | 2017-12-06 23:20 +0100 |
| Last post | 2017-12-07 08:50 +0100 |
| Articles | 20 on this page of 127 — 38 participants |
Back to article view | Back to linux.debian.user
Embarrassing security bug in systemd Urs Thuermann <urs@isnogud.escape.de> - 2017-12-06 23:20 +0100
Re: Embarrassing security bug in systemd Roberto C. Sánchez <roberto@debian.org> - 2017-12-06 23:50 +0100
Re: Embarrassing security bug in systemd Ben Caradoc-Davies <ben@transient.nz> - 2017-12-07 00:40 +0100
Re: Embarrassing security bug in systemd Roberto C. Sánchez <roberto@debian.org> - 2017-12-07 03:50 +0100
Re: Embarrassing security bug in systemd deloptes <deloptes@gmail.com> - 2017-12-07 07:30 +0100
Re: Embarrassing security bug in systemd Ben Caradoc-Davies <ben@transient.nz> - 2017-12-06 23:50 +0100
Re: Embarrassing security bug in systemd Dave Sherohman <dave@sherohman.org> - 2017-12-07 10:40 +0100
Re: Embarrassing security bug in systemd Tixy <tixy@yxit.co.uk> - 2017-12-07 11:30 +0100
Re: Embarrassing security bug in systemd Jonathan Dowland <jmtd@debian.org> - 2017-12-07 11:50 +0100
Re: Embarrassing security bug in systemd Jimmy Johnson <field.engineer@gmail.com> - 2017-12-09 03:50 +0100
Re: Embarrassing security bug in systemd David Wright <deblis@lionunicorn.co.uk> - 2017-12-09 17:50 +0100
Re: Embarrassing security bug in systemd Jimmy Johnson <field.engineer@gmail.com> - 2017-12-10 10:00 +0100
Re: Embarrassing security bug in systemd David Wright <deblis@lionunicorn.co.uk> - 2017-12-10 20:40 +0100
Re: Embarrassing security bug in systemd <tomas@tuxteam.de> - 2017-12-07 11:40 +0100
Re: Embarrassing security bug in systemd Roberto C. Sánchez <roberto@debian.org> - 2017-12-07 16:00 +0100
Re: Embarrassing security bug in systemd Michael Biebl <biebl@debian.org> - 2017-12-07 20:30 +0100
Re: Embarrassing security bug in systemd <tomas@tuxteam.de> - 2017-12-08 09:20 +0100
Re: Embarrassing security bug in systemd deloptes <deloptes@gmail.com> - 2017-12-08 12:40 +0100
Re: Embarrassing security bug in systemd <tomas@tuxteam.de> - 2017-12-08 13:40 +0100
Re: Embarrassing security bug in systemd deloptes <deloptes@gmail.com> - 2017-12-08 21:40 +0100
Re: Embarrassing security bug in systemd Jonathan Dowland <jmtd@debian.org> - 2017-12-08 17:10 +0100
Re: Embarrassing security bug in systemd Curt <curty@free.fr> - 2017-12-08 19:10 +0100
Re: Embarrassing security bug in systemd Menelaos Maglis <mmaglis@metacom.gr> - 2017-12-08 19:40 +0100
Re: Embarrassing security bug in systemd Menelaos Maglis <mmaglis@metacom.gr> - 2017-12-08 19:50 +0100
Re: Embarrassing security bug in systemd Jonathan Dowland <jmtd@debian.org> - 2017-12-08 20:50 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-08 21:20 +0100
Re: Embarrassing security bug in systemd Jonathan Dowland <jmtd@debian.org> - 2017-12-09 09:10 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-09 11:20 +0100
Re: Embarrassing security bug in systemd Jonathan Dowland <jmtd@debian.org> - 2017-12-09 19:40 +0100
Re: Embarrassing security bug in systemd Dejan Jocic <jodejka@gmail.com> - 2017-12-09 20:30 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-09 22:00 +0100
Re: Embarrassing security bug in systemd Dejan Jocic <jodejka@gmail.com> - 2017-12-10 00:40 +0100
Re: Embarrassing security bug in systemd Joe <joe@jretrading.com> - 2017-12-10 10:40 +0100
Re: Embarrassing security bug in systemd Dejan Jocic <jodejka@gmail.com> - 2017-12-10 11:20 +0100
Re: Embarrassing security bug in systemd Joe <joe@jretrading.com> - 2017-12-10 12:40 +0100
Re: Embarrassing security bug in systemd Dejan Jocic <jodejka@gmail.com> - 2017-12-10 16:10 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-11 15:10 +0100
Re: Embarrassing security bug in systemd Roberto C. Sánchez <roberto@debian.org> - 2017-12-09 21:10 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-09 21:10 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-08 21:50 +0100
Re: Embarrassing security bug in systemd John Hasler <jhasler@newsguy.com> - 2017-12-08 22:30 +0100
Re: Embarrassing security bug in systemd Glenn English <ghe2001@gmail.com> - 2017-12-09 02:50 +0100
Re: Embarrassing security bug in systemd John Hasler <jhasler@newsguy.com> - 2017-12-09 06:50 +0100
Re: Embarrassing security bug in systemd Jonathan Dowland <jmtd@debian.org> - 2017-12-09 09:20 +0100
Re: Embarrassing security bug in systemd Jonathan Dowland <jmtd@debian.org> - 2017-12-09 09:10 +0100
Re: Embarrassing security bug in systemd Christian Seiler <christian@iwakd.de> - 2017-12-15 13:30 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-15 14:10 +0100
Re: Embarrassing security bug in systemd John Hasler <jhasler@newsguy.com> - 2017-12-15 16:00 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-08 21:50 +0100
Re: Embarrassing security bug in systemd <tomas@tuxteam.de> - 2017-12-08 22:40 +0100
Re: Embarrassing security bug in systemd John Hasler <jhasler@newsguy.com> - 2017-12-09 00:30 +0100
Re: Embarrassing security bug in systemd <tomas@tuxteam.de> - 2017-12-09 10:00 +0100
Re: Embarrassing security bug in systemd Dave Sherohman <dave@sherohman.org> - 2017-12-08 10:00 +0100
Re: Embarrassing security bug in systemd Cindy-Sue Causey <butterflybytes@gmail.com> - 2017-12-08 23:40 +0100
Re: Embarrassing security bug in systemd Joe <joe@jretrading.com> - 2017-12-09 00:30 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-09 01:20 +0100
Re: Embarrassing security bug in systemd Joe <joe@jretrading.com> - 2017-12-09 11:40 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-09 15:30 +0100
Re: Embarrassing security bug in systemd The Wanderer <wanderer@fastmail.fm> - 2017-12-10 01:00 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-10 22:20 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-09 17:50 +0100
Re: Embarrassing security bug in systemd David Wright <deblis@lionunicorn.co.uk> - 2017-12-09 18:20 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-09 21:20 +0100
Re: Embarrassing security bug in systemd <tomas@tuxteam.de> - 2017-12-10 12:00 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-10 17:10 +0100
Re: Embarrassing security bug in systemd David Wright <deblis@lionunicorn.co.uk> - 2017-12-10 20:40 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-10 21:30 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-10 23:10 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-11 00:10 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-11 00:50 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-11 12:30 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-11 13:40 +0100
Re: Embarrassing security bug in systemd <tomas@tuxteam.de> - 2017-12-11 14:40 +0100
Re: Embarrassing security bug in systemd <tomas@tuxteam.de> - 2017-12-10 21:50 +0100
Re: Embarrassing security bug in systemd Eduardo M KALINOWSKI <eduardo@kalinowski.com.br> - 2017-12-11 13:00 +0100
Re: Embarrassing security bug in systemd <tomas@tuxteam.de> - 2017-12-11 13:40 +0100
Re: Embarrassing security bug in systemd David Wright <deblis@lionunicorn.co.uk> - 2017-12-11 16:30 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-10 23:10 +0100
Re: Embarrassing security bug in systemd David Wright <deblis@lionunicorn.co.uk> - 2017-12-11 01:30 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-11 04:40 +0100
Re: Embarrassing security bug in systemd David Wright <deblis@lionunicorn.co.uk> - 2017-12-11 06:10 +0100
Re: Embarrassing security bug in systemd Gene Heskett <gheskett@shentel.net> - 2017-12-11 07:40 +0100
Rust? (and a wordsmithing question) (was: Re: Embarrassing security bug in systemd) rhkramer@gmail.com - 2017-12-11 15:40 +0100
Re: Rust? (and a wordsmithing question) (was: Re: Embarrassing security bug in systemd) Darac Marjal <mailinglist@darac.org.uk> - 2017-12-11 16:00 +0100
Re: Rust? (and a wordsmithing question) (was: Re: Embarrassing security bug in systemd) rhkramer@gmail.com - 2017-12-11 18:30 +0100
Re: Rust? (and a wordsmithing question) (was: Re: Embarrassing security bug in systemd) Joe <joe@jretrading.com> - 2017-12-11 16:30 +0100
Re: Rust? (and a wordsmithing question) "James H. H. Lampert" <jamesl@touchtonecorp.com> - 2017-12-11 17:40 +0100
Re: Rust? (and a wordsmithing question) David Wright <deblis@lionunicorn.co.uk> - 2017-12-11 20:10 +0100
Re: Rust? (and a wordsmithing question) <tomas@tuxteam.de> - 2017-12-12 09:30 +0100
Re: Rust? (and a wordsmithing question) "James H. H. Lampert" <jamesl@touchtonecorp.com> - 2017-12-12 17:30 +0100
Re: Rust? (and a wordsmithing question) <tomas@tuxteam.de> - 2017-12-12 17:50 +0100
Re: Rust? (and a wordsmithing question) Curt <curty@free.fr> - 2017-12-12 18:20 +0100
Re: Rust? (and a wordsmithing question) Richard Hector <richard@walnut.gen.nz> - 2017-12-13 04:40 +0100
Re: Rust? (and a wordsmithing question) (was: Re: Embarrassing security bug in systemd) rhkramer@gmail.com - 2017-12-11 18:30 +0100
Re: Rust? (and a wordsmithing question) (was: Re: Embarrassing security bug in systemd) David Wright <deblis@lionunicorn.co.uk> - 2017-12-12 19:10 +0100
UID 1000 on Raspberry Pi (Was: Re: Embarrassing security bug in systemd) Jason <electron@emypeople.net> - 2018-01-09 05:10 +0100
Re: UID 1000 on Raspberry Pi (Was: Re: Embarrassing security bug in systemd) Christian Groessler <chris@groessler.org> - 2018-01-09 16:00 +0100
Re: UID 1000 on Raspberry Pi (Was: Re: Embarrassing security bug in systemd) Roberto C. Sánchez <roberto@debian.org> - 2018-01-09 16:30 +0100
Re: UID 1000 on Raspberry Pi (Was: Re: Embarrassing security bug in systemd) Christian Groessler <chris@groessler.org> - 2018-01-09 18:10 +0100
Re: UID 1000 on Raspberry Pi (Was: Re: Embarrassing security bug in systemd) Erik Christiansen <dvalin@internode.on.net> - 2018-01-10 04:50 +0100
Re: Embarrassing security bug in systemd Menelaos Maglis <mmaglis@metacom.gr> - 2017-12-09 01:40 +0100
Re: Embarrassing security bug in systemd Mark Fletcher <mark27q1@gmail.com> - 2017-12-09 03:10 +0100
Re: Embarrassing security bug in systemd Joe <joe@jretrading.com> - 2017-12-09 10:50 +0100
Re: Embarrassing security bug in systemd Ric Moore <wayward4now@gmail.com> - 2017-12-09 16:40 +0100
Re: Embarrassing security bug in systemd Tom Furie <tom@furie.org.uk> - 2017-12-09 17:10 +0100
Re: Embarrassing security bug in systemd Ben Caradoc-Davies <ben@transient.nz> - 2017-12-09 22:10 +0100
Re: Embarrassing security bug in systemd David Wright <deblis@lionunicorn.co.uk> - 2017-12-09 18:20 +0100
Re: Embarrassing security bug in systemd Michael Stone <mstone@debian.org> - 2017-12-07 00:00 +0100
Re: Embarrassing security bug in systemd Joe <joe@jretrading.com> - 2017-12-07 09:40 +0100
Re: Embarrassing security bug in systemd Glenn English <ghe2001@gmail.com> - 2017-12-07 00:10 +0100
Re: Embarrassing security bug in systemd Brian <ad44@cityscape.co.uk> - 2017-12-07 00:10 +0100
Re: Embarrassing security bug in systemd Roberto C. Sánchez <roberto@debian.org> - 2017-12-07 03:50 +0100
Re: Embarrassing security bug in systemd Michael Lange <klappnase@freenet.de> - 2017-12-07 00:20 +0100
Re: Embarrassing security bug in systemd "James H. H. Lampert" <jamesl@touchtonecorp.com> - 2017-12-07 00:50 +0100
Re: Embarrassing security bug in systemd Michael Stone <mstone@debian.org> - 2017-12-07 01:20 +0100
Re: Embarrassing security bug in systemd Roberto C. Sánchez <roberto@debian.org> - 2017-12-07 03:50 +0100
Re: Embarrassing security bug in systemd David Wright <deblis@lionunicorn.co.uk> - 2017-12-07 02:10 +0100
Re: Embarrassing security bug in systemd Nicholas Geovanis <nickgeovanis@gmail.com> - 2017-12-07 03:40 +0100
Re: Embarrassing security bug in systemd Eric S Fraga <e.fraga@ucl.ac.uk> - 2017-12-07 08:30 +0100
Re: Embarrassing security bug in systemd Michael Biebl <biebl@debian.org> - 2017-12-07 00:50 +0100
Re: Embarrassing security bug in systemd Dejan Jocic <jodejka@gmail.com> - 2017-12-07 02:40 +0100
Re: Embarrassing security bug in systemd Menelaos Maglis <mmaglis@metacom.gr> - 2017-12-08 10:40 +0100
Re: Embarrassing security bug in systemd Roberto C. Sánchez <roberto@debian.org> - 2017-12-08 13:40 +0100
Re: Embarrassing security bug in systemd deloptes <deloptes@gmail.com> - 2017-12-08 20:10 +0100
Re: Embarrassing security bug in systemd David Wright <deblis@lionunicorn.co.uk> - 2017-12-07 01:10 +0100
Re: Embarrassing security bug in systemd Eric S Fraga <e.fraga@ucl.ac.uk> - 2017-12-07 08:30 +0100
Re: Embarrassing security bug in systemd David Baron <dbaron770@gmail.com> - 2017-12-07 08:50 +0100
Page 1 of 7 [1] 2 3 4 5 6 7 Next page →
| From | Urs Thuermann <urs@isnogud.escape.de> |
|---|---|
| Date | 2017-12-06 23:20 +0100 |
| Subject | Embarrassing security bug in systemd |
| Message-ID | <uTQcO-62s-9@gated-at.bofh.it> |
Yesterday, my 10 years old son logged into my laptop running Debian
jessie using his account, and curiously asked if he is allowed to try
the /sbin/reboot command. Knowing I have a Linux system as opposed to
some crappy Win machine, I replied "sure, go ahead and try". Seconds
later I was completely shocked when the machine actually rebooted...
Of course, my son doesn't have any special privileges, no entry in
/etc/sudoers, etc. But then I see
$ ls -l /sbin/reboot
lrwxrwxrwx 1 root root 14 Apr 8 2017 /sbin/reboot -> /bin/systemctl
$ ls -l /bin/systemctl
-rwxr-xr-x 1 root root 538904 Apr 8 2017 /bin/systemctl
$ dpkg -S /bin/systemctl
systemd: /bin/systemctl
The /bin/systemctl binary is not suid root, so I assume[1] it
communicates to systemd which then reboots the machine without
checking what user the request comes from.
I wonder how can such a severe bug make it into a Debian stable
distribution? And is this just an insane default setting on Debian's
side or is it yet another instance of brain-dead systemd behavior?
Searching the man pages I couldn't find a way to fix this. How can
that be stopped?
[1] Of course, this is not docuemented in systemctl(1) as usual with
systemd. Also, according to the man page, systemctl must be
called with a "COMMAND" argument which /sbin/reboot doesn't do.
Obviously, systemctl looks at the name it was called and somehow
uses that as command. The admin shall guess about this.
urs
[toc] | [next] | [standalone]
| From | Roberto C. Sánchez <roberto@debian.org> |
|---|---|
| Date | 2017-12-06 23:50 +0100 |
| Message-ID | <uTQFQ-6bk-9@gated-at.bofh.it> |
| In reply to | #189609 |
On Wed, Dec 06, 2017 at 10:52:17PM +0100, Urs Thuermann wrote: > Yesterday, my 10 years old son logged into my laptop running Debian > jessie using his account, and curiously asked if he is allowed to try > the /sbin/reboot command. Knowing I have a Linux system as opposed to > some crappy Win machine, I replied "sure, go ahead and try". Seconds > later I was completely shocked when the machine actually rebooted... > I just tried this (in a VM) and was shocked to find that it works. > Of course, my son doesn't have any special privileges, no entry in > /etc/sudoers, etc. But then I see > > $ ls -l /sbin/reboot > lrwxrwxrwx 1 root root 14 Apr 8 2017 /sbin/reboot -> /bin/systemctl > $ ls -l /bin/systemctl > -rwxr-xr-x 1 root root 538904 Apr 8 2017 /bin/systemctl > $ dpkg -S /bin/systemctl > systemd: /bin/systemctl > Here are the other things in /sbin symlinked to systemctl: $ ls -l /sbin/ |grep systemctl lrwxrwxrwx 1 root root 14 Jul 5 16:31 halt -> /bin/systemctl lrwxrwxrwx 1 root root 14 Jul 5 16:31 poweroff -> /bin/systemctl lrwxrwxrwx 1 root root 14 Jul 5 16:31 reboot -> /bin/systemctl lrwxrwxrwx 1 root root 14 Jul 5 16:31 runlevel -> /bin/systemctl lrwxrwxrwx 1 root root 14 Jul 5 16:31 shutdown -> /bin/systemctl lrwxrwxrwx 1 root root 14 Jul 5 16:31 telinit -> /bin/systemctl > The /bin/systemctl binary is not suid root, so I assume[1] it > communicates to systemd which then reboots the machine without > checking what user the request comes from. > > I wonder how can such a severe bug make it into a Debian stable > distribution? And is this just an insane default setting on Debian's > side or is it yet another instance of brain-dead systemd behavior? > I too consider this a rather serious bug. However, I do not see any evidence in the BTS [0] that such a bug has yet been reported against systemd. > Searching the man pages I couldn't find a way to fix this. How can > that be stopped? > I wonder the same thing. Regards, -Roberto [0] https://bugs.debian.org/src:systemd -- Roberto C. Sánchez
[toc] | [prev] | [next] | [standalone]
| From | Ben Caradoc-Davies <ben@transient.nz> |
|---|---|
| Date | 2017-12-07 00:40 +0100 |
| Message-ID | <uTRsd-6Kx-7@gated-at.bofh.it> |
| In reply to | #189610 |
On 07/12/17 11:30, Roberto C. Sánchez wrote: > I too consider this a rather serious bug. However, I do not see any > evidence in the BTS [0] that such a bug has yet been reported against > systemd. Not a bug. We can file this one alongside "console user has access to keyboard". Where did I out that CVE? Five seconds of Googling informed me that systemd-inhibit can be used to prevent shutdown. If you are absolutely sure that you want to wreck the well-thought-out privileges for console users, craft a polkit rule. If you only want to avoid accidents, install molly-guard. Kind regards, -- Ben Caradoc-Davies <ben@transient.nz> Director Transient Software Limited <https://transient.nz/> New Zealand
[toc] | [prev] | [next] | [standalone]
| From | Roberto C. Sánchez <roberto@debian.org> |
|---|---|
| Date | 2017-12-07 03:50 +0100 |
| Message-ID | <uTUq6-7d-5@gated-at.bofh.it> |
| In reply to | #189617 |
On Thu, Dec 07, 2017 at 12:18:30PM +1300, Ben Caradoc-Davies wrote: > On 07/12/17 11:30, Roberto C. Sánchez wrote: > > I too consider this a rather serious bug. However, I do not see any > > evidence in the BTS [0] that such a bug has yet been reported against > > systemd. > > Not a bug. We can file this one alongside "console user has access to > keyboard". Where did I out that CVE? > Actually not. In my case I use GDM. I have a configuration directive in /etc/gdm3/greeter.dconf-defaults as follows: disable-restart-buttons=true Since I have decided to let GDM manage graphical login and otherwise depended on the fact that in order to reboot from a TTY or remote session root permissions are required, I find systemd's behavior to be buggy. > Five seconds of Googling informed me that systemd-inhibit can be used to > prevent shutdown. If you are absolutely sure that you want to wreck the > well-thought-out privileges for console users, craft a polkit rule. If you > only want to avoid accidents, install molly-guard. > This is not something that I should have to Google. I previously had a working configuration that prevented halting or rebooting the system by all non-root users. Then I upgraded, got systemd and it turns out that my configuration has been silently broken for a very long time. The fact that systemd does not respect conventions (i.e., must be root to halt/reboot) or established configuration directives (i.e., in display managers) should have at the very least been included in the release notes. This is the kind of nonsense that makes people dislike systemd. The priviliges for console users were already well thought out *BEFORE* systemd, then systemd came along and wrecked it. This is certainly not the only example where systemd does something like this. Regards, -Roberto -- Roberto C. Sánchez
[toc] | [prev] | [next] | [standalone]
| From | deloptes <deloptes@gmail.com> |
|---|---|
| Date | 2017-12-07 07:30 +0100 |
| Message-ID | <uTXQZ-2uq-1@gated-at.bofh.it> |
| In reply to | #189627 |
Roberto C. Sánchez wrote: > Then I upgraded, got systemd and it turns out that > my configuration has been silently broken for a very long time. to prevent this, keep a list with your customizations and use it as check list after upgrade I also see nothing wrong when someone that could press the halt button, can also run reboot. On the other hand a lot of us decided against systemd (at least as init daemon: there was a long discussion not that long ago here) So here it says $ /sbin/reboot reboot: must be superuser. regards
[toc] | [prev] | [next] | [standalone]
| From | Ben Caradoc-Davies <ben@transient.nz> |
|---|---|
| Date | 2017-12-06 23:50 +0100 |
| Message-ID | <uTQFQ-6bk-7@gated-at.bofh.it> |
| In reply to | #189609 |
On 07/12/17 10:52, Urs Thuermann wrote: > Yesterday, my 10 years old son logged into my laptop running Debian > jessie using his account, and curiously asked if he is allowed to try > the /sbin/reboot command. Knowing I have a Linux system as opposed to > some crappy Win machine, I replied "sure, go ahead and try". Seconds > later I was completely shocked when the machine actually rebooted... I think that allowing a user logged in at the console to reboot the system is the correct behaviour for most desktops, whether via GUI or terminal. Special privileges have been granted to console users for as long as I can remember, long before systemd, because they have physical access to the machine. Console users typically are also permitted to mount, unmount, and eject removable media, and have access to audio devices. Special configuration is required to remove this functionality on kiosks, for example. Please ask your son to try to reboot while logged remotely with ssh (loopback may be equivalent). I know that my local desktop permits passwordless shutdown while remote shutdown on another systemd machine requires a user password *and* that the user to be in sudoers. Kind regards, -- Ben Caradoc-Davies <ben@transient.nz> Director Transient Software Limited <https://transient.nz/> New Zealand
[toc] | [prev] | [next] | [standalone]
| From | Dave Sherohman <dave@sherohman.org> |
|---|---|
| Date | 2017-12-07 10:40 +0100 |
| Message-ID | <uU0OS-4hE-11@gated-at.bofh.it> |
| In reply to | #189611 |
On Thu, Dec 07, 2017 at 11:26:45AM +1300, Ben Caradoc-Davies wrote: > Special privileges have been granted to console users for as long as I can > remember, long before systemd, because they have physical access to the > machine. Console users typically are also permitted to mount, unmount, and > eject removable media, and have access to audio devices. I think this is a key point that's been overlooked in the complaints about this behavior: It has nothing to do with systemd. I no longer have any non-systemd machines handy to verify this on, but my memory is that I have *always* been able to use halt/poweroff/reboot commands from the console without requiring sudo or entering a password, and I've been using Debian since 2000ish, well before systemd was even a gleam in some programmer's eye. /sbin/shutdown may have also been freely available at the console, but I don't remember that one clearly, since I didn't use it all that often once I discovered the others. But, then, even if I'm remembering incorrectly, it's still a policy matter, not a technical one. If the policy was changed at the same time as Debian switched to systemd, that's just a coincidence of timing and the same policy change could have happened while still under sysvinit. -- Dave Sherohman
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| From | Tixy <tixy@yxit.co.uk> |
|---|---|
| Date | 2017-12-07 11:30 +0100 |
| Message-ID | <uU1Bg-4Ql-21@gated-at.bofh.it> |
| In reply to | #189635 |
On Thu, 2017-12-07 at 03:03 -0600, Dave Sherohman wrote: > > I no longer have any non-systemd machines handy to verify this on, but > my memory is that I have *always* been able to use halt/poweroff/reboot > commands from the console without requiring sudo or entering a password, > and I've been using Debian since 2000ish, well before systemd was even a > gleam in some programmer's eye. I'm running Jessie (with systemd running but booting with sysvinit) and trying to execute halt/poweroff/reboot/shutdown from a terminal without root privileges gives an error saying I must be superuser. Which has always been my experience in 10 years of using Debian. >From a desktop environment it's usually been possible to shut a machine down from a menu option, though at least on one release I ended up having to hack some policy config to allow that to work. -- Tixy
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| From | Jonathan Dowland <jmtd@debian.org> |
|---|---|
| Date | 2017-12-07 11:50 +0100 |
| Message-ID | <uU1UB-4WL-3@gated-at.bofh.it> |
| In reply to | #189636 |
On Thu, Dec 07, 2017 at 10:02:56AM +0000, Tixy wrote: >I'm running Jessie (with systemd running but booting with sysvinit) and >trying to execute halt/poweroff/reboot/shutdown from a terminal without >root privileges gives an error saying I must be superuser. Which has >always been my experience in 10 years of using Debian. Be careful to double check what you are testing: in your situation it's not clear whether /sbin/reboot is a symlink to systemctl (part of systemd, so I would expect this not to work if you were not running systemd as the init system) or a separate binary. -- ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢠⠒⠀⣿⡁ Jonathan Dowland ⢿⡄⠘⠷⠚⠋⠀ https://jmtd.net ⠈⠳⣄⠀⠀⠀⠀ Please do not CC me, I am subscribed to the list.
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| From | Jimmy Johnson <field.engineer@gmail.com> |
|---|---|
| Date | 2017-12-09 03:50 +0100 |
| Message-ID | <uUDnb-4cL-1@gated-at.bofh.it> |
| In reply to | #189638 |
On 12/07/2017 02:31 AM, Jonathan Dowland wrote: > On Thu, Dec 07, 2017 at 10:02:56AM +0000, Tixy wrote: >> I'm running Jessie (with systemd running but booting with sysvinit) and >> trying to execute halt/poweroff/reboot/shutdown from a terminal without >> root privileges gives an error saying I must be superuser. Which has >> always been my experience in 10 years of using Debian. > > Be careful to double check what you are testing: in your situation it's > not clear whether /sbin/reboot is a symlink to systemctl (part of > systemd, so I would expect this not to work if you were not running > systemd as the init system) or a separate binary. Jonathan, I started thinking about lost work where someone restarted the computer while I was away from it and thought what if you can lock-screen and lock access to console at the same time. Is that something that could be done? Helpful? I know someone can pull the cord or press the power button, I got past that. -- Jimmy Johnson Debian Buster - KDE Plasma 5.10.5 - AMD A8-7600 - EXT4 at sda7 Registered Linux User #380263
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| From | David Wright <deblis@lionunicorn.co.uk> |
|---|---|
| Date | 2017-12-09 17:50 +0100 |
| Message-ID | <uUQu6-49A-9@gated-at.bofh.it> |
| In reply to | #189706 |
On Fri 08 Dec 2017 at 18:30:08 (-0800), Jimmy Johnson wrote:
> On 12/07/2017 02:31 AM, Jonathan Dowland wrote:
> >On Thu, Dec 07, 2017 at 10:02:56AM +0000, Tixy wrote:
> >>I'm running Jessie (with systemd running but booting with sysvinit) and
> >>trying to execute halt/poweroff/reboot/shutdown from a terminal without
> >>root privileges gives an error saying I must be superuser. Which has
> >>always been my experience in 10 years of using Debian.
> >
> >Be careful to double check what you are testing: in your situation it's
> >not clear whether /sbin/reboot is a symlink to systemctl (part of
> >systemd, so I would expect this not to work if you were not running
> >systemd as the init system) or a separate binary.
>
>
> Jonathan, I started thinking about lost work where someone restarted
> the computer while I was away from it and thought what if you can
> lock-screen and lock access to console at the same time. Is that
> something that could be done? Helpful?
>
> I know someone can pull the cord or press the power button, I got past that.
I use vlock -a in a VC to lock all the consoles. I've been using
it for years so I hadn't noticed the -n switch that allows you to
run it in X (with switching to a VC first).
You can still ssh into, and scp to, the machine while it's locked.
AFAICT Debian's versions allow unlocking with the root password as
well as the user's, which is handy if you forget which username
you were logged in under when you vlock'd it.
https://lists.debian.org/debian-user/2017/11/msg00951.html
Cheers,
David.
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| From | Jimmy Johnson <field.engineer@gmail.com> |
|---|---|
| Date | 2017-12-10 10:00 +0100 |
| Message-ID | <uV5CO-5oC-9@gated-at.bofh.it> |
| In reply to | #189726 |
On 12/09/2017 08:23 AM, David Wright wrote: > On Fri 08 Dec 2017 at 18:30:08 (-0800), Jimmy Johnson wrote: >> On 12/07/2017 02:31 AM, Jonathan Dowland wrote: >>> On Thu, Dec 07, 2017 at 10:02:56AM +0000, Tixy wrote: >>>> I'm running Jessie (with systemd running but booting with sysvinit) and >>>> trying to execute halt/poweroff/reboot/shutdown from a terminal without >>>> root privileges gives an error saying I must be superuser. Which has >>>> always been my experience in 10 years of using Debian. >>> >>> Be careful to double check what you are testing: in your situation it's >>> not clear whether /sbin/reboot is a symlink to systemctl (part of >>> systemd, so I would expect this not to work if you were not running >>> systemd as the init system) or a separate binary. >> >> >> Jonathan, I started thinking about lost work where someone restarted >> the computer while I was away from it and thought what if you can >> lock-screen and lock access to console at the same time. Is that >> something that could be done? Helpful? >> >> I know someone can pull the cord or press the power button, I got past that. > > I use vlock -a in a VC to lock all the consoles. I've been using > it for years so I hadn't noticed the -n switch that allows you to > run it in X (with switching to a VC first). > > You can still ssh into, and scp to, the machine while it's locked. > AFAICT Debian's versions allow unlocking with the root password as > well as the user's, which is handy if you forget which username > you were logged in under when you vlock'd it. > > https://lists.debian.org/debian-user/2017/11/msg00951.html Thanks David, works great, KDE runs on VC7 I went to VC2 an ran '$ vlock -a' and I was NOT able to switch to any other VC it was locked with the message to press enter with passwd, if you press enter with wrong passwd or no passwd you will be prompted for ROOT passwd. For me that was no problem, but I can see the shock on someones face when they don't know the root passwd and I got a chuckle out of that. After entering the root passwd I was able to switch back to VC7 and all was well. :) Cheers! -- Jimmy Johnson Debian Buster - KDE Plasma 5.10.5 - AMD A8-7600 - EXT4 at sda7 Registered Linux User #380263
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| From | David Wright <deblis@lionunicorn.co.uk> |
|---|---|
| Date | 2017-12-10 20:40 +0100 |
| Message-ID | <uVfCa-3qr-9@gated-at.bofh.it> |
| In reply to | #189742 |
On Sun 10 Dec 2017 at 00:38:12 (-0800), Jimmy Johnson wrote: > On 12/09/2017 08:23 AM, David Wright wrote: > >On Fri 08 Dec 2017 at 18:30:08 (-0800), Jimmy Johnson wrote: > >>On 12/07/2017 02:31 AM, Jonathan Dowland wrote: > >>>On Thu, Dec 07, 2017 at 10:02:56AM +0000, Tixy wrote: > >>>>I'm running Jessie (with systemd running but booting with sysvinit) and > >>>>trying to execute halt/poweroff/reboot/shutdown from a terminal without > >>>>root privileges gives an error saying I must be superuser. Which has > >>>>always been my experience in 10 years of using Debian. > >>> > >>>Be careful to double check what you are testing: in your situation it's > >>>not clear whether /sbin/reboot is a symlink to systemctl (part of > >>>systemd, so I would expect this not to work if you were not running > >>>systemd as the init system) or a separate binary. > >> > >> > >>Jonathan, I started thinking about lost work where someone restarted > >>the computer while I was away from it and thought what if you can > >>lock-screen and lock access to console at the same time. Is that > >>something that could be done? Helpful? > >> > >>I know someone can pull the cord or press the power button, I got past that. > > > >I use vlock -a in a VC to lock all the consoles. I've been using > >it for years so I hadn't noticed the -n switch that allows you to > >run it in X (with switching to a VC first). > > > >You can still ssh into, and scp to, the machine while it's locked. > >AFAICT Debian's versions allow unlocking with the root password as > >well as the user's, which is handy if you forget which username > >you were logged in under when you vlock'd it. > > > > https://lists.debian.org/debian-user/2017/11/msg00951.html > > Thanks David, works great, KDE runs on VC7 I went to VC2 an ran '$ > vlock -a' and I was NOT able to switch to any other VC it was locked > with the message to press enter with passwd, if you press enter with > wrong passwd or no passwd you will be prompted for ROOT passwd. For > me that was no problem, but I can see the shock on someones face > when they don't know the root passwd and I got a chuckle out of > that. After entering the root passwd I was able to switch back to > VC7 and all was well. :) With nothing available but the Return key, methods of giving you user/root password choice are limited. The solution is alternation: just keep pressing the Return key until you get the prompt you want. Cheers, David.
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| From | <tomas@tuxteam.de> |
|---|---|
| Date | 2017-12-07 11:40 +0100 |
| Message-ID | <uU1KW-4TL-3@gated-at.bofh.it> |
| In reply to | #189635 |
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Thu, Dec 07, 2017 at 03:03:44AM -0600, Dave Sherohman wrote: > On Thu, Dec 07, 2017 at 11:26:45AM +1300, Ben Caradoc-Davies wrote: > > Special privileges have been granted to console users for as long as I can > > remember, long before systemd, because they have physical access to the > > machine. Console users typically are also permitted to mount, unmount, and > > eject removable media, and have access to audio devices. > > I think this is a key point that's been overlooked in the complaints > about this behavior: It has nothing to do with systemd. No. It has to do with polkit & friends. On my system (which is a pretty "classic" setup: no systemd, but also as little as possible from all this more "modern" desktop stuff, which I don't like very much [1]), /sbin/halt *wants* me to be root. This isn't inherently more secure (or less) but just The Way it Is (TM) -- an heritage from times *every* user on an Unix system was remote. The policy kit and its descendants try to make a guess whether the user is "physically present" to allow them to shut down the computer. As others have pointed out, this does make sense (as long as the above guess is sufficiently accurate, that is), because the user can pull the cord/extract the batteries/smash the box anyway. Now to that guess: for your vanilla PC/laptop/tablet/smartphone class of machine, if the user is at the console or the local terminal, implying presence is a pretty accurate guess. That's why the default configuration comes shipped as it is. If you are installing an ATM/voting computer/AS400, I'd hope that, as a system integrator you *know what you are doing* and set the defaults appropriately. So all is well. This isn't a bug. For someone coming from "traditional" Unix, this might be unexpected (and has thus some potential for damage), but that expectation hasn't been broken by systemd this time. There are Linux distros for big IBM iron: anyone cares to have a look how the default policy settings are there? (As that's SuSE's realm, mainly, I'd guess they are similar enough to RedHat that they're using something along these lines). Cheers [1] Don't take me wrong. Those desktop thingies have their place. Just not on "my" desktop, dammit :-) - -- tomás -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAlopFhsACgkQBcgs9XrR2kaUcwCeMgdvqAWryzSSxE5W3r8+Ol2o NE8AnAlA3wWeb2dJ4xdTN5Cyy+3Al/PT =xit+ -----END PGP SIGNATURE-----
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| From | Roberto C. Sánchez <roberto@debian.org> |
|---|---|
| Date | 2017-12-07 16:00 +0100 |
| Message-ID | <uU5Oy-7sA-7@gated-at.bofh.it> |
| In reply to | #189635 |
On Thu, Dec 07, 2017 at 03:03:44AM -0600, Dave Sherohman wrote: > > I no longer have any non-systemd machines handy to verify this on, but > my memory is that I have *always* been able to use halt/poweroff/reboot > commands from the console without requiring sudo or entering a password, > and I've been using Debian since 2000ish, well before systemd was even a > gleam in some programmer's eye. /sbin/shutdown may have also been > freely available at the console, but I don't remember that one clearly, > since I didn't use it all that often once I discovered the others. > I just did a fresh install of wheezy (7.11) with all defaults. Here is what happened: testuser@debian:~$ cat /etc/debian_version 7.11 testuser@debian:~$ /sbin/reboot reboot: must be superuser. testuser@debian:~$ ls -l /sbin/reboot lrwxrwxrwx 1 root root 4 Jul 14 2013 /sbin/reboot -> halt testuser@debian:~$ ls -l /sbin/halt -rwxr-xr-x 1 root root 15184 Jul 14 2013 /sbin/halt The situation is basically the same for /sbin/shutdown. Regards, -Roberto -- Roberto C. Sánchez
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| From | Michael Biebl <biebl@debian.org> |
|---|---|
| Date | 2017-12-07 20:30 +0100 |
| Message-ID | <uUa1Q-1PI-9@gated-at.bofh.it> |
| In reply to | #189643 |
[Multipart message — attachments visible in raw view] — view raw
Am 07.12.2017 um 15:37 schrieb Roberto C. Sánchez: > On Thu, Dec 07, 2017 at 03:03:44AM -0600, Dave Sherohman wrote: >> >> I no longer have any non-systemd machines handy to verify this on, but >> my memory is that I have *always* been able to use halt/poweroff/reboot >> commands from the console without requiring sudo or entering a password, >> and I've been using Debian since 2000ish, well before systemd was even a >> gleam in some programmer's eye. /sbin/shutdown may have also been >> freely available at the console, but I don't remember that one clearly, >> since I didn't use it all that often once I discovered the others. >> > I just did a fresh install of wheezy (7.11) with all defaults. Here is > what happened: > > testuser@debian:~$ cat /etc/debian_version > 7.11 > testuser@debian:~$ /sbin/reboot > reboot: must be superuser. > testuser@debian:~$ ls -l /sbin/reboot > lrwxrwxrwx 1 root root 4 Jul 14 2013 /sbin/reboot -> halt > testuser@debian:~$ ls -l /sbin/halt > -rwxr-xr-x 1 root root 15184 Jul 14 2013 /sbin/halt > > The situation is basically the same for /sbin/shutdown. Now try CTRL+ALT+DEL on the console. This will reboot your system. See /etc/inittab: # What to do when CTRL-ALT-DEL is pressed. ca:12345:ctrlaltdel:/sbin/shutdown -t1 -a -r now Next, try hitting the power button. This will shut down your system. On systems with acpi support, Debian has been installing acpid + acpi-support-base in the past. See /etc/acpi/powerbtn-acpi-support.sh Next install a display manager, like gdm3 or lightdm. This will allow you shutdown/reboot the system as well. Basically, it was a completely inconsistent mess before systemd. Now you at least have a central place where you can configure your system behaviour. Michael -- Why is it that all of the instruments seeking intelligent life in the universe are pointed away from Earth?
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| From | <tomas@tuxteam.de> |
|---|---|
| Date | 2017-12-08 09:20 +0100 |
| Message-ID | <uUm2Z-1sW-3@gated-at.bofh.it> |
| In reply to | #189655 |
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Thu, Dec 07, 2017 at 08:03:47PM +0100, Michael Biebl wrote: [...] > Basically, it was a completely inconsistent mess before systemd. > Now you at least have a central place where you can configure your > system behaviour. Hey, I'm "before systemd" (and plan to stay so). I disagree that I'm an inconsistent mess (yes, a bit tongue-in-cheek ;-P - -- t -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAloqRxQACgkQBcgs9XrR2kbLiQCeKvl/VX1lALeAA3a0OcCewZae 4c8AnR3qyJ01Pq/Hv18rbfrbpO3qWtMM =GJwl -----END PGP SIGNATURE-----
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| From | deloptes <deloptes@gmail.com> |
|---|---|
| Date | 2017-12-08 12:40 +0100 |
| Message-ID | <uUpax-3mU-9@gated-at.bofh.it> |
| In reply to | #189655 |
Michael Biebl wrote: > Basically, it was a completely inconsistent mess before systemd. > Now you at least have a central place where you can configure your > system behaviour. This is your opinion - if you can not understand the "mess" it is a mess. For most of us who dislike systemd your same statement is valid. I do not understand it and it is a mess. So we have 1:1 :) Perhaps we like the old mess better than the new mess ;-) Please do not try to impose your opinion on others. Free software is free for this reason and we want to stay like this. We respect each others opinion. regards
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| From | <tomas@tuxteam.de> |
|---|---|
| Date | 2017-12-08 13:40 +0100 |
| Message-ID | <uUq6B-40S-1@gated-at.bofh.it> |
| In reply to | #189669 |
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On Fri, Dec 08, 2017 at 12:17:16PM +0100, deloptes wrote:
> Michael Biebl wrote:
>
> > Basically, it was a completely inconsistent mess before systemd.
[...]
> This is your opinion - if you can not understand the "mess" it is a mess.
> For most of us who dislike systemd your same statement is valid [...]
Now watch all the old skoolers dashing out of their little caves and
waving their fists at something which could be read as a provocation
(I'm myself one of those, just look a bit upthread :)
In the sense of civilized discourse, I now do a bit of introspection
and think one could read Michael's statement differently. For those
using the computers "classically", there was no mess. Issue su at
any console (most of us did the migration to sudo a while ago, since
it's more convenient and a tad safer), done. No mess.
But for a desktop environment, which has been silently permeated
by the assumption "one computer -- one user -- one display/keyboard"
and which wants to offer their users transparent access to system
management tasks (install printer, package system, video resolution,
yadda yadda) in a way that looks somewhat like Those Other Operating
Systems, the implementations we have seen *are* a mess, all this
Gnome *kit horror and whatever KDE does (there's enough mess still
left: why have Gnome and KDE to invent their own virtual file
systems? Have you ever had a look at what Gnome does to attach
emblems to files? And so on).
So I understand perfectly that those desktop environments have
clinged desperately to systemd. They are constantly on the brink
of breaking down under their own complexity, so exporting some
of it to Some Other Place always feels like a bit of fresh air.
So in *this* context, I'd say Michael is spot on.
Now if you don't buy into that desktop thing, systemd doesn't
look like a simplification or sorting out some mess, I'd think.
But some agree to differ on that too.
Cheers
- -- tomás
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| From | deloptes <deloptes@gmail.com> |
|---|---|
| Date | 2017-12-08 21:40 +0100 |
| Message-ID | <uUxB8-uO-9@gated-at.bofh.it> |
| In reply to | #189670 |
tomas@tuxteam.de wrote: > Now watch all the old skoolers dashing out of their little caves and > waving their fists at something which could be read as a provocation > (I'm myself one of those, just look a bit upthread :) > It is not about old or new, but about known and unknown. Unkown exposes me to risk. As also highlighted here the solution is not the best on multiuser environment, but I think one could configure systemd to respect the requirements. I first accepted systemd also advocated for "progress", but after a long discussion here (at least 6months ago) I revisited my opinion and installed sysvinit first on the server and then on the desktop, notebook etc. > In the sense of civilized discourse, I now do a bit of introspection > and think one could read Michael's statement differently. For those > using the computers "classically", there was no mess. Issue su at > any console (most of us did the migration to sudo a while ago, since > it's more convenient and a tad safer), done. No mess. > This is true and I think we'll find time to learn systemd and get comfortable with that. > But for a desktop environment, which has been silently permeated > by the assumption "one computer -- one user -- one display/keyboard" > and which wants to offer their users transparent access to system > management tasks (install printer, package system, video resolution, > yadda yadda) in a way that looks somewhat like Those Other Operating > Systems, the implementations we have seen are a mess, all this > Gnome *kit horror and whatever KDE does (there's enough mess still > left: why have Gnome and KDE to invent their own virtual file > systems? Have you ever had a look at what Gnome does to attach > emblems to files? And so on). > This is also true - gnome went insane and KDE unusable as of v4. > So I understand perfectly that those desktop environments have > clinged desperately to systemd. They are constantly on the brink > of breaking down under their own complexity, so exporting some > of it to Some Other Place always feels like a bit of fresh air. > > So in this context, I'd say Michael is spot on. > > Now if you don't buy into that desktop thing, systemd doesn't > look like a simplification or sorting out some mess, I'd think. > But some agree to differ on that too. For me personally systemd is very new and I need to find time to understand it and be able to manage it.
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