Comment 57 for bug 1967632

The snap on stable/pkcs has been built with (what I gather are) the essential components — opensc-pkcs11, libpcsclite, and also a couple of debugging utilities — for the most basic and supported smart cards. You may want to test it, if so keep reading.

You would also need pcscd installed and started in your system.

There is a merge request[1] currently under review to allow the snap to use the pcscd socket; Until it's merged you'd need to manually allow access to the socket in /var/lib/snapd/apparmor/profiles/snap.chromium.chromium.

So if your smart card is supported by OpenSC[2], the full recipe is

--->
snap install --channel stable/pkcs chromium
apt install pcscd
systemctl start pcscd.socket
editor /var/lib/snapd/apparmor/profiles/snap.chromium.chromium
#Insert "/{var/,}run/pcscd/pcscd.comm rwm," before the last bracket.
apparmor_parser -r
chromium --enable-logging=stderr &> chr.log
<---

Attach chr.log or the system's journal if you see any relevant error or denial there.

Bear in mind that I was oblivious to the components involved until I started looking at this bug and I still don't have a complete picture of them. So please point out any mistake or omission you can find.

[1] https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1843392/comments/9
[2] https://github.com/snapcore/snapd/pull/12847