metasploit-framework/lib/net/ssh/config.rb

181 lines
6.2 KiB
Ruby

module Net; module SSH
# The Net::SSH::Config class is used to parse OpenSSH configuration files,
# and translates that syntax into the configuration syntax that Net::SSH
# understands. This lets Net::SSH scripts read their configuration (to
# some extent) from OpenSSH configuration files (~/.ssh/config, /etc/ssh_config,
# and so forth).
#
# Only a subset of OpenSSH configuration options are understood:
#
# * Ciphers => maps to the :encryption option
# * Compression => :compression
# * CompressionLevel => :compression_level
# * ConnectTimeout => maps to the :timeout option
# * ForwardAgent => :forward_agent
# * GlobalKnownHostsFile => :global_known_hosts_file
# * HostBasedAuthentication => maps to the :auth_methods option
# * HostKeyAlgorithms => maps to :host_key option
# * HostKeyAlias => :host_key_alias
# * HostName => :host_name
# * IdentityFile => maps to the :keys option
# * Macs => maps to the :hmac option
# * PasswordAuthentication => maps to the :auth_methods option
# * Port => :port
# * PreferredAuthentications => maps to the :auth_methods option
# * RekeyLimit => :rekey_limit
# * User => :user
# * UserKnownHostsFile => :user_known_hosts_file
#
# Note that you will never need to use this class directly--you can control
# whether the OpenSSH configuration files are read by passing the :config
# option to Net::SSH.start. (They are, by default.)
class Config
class <<self
@@default_files = %w(~/.ssh/config /etc/ssh_config /etc/ssh/ssh_config)
# Returns an array of locations of OpenSSH configuration files
# to parse by default.
def default_files
@@default_files
end
# Loads the configuration data for the given +host+ from all of the
# given +files+ (defaulting to the list of files returned by
# #default_files), translates the resulting hash into the options
# recognized by Net::SSH, and returns them.
def for(host, files=default_files)
translate(files.inject({}) { |settings, file| load(file, host, settings) })
end
# Load the OpenSSH configuration settings in the given +file+ for the
# given +host+. If +settings+ is given, the options are merged into
# that hash, with existing values taking precedence over newly parsed
# ones. Returns a hash containing the OpenSSH options. (See
# #translate for how to convert the OpenSSH options into Net::SSH
# options.)
def load(file, host, settings={})
file = File.expand_path(file)
return settings unless File.readable?(file)
in_match = false
IO.foreach(file) do |line|
next if line =~ /^\s*(?:#.*)?$/
if line =~ /^\s*(\S+)\s*=(.*)$/
key, value = $1, $2
else
key, value = line.strip.split(/\s+/, 2)
end
# silently ignore malformed entries
next if value.nil?
key.downcase!
value = $1 if value =~ /^"(.*)"$/
value = case value.strip
when /^\d+$/ then value.to_i
when /^no$/i then false
when /^yes$/i then true
else value
end
if key == 'host'
in_match = (host =~ pattern2regex(value))
elsif in_match
if key == 'identityfile'
settings[key] ||= []
settings[key] << value
else
settings[key] = value unless settings.key?(key)
end
end
end
return settings
end
# Given a hash of OpenSSH configuration options, converts them into
# a hash of Net::SSH options. Unrecognized options are ignored. The
# +settings+ hash must have Strings for keys, all downcased, and
# the returned hash will have Symbols for keys.
def translate(settings)
settings.inject({}) do |hash, (key, value)|
case key
when 'ciphers' then
hash[:encryption] = value.split(/,/)
when 'compression' then
hash[:compression] = value
when 'compressionlevel' then
hash[:compression_level] = value
when 'connecttimeout' then
hash[:timeout] = value
when 'forwardagent' then
hash[:forward_agent] = value
when 'globalknownhostsfile'
hash[:global_known_hosts_file] = value
when 'hostbasedauthentication' then
if value
hash[:auth_methods] ||= []
hash[:auth_methods] << "hostbased"
end
when 'hostkeyalgorithms' then
hash[:host_key] = value.split(/,/)
when 'hostkeyalias' then
hash[:host_key_alias] = value
when 'hostname' then
hash[:host_name] = value
when 'identityfile' then
hash[:keys] = value
when 'macs' then
hash[:hmac] = value.split(/,/)
when 'passwordauthentication'
if value
hash[:auth_methods] ||= []
hash[:auth_methods] << "password"
end
when 'port'
hash[:port] = value
when 'preferredauthentications'
hash[:auth_methods] = value.split(/,/)
when 'pubkeyauthentication'
if value
hash[:auth_methods] ||= []
hash[:auth_methods] << "publickey"
end
when 'rekeylimit'
hash[:rekey_limit] = interpret_size(value)
when 'user'
hash[:user] = value
when 'userknownhostsfile'
hash[:user_known_hosts_file] = value
end
hash
end
end
private
# Converts an ssh_config pattern into a regex for matching against
# host names.
def pattern2regex(pattern)
pattern = "^" + pattern.to_s.gsub(/\./, "\\.").
gsub(/\?/, '.').
gsub(/\*/, '.*') + "$"
Regexp.new(pattern, true)
end
# Converts the given size into an integer number of bytes.
def interpret_size(size)
case size
when /k$/i then size.to_i * 1024
when /m$/i then size.to_i * 1024 * 1024
when /g$/i then size.to_i * 1024 * 1024 * 1024
else size.to_i
end
end
end
end
end; end