[CentOS] selinux prevents lighttpd from printing

[hw]

Daniel Walsh wrote:
> On 09/22/2017 06:58 AM, hw wrote:
>>
>> PS: Now I found this:
>>
>>
>> type=PROCTITLE msg=audit(09/22/2017 12:08:29.911:1023) : proctitle=/usr/lib/sendmail -t -oi -oem -fwawi-genimp
>> type=SYSCALL msg=audit(09/22/2017 12:08:29.911:1023) : arch=x86_64 syscall=setgroups success=no exit=EPERM(Operation not permitted) a0=0x1 a1=0x7ffc1df3b0d0 a2=0x0 a3=0x7f5d77c3a300 items=0 ppid=19417 pid=19418 auid=unset uid=lighttpd gid=lighttpd euid=root suid=root fsuid=root egid=lighttpd sgid=lighttpd fsgid=lighttpd tty=(none) ses=unset comm=sendmail exe=/usr/sbin/exim subj=system_u:system_r:httpd_sys_script_t:s0 key=(null)
>> type=AVC msg=audit(09/22/2017 12:08:29.911:1023) : avc:  denied  { setgid } for  pid=19418 comm=sendmail capability=setgid scontext=system_u:system_r:httpd_sys_script_t:s0 tcontext=system_u:system_r:httpd_sys_script_t:s0 tclass=capability
>>
>> type=SYSCALL msg=audit(09/15/2017 12:12:14.551:31746) : arch=x86_64 syscall=open success=yes exit=7 a0=0x7ffd1659ec70 a1=O_RDONLY a2=0x0 a3=0x9 items=0 ppid=27605 pid=27633 auid=unset uid=lighttpd gid=lighttpd euid=lighttpd suid=lighttpd fsuid=lighttpd egid=lighttpd sgid=lighttpd fsgid=lighttpd tty=(none) ses=unset comm=lpr exe=/usr/bin/lpr.cups subj=system_u:system_r:httpd_sys_script_t:s0 key=(null)
>> type=AVC msg=audit(09/15/2017 12:12:14.551:31746) : avc:  denied { open } for  pid=27633 comm=lpr path=/etc/cups/lpoptions dev="sdb2" ino=153957 scontext=system_u:system_r:httpd_sys_script_t:s0 tcontext=system_u:object_r:cupsd_rw_etc_t:s0 tclass=file
>> type=AVC msg=audit(09/15/2017 12:12:14.551:31746) : avc:  denied { read } for  pid=27633 comm=lpr name=lpoptions dev="sdb2" ino=153957 scontext=system_u:system_r:httpd_sys_script_t:s0 tcontext=system_u:object_r:cupsd_rw_etc_t:s0 tclass=file
>>
>>
>> So I can see that sending email and printing was denied -- which I already
>> found out --- and I don´t have any idea how to allow it.
>>
>>
>> hw wrote:
>>> Johnny Hughes wrote:
>>>> On 09/20/2017 07:19 AM, hw wrote:
>>>>> hw wrote:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> how do I allow CGI programs to print (using 'lpr -P some-printer
>>>>>> some-file.pdf') when
>>>>>> lighttpd is being used for a web server?
>>>>>>
>>>>>> When selinux is permissive, the printer prints; when it´s enforcing,
>>>>>> the printer
>>>>>> does not print, and I´m getting the log message '/bin/lpr: Permission
>>>>>> denied'.
>>>>>>
>>>>>> 'getsebool -a | grep http' doesn´t show any boolean I could make out
>>>>>> to be responsible
>>>>>> for this.
>>>>>>
>>>>>> Any idea what I need to do/change to allow printing without disabling
>>>>>> selinux?
>>>>>> _______________________________________________
>>>>>> CentOS mailing list
>>>>>> CentOS at centos.org
>>>>>> https://lists.centos.org/mailman/listinfo/centos
>>>>>
>>>>> Nobody knows?
>>>>
>>>>
>>>> Look in your audit logs while in permissive mode and you should see the
>>>> issue in there, the wiki has details:
>>>>
>>>> https://wiki.centos.org/HowTos/SELinux#head-798c98ef37cb8a00425a048152113b7a7dc14f1b
>>>
>>> Thanks!  I´m guessing I´m supposed to use ausearch to search for something, and
>>> I don´t know what to search for.
>>>
>>> So far, lighttpd can not print and can not send emails (using MIME::Lite) unless
>>> selinux is permissive.  Using
>>>
>>> 'ausearch -c "httpd" -m AVC,USER_AVC,SELINUX_ERR,USER_SELINUX_ERR -i'
>>>
>>> , I only get
>>>
>>>
>>> type=PROCTITLE msg=audit(09/21/2017 14:08:40.569:559) : proctitle=/usr/sbin/lighttpd -D -f /etc/lighttpd/lighttpd.conf
>>> type=SYSCALL msg=audit(09/21/2017 14:08:40.569:559) : arch=x86_64 syscall=open success=no exit=EACCES(Permission denied) a0=0x559fc8094740 a1=O_WRONLY|O_CREAT|O_EXCL|O_NOCTTY|O_TRUNC|O_CLOEXEC a2=0644 a3=0x7 items=0 ppid=1 pid=14081 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=unset comm=lighttpd exe=/usr/sbin/lighttpd subj=system_u:system_r:httpd_t:s0 key=(null)
>>> type=AVC msg=audit(09/21/2017 14:08:40.569:559) : avc:  denied { write } for  pid=14081 comm=lighttpd name=www dev="sda2" ino=64608 scontext=system_u:system_r:httpd_t:s0 tcontext=system_u:object_r:httpd_sys_content_t:s0 tclass=dir
>>>
>>>
>>> Any idea what I would need to search for, or how to figure out what I would
>>> need to allow?
>>> _______________________________________________
>>> CentOS mailing list
>>> CentOS at centos.org
>>> https://lists.centos.org/mailman/listinfo/centos
>>
>> _______________________________________________
>> CentOS mailing list
>> CentOS at centos.org
>> https://lists.centos.org/mailman/listinfo/centos
>
> First thing to enable httpd to send mail, you can turn on the send mail boolean.
>
> # setsebool -P httpd_can_sendmail 1

Oh I looked at these variables and somehow didn´t see it.

> The ability to print you would need to add custom rules.
>
> # grep lpr /var/log/audit/audit.log | audit2allow -R -M myprint
>
> # semodule -i myprint.pp
>
> If you get another failure on lpt, you might have to run these commands a couple of times.

Thank you very much!  Both problems are now fixed :)

However:

grep lpr /var/log/audit/audit.log | audit2allow -R -M myprint
could not open interface info [/var/lib/sepolgen/interface_info]


I don´t know what´s missing, so I omitted the -R option, and it worked.