Parent

Class Index [+]

Quicksearch

Net::SSH::KnownHosts

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.

Constants

SUPPORTED_TYPE
SUPPORTED_TYPE

Attributes

source[R]

The host-key file name that this KnownHosts instance will use to search for keys.

Public Class Methods

add(host, key, options={}) click to toggle source

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.

    # File lib/net/ssh/known_hosts.rb, line 64
64:       def add(host, key, options={})
65:         hostfiles(options, :user).each do |file|
66:           begin
67:             KnownHosts.new(file).add(host, key)
68:             return
69:           rescue SystemCallError
70:             # try the next hostfile
71:           end
72:         end
73:       end
hostfiles(options, which=:all) click to toggle source

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.

    # File lib/net/ssh/known_hosts.rb, line 47
47:       def hostfiles(options, which=:all)
48:         files = []
49: 
50:         if which == :all || which == :user
51:           files += Array(options[:user_known_hosts_file] || %(~/.ssh/known_hosts ~/.ssh/known_hosts2))
52:         end
53: 
54:         if which == :all || which == :global
55:           files += Array(options[:global_known_hosts_file] || %(/etc/ssh/known_hosts /etc/ssh/known_hosts2))
56:         end
57: 
58:         return files
59:       end
new(source) click to toggle source

Instantiate a new KnownHosts instance that will search the given known-hosts file. The path is expanded file File.expand_path.

    # File lib/net/ssh/known_hosts.rb, line 82
82:     def initialize(source)
83:       @source = File.expand_path(source)
84:     end
search_for(host, options={}) click to toggle source

Searches all known host files (see KnownHosts.hostfiles) for all keys of the given host. Returns an array of keys found.

    # File lib/net/ssh/known_hosts.rb, line 28
28:       def search_for(host, options={})
29:         search_in(hostfiles(options), host)
30:       end
search_in(files, host) click to toggle source

Search for all known keys for the given host, in every file given in the files array. Returns the list of keys.

    # File lib/net/ssh/known_hosts.rb, line 34
34:       def search_in(files, host)
35:         files.map { |file| KnownHosts.new(file).keys_for(host) }.flatten
36:       end

Public Instance Methods

add(host, key) click to toggle source

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.

     # File lib/net/ssh/known_hosts.rb, line 133
133:     def add(host, key)
134:       File.open(source, "a") do |file|
135:         blob = [Net::SSH::Buffer.from(:key, key).to_s].pack("m*").gsub(/\s/, "")
136:         file.puts "#{host} #{key.ssh_type} #{blob}"
137:       end
138:     end
keys_for(host) click to toggle source

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
     # File lib/net/ssh/known_hosts.rb, line 99
 99:     def keys_for(host)
100:       keys = []
101:       return keys unless File.readable?(source)
102: 
103:       entries = host.split(/,/)
104: 
105:       File.open(source) do |file|
106:         scanner = StringScanner.new("")
107:         file.each_line do |line|
108:           scanner.string = line
109: 
110:           scanner.skip(/\s*/)
111:           next if scanner.match?(/$|#/)
112: 
113:           hostlist = scanner.scan(/\S+/).split(/,/)
114:           next unless entries.all? { |entry| hostlist.include?(entry) }
115: 
116:           scanner.skip(/\s*/)
117:           type = scanner.scan(/\S+/)
118: 
119:           next unless SUPPORTED_TYPE.include?(type)
120: 
121:           scanner.skip(/\s*/)
122:           blob = scanner.rest.unpack("m*").first
123:           keys << Net::SSH::Buffer.new(blob).read_key
124:         end
125:       end
126: 
127:       keys
128:     end

Disabled; run with --debug to generate this.

[Validate]

Generated with the Darkfish Rdoc Generator 1.1.6.