Comment 0 for bug 2067610

[ Impact ]

When creating QR Code images for long(er) URIs we may end up creating qr codes whose size isn't matching the expected one and this may lead to a wrongly generated texture (and potential memory access errors).

An example: https://i.imgur.com/x3P4dzQ.png

[ Test case ]

In order to test this from GNOME shell, many components have to be set up that are harder to check so this can be easily simulated using a simple test program that replicates what the shell does to generate the image: https://www.pastery.net/uyzeca/

1. Download and run the test script:
   $ wget -O /tmp/shell-qrcode-tester.py https://www.pastery.net/uyzeca/raw
2. Run it with:
   $ python3 /tmp/shell-qrcode-tester.py
3. The qrcode should open in a new window and display correctly as
   https://imgur.com/dddTL6u.png (pointing to https://bugs.launchpad.net/ubuntu/+source/gnome-shell)

[ Regression potential ]

QrCodes are used only during web authentication that is not something that is generally exposed to users, but this may potentially lead to wrong or missing qr codes textures.