Request to backport fix for endianness issue in TigerVNC vncviewer
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| Ubuntu on IBM z Systems |
Fix Released
|
Medium
|
Skipper Bug Screeners | ||
| tigervnc (Ubuntu) |
Fix Released
|
Medium
|
Skipper Bug Screeners | ||
| Hirsute |
Fix Released
|
Medium
|
Unassigned | ||
| Impish |
Fix Released
|
Medium
|
Skipper Bug Screeners | ||
Bug Description
SRU Justification:
==================
[Impact]
* TigerVNC 1.11.0 contains a (pixel order) regression that causes
vncviewer to display incorrect colors when vncviewer and X11 server
use different endianness
(e.g. when using X11 forwarding via SSH between an amd64 desktop
and a Linux on s390x).
* The regression was originally reported in github issue
https:/
and fixed in github pull request
https:/
* The issue got fixed by a respin of the
ARGB runtime XImage byteorder selection.
[Test Plan]
* Setup two systems with different endianness, ideally:
a (little endian) Ubuntu (Desktop) system (amd64) and
a (big endian) Ubuntu (Server) system (s390x)
* Install tigervnc-
and tigervnc-vieweron the amd64 system (incl. all dependencies).
* now start the server with: vncserver
* run the client: xtigervncviewer <server-IP>:1
* detailed instructions how to reproduce the bug
* The issue results in the display of wrong colors, 'similar' to:
https:/
* Another (regression) test will be using both,
tigervnc server and client, on amd64 only.
[Where problems could occur]
* An onerousness patch would maybe not solve the endian problem
and wrong colors (maybe different) still exist,
* or in worst case it may have an impact on system combinations
that use the same endianness.
* The latter one is very unlikely, since there is only line 126
that enters to code that handles the endianness.
* And the fix here is a respin of the original runtime ARGB
selection pull request, hence one that worked already before.
* And the changes are very limited and only cover 3 lines
of a single if/else statement in vncviewer/
[Other Info]
* The reported issue is a regression that got (upstream) introduced into 1.10.
* It is fixed be code that is known to work and that was tested on different
platforms.
* The patch is upstream accepted with v1.11.90 since Aug 28, 2020,
* hence it's highly like no longer needed once Debian/Ubuntu pick up
the next upstream version, since it's fixed with > 1.10.
* Patched tigervnc versions are available for impish and hirsute via the PPA:
https:/
* And the issue was in detail discussed upstream at:
https:/
https:/
__________
---Problem Description---
TigerVNC 1.11.0 contains a regression that causes vncviewer to display
incorrect colors when vncviewer and X11 server use different endianness (e.g.,
when using X11 forwarding via SSH between an x86-64 desktop and a Linux system
on s390x). The regression was originally reported in github issue
https:/
request https:/
The regression caused vncviewer to always use the system byte order for pixel
values instead of the byte order required by the X11 display. With the fix,
vncviewer queries the X11 display for the required byte order.
As of now, the fix has not made it into a release yet. Please consider
backporting the fix (upstream commit 7ab92639848). I confirmed that this commit
cleanly applies on top of release 1.11.0 and fixes the regression.
---uname output---
Linux s390x
Machine Type = x15
---Debugger---
A debugger is not configured
---Steps to Reproduce---
See also https:/
- From a Linux x86 system, connect to a Linux system on s390x via SSH with X forwarding
- Start a Xvnc session on that Linux system
tigervncserver :0 -geometry 800x600 -depth 32
- Start vncviewer on the same Linux system
xtigervncviewer :0
- On vncviewer's window on your origin X session, observe incorrect colors.
- Optionally, start X11 programs such as xlogo, xclock, or xeyes to make the problem obvious
- Optionally, connect to the vnc session directly (i.e., with a vnc client on the origin system) to compare
Userspace tool common name: vncviewer
The userspace tool has the following bit modes: 64-bit
Userspace rpm: tigervnc-viewer
Userspace tool obtained from project website: na
Related branches
- Christian Ehrhardt (community): Approve
-
Diff: 102 lines (+68/-1)4 files modifieddebian/changelog (+9/-0)
debian/control (+2/-1)
debian/patches/0001-Update-Surface_X11.cxx.patch (+55/-0)
debian/patches/series (+2/-0)
- Christian Ehrhardt (community): Approve
-
Diff: 101 lines (+67/-1)4 files modifieddebian/changelog (+9/-0)
debian/control (+2/-1)
debian/patches/0001-Update-Surface_X11.cxx.patch (+54/-0)
debian/patches/series (+2/-0)
| tags: | added: architecture-s39064 bugnameltc-192826 severity-medium targetmilestone-inin--- |
| Changed in ubuntu: | |
| assignee: | nobody → Skipper Bug Screeners (skipper-screen-team) |
| affects: | ubuntu → linux (Ubuntu) |
| Changed in ubuntu-z-systems: | |
| importance: | Undecided → Medium |
| Changed in ubuntu-z-systems: | |
| assignee: | nobody → Skipper Bug Screeners (skipper-screen-team) |
| affects: | linux (Ubuntu) → tigervnc (Ubuntu) |
| tags: | added: universe |
| Frank Heimes (fheimes) wrote | #1 |
| Ubuntu Foundations Team Bug Bot (crichton) wrote | #2 |
| tags: | added: patch |
| Frank Heimes (fheimes) wrote | #3 |
| Frank Heimes (fheimes) wrote | #4 |
| Changed in ubuntu-z-systems: | |
| status: | New → In Progress |
| Changed in tigervnc (Ubuntu): | |
| status: | New → In Progress |
| tags: | added: ubuntu-sponsors |
| description: | updated |
| Changed in tigervnc (Ubuntu Hirsute): | |
| status: | New → In Progress |
| description: | updated |
| description: | updated |
| Frank Heimes (fheimes) wrote | #5 |
| Frank Heimes (fheimes) wrote | #6 |
| Frank Heimes (fheimes) wrote | #7 |
| bugproxy (bugproxy) wrote tigervnc debdiff (impish) | #8 |
| bugproxy (bugproxy) wrote tigervnc debdiff (hirsute) | #9 |
| Changed in tigervnc (Ubuntu Hirsute): | |
| importance: | Undecided → Medium |
| Changed in tigervnc (Ubuntu Impish): | |
| importance: | Undecided → Medium |
| Christian Ehrhardt (paelzer) wrote | #10 |
| Frank Heimes (fheimes) wrote | #11 |
| Changed in tigervnc (Ubuntu Hirsute): | |
| status: | In Progress → Fix Committed |
| status: | Fix Committed → In Progress |
| Changed in tigervnc (Ubuntu Impish): | |
| status: | In Progress → Fix Committed |
| bugproxy (bugproxy) wrote Comment bridged from LTC Bugzilla | #12 |
| Launchpad Janitor (janitor) wrote | #13 |
| Changed in tigervnc (Ubuntu Impish): | |
| status: | Fix Committed → Fix Released |
| Robie Basak (racb) wrote Please test proposed package | #14 |
| Changed in tigervnc (Ubuntu Hirsute): | |
| status: | In Progress → Fix Committed |
| tags: | added: verification-needed verification-needed-hirsute |
| Robie Basak (racb) wrote | #15 |
| bugproxy (bugproxy) wrote Comment bridged from LTC Bugzilla | #16 |
| Frank Heimes (fheimes) wrote | #17 |
| tags: |
added: verification-done verification-done-hirsute removed: ubuntu-sponsors verification-needed verification-needed-hirsute |
| Changed in ubuntu-z-systems: | |
| status: | In Progress → Fix Committed |
| Launchpad Janitor (janitor) wrote | #18 |
| Changed in tigervnc (Ubuntu Hirsute): | |
| status: | Fix Committed → Fix Released |
| Brian Murray (brian-murray) wrote Update Released | #19 |
| Changed in ubuntu-z-systems: | |
| status: | Fix Committed → Fix Released |
| bugproxy (bugproxy) wrote Comment bridged from LTC Bugzilla | #20 |
| tags: |
added: targetmilestone-inin2104 removed: targetmilestone-inin--- |
| Frank Heimes (fheimes) wrote | #21 |
tigervnc debdiff (impish)