Bug 1870201

Summary: xauth (called from x2go) crashes when homedir contains directory named liked hostname
Product: [Fedora] Fedora Reporter: Wilfried Philips <Wilfried.Philips>
Component: xorg-x11-xauthAssignee: X/OpenGL Maintenance List <xgl-maint>
Status: CLOSED EOL QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 31CC: airlied, ajax, caillon+fedoraproject, jglisse, john.j5live, rhughes, rstrode, tilmann, xgl-maint
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Last Closed: 2020-11-24 20:27:56 UTC Type: Bug
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Description Wilfried Philips 2020-08-19 14:10:14 UTC
Description of problem:

x2go allows creating and displaying a terminal on a remote system. It uses
ssh and xauth to set up an x connection. This fails when the user's homedir
on the remote system contains a directory named like the hostname.

For example: remote host is "myhost.mynet"
homedir of remote user contains subdir myhost
=> xauth crashes (not sure how it is actually invoked):

dmesg -T reports 
xauth[14378]: segfault at 1 ip 00007f5aabbc6365 sp 00007ffc61339498 error 4 in libc-2.30.so[7f5aabb46000+14f000]
[Wed Aug 19 15:57:40 2020] Code: bc d1 f3 0f 7f 27 f3 0f 7f 6f 10 f3 0f 7f 77 20 f3 0f 7f 7f 30 49 83 c0 0f 49 29 d0 48 8d 7c 17 31 e9 9f 0b 00 00 66 0f ef c0 <f3> 0f 6f 0e f3 0f 6f 56 10 66 0f 74 c1 66 0f d7 d0 49 83 f8 11 0f

Also two lock files are left: .Xauthority-l and .Xauthority-c
making any future xauth call timeout.

Version-Release number of selected component (if applicable):
rpm -q -f /usr/bin/xauth

rpm -q -a|grep x2go

How reproducible:

Steps to Reproduce:
1. test that x2go actually works on 
2. stop x2go session and on the remote system mkdir ~/remotehost
3. try the test in 1 again. x2go reports a problem

Error: Aborting session with 'Unable to open display 'nx/nx,options=/tmp/.x2go-xxx/C-xxx-50-1597844645_stRterminator_dp24/options:50''.
Session: Aborting session at 'Wed Aug 19 15:44:21 2020'.
Session: Session aborted at 'Wed Aug 19 15:44:21 2020'.
Loop: WARNING! Signals were not blocked in process with pid '105256'.
Warning: Signals were not blocked in process with pid '105256'.
Info: Your session has died before reaching an usable state.
Info: This can be due to the remote X server refusing access to the client.
Info: Please check the authorization provided by your X application.
Info: Waiting the cleanup timeout to complete.

Lock files remain: .Xauthority-c .Xauthority-l

Actual results:
x2go not working; xauth stops working until lock files are removed

Expected results:
No weird behaviour.

Additional info:

After removing the empty directory and the lock files all works fine again.

Comment 1 Dr. Tilmann Bubeck 2020-08-20 12:35:23 UTC
Thanks for the detailed bug description. I was able to reproduce the bug and I will now start investigating the root cause.

Comment 2 Dr. Tilmann Bubeck 2020-08-20 17:48:41 UTC
Fixed. Please take a look at https://koji.fedoraproject.org/koji/taskinfo?taskID=49730330 and let me know, if its works.
The patch will be sent upstream, as this is a bug in xauth.

Comment 3 Wilfried Philips 2020-08-20 18:35:30 UTC
I installed the new rpm and tested. Problem is now solved.

Thanks for the quick response.

Comment 5 Ben Cotton 2020-11-03 16:44:43 UTC
This message is a reminder that Fedora 31 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora 31 on 2020-11-24.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
Fedora 'version' of '31'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 31 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

Comment 6 Ben Cotton 2020-11-24 20:27:56 UTC
Fedora 31 changed to end-of-life (EOL) status on 2020-11-24. Fedora 31 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen this bug against that version. If you
are unable to reopen this bug, please file a new report against the
current release. If you experience problems, please add a comment to this

Thank you for reporting this bug and we are sorry it could not be fixed.