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  • Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ]
From: Justin R. Smith <jsmith_at_mcs.drexel.edu>
subject: Some questions
Date: 05 Oct 2001 08:50:53 -0400
  • This message: [ Message body ]
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  • Reply: Stephen Smalley: "Re: Some questions"


I've installed the latest version of SELinux in permissive mode.

  1. I've noticed no unusual messages in dmesg or /var/log/messages. Does this mean that my normal activities do not violate any of the new access restrictions? (So enabling secure mode would not disrupt any of the things I normally do)?
  2. If I toggle fully secure mode, can I reverse this remotely (i.e., ssh to the host, su, and execute the toggle command again)?
  3. SSH no longer recognizes my authorized keys --- I must always enter a password to use it. I've regenerated the keys several times (putting the appropriate public keys in 'authorized_keys') without success. I know the sshd on my system was replaced by another. Does it function differently?

Here's a log from the debug mode for ssh (on my home computer, I use the latest version of ssh and a DSA key):

debug1: authentications that can continue:

publickey,password,keyboard-interactive
debug3: start over, passed a different list
publickey,password,keyboard-interactive
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: next auth method to try is publickey
debug2: userauth_pubkey_agent: no keys at all
debug2: userauth_pubkey_agent: no more keys
debug2: userauth_pubkey_agent: no message sent
debug1: try privkey: /home/jsmith/.ssh/identity
debug3: no such identity: /home/jsmith/.ssh/identity
debug1: try privkey: /home/jsmith/.ssh/id_rsa
debug3: no such identity: /home/jsmith/.ssh/id_rsa
debug1: try pubkey: /home/jsmith/.ssh/id_dsa
debug3: send_pubkey_test

debug2: we sent a publickey packet, wait for reply debug1: authentications that can continue: publickey,password,keyboard-interactive
debug2: userauth_pubkey_agent: no more keys

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From: Stephen Smalley <sds_at_tislabs.com>
subject: Re: Some questions
Date: Fri, 5 Oct 2001 09:57:04 -0400 (EDT)
  • This message: [ Message body ]
  • Next message: Russell Coker: "Re: Compiling for SuSE 7.2"
  • Previous message: Stephen Smalley: "Re: Compiling for SuSE 7.2"
  • In reply to: Justin R. Smith: "Some questions"
  • Next in thread: Paul Krumviede: "Re: Some questions"
  • Reply: Paul Krumviede: "Re: Some questions"

On 5 Oct 2001, Justin R. Smith wrote:

> I've installed the latest version of SELinux in permissive mode.
>
> 1. I've noticed no unusual messages in dmesg or /var/log/messages. Does
> this mean that my normal activities do not violate any of the new access
> restrictions? (So enabling secure mode would not disrupt any of the
> things I normally do)?

Possibly. Please check the 'ps -e --context' output and verify that each system process is running in the correct security context. Also, please verify that your security context is set properly when you login (run 'id' or 'ps --context'). And make sure that you aren't running a X Display Manager, as I mentioned in my prior email to James Bishop.

> 2. If I toggle fully secure mode, can I reverse this remotely (i.e., ssh
> to the host, su, and execute the toggle command again)?

You don't need to 'su' - you need to run 'newrole -r sysadm_r'. SELinux doesn't care whether you are root. It cares about your role and domain. Yes, this should work remotely (unless you change the policy to prohibit it). You can test it while still in permissive mode - simply try it and check /var/log/messages and the output of dmesg for any messages.

> 3. SSH no longer recognizes my authorized keys --- I must always enter a
> password to use it. I've regenerated the keys several times (putting the
> appropriate public keys in 'authorized_keys') without success. I know
> the sshd on my system was replaced by another. Does it function
> differently?

The utils Makefile only installs the modified sshd, not the rest of the package, since we only modified sshd. So if you were using a different version of OpenSSH, you might have a compatibility problem. The openssh package provided with SELinux is the default one provided with RedHat 7.1 with the SELinux modifications. If you are using a newer version of OpenSSH, then I would suggest porting the SELinux patch forward to the newer version (and please feed the resulting patch back to us). If you are using an older version of OpenSSH, then I would suggest doing a 'make install' in the openssh-2.5.2p2-5 directory and then doing a 'make relabel' in the utils directory.

--
Stephen D. Smalley, NAI Labs
ssmalley@nai.com




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From: Paul Krumviede <pwk_at_acm.org>
subject: Re: Some questions
Date: Fri, 05 Oct 2001 09:36:51 -0700
  • This message: [ Message body ]
  • Next message: Conan Callen: "RE: debugging tools"
  • Previous message: Stephen Smalley: "Re: Compiling for SuSE 7.2"
  • In reply to: Stephen Smalley: "Re: Some questions"


trimmed to ssh only...

--On Friday, 05 October, 2001 09:57 -0400 Stephen Smalley <sds@tislabs.com> wrote:

>
> On 5 Oct 2001, Justin R. Smith wrote:
>
>> 3. SSH no longer recognizes my authorized keys --- I must always enter a
>> password to use it. I've regenerated the keys several times (putting the
>> appropriate public keys in 'authorized_keys') without success. I know
>> the sshd on my system was replaced by another. Does it function
>> differently?
>
> The utils Makefile only installs the modified sshd, not the rest of the
> package, since we only modified sshd. So if you were using a different
> version of OpenSSH, you might have a compatibility problem. The openssh
> package provided with SELinux is the default one provided with RedHat 7.1
> with the SELinux modifications. If you are using a newer version of
> OpenSSH, then I would suggest porting the SELinux patch forward to the
> newer version (and please feed the resulting patch back to us). If you
> are using an older version of OpenSSH, then I would suggest doing a 'make
> install' in the openssh-2.5.2p2-5 directory and then doing a 'make
> relabel' in the utils directory.

i've had to force use of the version 2 protocol to make this work, either via the command line option to ssh or by changing the sshd_config file to only use protocol version 2. doing what is suggested above was not sufficient for me - i was trying to make this work separately some time ago (and i think i've had to do this on a base redhat 7.0 system, if i recall the circumstances correctly). i don't know if it matters or not, but this was when i had a DSA key present; i haven't tried it with only RSA keys.

-paul

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