Selinux: SSH broken after F-13 --> F-14 upgrade

Daniel J Walsh dwalsh at redhat.com
Wed Oct 13 14:14:15 UTC 2010


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On 10/12/2010 05:51 PM, yersinia wrote:
> On Tue, Oct 12, 2010 at 8:02 PM, Daniel J Walsh <dwalsh at redhat.com> wrote:
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>> On 10/12/2010 01:49 PM, Michal Hlavinka wrote:
>>> Hi all,
>>>
>>> I've recently upgraded my system, but after that I was not able to connect through ssh. More things are wrong (from my POV):
>>> 1)SELinux blocks all nondefault ports for ssh
>>>
>>> I have ssh confugured to use different port than 22 for security reasons and I think there is a lot of people doing that.
>>>
>> You need to tell SELinux which port to use for sshd.
>>
>> semanage port -a -t sshd_port_t -p tcp 6520
>>
>>> Question: Is it worth blocking all ports for ssh?
>>>
>>> 2)SELinux did not show any sealert warning about this. Running sealert -b shows no problem. There is one message in /var/log/messages:
>>> kernel: [90346.301108] type=1400 audit(1286901219.350:29): avc:  denied  { name_bind } for  pid=6830 comm="sshd" src=6520 scontext=unconfined_u:system_r:sshd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:port_t:s0 tclass=tcp_socket
>>>
>>> Question: This should be reported afaik, so it's a bug, right?
>>>
>> No.  Hacker gets some control over ssh and is able to make it bind to
>> port 80, now he can read apache content.
> Hmmm, it is  enough that sshd bind to port 80 to access the files of
> apache? it seems strange. am i missing something in the TE rule?
No but it could interecept traffic intended for the apache server on the
machine. The problem here is the ability to impersonate other apps.
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