Missing newline broke sshd_config

[laurikimmel]

Metadata:

• Operating System: Debian 9.4 and 8.10
• Installation method: install.sh script
• AWS CLI Version: aws-cli/1.11.13 Python/3.5.3 Linux/4.9.0-6-amd64 botocore/1.4.70

Installation script broke sshd_config and service refused to start.
Installation script appended two new config statments to the /etc/ssh/sshd_config.
Apparently original config file was missing new line at the end and first new statement was appended to the last existing one

UseDNS noAuthorizedKeysCommand /opt/authorized_keys_command.sh
AuthorizedKeysCommandUser nobody

Although it was trivial to fix the config file it might render instance inaccessible.

1. add extra new lines in install_configure_sshd.sh
2. consider making backup from /etc/ssh/sshd_config before modifying it
3. provide revert / uninstall script

[michaelwittig]

First, Debian is not yet supported as documented in the README and therefore not save to use (as you proofed).

Question: Besides the issues #121 and #122 that you discovered when using Debian, anything else that needs to be adjusted? If not, I believe we can support Debian with minimal effort using the information you provided.

Which AMIs are you using?

[laurikimmel]

I was aware about Debian not listed in supported OS list when I started.

OTOH missing newline at the end of file is not depending on the specific distro. By mistake or not - user might remove it, some script might remove it etc. To be on the safe side - it would be good to check and add one if necessary.

IMHO having a backup and uninstall script would make things bit more safe for any platform.

--

No other issues beside #121 and #122 seen on Debian so far.

Both instances started from ami-e079f893, regularly updated, one upgraded to Stretch.

[michaelwittig]

fixed in 9dd1c4d#diff-07f1ffb4c0e0e30582f96ab41b539ba7