distributing a linux server for commercial use

Question

Let say you were to develop an embedded device powered by Debian, Ubuntu, etc. The device is plug an play. There is no need for the customer to SSH into your device and make modifications. However, does the GPL license require me to give the customer full access to the Linux system in case s/he wanted to install security updates, add/remove packages etc.

Another example, let's say I buy a Roku box for my TV. Am I entitled to get Linux access to the Roku box so that I can maintain and run security updates?

Answer 1

Am I entitled to get Linux access to the Roku box so that I can maintain and run security updates?

No. This is Tivoization and is considered by some (not including Linus) that it is a "bug" in the GPL v2 which is fixed in GPL v3.

Answer 2

However, does the GPL license require me to give the customer full access to the Linux system in case s/he wanted to install security updates, add/remove packages etc

That depends on the version of the GPL license involved.

If you use only software under the GPLv2 license (and the Linux kernel is GPLv2), then you are not required to give your customers the means to perform software updates by their own with unofficial software.

If you use software under the GPLv3 license, then the license requires that you also give your customers the means (in the form of signing keys, etc.) to perform updates with their own versions of that software.