Fwd: Proprietary telnet daemon fails login when SELinux is enabled

Maurizio D'Antonio maurizio.dantonio at gmail.com
Thu Jul 26 18:21:06 UTC 2012


Hi, Dave
If I understand your problem you need add this port 52000 in the
ports.local file for inherit the correct selinux context.

The command is:

root at localhost # semanage port -a -t telnetd_port_t -p tcp 52000

and probably you need enable the appropriate boolean because you have
a denied { entrypoint } for qmail_t domain.

Try


>>> Maurizio D'Antonio
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> 2012/7/26 Dave Stoner <dave.stoner at northgate-is.com>:
> I apologise in advance for asking questions which I feel I should have been
> able to answer from sources on the internet. If you could possibly give me
> some pointers on where to look it would be so much appreciated.
>
>
>
> My system is centos 6.2 –
>
> Linux MyHostName 2.6.32-220.el6.x86_64 #1 SMP Tue Dec 6 19:48:22
>
> GMT 2011 x86_64 x86_64 x86_64 GNU/Linux
>
>
>
> SELinux mode is set ‘enforced’.
>
>
>
> I have a proprietary telnet daemon which upon a telnet to port 52000, is
> started OK when SELinux is disabled. But when it is enabled the same telnet
> results in /var/log/audit/audit.log showing:
>
>
>
> type=USER_LOGIN msg=audit(1343048458.345:69): user pid=2536 uid=0 auid=799
> ses=7 subj=system_u:system_r:inetd_t:s0-s0:c0.c1023 msg='op=login id=799
> exe="/bin/login" hostname=0.0.0.0 addr=0.0.0.0 termi
>
> nal=pts/2 res=success'
>
>
>
> A normal telnet gives a message similar to above, my telnet adds the
> following:
>
>
>
> type=AVC msg=audit(1343048458.353:70): avc:  denied  { entrypoint } for
> pid=2543 comm="login" path="/bin/bash" dev=sda2 ino=135083
> scontext=unconfined_u:system_r:qmail_tcp_env_t:s0-s0:c0.c1023 tconte
>
> xt=system_u:object_r:shell_exec_t:s0 tclass=file
>
>
>
> I believe I can create a policy to overcome this using audit2allow, i.e. it
> comes up with:
>
>
>
> module mypola 1.0;
>
>
>
> require {
>
>         type qmail_tcp_env_t;
>
>         type shell_exec_t;
>
>         class file entrypoint;
>
> }
>
>
>
> #============= qmail_tcp_env_t ==============
>
> allow qmail_tcp_env_t shell_exec_t:file entrypoint;
>
>
>
> But it seems to me what I ought to be doing is somehow to get my daemon to
> run with a domain of ‘remote_logon_t’ as is used by the standard telnet
> daemon, as here:
>
>
>
> type=USER_LOGIN msg=audit(1343058924.928:212): user pid=3759 uid=0 auid=799
> ses=29 subj=system_u:system_r:remote_login_t:s0-s0:c0.c1023 msg='op=login
> id=799 exe="/bin/login" hostname=localhost addr=::
>
> 1 terminal=pts/2 res=success'
>
>
>
> This is unfamiliar territory and any hints or pointers would really be
> appreciated.
>
>
>
> Dave.
>
>
>
>
>
> Dave Stoner
>
> Principal Systems Architect
> Northgate Reality
>
> Direct:    +44 (0)1442 272071 - VPN: 872 2071
>
> www.northgate-is.com/reality
>
>
>
>
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