Bug#975039: Evolution 3.38.1-2 fails to render emails: WebKitWebProcess crashed. Sandbox

[Kai Juse]

Hi,

I have the same issue with evolution update (3.38.1-2) over (3.36.4-2) on 
2020-12-05.

When opening any email message in a seperate window the window opens with 
title menu but without mail header and body content.

Instead: "A WebKitWebProcess crashed when displaying the message. You can 
try again by moving to another message and back. If the issue persists, 
please file a bug report in GNOME Gitlab.".

As mentioned in earlier message, "new email" and "forward" also don't 
work due to no window opening at all in that case.


The issue appears to be related to sandboxing; it diappears disappears 
with running evolution this way:
$ WEBKIT_FORCE_SANDBOX=0 evolution

I am running evolution though an X11 ssh forward and see messages like 
these in the terminal every time I open an email:

Unable to init server: Could not connect: Connection refused
(WebKitWebProcess:3): Gtk-WARNING **: 13:43:24.795: cannot open display: 
:10.0

However, the message also appears at evolution startup and drawing the 
main window without causing apparent problems. I have seen the error 
message before also the upgrade and the problem, but am unsure of the 
exact times they were shown.

Using strace, I find the WebKitWebProcess child process indeed unable to 
connect to localhost:6010 (as well as expected domain sockets)

(Also:
bwrap: No permissions to creating new namespace, likely because the kernel 
does not allow non-privileged user namespaces. On e.g. debian this can be 
enabled with 'sysctl kernel.unprivileged_userns_clone=1'.
)

Best Regards,
Kai