GnuPG can see a card under root user, but not under normal user

Question

When under an unprivileged user:

$ gpg --card-status
gpg: selecting openpgp failed: No such device
gpg: OpenPGP card not available: No such device

With sudo or under a root user:

$ sudo gpg --card-status
Reader ...........: ...

Problem similar to that circa 2011.

Answer 1

When comparing with a different card reader it is immediately obvious a permission problem.

$ getfacl /dev/bus/usb/003/021
getfacl: Removing leading '/' from absolute path names
# file: dev/bus/usb/003/021
# owner: root
# group: root
user::rw-
user:sanmai:rw-
group::rw-
mask::rw-
other::r--

Where for the problematic card reader there's no extra user permission:

$ getfacl /dev/bus/usb/003/020
getfacl: Removing leading '/' from absolute path names
# file: dev/bus/usb/003/020
# owner: root
# group: root
user::rw-
group::rw-
other::r--

Under Debian-based these extra permissions are set by udev rules:

cat /lib/udev/rules.d/60-scdaemon.rules

These rules can be extended by adding a line to, say, /etc/udev/rules.d/60-scdaemon-local.rules with vendor and product IDs of the problematic reader:

SUBSYSTEM=="usb", ATTR{idVendor}=="xxxx", ATTR{idProduct}=="yyyy", ENV{ID_SMARTCARD_READER}="1", ENV{ID_SMARTCARD_READER_DRIVER}="gnupg"

Then reloading the rules:

udevadm control --reload-rules