Class: SSH::Key::Verifier

Inherits:
Object
  • Object
show all
Includes:
Helper
Defined in:
lib/ssh/key/verifier.rb

Constant Summary collapse

AUTHORIZED_KEYS_REGEX =

We only support protocol 2 public keys. protocol2 is: options keytype b64key comment

/^((?:[A-Za-z0-9-]+(?:="[^"]+")?,?)+ *)?(ssh-(?:dss|rsa)) *([^ ]*) *(.*)/

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Helper

#add_key_file, #add_key_from_host, #add_public_key_data

Constructor Details

#initialize(account = nil) ⇒ Verifier

A new SSH Key Verifier.

  • account - optional string username. Should be a valid user on the system.

If account is nil or omitted, then it defaults to the user running this process (current user)



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# File 'lib/ssh/key/verifier.rb', line 30

def initialize(=nil)
  if  == nil
     = Etc.getlogin
  end

  @account = 
  @agent = Net::SSH::Authentication::Agent.new
  @use_agent = true
  @use_authorized_keys = true
  @sshd_config_file = "/etc/ssh/sshd_config"
  @authorized_keys_file = nil
  @logger = Logger.new(STDERR)
  @logger.level = $DEBUG ? Logger::DEBUG : Logger::WARN
  @keys = []
end

Instance Attribute Details

#account ⇒ Object

Returns the value of attribute account.



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# File 'lib/ssh/key/verifier.rb', line 12

def 
  @account
end

#authorized_keys_file ⇒ Object

Returns the value of attribute authorized_keys_file.



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# File 'lib/ssh/key/verifier.rb', line 14

def authorized_keys_file
  @authorized_keys_file
end

#logger ⇒ Object

Returns the value of attribute logger.



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# File 'lib/ssh/key/verifier.rb', line 15

def logger
  @logger
end

#sshd_config_file ⇒ Object

Returns the value of attribute sshd_config_file.



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# File 'lib/ssh/key/verifier.rb', line 13

def sshd_config_file
  @sshd_config_file
end

#use_agent ⇒ Object

Returns the value of attribute use_agent.



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# File 'lib/ssh/key/verifier.rb', line 16

def use_agent
  @use_agent
end

#use_authorized_keys ⇒ Object

Returns the value of attribute use_authorized_keys.



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# File 'lib/ssh/key/verifier.rb', line 17

def use_authorized_keys
  @use_authorized_keys
end

Instance Method Details

#add_private_key_file(path, passphrase = nil) ⇒ Object

Add a private key to this Verifier from a file (like “.ssh/id_rsa”)

  • path - the string path to the key

  • passphrase - the passphrase for this key, omit if no passphrase.



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# File 'lib/ssh/key/verifier.rb', line 234

def add_private_key_file(path, passphrase=nil)
  @keys << Net::SSH::KeyFactory.load_private_key(path, passphrase)
end

#add_public_key_file(path) ⇒ Object

Add a public key to this Verifier from a file (like “.ssh/id_rsa.pub”)

This is for individual key files. If you want to specify an alternate location for your authorized_keys file, set:

Verifier#authorized_keys_file = "/path/to/authorized_keys"

  • path - the string path to the public key



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# File 'lib/ssh/key/verifier.rb', line 245

def add_public_key_file(path)
  @keys << Net::SSH::KeyFactory.load_public_key(path)
end

#authorized_keys ⇒ Object

find_authorized_keys_file



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# File 'lib/ssh/key/verifier.rb', line 182

def authorized_keys
  if @authorized_keys_file
    authorized_keys_file = @authorized_keys_file
  else
    authorized_keys_file = find_authorized_keys_file
  end

  if authorized_keys_file == nil
    @logger.info("No authorized keys file found.")
    return []
  end

  if !File.exists?(authorized_keys_file)
    @logger.info("User '#{@account}' has no authorized keys file '#{authorized_keys_file}'")
    return []
  end

  keys = []
  @logger.info("AuthorizedKeysFile ==> #{authorized_keys_file}")
  File.new(authorized_keys_file).each do |line|
    next if line =~ /^\s*$/    # Skip blanks
    next if line =~ /^\s*\#/  # Skip comments
    @logger.info line

    comment = nil

    # TODO(sissel): support more known_hosts formats
    if line =~ /^\|1\|/ # hashed known_hosts format
      comment, line = line.split(" ",2)
    end

    identity = Net::SSH::KeyFactory.load_data_public_key(line)

    # Add the '.comment' attribute to our key
    identity.extend(Net::SSH::Authentication::Agent::Comment)

    match = AUTHORIZED_KEYS_REGEX.match(line)
    if match
      comment = match[-1] 
    else
      puts "No comment or could not parse #{line}"
    end
    identity.comment = comment if comment

    keys << identity
  end
  return keys
end

#ensure_connected ⇒ Object

def initialize



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# File 'lib/ssh/key/verifier.rb', line 46

def ensure_connected
  begin
    @agent.connect! if !@agent.socket
  rescue Net::SSH::Authentication::AgentNotAvailable => e
    @use_agent = false
    @logger.info "SSH Agent not available"
  rescue => e
    @use_agent = false
    @logger.warn "Unexpected error ocurred. Disabling agent usage."
  end
end

#find_authorized_keys_file ⇒ Object

def verifying_identities



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# File 'lib/ssh/key/verifier.rb', line 132

def find_authorized_keys_file
  # Look up the @account's home directory.
  begin
     = Etc.getpwnam(@account)
  rescue ArgumentError => e
    @logger.warn("User '#{@account}' does not exist.")
  end

  # TODO(sissel): It's not clear how we should handle empty homedirs, if
  # that happens?

  # Default authorized_keys location
  authorized_keys_file = ".ssh/authorized_keys"

  # Try to find the AuthorizedKeysFile definition in the config.
  if File.exists?(@sshd_config_file)
    begin
      authorized_keys_file = File.new(@sshd_config_file).grep(/^\s*AuthorizedKeysFile/)[-1].split(" ")[-1]
    rescue 
      @logger.info("No AuthorizedKeysFile setting found in #{@sshd_config_file}, assuming '#{authorized_keys_file}'")
    end
  else
    @logger.warn("No sshd_config file found '#{@sshd_config_file}'. Won't check for authorized keys files. Assuming '#{authorized_keys_file}'")
  end

  # Support things sshd_config does.
  authorized_keys_file.gsub!(/%%/, "%")
  authorized_keys_file.gsub!(/%u/, @account)
  if authorized_keys_file =~ /%h/
    if  == nil
      @logger.warn("No homedirectory for #{@account}, skipping authorized_keys")
      return nil
    end

    authorized_keys_file.gsub!(/%h/, .dir)
  end

  # If relative path, use the homedir.
  if authorized_keys_file[0,1] != "/"
    if  == nil
      @logger.warn("No homedirectory for #{@account} and authorized_keys path is relative, skipping authorized_keys")
      return nil
    end

    authorized_keys_file = "#{.dir}/#{authorized_keys_file}"
  end

  return authorized_keys_file
end

#verify(signatures, original) ⇒ Object

Verify an original with the signatures.

  • signatures - a hash of { identity => signature } values or, it can be an array of signature strings or, it can simply be a signature string.

  • original - the original string value to verify



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# File 'lib/ssh/key/verifier.rb', line 78

def verify(signatures, original)
  @logger.info "Getting identities"
  identities = verifying_identities
  @logger.info "Have #{identities.length} identities"
  results = {}

  if signatures.is_a? Hash
    @logger.debug("verify 'signatures' is a Hash")
    inputs = signatures.values
  elsif signatures.is_a? Array
    @logger.debug("verify 'signatures' is an Array")
    inputs = signatures
  elsif signatures.is_a? String
    @logger.debug("verify 'signatures' is an String")
    inputs = [signatures]
  end

  if inputs[0].is_a? SSH::Key::Signature
    @logger.debug("verify 'signatures' is an array of Signatures")
    inputs = inputs.collect { |i| i.signature }
  end

  inputs.each do |signature|
    identities.each do |identity|
      key = [signature, identity]
      results[key] = identity.ssh_do_verify(signature, original)
      @logger.info "Trying key #{identity.to_s.split("\n")[1]}... #{results[key]}"
    end
  end
  return results
end

#verify?(signature, original) ⇒ Boolean

Can we validate ‘original’ against the signature(s)?

  • signature - a single SSH::Key::Signature or hash of { identity => signature } values.

  • original - the original string to verify against

See also: SSH::Key::Signer#sign

Returns:

  • (Boolean) 


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# File 'lib/ssh/key/verifier.rb', line 65

def verify?(signature, original)
  results = verify(signature, original)
  results.each do |identity, verified|
    return true if verified
  end
  return false
end

#verifying_identities ⇒ Object

def verify



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# File 'lib/ssh/key/verifier.rb', line 110

def verifying_identities
  identities = []
  ensure_connected 
  if @use_agent
    begin
      @agent.identities.each { |id| identities << id }
    rescue ArgumentError => e
      @logger.warn("Error from agent query: #{e}")
      @use_agent = false
    end
  end

  if @use_authorized_keys
    # Verifying should include your authorized_keys file, too, if we can 
    # find it.
    authorized_keys.each { |id| identities << id }
  end

  @keys.each { |id| identities << id }
  return identities
end