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require "log4r"
require 'childprocess'
require "vagrant/util/file_mode"
require "vagrant/util/platform"
require "vagrant/util/safe_exec"
require "vagrant/util/safe_puts"
require "vagrant/util/subprocess"
require "vagrant/util/which"
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
extend SafePuts
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? || Platform.wsl_windows_access_bypass?(key_path)
LOGGER.debug("Checking key permissions: #{key_path}")
stat = key_path.stat
if !stat.owned? && Process.uid != 0
# The SSH key must be owned by ourselves, unless we're root
raise Errors::SSHKeyBadOwner, key_path: key_path
end
if 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 self.exec(ssh_info, opts={})
# Ensure the platform supports ssh. On Windows there are several programs which
# include ssh, notably git, mingw and cygwin, but make sure ssh is in the path!
# First try using the original path provided
if ENV["VAGRANT_PREFER_SYSTEM_BIN"] != "0"
ssh_path = Which.which("ssh", original_path: true)
end
# If we didn't find an ssh executable, see if we shipped one
if !ssh_path
ssh_path = Which.which("ssh")
if ssh_path && Platform.windows? && (Platform.cygwin? || Platform.msys?)
LOGGER.warn("Failed to locate native SSH executable. Using vendored version.")
LOGGER.warn("If display issues are encountered, install the ssh package for your environment.")
end
end
if !ssh_path
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].join(", ")
end
raise Errors::SSHUnavailable
end
if Platform.windows?
# On Windows, we need to detect whether SSH is actually "plink"
# underneath the covers. In this case, we tell the user.
r = Subprocess.execute(ssh_path)
if r.stdout.include?("PuTTY Link") || r.stdout.include?("Plink: command-line connection utility")
raise Errors::SSHIsPuttyLink,
host: ssh_info[:host],
port: ssh_info[:port],
username: ssh_info[:username],
key_path: ssh_info[:private_key_path].join(", ")
end
end
# 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]
log_level = ssh_info[:log_level] || "FATAL"
# Command line options
command_options = [
"-p", options[:port].to_s,
"-o", "LogLevel=#{log_level}"]
if ssh_info[:compression]
command_options += ["-o", "Compression=yes"]
end
if ssh_info[:dsa_authentication]
command_options += ["-o", "DSAAuthentication=yes"]
end
# Solaris/OpenSolaris/Illumos uses SunSSH which doesn't support the
# IdentitiesOnly option. Also, we don't enable it in plain mode or if
# if keys_only is false so that SSH and Net::SSH properly search our identities
# and tries to do it itself.
if !Platform.solaris? && !plain_mode && ssh_info[:keys_only]
command_options += ["-o", "IdentitiesOnly=yes"]
end
# no strict hostkey checking unless paranoid
if ssh_info[:verify_host_key] == :never || !ssh_info[:verify_host_key]
command_options += [
"-o", "StrictHostKeyChecking=no",
"-o", "UserKnownHostsFile=/dev/null"]
end
# If we're not in plain mode and :private_key_path is set attach the private key path(s).
if !plain_mode && options[:private_key_path]
options[:private_key_path].each do |path|
private_key_arr = []
if path.include?('%')
if path.include?(' ') && Platform.windows?
LOGGER.warn("Paths with spaces and % on windows is not supported and will fail to read the file")
end
# Use '-o' instead of '-i' because '-i' does not call
# percent_expand in misc.c, but '-o' does. when passing the path,
# replace '%' in the path with '%%' to escape the '%'
path = path.to_s.gsub('%', '%%')
private_key_arr = ["-o", "IdentityFile=\"#{path}\""]
else
# Pass private key file directly with '-i', which properly supports
# paths with spaces on Windows guests
private_key_arr = ["-i", path]
end
command_options += private_key_arr
end
end
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
if ssh_info[:proxy_command]
command_options += ["-o", "ProxyCommand=#{ssh_info[:proxy_command]}"]
end
if ssh_info[:forward_env]
command_options += ["-o", "SendEnv=#{ssh_info[:forward_env].join(" ")}"]
end
# Configurables -- extra_args should always be last due to the way the
# ssh args parser works. e.g. if the user wants to use the -t option,
# any shell command(s) she'd like to run on the remote server would
# have to be the last part of the 'ssh' command:
#
# $ ssh localhost -t -p 2222 "cd mydirectory; bash"
#
# Without having extra_args be last, the user loses this ability
command_options += ["-o", "ForwardAgent=yes"] if ssh_info[:forward_agent]
# Note about :extra_args
# ssh_info[:extra_args] comes from a machines ssh config in a Vagrantfile,
# where as opts[:extra_args] comes from running the ssh command
command_options += Array(ssh_info[:extra_args]) if ssh_info[:extra_args]
command_options.concat(opts[:extra_args]) if opts[:extra_args]
# Build up the host string for connecting
host_string = options[:host]
host_string = "#{options[:username]}@#{host_string}" if !plain_mode
command_options.unshift(host_string)
# On Cygwin we want to get rid of any DOS file warnings because
# we really don't care since both work.
ENV["nodosfilewarning"] = "1" if Platform.cygwin?
# If an ssh command is defined, use that. If an ssh binary was
# discovered on the path, use that. Otherwise fail to just trying `ssh`
ssh = ssh_info[:ssh_command] || ssh_path || 'ssh'
# Invoke SSH with all our options
if !opts[:subprocess]
LOGGER.info("Invoking SSH: #{ssh} #{command_options.inspect}")
SafeExec.exec(ssh, *command_options)
return
end
# If we're still here, it means we're supposed to subprocess
# out to ssh rather than exec it.
LOGGER.info("Executing SSH in subprocess: #{ssh} #{command_options.inspect}")
process = ChildProcess.build(ssh, *command_options)
process.io.inherit!
# Forward configured environment variables.
if ssh_info[:forward_env]
ssh_info[:forward_env].each do |key|
process.environment[key] = ENV[key]
end
end
process.start
process.wait
return process.exit_code
end
end
end
end