Whonix 18 - Wayland based - VirtualBox - Clipboard Sharing - Broken

Patrick · September 28, 2025, 11:34am

For users:

related user documentation:
VirtualBox, Shared Folder

For developers:

VirtualBox bug report:

github.com/VirtualBox/virtualbox

Clipboard sharing with wayland guest not working

opened 07:01AM - 09 Jun 25 UTC

sledgehammer999

Host: Windows 10 Guest: EndeavourOS (Arch based) with Plasma 6 Virtualbox versio…n: 7.1.10 Guest additions version: 7.1.10 ### Problem description Pasting from host to guest (wayland) -> works Pasting from guest (x11) to host -> works Pasting from guest (wayland) to host -> doesn't work ### Pinpointing the problem I did some debugging and the problem is that this check is always false: https://github.com/VirtualBox/virtualbox/blob/ecf221fc944207a749ec5c1e3fb3071e175c54ef/src/VBox/Additions/x11/VBoxClient/wayland-helper-dcp.cpp#L831 Small description of the codeflow: 1. `vbcl_wayland_hlp_dcp_gh_clip_report_cb()` waits on `g_DcpCtx.Session.clip.uFmt` and, if successful, it sets `Session.clip.pvClipboardBuf` and `Session.clip.cbClipboardBuf` (via a call to `vbcl_wayland_hlp_dcp_receive_offer()`) 2. `vbcl_wayland_hlp_dcp_gh_clip_read_join_cb()` sets `g_DcpCtx.Session.clip.uFmt` and waits on `Session.clip.pvClipboardBuf` and `Session.clip.cbClipboardBuf` 3. `vbcl_wayland_hlp_dcp_gh_clip_read_join_cb()` is called after `vbcl_wayland_hlp_dcp_gh_clip_report_cb()` This is a cyclic dependency that results in all those values being empty (defaulted) when read. I think there is a logic problem here. `vbcl_wayland_hlp_dcp_gh_clip_report_cb()` does 2 actions that are meant to be distinct. It both reports to the host that clipboard data is available AND copies the clipboard data to internal buffers. The latter fails because it doesn't know which format the host expects at this point. The data should be copied only after the host requests them.

Patrick · October 2, 2025, 2:02am

For developers:

wl-clipboard won’t work as a workaround either.

clipboard is not synced with Wayland or Xwayland so wl-clipboard cannot be used to circumvent the issue.

chadsec · October 3, 2025, 12:54pm

Hey Patrick, bit off topic, but why are you posting this? Will Whonix 18 get ported to Wayland? How ? XFCE doesn’t support wayland afaik…

Have you decided on a DE change?, or will it be a WM ? If latter, I highly recommend checking out Sway.

Patrick · October 3, 2025, 2:15pm

Thanks to your question, a update has been posted here just now:

chadsec · October 3, 2025, 3:00pm

Awesome, switching to Wayland is definitely the right call!

But I think it could’ve been improved further by switching to something like SwayWM.