bwrap: setting up uid map: Permission denied (with Apparmor)

[Franck]

After upgrading from Ubuntu 20.04 to 20.10, evolution is unable to display my mails.

Launching from a shell, I get this error message: "bwrap: setting up uid map: Permission denied"

Also, double clicking on a mail shows: "Something has gone wrong when displaying the message
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."

I found this Archlinux thread https://bbs.archlinux.org/viewtopic.php?id=259928 regarding the problem. A workaround is proposed, that consists in exporting WEBKIT_FORCE_SANDBOX=0 before running Evolution. This works.

Notice I have Apparmor enforced. Disableing Apparomor for usr.bin.evolution also works around the problem.

Both are not required, either one is sufficient. I guess a modification in apparmor profile is necessary, but I'm not sure I can figure out out to do that...

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: evolution 3.38.1-1
ProcVersionSignature: Ubuntu 5.8.0-25.26-generic 5.8.14
Uname: Linux 5.8.0-25-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu50
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: GNOME
Date: Mon Oct 26 16:47:39 2020
EcryptfsInUse: Yes
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=fr_FR.UTF-8
 SHELL=/bin/bash
SourcePackage: evolution
UpgradeStatus: Upgraded to groovy on 2020-10-26 (0 days ago)

[Franck (alci)]

Also notice that setting apparmor in complain mode for usr.bin.evolution is not enough to get it working. You have to disable the profile...