Note: This is a beta release of Red Hat Bugzilla 5.0. The data contained within is a snapshot of the live data so any changes you make will not be reflected in the production Bugzilla. Also email is disabled so feel free to test any aspect of the site that you want. File any problems you find or give feedback here.
Bug 589092 - SSH originating host check fails if specified symbolically and no PTR record
Summary: SSH originating host check fails if specified symbolically and no PTR record
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: openssh
Version: 5.4
Hardware: All
OS: Linux
low
medium
Target Milestone: rc
: ---
Assignee: Jan F. Chadima
QA Contact: BaseOS QE Security Team
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2010-05-05 11:31 UTC by David Tonhofer
Modified: 2010-05-12 06:41 UTC (History)
0 users

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2010-05-12 05:28:32 UTC
Target Upstream Version:


Attachments (Terms of Use)

Description David Tonhofer 2010-05-05 11:31:00 UTC
Description of problem:

In $USER/.ssh/authorized_keys, a login for $USER is permitted with an originating host check:

-----------
no-pty,permitopen="127.0.0.1:3306",from="kyoko.m-plify.net" ssh-rsa AAAAB....
-----------

A login from a remote machine fails however. The sshd log says:

"Authentication tried for $USER with correct key but not from a permitted host (host=85.93.216.17, ip=85.93.216.17).

There might be a problem with the IP address comparison function?

Replacing the symbolic hostname with the IP address makes things work:

-----------
no-pty,permitopen="127.0.0.1:3306",from="85.93.216.17" ssh-rsa AAAAB
-----------

A login from a remote machine succeeds. The sshd log says:

"Accepted publickey for $USER from 85.93.216.17 port 59015 ssh2"

However, login from other machines specified using the symbolic name _do_ succeed.

kyoko.m-plify.net has no PTR record yet though. So I suppose that is the problem.

In which case, the logline is misleading and should read "no PTR record available for verification"...

openssh-server-4.3p2-36.el5_4.3






Version-Release number of selected component (if applicable):


How reproducible:

Comment 1 Jan F. Chadima 2010-05-12 05:28:32 UTC
There is an intentional test of the reverse lookup.

Comment 2 David Tonhofer 2010-05-12 06:41:10 UTC
Hi,

Makes sense. Still, in that case the error message in the log should be clearer. 

"but not from a permitted host (host=85.93.216.17, ip=85.93.216.17)."

does not make much sense, "no PTR record available for verification" would be clearer.

Best regards,


Note You need to log in before you can comment on or make changes to this bug.