Issue using docker cp on docker installed with snap

[Joachim Lasserre]

Hello, i recently needed to backup some keys off a docker container using docker cp, but i'm always getting permission denied no matter if i am root or not, seeing what people are saying, this is an issue caused by docker being installed with snap and not an issue of docker itself

i'm encountering the bug mentionned in this issue https://github.com/docker/for-linux/issues/564 and i saw that no one bothered to report the bug here, i'll mention that i am a complete linux AND docker newbie, but when i asked friends to help me with the issue, none of them could help me after a lot of tries, so i can only assume that it is a bug as mentionned on the github issue above.

TLDR: me using the docker cp command with a snap install of docker will result in an unsolvable permission denied output