Bug 531849

Summary: gssapi patch from 4.3p2 (patch49) causes gssapi failures when host is accessed via pipe proxy
Product: [Fedora] Fedora Reporter: Richard Monk <rmonk>
Component: opensshAssignee: Jan F. Chadima <jchadima>
Status: CLOSED CURRENTRELEASE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: low    
Version: 12CC: dash, jchadima, mgrepl, tmraz
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OS: Linux   
Fixed In Version: Doc Type: Bug Fix
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: 627139 (view as bug list) Environment:
Last Closed: 2010-11-04 07:36:07 EDT Type: ---
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Description Flags
Patch to revert to old gssapi hostname behaviour if get_canonical_hostname fails none

Description Richard Monk 2009-10-29 12:45:21 EDT
Created attachment 366662 [details]
Patch to revert to old gssapi hostname behaviour if get_canonical_hostname fails

Description of problem:
The patch openssh-4.3p2-gssapi-canohost.patch , named patch49 in the spec file, fixes an instance where the DNS name changes such as a DNS round robin.  The problem is that if for any reason get_canonical_hostname returns "UNKNOWN", such as the case where the connection is not a socket connection but a pipe (ProxyConnect nc ... ) then gssapi will always fail.

This patch replaces the older patch so that it reverts to the old pre-patch behavior if get_canonical_hostname fails.  The older behavior uses the hostname provided by the user.

Steven (smilner@redhat.com) mentioned also that using the string "UNKNOWN" as a failure might cause problems with the corner case of a host named "unknown".  Possibly a better failure return for get_canonical_hostname would help there (a null string?)

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

How reproducible:
Attempt to use GSSAPI auth through a pipe proxy

Steps to Reproduce:
1. ssh -D 9999 my.bastion.host -N -f
2. ssh -oProxyCommand="/usr/bin/nc -X 5 -x localhost:9999 %h %p" my.host.with.gssapi
Actual results:
GSSAPI tries to canonicalize "UNKNOWN" via DNS queries and fails.

Expected results:
GSSAPI auth works correctly and allows access.
Comment 1 Jan F. Chadima 2009-11-02 08:37:07 EST
Patch applied in f13 and f12 also.
Comment 2 Bug Zapper 2009-11-16 09:36:30 EST
This bug appears to have been reported against 'rawhide' during the Fedora 12 development cycle.
Changing version to '12'.

More information and reason for this action is here:
Comment 3 Bug Zapper 2010-11-04 03:01:41 EDT
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Comment 4 Richard Monk 2010-11-04 07:36:07 EDT
I believe this patch was accepted awhile ago, I see it in the current F14 openssh RPM.