Correct file permissions for ssh keys and config.

generate-ssh-key.sh

ssh-keygen -t rsa -b 4096 -N '' -C "[email protected]" -f ~/.ssh/id_rsa
ssh-keygen -t rsa -b 4096 -N '' -C "[email protected]" -f ~/.ssh/github_rsa
ssh-keygen -t rsa -b 4096 -N '' -C "[email protected]" -f ~/.ssh/mozilla_rsa

ssh-key-add.sh

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_rsa
ssh-add ~/.ssh/github_rsa
ssh-add ~/.ssh/mozilla_rsa

ssh-key-permissions.sh

chmod 700 ~/.ssh
chmod 644 ~/.ssh/authorized_keys
chmod 644 ~/.ssh/known_hosts
chmod 644 ~/.ssh/config
chmod 600 ~/.ssh/id_rsa
chmod 644 ~/.ssh/id_rsa.pub
chmod 600 ~/.ssh/github_rsa
chmod 644 ~/.ssh/github_rsa.pub
chmod 600 ~/.ssh/mozilla_rsa
chmod 644 ~/.ssh/mozilla_rsa.pub

# replace 'username' through your account :)
sudo chown -R username:username ~/.ssh

the original gist have those suggestion https://gist.github.com/grenade/6318301?permalink_comment_id=3289864#gistcomment-3289864

# Fix directory permissions
chmod 700 ~/.ssh

# Fix all key permissions
chmod 600 ~/.ssh/*
chmod 644 ~/.ssh/*.pub

# Fix special files permissions
chmod 644 ~/.ssh/authorized_keys
chmod 644 ~/.ssh/known_hosts
chmod 644 ~/.ssh/config

For copy and paste:

chmod 700 ~/.ssh && \
chmod 600 ~/.ssh/* && \
chmod 644 -f ~/.ssh/*.pub ~/.ssh/authorized_keys ~/.ssh/known_hosts ~/.ssh/config