Gem::Security::Policy

A Gem::Security::Policy object encapsulates the settings for verifying signed gem files. This is the base class. You can either declare an instance of this or use one of the preset security policies in Gem::Security::Policies.

Attributes

name[R]

only_signed[RW]

only_trusted[RW]

to_s[R]

verify_chain[RW]

verify_data[RW]

verify_root[RW]

verify_signer[RW]

Public Class Methods

new(name, policy = {}) click to toggle source

Create a new Gem::Security::Policy object with the given mode and options.

 
               # File rubygems/security/policy.rb, line 22
def initialize name, policy = {}, opt = {}
  require 'openssl'

  @name = name

  @opt = opt

  # Default to security
  @only_signed   = true
  @only_trusted  = true
  @verify_chain  = true
  @verify_data   = true
  @verify_root   = true
  @verify_signer = true

  policy.each_pair do |key, val|
    case key
    when :verify_data   then @verify_data   = val
    when :verify_signer then @verify_signer = val
    when :verify_chain  then @verify_chain  = val
    when :verify_root   then @verify_root   = val
    when :only_trusted  then @only_trusted  = val
    when :only_signed   then @only_signed   = val
    end
  end
end

Public Instance Methods

check_cert(signer, issuer, time) click to toggle source

Ensures that signer is valid for time and was signed by the issuer. If the issuer is nil no verification is performed.

 
               # File rubygems/security/policy.rb, line 83
def check_cert signer, issuer, time
  raise Gem::Security::Exception, 'missing signing certificate' unless
    signer

  message = "certificate #{signer.subject}"

  if not_before = signer.not_before and not_before > time then
    raise Gem::Security::Exception,
          "#{message} not valid before #{not_before}"
  end

  if not_after = signer.not_after and not_after < time then
    raise Gem::Security::Exception, "#{message} not valid after #{not_after}"
  end

  if issuer and not signer.verify issuer.public_key then
    raise Gem::Security::Exception,
          "#{message} was not issued by #{issuer.subject}"
  end

  true
end

check_chain(chain, time) click to toggle source

Verifies each certificate in chain has signed the following certificate and is valid for the given time.

 
               # File rubygems/security/policy.rb, line 53
def check_chain chain, time
  raise Gem::Security::Exception, 'missing signing chain' unless chain
  raise Gem::Security::Exception, 'empty signing chain' if chain.empty?

  begin
    chain.each_cons 2 do |issuer, cert|
      check_cert cert, issuer, time
    end

    true
  rescue Gem::Security::Exception => e
    raise Gem::Security::Exception, "invalid signing chain: #{e.message}"
  end
end

check_data(public_key, digest, signature, data) click to toggle source

Verifies that data matches the signature created by public_key and the digest algorithm.

 
               # File rubygems/security/policy.rb, line 72
def check_data public_key, digest, signature, data
  raise Gem::Security::Exception, "invalid signature" unless
    public_key.verify digest.new, signature, data.digest

  true
end

check_key(signer, key) click to toggle source

Ensures the public key of key matches the public key in signer

 
               # File rubygems/security/policy.rb, line 109
def check_key signer, key
  unless signer and key then
    return true unless @only_signed

    raise Gem::Security::Exception, 'missing key or signature'
  end

  raise Gem::Security::Exception,
    "certificate #{signer.subject} does not match the signing key" unless
      signer.public_key.to_pem == key.public_key.to_pem

  true
end

check_root(chain, time) click to toggle source

Ensures the root certificate in chain is self-signed and valid for time.

 
               # File rubygems/security/policy.rb, line 127
def check_root chain, time
  raise Gem::Security::Exception, 'missing signing chain' unless chain

  root = chain.first

  raise Gem::Security::Exception, 'missing root certificate' unless root

  raise Gem::Security::Exception,
        "root certificate #{root.subject} is not self-signed " +
        "(issuer #{root.issuer})" if
    root.issuer.to_s != root.subject.to_s # HACK to_s is for ruby 1.8

  check_cert root, root, time
end

check_trust(chain, digester, trust_dir) click to toggle source

Ensures the root of chain has a trusted certificate in trust_dir and the digests of the two certificates match according to digester

 
               # File rubygems/security/policy.rb, line 146
def check_trust chain, digester, trust_dir
  raise Gem::Security::Exception, 'missing signing chain' unless chain

  root = chain.first

  raise Gem::Security::Exception, 'missing root certificate' unless root

  path = Gem::Security.trust_dir.cert_path root

  unless File.exist? path then
    message = "root cert #{root.subject} is not trusted"

    message << " (root of signing cert #{chain.last.subject})" if
      chain.length > 1

    raise Gem::Security::Exception, message
  end

  save_cert = OpenSSL::X509::Certificate.new File.read path
  save_dgst = digester.digest save_cert.public_key.to_s

  pkey_str = root.public_key.to_s
  cert_dgst = digester.digest pkey_str

  raise Gem::Security::Exception,
        "trusted root certificate #{root.subject} checksum " +
        "does not match signing root certificate checksum" unless
    save_dgst == cert_dgst

  true
end

verify(chain, key = nil, digests = {}) click to toggle source

Verifies the certificate chain is valid, the digests match the signatures signatures created by the signer depending on the policy settings.

If key is given it is used to validate the signing certificate.

 
               # File rubygems/security/policy.rb, line 193
def verify chain, key = nil, digests = {}, signatures = {}
  if @only_signed and signatures.empty? then
    raise Gem::Security::Exception,
      "unsigned gems are not allowed by the #{name} policy"
  end

  opt       = @opt
  digester  = Gem::Security::DIGEST_ALGORITHM
  trust_dir = opt[:trust_dir]
  time      = Time.now

  _, signer_digests = digests.find do |algorithm, file_digests|
    file_digests.values.first.name == Gem::Security::DIGEST_NAME
  end

  if @verify_data then
    raise Gem::Security::Exception, 'no digests provided (probable bug)' if
      signer_digests.nil? or signer_digests.empty?
  else
    signer_digests = {}
  end

  signer = chain.last

  check_key signer, key if key

  check_cert signer, nil, time if @verify_signer

  check_chain chain, time if @verify_chain

  check_root chain, time if @verify_root

  check_trust chain, digester, trust_dir if @only_trusted

  signatures.each do |file, _|
    digest = signer_digests[file]

    raise Gem::Security::Exception, "missing digest for #{file}" unless
      digest
  end

  signer_digests.each do |file, digest|
    signature = signatures[file]

    raise Gem::Security::Exception, "missing signature for #{file}" unless
      signature

    check_data signer.public_key, digester, signature, digest if @verify_data
  end

  true
end

verify_signatures(spec, digests, signatures) click to toggle source

Extracts the certificate chain from the spec and calls verify to ensure the signatures and certificate chain is valid according to the policy..

 
               # File rubygems/security/policy.rb, line 250
def verify_signatures spec, digests, signatures
  chain = spec.cert_chain.map do |cert_pem|
    OpenSSL::X509::Certificate.new cert_pem
  end

  verify chain, nil, digests, signatures

  true
end

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