Mailing List Archive: Gentoo: Security

Re : Running app-admin/syslog-ng without rootprivileges

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varagnat at bertin

Nov 16, 2005, 4:54 AM

Post #1 of 4 (582 views)
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Re : Running app-admin/syslog-ng without rootprivileges

> dedicated non-root account. May be we need to ask syslog-ng authors to
> implement the same scheme as in sysklogd?

Or syslog-ng could have root permissions just for opening /proc/kmsg and then leave its rights when switching to normal user. But by saying that I make some assumptions on how /proc/kmsg works and how it must be used.

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bplant at westnet

Nov 16, 2005, 5:13 AM

Post #2 of 4 (546 views)
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Re: Re : Running app-admin/syslog-ng without rootprivileges [In reply to]

On Wed, 2005-11-16 at 12:54 +0100, varagnat [at] bertin wrote:
> > dedicated non-root account. May be we need to ask syslog-ng authors to
> > implement the same scheme as in sysklogd?
>
> Or syslog-ng could have root permissions just for opening /proc/kmsg and then leave its rights when switching to normal user. But by saying that I make some assumptions on how /proc/kmsg works and how it must be used.

I ran syslog-ng as a non-root user once before, but now I run it as
root. From what I can remember, syslog-ng opened /proc/kmsg before
dropping privileges, however when you sent the HUP signal (i.e. after
running logrotate) it closed all the files and reopened them again.
Because it no longer had root permissions, it couldn't
reopen /proc/kmsg.

If /proc/kmsg was group readable and the group was set to a special
logger group, then I don't see why syslog-ng couldn't be run as a
non-root user.

Cheers,

Brad

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Jerome.Poggi at hsc

Nov 17, 2005, 6:50 AM

Post #3 of 4 (545 views)
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Re: Running app-admin/syslog-ng without rootprivileges [In reply to]

On Wed, 16 Nov 2005, Brad Plant wrote:
> I ran syslog-ng as a non-root user once before, but now I run it as
> root. From what I can remember, syslog-ng opened /proc/kmsg before
> dropping privileges, however when you sent the HUP signal (i.e. after
> running logrotate) it closed all the files and reopened them again.
> Because it no longer had root permissions, it couldn't
> reopen /proc/kmsg.

Why did you rotate yourself your log ?
You better use MACRO like :

destination full {
file("/var/log/full/full_$YEAR.$MONTH.$DAY.log" log_fifo_size(1000) dir_perm(0755) create_dirs(yes));
file("/dev/tty12");
};
destination full_net {
file("/var/log/net/net_$HOST.$YEAR/$MONTH.$DAY.log" dir_perm(0755) create_dirs(yes));
};

Its better usable :-)

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Jerome POGGI Jerome.Poggi [at] hsc
Herve Schauer Consultants -=- Consultant Sécurité Informatique, CISSP
http://www.hsc.fr/ Tèl : +33 141 409 700

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miguel.filipe at gmail

Oct 9, 2006, 6:02 AM

Post #4 of 4 (548 views)
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Re: Re : Running app-admin/syslog-ng without rootprivileges [In reply to]

On 11/16/05, Brad Plant <bplant [at] westnet> wrote:
> On Wed, 2005-11-16 at 12:54 +0100, varagnat [at] bertin wrote:
> > > dedicated non-root account. May be we need to ask syslog-ng authors to
> > > implement the same scheme as in sysklogd?
> >
> > Or syslog-ng could have root permissions just for opening /proc/kmsg and then leave its rights when switching to normal user. But by saying that I make some assumptions on how /proc/kmsg works and how it must be used.
>
> I ran syslog-ng as a non-root user once before, but now I run it as
> root. From what I can remember, syslog-ng opened /proc/kmsg before
> dropping privileges, however when you sent the HUP signal (i.e. after
> running logrotate) it closed all the files and reopened them again.
> Because it no longer had root permissions, it couldn't
> reopen /proc/kmsg.

the workaround is to "lseek(0)" instead of closing and open
/proc/kmsg, but doing a lseek in a virtual file li /proc/kmsg is weird
and I don't know it's implications..
Other way, is to simply skip the reopen of /proc/kmsg.

>
> If /proc/kmsg was group readable and the group was set to a special
> logger group, then I don't see why syslog-ng couldn't be run as a
> non-root user.

that means patching the kernel...
I guess it's better to patch on userland, and leave the kernel to
kernel hackers...
Also, it's cleaner to make the app secure within itselft, instead of
relying on the OS to change the permission and group of /proc/kmsg..

>
> Cheers,
>
> Brad
>
> --
> gentoo-security [at] gentoo mailing list
>
>

Best regards,

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Miguel Sousa Filipe
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