[Qemu-devel] [Bug 925405] [NEW] VNC server does not work with Mac Screen Sharing

[Rui Carmo]

Public bug reported:

When connecting to a QEMU instance from a Mac using any VNC settings on
the QEMU CLI and any target arch (ARM, Intel, etc.), the connection is
attempted but the negotiation never finishes.

I've verified this when building QEMU from source (1.0 and HEAD) on
Ubuntu, Fedora and Debian or when using Ubuntu (Oneiric) and Debian
(Lenny) packages.

It does not matter whether I specify authentication (or anything else)
on QEMU's side, the behavior is always the same - I see the connection
being established using netstat and tcpdump, but QEMU does not seem to
send back any pixmap data after the connection setup.

Best guess as to why this happens is that the VNC negotiation on QEMU
does not like the protocol version and VNC encoding sent by the Mac's
built-in VNC client, or that its negotiation logic is subtly broken. I
appreciate that it's not meant to be a full VNC server, but it prevents
me from using it remotely until a stable Mac build is feasible.

Background info:

Mac OS X includes a VNC client called Screen Sharing that you can invoke
in two different ways:

* At a terminal, by typing "open vnc://hostname:tcp_port"
* From any URI-enabled field (such as the Safari URI field), where you can just 
type the URI as vnc://hostname:tcp_port

Please do not confuse the enhanced VNC protocol Apple Remote Desktop
uses with Screen Sharing - they are not mutually exclusive, but they are
not incompatible either, since what Apple does is to negotiate extra
pixmap encoding and authentication options - I use Screen Sharing to
access many VNC servers such as vnc4server, tightvncserver, vino, etc.
without any issues whatsoever, so the issue I'm reporting is not an
issue with Apple's implementation.

** Affects: qemu
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/925405

Title:
  VNC server does not work with Mac Screen Sharing

Status in QEMU:
  New

Bug description:
  When connecting to a QEMU instance from a Mac using any VNC settings
  on the QEMU CLI and any target arch (ARM, Intel, etc.), the connection
  is attempted but the negotiation never finishes.

  I've verified this when building QEMU from source (1.0 and HEAD) on
  Ubuntu, Fedora and Debian or when using Ubuntu (Oneiric) and Debian
  (Lenny) packages.

  It does not matter whether I specify authentication (or anything else)
  on QEMU's side, the behavior is always the same - I see the connection
  being established using netstat and tcpdump, but QEMU does not seem to
  send back any pixmap data after the connection setup.

  Best guess as to why this happens is that the VNC negotiation on QEMU
  does not like the protocol version and VNC encoding sent by the Mac's
  built-in VNC client, or that its negotiation logic is subtly broken. I
  appreciate that it's not meant to be a full VNC server, but it
  prevents me from using it remotely until a stable Mac build is
  feasible.

  Background info:

  Mac OS X includes a VNC client called Screen Sharing that you can
  invoke in two different ways:

  * At a terminal, by typing "open vnc://hostname:tcp_port"
  * From any URI-enabled field (such as the Safari URI field), where you can 
just type the URI as vnc://hostname:tcp_port

  Please do not confuse the enhanced VNC protocol Apple Remote Desktop
  uses with Screen Sharing - they are not mutually exclusive, but they
  are not incompatible either, since what Apple does is to negotiate
  extra pixmap encoding and authentication options - I use Screen
  Sharing to access many VNC servers such as vnc4server, tightvncserver,
  vino, etc. without any issues whatsoever, so the issue I'm reporting
  is not an issue with Apple's implementation.

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