Make the master.key readable only by the owner

[jlduran]

This change may only apply to POSIX-compliant systems.

Previously:

$ ls -l config/master.key
-rw-r--r--   1 owner  group      32 Jan 1 00:00 master.key

Now:

$ ls -l config/master.key
-rw-------   1 owner  group      32 Jan 1 00:00 master.key

Fixes #32604.

[rails-bot]

Thanks for the pull request, and welcome! The Rails team is excited to review your changes, and you should hear from @schneems (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

This repository is being automatically checked for code quality issues using Code Climate. You can see results for this analysis in the PR status below. Newly introduced issues should be fixed before a Pull Request is considered ready to review.

Please see the contribution instructions for more information.

[pixeltrix]

@jlduran thanks for the PR - does the chmod command silently fail on Windows or does it raise an error? if the latter we need a check before running the command. Also a test added to app_generator_test.rb would be good too. 👍

[jlduran]

@pixeltrix

does the chmod command silently fail on Windows or does it raise an error?

According to this SO answer, chmod is a noop on Windows. I do not have a machine to test it at the moment.

Also a test added to app_generator_test.rb would be good too.

What is the recommended way to skip testing on Windows?

unless Gem.win_platform?
  # test here
end

[pixeltrix]

@jlduran yes, looks like Gem.win_platform? is the check we've used elsewhere.

[pixeltrix]

Since we're setting the group read bit as well we should make this more explicit like:

stat = File.stat("config/master.key")
assert_equal "100600", sprintf("%o, stat.mode)

[pixeltrix]

Once you've made the test change can you squash your commits and then we're good to go - thanks 👍

[pixeltrix]

@jlduran thanks! 👍