From 2c697c574a6844c6cec3dc0cb6498cc0f87ff072 Mon Sep 17 00:00:00 2001 From: elijah Date: Wed, 5 Nov 2014 15:44:24 -0800 Subject: prompt user to update ssh host keys when a better one is available. closes #6320 --- lib/leap_cli/commands/node_init.rb | 167 +++++++++++++++++++++++++++++++++++++ 1 file changed, 167 insertions(+) create mode 100644 lib/leap_cli/commands/node_init.rb (limited to 'lib/leap_cli/commands/node_init.rb') diff --git a/lib/leap_cli/commands/node_init.rb b/lib/leap_cli/commands/node_init.rb new file mode 100644 index 0000000..49030a7 --- /dev/null +++ b/lib/leap_cli/commands/node_init.rb @@ -0,0 +1,167 @@ +# +# Node initialization. +# Most of the fun stuff is in tasks.rb. +# + +module LeapCli; module Commands + + desc 'Node management' + command :node do |node| + node.desc 'Bootstraps a node or nodes, setting up SSH keys and installing prerequisite packages' + node.long_desc "This command prepares a server to be used with the LEAP Platform by saving the server's SSH host key, " + + "copying the authorized_keys file, installing packages that are required for deploying, and registering important facts. " + + "Node init must be run before deploying to a server, and the server must be running and available via the network. " + + "This command only needs to be run once, but there is no harm in running it multiple times." + node.arg_name 'FILTER' + node.command :init do |init| + init.switch 'echo', :desc => 'If set, passwords are visible as you type them (default is hidden)', :negatable => false + init.flag :port, :desc => 'Override the default SSH port.', :arg_name => 'PORT' + init.flag :ip, :desc => 'Override the default SSH IP address.', :arg_name => 'IPADDRESS' + + init.action do |global,options,args| + assert! args.any?, 'You must specify a FILTER' + finished = [] + manager.filter!(args).each_node do |node| + is_node_alive(node, options) + save_public_host_key(node, global, options) unless node.vagrant? + update_compiled_ssh_configs + ssh_connect_options = connect_options(options).merge({:bootstrap => true, :echo => options[:echo]}) + ssh_connect(node, ssh_connect_options) do |ssh| + if node.vagrant? + ssh.install_insecure_vagrant_key + end + ssh.install_authorized_keys + ssh.install_prerequisites + ssh.leap.log(:checking, "SSH host keys") do + ssh.leap.capture(get_ssh_keys_cmd) do |response| + update_local_ssh_host_keys(node, response[:data]) if response[:exitcode] == 0 + end + end + ssh.leap.log(:updating, "facts") do + ssh.leap.capture(facter_cmd) do |response| + if response[:exitcode] == 0 + update_node_facts(node.name, response[:data]) + else + log :failed, "to run facter on #{node.name}" + end + end + end + end + finished << node.name + end + log :completed, "initialization of nodes #{finished.join(', ')}" + end + end + end + + private + + ## + ## PRIVATE HELPERS + ## + + def is_node_alive(node, options) + address = options[:ip] || node.ip_address + port = options[:port] || node.ssh.port + log :connecting, "to node #{node.name}" + assert_run! "nc -zw3 #{address} #{port}", + "Failed to reach #{node.name} (address #{address}, port #{port}). You can override the configured IP address and port with --ip or --port." + end + + # + # saves the public ssh host key for node into the provider directory. + # + # see `man sshd` for the format of known_hosts + # + def save_public_host_key(node, global, options) + log :fetching, "public SSH host key for #{node.name}" + address = options[:ip] || node.ip_address + port = options[:port] || node.ssh.port + host_keys = get_public_keys_for_ip(address, port) + pub_key_path = Path.named_path([:node_ssh_pub_key, node.name]) + + if Path.exists?(pub_key_path) + if host_keys.include? SshKey.load(pub_key_path) + log :trusted, "- Public SSH host key for #{node.name} matches previously saved key", :indent => 1 + else + bail! do + log :error, "The public SSH host keys we just fetched for #{node.name} doesn't match what we have saved previously.", :indent => 1 + log "Delete the file #{pub_key_path} if you really want to remove the trusted SSH host key.", :indent => 2 + end + end + else + known_key = host_keys.detect{|k|k.in_known_hosts?(node.name, node.ip_address, node.domain.name)} + if known_key + log :trusted, "- Public SSH host key for #{node.name} is trusted (key found in your ~/.ssh/known_hosts)" + else + public_key = SshKey.pick_best_key(host_keys) + if public_key.nil? + bail!("We got back #{host_keys.size} host keys from #{node.name}, but we can't support any of them.") + else + say(" This is the SSH host key you got back from node \"#{node.name}\"") + say(" Type -- #{public_key.bits} bit #{public_key.type.upcase}") + say(" Fingerprint -- " + public_key.fingerprint) + say(" Public Key -- " + public_key.key) + if !global[:yes] && !agree(" Is this correct? ") + bail! + else + known_key = public_key + end + end + end + puts + write_file! [:node_ssh_pub_key, node.name], known_key.to_s + end + end + + # + # Get the public host keys for a host using ssh-keyscan. + # Return an array of SshKey objects, one for each key. + # + def get_public_keys_for_ip(address, port=22) + assert_bin!('ssh-keyscan') + output = assert_run! "ssh-keyscan -p #{port} #{address}", "Could not get the public host key from #{address}:#{port}. Maybe sshd is not running?" + if output.empty? + bail! :failed, "ssh-keyscan returned empty output." + end + + if output =~ /No route to host/ + bail! :failed, 'ssh-keyscan: no route to %s' % address + else + keys = SshKey.parse_keys(output) + if keys.empty? + bail! "ssh-keyscan got zero host keys back (that we understand)! Output was: #{output}" + else + return keys + end + end + end + + # run on the server to generate a string suitable for passing to SshKey.parse_keys() + def get_ssh_keys_cmd + "/bin/grep ^HostKey /etc/ssh/sshd_config | /usr/bin/awk '{print $2 \".pub\"}' | /usr/bin/xargs /bin/cat" + end + + # + # Sometimes the ssh host keys on the server will be better than what we have + # stored locally. In these cases, ask the user if they want to upgrade. + # + def update_local_ssh_host_keys(node, remote_keys_string) + remote_keys = SshKey.parse_keys(remote_keys_string) + return unless remote_keys.any? + current_key = SshKey.load(Path.named_path([:node_ssh_pub_key, node.name])) + best_key = SshKey.pick_best_key(remote_keys) + return unless best_key + if current_key != best_key + say(" One of the SSH host keys for node '#{node.name}' is better than what you currently have trusted.") + say(" Current key: #{current_key.summary}") + say(" Better key: #{best_key.summary}") + if agree(" Do you want to use the better key? ") + write_file! [:node_ssh_pub_key, node.name], best_key.to_s + end + else + log(3, "current host key does not need updating") + end + end + +end; end -- cgit v1.2.3