:: Re: [DNG] Printing -- now a permiss…
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Autore: Hendrik Boom
Data:  
To: dng
Oggetto: Re: [DNG] Printing -- now a permissions problem
On Mon, Oct 19, 2015 at 05:28:04PM +0200, Didier Kryn wrote:
> Le 19/10/2015 16:38, Thaddeus Nielsen a écrit :
> >On Mon, 19 Oct 2015 16:05:37 +0200
> >Didier Kryn <kryn@???> wrote:
> >
> >>Le 19/10/2015 15:24, Hendrik Boom a écrit :
> >>>On Mon, Oct 05, 2015 at 05:13:40PM -0400, Hendrik Boom wrote:
> >>>>On Mon, Oct 05, 2015 at 09:47:02PM +0200, Riccardo Boninsegna wrote:
> >>>>>On Mon, Oct 5, 2015 at 9:12 PM, Hendrik Boom <hendrik@???> wrote:
> >>>>>>I installed lpr, and it did take a lot of cups off. Do I really need cups?
> >>>>>Nope, especially with a Brother that's very LPR-friendly!
> >>>>>As you found out, cups-bsd is just a port of LPR programs to CUPS.
> >>>>>
> >>>>>>But I still don't know how to specify my network printer.
> >>>>>I'm not familiar at all with LPR, but I know a printcap entry for the
> >>>>>printer is created (if it's currently connected via USB) by the
> >>>>>driver's postinst somewhere under /opt/Brother; according to the
> >>>>>printcap manpage, you'd have to edit the "lp" option -- the
> >>>>>description says "local printer device, or port@host for remote"!
> >>>>Presumeably that would be port 515 at whatever the IP number for the
> >>>>printer is. Will try that wen I'm home near the priniter again.
> >>>>
> >>>>And what's there in the way of termcap is a shell script
> >>>>/opt/brother/Printers/hl3170cdw/inf/setupPrintcapij that creates a
> >>>>termcap. I hope it will get executed at the right time. At bootup,
> >>>>perhaps?
> >>>>
> >>>>I'll see when I'm home again.
> >>>Hand-edited /etc/termcap:
> >>>root@notlookedfor:/home/hendrik# cat /etc/printcap
> >>>HL3170CDW:\
> >>>          :mx=0:\
> >>>          :sd=/var/spool/lpd/hl3170cdw:\
> >>>          :sh:\
> >>>          :lp=515@172.25.1.122:\
> >>>          :if=/opt/brother/Printers/hl3170cdw/lpd/filterhl3170cdw:
> >>>root@notlookedfor:/home/hendrik#

> >>>
> >>>Now I get
> >>>
> >>>hendrik@notlookedfor:~$ lpr -h -PHL3170CDW Documents/math/Librationism=1407.3877v3.ps
> >>>lpr: cannot open /var/spool/lpd/hl3170cdw/.seq: Permission denied
> >>>hendrik@notlookedfor:~$
> >>>
> >>>This happens even if I run as root:
> >>>
> >>>root@notlookedfor:/home/hendrik# lpr -h -PHL3170CDW Documents/math/Librationism=1407.3877v3.ps
> >>>lpr: cannot open /var/spool/lpd/hl3170cdw/.seq: Permission denied
> >>>root@notlookedfor:/home/hendrik#
> >>>
> >>>That directory is owned by the lp daemon:
> >>>
> >>>oot@notlookedfor:/home/hendrik# ls -al /var/spool/lpd/hl3170cdwtotal 8
> >>>drwx------ 2 daemon lp   4096 Oct  5 14:40 .
> >>>drwxr-xr-x 5 root   root 4096 Oct 19 09:02 ..
> >>>-rw------- 1 daemon lp      0 Oct  5 14:32 acct
> >>>-rw------- 1 daemon lp      0 Oct  5 14:32 log
> >>>-rw------- 1 daemon lp      0 Oct  5 14:32 status
> >>>-rw------- 1 daemon lp      0 Oct  5 14:32 status.pr
> >>>root@notlookedfor:/home/hendrik#

> >>>
> >>>and it contains no .seq file. Preumably that fle would be created as needed.
> >>>And presumably the permissions are checked in some way that can exclude root.
> >>>
> >>>
> >>      Hi Hendrik.

> >>
> >>      I can see one reason for root to be unable to get the permission:
> >>lpr being owned by another user than root and being suid; this is fine
> >>at the condidiont that this owner is 'daemon', given the owner and
> >>permissions of /var/spool/lpd.

> >>
> >>      Didier

> >>
> >Another thing to examine: lp is the group on the directory but that directory had no write permission for the group, if I recall correctly.
> >
> >    RPTN

> >
>
>     Since group has no permission and owner has all, only the owner
> should matter. But the group s bit, AFAIR is something which
> disallows overwriting a file owned by someone else. Maybe try to
> make daemon the owner of /usr/bin/lpr, just to see what happens

>
>     Didier

>
> _______________________________________________


Did that. It didn't help. I even did the lpr command as root. Might
root be excluded from printing for some reason? Might it try
writing to the directory as the user that invoked the lpr command
instead of as the suid'd user? Might I have to add
users, one by one, to group lp?

I added blank lines for readability:

root@notlookedfor:/home/hendrik# ls -l /usr/bin/lpr
-rwsr-sr-x 1 root lp 26536 Nov 20 2014 /usr/bin/lpr

root@notlookedfor:/home/hendrik# chown daemon /usr/bin/lpr

root@notlookedfor:/home/hendrik# ls -l /usr/bin/lpr
-rwxr-xr-x 1 daemon lp 26536 Nov 20 2014 /usr/bin/lpr

root@notlookedfor:/home/hendrik# /usr/bin/lpr -h -PHL3170CDW Documents/math/Librationism=1407.3877v3.ps
lpr: cannot open /var/spool/lpd/hl3170cdw/.seq: Permission denied

root@notlookedfor:/home/hendrik# ls -ald /var/spool/lpd/hl3170cdw
drwx------ 2 daemon lp 4096 Oct 5 14:40 /var/spool/lpd/hl3170cdw

oot@notlookedfor:/home/hendrik# ls -al /var/spool/lpd/hl3170cdw
total 8
drwx------ 2 daemon lp   4096 Oct  5 14:40 .
drwxr-xr-x 5 root   root 4096 Oct 19 09:02 ..
-rw------- 1 daemon lp      0 Oct  5 14:32 acct
-rw------- 1 daemon lp      0 Oct  5 14:32 log
-rw------- 1 daemon lp      0 Oct  5 14:32 status
-rw------- 1 daemon lp      0 Oct  5 14:32 status.pr
root@notlookedfor:/home/hendrik# 


-- hendrik