/usr/lib/ruby/vendor_ruby/net/ssh/known_hosts.rb is in ruby-net-ssh 1:2.5.2-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 | require 'strscan'
require 'net/ssh/buffer'
module Net; module SSH
# Searches an OpenSSH-style known-host file for a given host, and returns all
# matching keys. This is used to implement host-key verification, as well as
# to determine what key a user prefers to use for a given host.
#
# This is used internally by Net::SSH, and will never need to be used directly
# by consumers of the library.
class KnownHosts
if defined?(OpenSSL::PKey::EC)
SUPPORTED_TYPE = %w(ssh-rsa ssh-dss
ecdsa-sha2-nistp256
ecdsa-sha2-nistp384
ecdsa-sha2-nistp521)
else
SUPPORTED_TYPE = %w(ssh-rsa ssh-dss)
end
class <<self
# Searches all known host files (see KnownHosts.hostfiles) for all keys
# of the given host. Returns an array of keys found.
def search_for(host, options={})
search_in(hostfiles(options), host)
end
# Search for all known keys for the given host, in every file given in
# the +files+ array. Returns the list of keys.
def search_in(files, host)
files.map { |file| KnownHosts.new(file).keys_for(host) }.flatten
end
# Looks in the given +options+ hash for the :user_known_hosts_file and
# :global_known_hosts_file keys, and returns an array of all known
# hosts files. If the :user_known_hosts_file key is not set, the
# default is returned (~/.ssh/known_hosts and ~/.ssh/known_hosts2). If
# :global_known_hosts_file is not set, the default is used
# (/etc/ssh/known_hosts and /etc/ssh/known_hosts2).
#
# If you only want the user known host files, you can pass :user as
# the second option.
def hostfiles(options, which=:all)
files = []
if which == :all || which == :user
files += Array(options[:user_known_hosts_file] || %w(~/.ssh/known_hosts ~/.ssh/known_hosts2))
end
if which == :all || which == :global
files += Array(options[:global_known_hosts_file] || %w(/etc/ssh/known_hosts /etc/ssh/known_hosts2))
end
return files
end
# Looks in all user known host files (see KnownHosts.hostfiles) and tries to
# add an entry for the given host and key to the first file it is able
# to.
def add(host, key, options={})
hostfiles(options, :user).each do |file|
begin
KnownHosts.new(file).add(host, key)
return
rescue SystemCallError
# try the next hostfile
end
end
end
end
# The host-key file name that this KnownHosts instance will use to search
# for keys.
attr_reader :source
# Instantiate a new KnownHosts instance that will search the given known-hosts
# file. The path is expanded file File.expand_path.
def initialize(source)
@source = File.expand_path(source)
end
# Returns an array of all keys that are known to be associatd with the
# given host. The +host+ parameter is either the domain name or ip address
# of the host, or both (comma-separated). Additionally, if a non-standard
# port is being used, it may be specified by putting the host (or ip, or
# both) in square brackets, and appending the port outside the brackets
# after a colon. Possible formats for +host+, then, are;
#
# "net.ssh.test"
# "1.2.3.4"
# "net.ssh.test,1.2.3.4"
# "[net.ssh.test]:5555"
# "[1,2,3,4]:5555"
# "[net.ssh.test]:5555,[1.2.3.4]:5555
def keys_for(host)
keys = []
return keys unless File.readable?(source)
entries = host.split(/,/)
File.open(source) do |file|
scanner = StringScanner.new("")
file.each_line do |line|
scanner.string = line
scanner.skip(/\s*/)
next if scanner.match?(/$|#/)
hostlist = scanner.scan(/\S+/).split(/,/)
next unless entries.all? { |entry| hostlist.include?(entry) }
scanner.skip(/\s*/)
type = scanner.scan(/\S+/)
next unless SUPPORTED_TYPE.include?(type)
scanner.skip(/\s*/)
blob = scanner.rest.unpack("m*").first
keys << Net::SSH::Buffer.new(blob).read_key
end
end
keys
end
# Tries to append an entry to the current source file for the given host
# and key. If it is unable to (because the file is not writable, for
# instance), an exception will be raised.
def add(host, key)
File.open(source, "a") do |file|
blob = [Net::SSH::Buffer.from(:key, key).to_s].pack("m*").gsub(/\s/, "")
file.puts "#{host} #{key.ssh_type} #{blob}"
end
end
end
end; end
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