Add Util::SSH which has methods for checking key permissions and exec

This commit is contained in:
Mitchell Hashimoto 2012-08-05 13:12:53 -07:00
parent 1a2a8b49c0
commit 984c4f4025
5 changed files with 151 additions and 159 deletions

View File

@ -78,7 +78,6 @@ module Vagrant
autoload :Hosts, 'vagrant/hosts' autoload :Hosts, 'vagrant/hosts'
autoload :Machine, 'vagrant/machine' autoload :Machine, 'vagrant/machine'
autoload :Plugin, 'vagrant/plugin' autoload :Plugin, 'vagrant/plugin'
autoload :SSH, 'vagrant/ssh'
autoload :TestHelpers, 'vagrant/test_helpers' autoload :TestHelpers, 'vagrant/test_helpers'
autoload :UI, 'vagrant/ui' autoload :UI, 'vagrant/ui'
autoload :Util, 'vagrant/util' autoload :Util, 'vagrant/util'

View File

@ -1,128 +0,0 @@
require 'log4r'
require 'vagrant/util/file_mode'
require 'vagrant/util/platform'
require 'vagrant/util/safe_exec'
module Vagrant
# Manages SSH connection information as well as allows opening an
# SSH connection.
class SSH
include Util::SafeExec
def initialize(vm)
@vm = vm
@logger = Log4r::Logger.new("vagrant::ssh")
end
# Returns a hash of information necessary for accessing this
# virtual machine via SSH.
#
# @return [Hash]
def info
results = {
:host => @vm.config.ssh.host,
:port => @vm.config.ssh.port || @vm.driver.ssh_port(@vm.config.ssh.guest_port),
:username => @vm.config.ssh.username,
:forward_agent => @vm.config.ssh.forward_agent,
:forward_x11 => @vm.config.ssh.forward_x11
}
# This can happen if no port is set and for some reason Vagrant
# can't detect an SSH port.
raise Errors::SSHPortNotDetected if !results[:port]
# Determine the private key path, which is either set by the
# configuration or uses just the built-in insecure key.
pk_path = @vm.config.ssh.private_key_path || @vm.env.default_private_key_path
results[:private_key_path] = File.expand_path(pk_path, @vm.env.root_path)
# We need to check and fix the private key permissions
# to make sure that SSH gets a key with 0600 perms.
check_key_permissions(results[:private_key_path])
# Return the results
return results
end
# Connects to the environment's virtual machine, replacing the ruby
# process with an SSH process.
#
# @param [Hash] opts Options hash
# @options opts [Boolean] :plain_mode If True, doesn't authenticate with
# the machine, only connects, allowing the user to connect.
def exec(opts={})
# Get the SSH information and cache it here
ssh_info = info
if Util::Platform.windows?
raise Errors::SSHUnavailableWindows, :host => ssh_info[:host],
:port => ssh_info[:port],
:username => ssh_info[:username],
:key_path => ssh_info[:private_key_path]
end
raise Errors::SSHUnavailable if !Kernel.system("which ssh > /dev/null 2>&1")
# If plain mode is enabled then we don't do any authentication (we don't
# set a user or an identity file)
plain_mode = opts[:plain_mode]
options = {}
options[:host] = ssh_info[:host]
options[:port] = ssh_info[:port]
options[:username] = ssh_info[:username]
options[:private_key_path] = ssh_info[:private_key_path]
# Command line options
command_options = ["-p", options[:port].to_s, "-o", "UserKnownHostsFile=/dev/null",
"-o", "StrictHostKeyChecking=no", "-o", "LogLevel=FATAL"]
# Solaris/OpenSolaris/Illumos uses SunSSH which doesn't support the IdentitiesOnly option
# (Also don't use it in plain mode, it'll skip user agents.)
command_options += ["-o", "IdentitiesOnly=yes"] if !(Util::Platform.solaris? || plain_mode)
command_options += ["-i", options[:private_key_path]] if !plain_mode
command_options += ["-o", "ForwardAgent=yes"] if ssh_info[:forward_agent]
# If there are extra options, then we append those
command_options.concat(opts[:extra_args]) if opts[:extra_args]
if ssh_info[:forward_x11]
# Both are required so that no warnings are shown regarding X11
command_options += ["-o", "ForwardX11=yes"]
command_options += ["-o", "ForwardX11Trusted=yes"]
end
host_string = options[:host]
host_string = "#{options[:username]}@#{host_string}" if !plain_mode
command_options << host_string
@logger.info("Invoking SSH: #{command_options.inspect}")
safe_exec("ssh", *command_options)
end
# Checks the file permissions for a private key, resetting them
# if needed.
def check_key_permissions(key_path)
# Windows systems don't have this issue
return if Util::Platform.windows?
@logger.debug("Checking key permissions: #{key_path}")
stat = File.stat(key_path)
if stat.owned? && Util::FileMode.from_octal(stat.mode) != "600"
@logger.info("Attempting to correct key permissions to 0600")
File.chmod(0600, key_path)
stat = File.stat(key_path)
if Util::FileMode.from_octal(stat.mode) != "600"
raise Errors::SSHKeyBadPermissions, :key_path => key_path
end
end
rescue Errno::EPERM
# This shouldn't happen since we verified we own the file, but
# it is possible in theory, so we raise an error.
raise Errors::SSHKeyBadPermissions, :key_path => key_path
end
end
end

121
lib/vagrant/util/ssh.rb Normal file
View File

@ -0,0 +1,121 @@
require "log4r"
require "vagrant/util/file_mode"
require "vagrant/util/platform"
require "vagrant/util/safe_exec"
module Vagrant
module Util
# This is a class that has helpers on it for dealing with SSH. These
# helpers don't depend on any part of Vagrant except what is given
# via the parameters.
class SSH
include SafeExec
LOGGER = Log4r::Logger.new("vagrant::util::ssh")
# Checks that the permissions for a private key are valid, and fixes
# them if possible. SSH requires that permissions on the private key
# are 0600 on POSIX based systems. This will make a best effort to
# fix these permissions if they are not properly set.
#
# @param [Pathname] key_path The path to the private key.
def self.check_key_permissions(key_path)
# Don't do anything if we're on Windows, since Windows doesn't worry
# about key permissions.
return if Platform.windows?
LOGGER.debug("Checking key permissions: #{key_path}")
stat = key_path.stat
if stat.owned? && FileMode.from_octal(stat.mode) != "600"
LOGGER.info("Attempting to correct key permissions to 0600")
key_path.chmod(0600)
# Re-stat the file to get the new mode, and verify it worked
stat = key_path.stat
if FileMode.from_octal(stat.mode) != "600"
raise Errors::SSHKeyBadPermissions, :key_path => key_path
end
end
rescue Errno::EPERM
# This shouldn't happen since we verify we own the file, but
# it is possible in theory, so we raise an error.
raise Errors::SSHKeyBadPermissions, :key_path => key_path
end
# Halts the running of this process and replaces it with a full-fledged
# SSH shell into a remote machine.
#
# Note: This method NEVER returns. The process ends after this.
#
# @param [Hash] ssh_info This is the SSH information. For the keys
# required please see the documentation of {Machine#ssh_info}.
# @param [Hash] opts These are additional options that are supported
# by exec.
def exec(ssh_info, opts={})
# If we're running Windows, raise an exception since we currently
# still don't support exec-ing into SSH. In the future this should
# certainly be possible if we can detect we're in an environment that
# supports it.
if Platform.windows?
raise Errors::SSHUnavailableWindows,
:host => ssh_info[:host],
:port => ssh_info[:port],
:username => ssh_info[:username],
:key_path => ssh_info[:private_key_path]
end
# Verify that we have SSH available on the system.
raise Errors::SSHUnavailable if !Kernel.system("which ssh > /dev/null 2>&1")
# If plain mode is enabled then we don't do any authentication (we don't
# set a user or an identity file)
plain_mode = opts[:plain_mode]
options = {}
options[:host] = ssh_info[:host]
options[:port] = ssh_info[:port]
options[:username] = ssh_info[:username]
options[:private_key_path] = ssh_info[:private_key_path]
# Command line options
command_options = [
"-p", options[:port].to_s,
"-o", "LogLevel=FATAL",
"-o", "StrictHostKeyChecking=no",
"-o", "UserKnownHostsFile=/dev/null"]
# Configurables
command_options += ["-o", "ForwardAgent=yes"] if ssh_info[:forward_agent]
command_options.concat(opts[:extra_args]) if opts[:extra_args]
# Solaris/OpenSolaris/Illumos uses SunSSH which doesn't support the
# IdentitiesOnly option. Also, we don't enable it in plain mode so
# that SSH properly searches our identities and tries to do it itself.
if !Platform.solaris? && !plain_mode
command_options += ["-o", "IdentitiesOnly=yes"]
end
# If we're not in plain mode, attach the private key path.
command_options += ["-i", options[:private_key_path]] if !plain_mode
if ssh_info[:forward_x11]
# Both are required so that no warnings are shown regarding X11
command_options += [
"-o", "ForwardX11=yes",
"-o", "ForwardX11Trusted=yes"]
end
# Build up the host string for connecting
host_string = options[:host]
host_string = "#{options[:username]}@#{host_string}" if !plain_mode
command_options << host_string
# Invoke SSH with all our options
@logger.info("Invoking SSH: #{command_options.inspect}")
safe_exec("ssh", *command_options)
end
end
end
end

View File

@ -1,30 +0,0 @@
require File.expand_path("../../base", __FILE__)
describe Vagrant::SSH do
context "check_key_permissions" do
let(:key_path) do
# We create a tempfile to guarantee some level of uniqueness
# then explicitly close/unlink but save the path so we can re-use
temp = Tempfile.new("vagrant")
result = Pathname.new(temp.path)
temp.close
temp.unlink
result
end
let(:ssh_instance) { Vagrant::SSH.new(double) }
it "should not raise an exception if we set a keyfile permission correctly" do
# Write some stuff to our key file and chmod it to some
# incorrect permissions.
key_path.open("w") { |f| f.write("hello!") }
key_path.chmod(0644)
# This should work!
expect { ssh_instance.check_key_permissions(key_path) }.
to_not raise_error
end
end
end

View File

@ -0,0 +1,30 @@
require File.expand_path("../../../base", __FILE__)
require "vagrant/util/platform"
require "vagrant/util/ssh"
describe Vagrant::Util::SSH do
include_context "unit"
describe "checking key permissions" do
let(:key_path) { temporary_file }
it "should do nothing on Windows" do
Vagrant::Util::Platform.stub(:windows?).and_return(true)
key_path.chmod(0700)
# Get the mode now and verify that it is untouched afterwards
mode = key_path.stat.mode
described_class.check_key_permissions(key_path)
key_path.stat.mode.should == mode
end
it "should fix the permissions" do
key_path.chmod(0644)
described_class.check_key_permissions(key_path)
key_path.stat.mode.should == 0100600
end
end
end