Bug 1449898

Summary:	OpenSSH doesn't ignore unknown SSH certificate extensions
Product:	Red Hat Enterprise Linux 6	Reporter:	Stanislav Grozev <tacho>
Component:	openssh	Assignee:	Jakub Jelen <jjelen>
Status:	CLOSED WONTFIX	QA Contact:	BaseOS QE Security Team <qe-baseos-security>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	6.10
Target Milestone:	rc
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Hardware:	All
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Last Closed:	2017-05-31 11:46:59 UTC	Type:	Bug
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Description Stanislav Grozev 2017-05-11 06:19:31 UTC

Description of problem:

Per the upstream OpenSSH documentation, unknown certificate extensions should just print a warning and continue. The version in RHEL7 erroneously treats them the same as critical extensions - any unknown one is treated as fatal. This is an OpenSSH bug, that was fixed in https://anongit.mindrot.org/openssh.git/commit/?id=ca42c1758575e592239de1d5755140e054b91a0d

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

Any RHEL6 version, even in the latest (openssh-5.3p1-122.el6)

How reproducible:

Steps to Reproduce:
1. Sign an SSH certificate containing a custom extension.
2. Try to log in with it.
3. See the sshd logs.

Actual results:

Login fails, due to a fatal error due to an unknown certificate extension.

Expected results:

Login succeeds, a warning about an unknown certificate extension is logged.

Additional info:

Same is present in RHEL7 (it was a bug introduced in the original OpenSSH code, that they have since fixed, see above). I have opened https://bugzilla.redhat.com/show_bug.cgi?id=1449897 against RHEL7 as well.

Comment 2 Stanislav Grozev 2017-05-11 06:37:58 UTC

Here's the original OpenSSH bug report - https://bugzilla.mindrot.org/show_bug.cgi?id=2387

Comment 3 Jakub Jelen 2017-05-11 07:21:42 UTC

    Thank you for taking the time to enter a bug report with us. We appreciate the feedback and look to use reports such as this to guide our efforts at improving our products. That being said, this bug tracking system is not a mechanism for requesting support, and we are not able to  guarantee the timeliness or suitability of a resolution.

     

    If this issue is critical or in any way time sensitive, please raise a ticket through your regular Red Hat support channels to make certain  it receives the proper attention and prioritization to assure a timely resolution. 

     

    For information on how to contact the Red Hat production support team, please visit:

    https://access.redhat.com/support/


Above that, RHEL6 is already in production phase 3, which means that only critical security issues are fixed.

    https://access.redhat.com/support/policy/updates/errata#Production_3_Phase