[arch-projects] [initscripts][PATCH 2/2] rc.d: Add check to cleanly abort rc.d script if user doesn't have root privileges
Eric Bélanger
snowmaniscool at gmail.com
Fri Jun 17 23:34:23 EDT 2011
On Fri, Jun 17, 2011 at 7:25 PM, Seblu <seblu at seblu.net> wrote:
> On Thu, Jun 2, 2011 at 2:30 AM, Eric Bélanger <snowmaniscool at gmail.com> wrote:
>> On Tue, May 31, 2011 at 7:29 PM, Eric Bélanger <snowmaniscool at gmail.com> wrote:
>>> On Mon, May 30, 2011 at 6:23 PM, Seblu <seblu at seblu.net> wrote:
>>>> On Sat, May 28, 2011 at 5:52 AM, Eric Bélanger <snowmaniscool at gmail.com> wrote:
>>>>> On Fri, May 27, 2011 at 10:19 AM, Seblu <seblu at seblu.net> wrote:
>>>>>> On Fri, May 27, 2011 at 11:42 AM, Eric Bélanger <snowmaniscool at gmail.com> wrote:
>>>>>>> This implements FS#24095. The check is only made for the start, stop and restart
>>>>>>> actions of the daemon scripts. This allows regular user to use the help and list
>>>>>>> functionality of rc.d and also to use rc.d for actions that doesn't require root
>>>>>>> privileges, like the status action of some daemon scripts.
>>>>>>>
>>>>>>> Signed-off-by: Eric Bélanger <snowmaniscool at gmail.com>
>>>>>>> ---
>>>>>>> rc.d | 4 ++++
>>>>>>> 1 files changed, 4 insertions(+), 0 deletions(-)
>>>>>>>
>>>>>>> diff --git a/rc.d b/rc.d
>>>>>>> index 97f266a..2325623 100755
>>>>>>> --- a/rc.d
>>>>>>> +++ b/rc.d
>>>>>>> @@ -43,6 +43,10 @@ case $1 in
>>>>>>> ;;
>>>>>>> *)
>>>>>>> action=$1
>>>>>>> + if [[ "$EUID" != '0' ]] && [[ "$action" == 'start' || "$action" == 'stop' || "$action" == 'restart' ]] ; then
>>>>>>> + echo 'Error: this script must be run as root to use this functionality.'
>>>>>>> + exit 1
>>>>>>> + fi
>>>>>>> shift
>>>>>>> # set same environment variables as init
>>>>>>> runlevel=$(/sbin/runlevel)
>>>>>>
>>>>>> As i said in FS#24095, if we really want do this, we should not do
>>>>>> this in rc.d script but in functions which is loaded by real rc
>>>>>> scripts.
>>>>>>
>>>>>> Increasingly, why choose start/stop/restart and not reload by example?
>>>>>> By example, in virtualbox_bin we have fixusb, which must be run as root.
>>>>>>
>>>>>
>>>>> I only chose start/stop/restart because they are the only standard
>>>>> ones.
>>>> There is a page describing arch standard, or at least, a namming convention?
>>>
>>> The only one I can think of is the daemon prototype file which has a
>>> status function to display if the daemon is running or not. There are
>>> 2 packages that I maintain (or have maintained) that use the status
>>> for something else so it seem to be more standard than I thought. The
>>> reload action seem to be quite common and standard. Later tonight,
>>> I'll go through all the daemons in the repos and list what action they
>>> have (except start/stop/restart) and what these actions do. It'll
>>> give use a better idea if there is a genereal concensus on these
>>> various actions.
>>>
>>>>
>>>>> Not only all daemons script have them but they all do the same
>>>>> things: start/stop a binary before creating/removing a file
>>>>> contatining the PID in a directory that needs root privileges. I am
>>>>> 100% sure that root privilege is required. The other actions are not
>>>>> used by all daemons and what they do depends on the daemon itself. So
>>>>> we can't be really sure if root privileges are required or not.
>>>>>
>>>>> I decided to play it safe and to treat everything else than
>>>>> start/stop/restart as edge cases.
>>>> It makes sense, but I am forbidden to do
>>>>
>>>>>> I think we should offer a check_root function which can be called in
>>>>>> rc scripts to ensure rootitude. Be we cannot generically know if a rc
>>>>>> need to be root or not.
>>>>>
>>>>> That might be ideal. But for the reason I mentionned above, the
>>>>> daemon scripts will probably need to be modified to indicate what
>>>>> privileges are needed for all actions. Perhaps, demanding root
>>>>> privileges by default except when there is a NEED_ROOT=0 defined in
>>>>> the case, e.g.
>>>> i agree. Idea is better.
>>>>
>>>>>
>>>>> status)
>>>>> NEED_ROOT=0
>>>>> do stuff that don't need root privs...
>>>> Don't easy to implement in bash...
>>>>
>>>>> would reduce the workload on fixing the packages. That will surely
>>>>> take some time before it's implemented unless that can be done without
>>>>> modifying the daemon scripts.
>>>> As said before, we can use functions scripts which is sourced by all
>>>> rc.d scripts to make this check rather than doing it in rc.d
>>>>
>>>>>
>>>>> Until this is done, this proposed patch is a good compromise between
>>>>> the ideal situation and the current situation where no check is done
>>>>> at all.
>>>> Basically, there is maybe no problem to don't check. This is not done
>>>> from the beginning.
>>>> If you can, you can. If you need right it will fail. KISS.
>>>>
>>>>> The majority of users will use rc.d to start/stop/restart
>>>>> daemons anyway. Since you can use rc.d on many daemons at once, it's
>>>>> better to abort the rc.d script early so you can rerun it with
>>>>> sufficient privileges instead of having to wait for all the daemons to
>>>>> fail. It would also be trivial to remove this check in rc.d once (or
>>>>> if) we have implemented something better.
>>>>>
>>>> I do not see the difference. If all daemons will need root privileges,
>>>> they will fail.
>>>>
>>>> I think a lots of users will still use /etc/rc.d/x start/stop/restart,
>>>> and it's kind of sugar around if you can or not run a daemon.
>>>>
>>>> I propose a patch following your recommendation here :
>>>> https://github.com/seblu/arch-initscripts/commit/5a59a30
>>>>
>>>> What do you think?
>>>
>>> Your patch doesn't do what I was thinking mainly because my idea
>>> wasn't a good one. The problem is that the checking is done in
>>> /etc/rc.d/functions which is sourced at the begining of the script so
>>> the NEED_ROOT variable needs to be defined globally while I wanted a
>>> local approach that would depend on the items in the case statement.
>>> I don't know if it's clear but it doesn't matter because I found a
>>> better solution that works without needing the NEED_ROOT variable.
>>>
>>> We need to add in /etc/rc.d/functions your need_root function followed by:
>>>
>>> if [[ "$1" == 'start' || "$1" == 'stop' || "$1" == 'restart' ]]; then
>>> need_root
>>> fi
>>>
>>> I only have start/stop/restart in that code sample but we'll probably
>>> need to add more actions , like reload, depending on what I find in
>>> the daemon investigation I described above. I did tests with deamon
>>> scripts and rc.d and it works without any modifications needed to
>>> them.
>>>
>>> Couple drawbacks:
>>>
>>> - The list of actions to test for root is hard-coded. If I add a
>>> foobar action which requires root privileges to a daemon, it'll need
>>> to be added to the list in /etc/rc.d/functions. As this should happen
>>> often, it would be minimal maintenance.
>>>
>>> - It suppose that all daemon using a given action need the same
>>> privileges. If it's not the case, we'll need to either fix the
>>> packages, enforce root privileges or go with the majority depnding on
>>> the case.
>>>
>>> - When thinking about this, I only had the rc.d and daemon scripts in
>>> mind and I monly testes these. If there are other scripts which
>>> sources /etc/rc.d/functions, we'll need to check them to see if they
>>> still work fine with my change.
>>>
>>
>> Hi,
>>
>> Here's my findings. Basically, all daemons actions need root
>> privileges except a few of them:
>>
>> - iflist) and rtlist) from network daemon
>> - reload) action for the dbus daemon. As all other daemon require
>> root privileges for reload, it will be best to enforce it for the
>> reload action.
>> - status). A majority of daemon don't need root privilege for it but,
>> again, there are exceptions:
>> - ufw: looks like a bug in its daemon file. I'll submit a bug report.
>> - laptop-mode-tools: With user privs, you get some information
>> about the system except the ones that need
>> direct access to the hard drive devices. Not really worth
>> fixing. Let's ignore it.
>> - apcupsd: I can't test this one as I don't have a UPS.I get the
>> same error message whether I have root
>> privileges or not so it might not require them.
>>
>> Long story short: I suggest enforcing root privileges for all daemon
>> actions except: iflist, rtlist and status. So we have:
>>
>>
>> need_root() {
>> (( $EUID != 0 )) && printf 'You need to be root.\n' && exit 1
>> }
>>
>> if [[ "$1" == 'attach' || "$1" == 'careless_start' || "$1" == 'check' || \
>> "$1" == 'clean' || "$1" == 'condrestart' || "$1" == 'down' || \
>> "$1" == 'force-quit' || "$1" == 'force-reload' || "$1" ==
>> 'force-restart' || \
>> "$1" == 'ifdown' || "$1" == 'ifup' || "$1" == 'load' || \
>> "$1" == 'logrotate' || "$1" == 'purge' || "$1" == 'reload' || \
>> "$1" == 'restart' || "$1" == 'resume' || "$1" == 'rtdown' ||
>> "$1" == 'rtup' || \
>> "$1" == 'save' || "$1" == 'setup' || "$1" == 'start' || "$1" ==
>> 'stop' || \
>> "$1" == 'suspend' || "$1" == 'unload' || "$1" == 'up' ]]; then
>> need_root
>> fi
>>
> Hi,
>
> Thanks for crawling initscripts to find problematic options.
> You probably miss some case in aur, where rc.d scripts implement
> "strange" options which need root priv, for example virtualbox_bin
> which have a fixsub.
When you mentionned virtualbox_bin in an earlier post, I thought it
was one of the virtualbox packages in community but couldn't find it
when I went trough the daemon scripts. FTR, I didn't check the AUR,
the repos were enough work. ;)
>
> I really don't like this idea of hardcode which options should or
> should not needs root priv in initscripts, because, I think we should
> let rc.d scripts depends of initscripts package, and not initscripts
> package depends of ufw, laptop-tools or others.
>
Yeah, hardcoding is not very practical. That's why I initially wanted
to have the permission info in the individual daemon file but that
doesn't work.
> I also think we should be able to resume by a clear and simple policy like :
> By default initscripts need to be root (Thomas in FS#24095). If you
> want bypass this assumption to offer a by options (or by what you
> want) right management, just disable and do what you want.
> need_root is just a proposed generic helper to enforce root policy.
> But, scripts maintainer can check if user who ask something is member
> of a group to allow his script.
>
Sure, checking for root privileges for all actions is the easiest and
simplest method. However, the status actions which currently, in most
cases, can done as a regular user will require root privileges from
now on if we go this way.
I have another (better, IMO) idea: enforce root privilege for all
actions except status.
Pros:
- no hardcoded list
- regular users will still need be able to do: /etc/rc.d/foo status
For the few packages that currently require root privilege for the
status action, we can argue that they are misusing the status function
as they don't follow the daemon prototype
/usr/share/pacman/rc-script.proto which has:
status)
stat_busy "Checking $daemon_name status";
ck_status $daemon_name
;;
which doesn't need root privilege. So their current status function
should be renamed to info, for example.
This would imply simply adding the following to /etc/rc.d/functions :
need_root() {
(( $EUID != 0 )) && printf 'You need to be root.\n' && exit 1
}
if [[ "$1" != 'status' ]]; then
need_root
fi
Eric
> Intelligence is in the script, we should not try to predict what it
> will do a in special cases (options). Let script maintainers choose.
>
> Cheers,
>
> --
> Sébastien Luttringer
> www.seblu.net
>
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