diff options
Diffstat (limited to 'lib/mixlib/authentication/signedheaderauth.rb')
| -rw-r--r-- | lib/mixlib/authentication/signedheaderauth.rb | 89 |
1 files changed, 81 insertions, 8 deletions
diff --git a/lib/mixlib/authentication/signedheaderauth.rb b/lib/mixlib/authentication/signedheaderauth.rb index 6b9b850..dcc9ee1 100644 --- a/lib/mixlib/authentication/signedheaderauth.rb +++ b/lib/mixlib/authentication/signedheaderauth.rb @@ -95,9 +95,27 @@ module Mixlib # Build the canonicalized request based on the method, other headers, etc. # compute the signature from the request, using the looked-up user secret - # ====Parameters - # private_key<OpenSSL::PKey::RSA>:: user's RSA private key. - def sign(private_key, sign_algorithm = algorithm, sign_version = proto_version) + # + # @param rsa_key [OpenSSL::PKey::RSA] User's RSA key. If `use_ssh_agent` is + # true, this must have the public key portion populated. If `use_ssh_agent` + # is false, this must have the private key portion populated. + # @param use_ssh_agent [Boolean] If true, use ssh-agent for request signing. + def sign(rsa_key, sign_algorithm = algorithm, sign_version = proto_version, **opts) + # Backwards compat stuff. + if sign_algorithm.is_a?(Hash) + # Was called like sign(key, sign_algorithm: 'foo', other: 'bar') + opts.update(sign_algorithm) + opts[:sign_algorithm] ||= algorithm + else + # Was called like sign(key, 'foo', '1.3', other: 'bar') + Mixlib::Authentication.logger.warn("Using deprecated positional arguments for sign(), please update to keyword arguments (from #{caller[1][/^(.*:\d+):in /, 1]})") + opts[:sign_algorithm] ||= sign_algorithm + opts[:sign_version] ||= sign_version + end + sign_algorithm = opts[:sign_algorithm] + sign_version = opts[:sign_version] + use_ssh_agent = opts[:use_ssh_agent] + digest = validate_sign_version_digest!(sign_algorithm, sign_version) # Our multiline hash for authorization will be encoded in multiple header # lines - X-Ops-Authorization-1, ... (starts at 1, not 0!) @@ -108,7 +126,7 @@ module Mixlib "X-Ops-Content-Hash" => hashed_body(digest), } - signature = Base64.encode64(do_sign(private_key, digest, sign_algorithm, sign_version)).chomp + signature = Base64.encode64(do_sign(rsa_key, digest, sign_algorithm, sign_version, use_ssh_agent)).chomp signature_lines = signature.split(/\n/) signature_lines.each_index do |idx| key = "X-Ops-Authorization-#{idx + 1}" @@ -244,18 +262,73 @@ module Mixlib Mixlib::Authentication::Digester end - # private - def do_sign(private_key, digest, sign_algorithm, sign_version) + # Low-level RSA signature implementation used in {#sign}. + # + # @api private + # @param rsa_key [OpenSSL::PKey::RSA] User's RSA key. If `use_ssh_agent` is + # true, this must have the public key portion populated. If `use_ssh_agent` + # is false, this must have the private key portion populated. + # @param digest [Class] Sublcass of OpenSSL::Digest to use while signing. + # @param sign_algorithm [String] Hash algorithm to use while signing. + # @param sign_version [String] Version number of the signing protocol to use. + # @param use_ssh_agent [Boolean] If true, use ssh-agent for request signing. + # @return [String] + def do_sign(rsa_key, digest, sign_algorithm, sign_version, use_ssh_agent) string_to_sign = canonicalize_request(sign_algorithm, sign_version) Mixlib::Authentication.logger.trace "String to sign: '#{string_to_sign}'" case sign_version when "1.3" - private_key.sign(digest.new, string_to_sign) + if use_ssh_agent + do_sign_ssh_agent(rsa_key, string_to_sign) + else + raise AuthenticationError, "RSA private key is required to sign requests, but a public key was provided" unless rsa_key.private? + rsa_key.sign(digest.new, string_to_sign) + end else - private_key.private_encrypt(string_to_sign) + raise AuthenticationError, "Agent signing mode requires signing protocol version 1.3 or newer" if use_ssh_agent + raise AuthenticationError, "RSA private key is required to sign requests, but a public key was provided" unless rsa_key.private? + rsa_key.private_encrypt(string_to_sign) end end + # Low-level signing logic for using ssh-agent. This requires the user has + # already set up ssh-agent and used ssh-add to load in a (possibly encrypted) + # RSA private key. ssh-agent supports keys other than RSA, however they + # are not supported as Chef's protocol explicitly requires RSA keys/sigs. + # + # @api private + # @param rsa_key [OpenSSL::PKey::RSA] User's RSA public key. + # @param string_to_sign [String] String data to sign with the requested key. + # @return [String] + def do_sign_ssh_agent(rsa_key, string_to_sign) + # First try loading net-ssh as it is an optional dependency. + begin + require "net/ssh" + rescue LoadError => e + # ???: Since agent mode is explicitly enabled, should we even catch + # this in the first place? Might be cleaner to let the LoadError bubble. + raise AuthenticationError, "net-ssh gem is not available, unable to use ssh-agent signing: #{e.message}" + end + + # Try to connect to ssh-agent. + begin + agent = Net::SSH::Authentication::Agent.connect + rescue Net::SSH::Authentication::AgentNotAvailable => e + raise AuthenticationError, "Could not connect to ssh-agent. Make sure the SSH_AUTH_SOCK environment variable is set and ssh-agent is running: #{e.message}" + end + + begin + ssh2_signature = agent.sign(rsa_key.public_key, string_to_sign, Net::SSH::Authentication::Agent::SSH_AGENT_RSA_SHA2_256) + rescue Net::SSH::Authentication::AgentError => e + raise AuthenticationError, "Unable to sign request with ssh-agent. Make sure your key is loaded with ssh-add: #{e.class.name} #{e.message})" + end + + # extract signature from SSH Agent response => skip first 20 bytes for RSA keys + # "\x00\x00\x00\frsa-sha2-256\x00\x00\x01\x00" + # (see http://api.libssh.org/rfc/PROTOCOL.agent for details) + ssh2_signature[20..-1] + end + private :canonical_time, :canonical_path, :parse_signing_description, :digester, :canonicalize_user_id end |