AlkantarClanX12
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# frozen_string_literal: true
require_relative "visitor"
module Gem::SafeMarshal
module Visitors
class ToRuby < Visitor
def initialize(permitted_classes:, permitted_symbols:, permitted_ivars:)
@permitted_classes = permitted_classes
@permitted_symbols = ["E"].concat(permitted_symbols).concat(permitted_classes)
@permitted_ivars = permitted_ivars
@objects = []
@symbols = []
@class_cache = {}
@stack = ["root"]
@stack_idx = 1
end
def inspect # :nodoc:
format("#<%s permitted_classes: %p permitted_symbols: %p permitted_ivars: %p>",
self.class, @permitted_classes, @permitted_symbols, @permitted_ivars)
end
def visit(target)
stack_idx = @stack_idx
super
ensure
@stack_idx = stack_idx - 1
end
private
def push_stack(element)
@stack[@stack_idx] = element
@stack_idx += 1
end
def visit_Gem_SafeMarshal_Elements_Array(a)
array = register_object([])
elements = a.elements
size = elements.size
idx = 0
# not idiomatic, but there's a huge number of IMEMOs allocated here, so we avoid the block
# because this is such a hot path when doing a bundle install with the full index
until idx == size
push_stack idx
array << visit(elements[idx])
idx += 1
end
array
end
def visit_Gem_SafeMarshal_Elements_Symbol(s)
name = s.name
raise UnpermittedSymbolError.new(symbol: name, stack: formatted_stack) unless @permitted_symbols.include?(name)
visit_symbol_type(s)
end
def map_ivars(klass, ivars)
stack_idx = @stack_idx
ivars.map.with_index do |(k, v), i|
@stack_idx = stack_idx
push_stack "ivar_"
push_stack i
k = resolve_ivar(klass, k)
@stack_idx = stack_idx
push_stack k
next k, visit(v)
end
end
def visit_Gem_SafeMarshal_Elements_WithIvars(e)
object_offset = @objects.size
push_stack "object"
object = visit(e.object)
ivars = map_ivars(object.class, e.ivars)
case e.object
when Elements::UserDefined
if object.class == ::Time
internal = []
ivars.reject! do |k, v|
case k
when :offset, :zone, :nano_num, :nano_den, :submicro
internal << [k, v]
true
else
false
end
end
s = e.object.binary_string
marshal_string = "\x04\bIu:\tTime".b
marshal_string.concat(s.size + 5)
marshal_string << s
marshal_string.concat(internal.size + 5)
internal.each do |k, v|
marshal_string.concat(":")
marshal_string.concat(k.size + 5)
marshal_string.concat(k.to_s)
dumped = Marshal.dump(v)
dumped[0, 2] = ""
marshal_string.concat(dumped)
end
object = @objects[object_offset] = Marshal.load(marshal_string)
end
when Elements::String
enc = nil
ivars.reject! do |k, v|
case k
when :E
case v
when TrueClass
enc = "UTF-8"
when FalseClass
enc = "US-ASCII"
else
raise FormatError, "Unexpected value for String :E #{v.inspect}"
end
when :encoding
enc = v
else
next false
end
true
end
object.force_encoding(enc) if enc
end
ivars.each do |k, v|
object.instance_variable_set k, v
end
object
end
def visit_Gem_SafeMarshal_Elements_Hash(o)
hash = register_object({})
o.pairs.each_with_index do |(k, v), i|
push_stack i
k = visit(k)
push_stack k
hash[k] = visit(v)
end
hash
end
def visit_Gem_SafeMarshal_Elements_HashWithDefaultValue(o)
hash = visit_Gem_SafeMarshal_Elements_Hash(o)
push_stack :default
hash.default = visit(o.default)
hash
end
def visit_Gem_SafeMarshal_Elements_Object(o)
register_object(resolve_class(o.name).allocate)
end
def visit_Gem_SafeMarshal_Elements_ObjectLink(o)
@objects[o.offset]
end
def visit_Gem_SafeMarshal_Elements_SymbolLink(o)
@symbols[o.offset]
end
def visit_Gem_SafeMarshal_Elements_UserDefined(o)
register_object(call_method(resolve_class(o.name), :_load, o.binary_string))
end
def visit_Gem_SafeMarshal_Elements_UserMarshal(o)
klass = resolve_class(o.name)
compat = COMPAT_CLASSES.fetch(klass, nil)
idx = @objects.size
object = register_object(call_method(compat || klass, :allocate))
push_stack :data
ret = call_method(object, :marshal_load, visit(o.data))
if compat
object = @objects[idx] = ret
end
object
end
def visit_Gem_SafeMarshal_Elements_Integer(i)
i.int
end
def visit_Gem_SafeMarshal_Elements_Nil(_)
nil
end
def visit_Gem_SafeMarshal_Elements_True(_)
true
end
def visit_Gem_SafeMarshal_Elements_False(_)
false
end
def visit_Gem_SafeMarshal_Elements_String(s)
register_object(+s.str)
end
def visit_Gem_SafeMarshal_Elements_Float(f)
case f.string
when "inf"
::Float::INFINITY
when "-inf"
-::Float::INFINITY
when "nan"
::Float::NAN
else
f.string.to_f
end
end
def visit_Gem_SafeMarshal_Elements_Bignum(b)
result = 0
b.data.each_byte.with_index do |byte, exp|
result += (byte * 2**(exp * 8))
end
case b.sign
when 43 # ?+
result
when 45 # ?-
-result
else
raise FormatError, "Unexpected sign for Bignum #{b.sign.chr.inspect} (#{b.sign})"
end
end
def visit_Gem_SafeMarshal_Elements_UserClass(r)
if resolve_class(r.name) == ::Hash && r.wrapped_object.is_a?(Elements::Hash)
hash = register_object({}.compare_by_identity)
o = r.wrapped_object
o.pairs.each_with_index do |(k, v), i|
push_stack i
k = visit(k)
push_stack k
hash[k] = visit(v)
end
if o.is_a?(Elements::HashWithDefaultValue)
push_stack :default
hash.default = visit(o.default)
end
hash
else
raise UnsupportedError.new("Unsupported user class #{resolve_class(r.name)} in marshal stream", stack: formatted_stack)
end
end
def resolve_class(n)
@class_cache[n] ||= begin
to_s = resolve_symbol_name(n)
raise UnpermittedClassError.new(name: to_s, stack: formatted_stack) unless @permitted_classes.include?(to_s)
visit_symbol_type(n)
begin
::Object.const_get(to_s)
rescue NameError
raise ArgumentError, "Undefined class #{to_s.inspect}"
end
end
end
class RationalCompat
def marshal_load(s)
num, den = s
raise ArgumentError, "Expected 2 ints" unless s.size == 2 && num.is_a?(Integer) && den.is_a?(Integer)
Rational(num, den)
end
end
private_constant :RationalCompat
COMPAT_CLASSES = {}.tap do |h|
h[Rational] = RationalCompat
end.compare_by_identity.freeze
private_constant :COMPAT_CLASSES
def resolve_ivar(klass, name)
to_s = resolve_symbol_name(name)
raise UnpermittedIvarError.new(symbol: to_s, klass: klass, stack: formatted_stack) unless @permitted_ivars.fetch(klass.name, [].freeze).include?(to_s)
visit_symbol_type(name)
end
def visit_symbol_type(element)
case element
when Elements::Symbol
sym = element.name.to_sym
@symbols << sym
sym
when Elements::SymbolLink
visit_Gem_SafeMarshal_Elements_SymbolLink(element)
end
end
# This is a hot method, so avoid respond_to? checks on every invocation
if :read.respond_to?(:name)
def resolve_symbol_name(element)
case element
when Elements::Symbol
element.name
when Elements::SymbolLink
visit_Gem_SafeMarshal_Elements_SymbolLink(element).name
else
raise FormatError, "Expected symbol or symbol link, got #{element.inspect} @ #{formatted_stack.join(".")}"
end
end
else
def resolve_symbol_name(element)
case element
when Elements::Symbol
element.name
when Elements::SymbolLink
visit_Gem_SafeMarshal_Elements_SymbolLink(element).to_s
else
raise FormatError, "Expected symbol or symbol link, got #{element.inspect} @ #{formatted_stack.join(".")}"
end
end
end
def register_object(o)
@objects << o
o
end
def call_method(receiver, method, *args)
receiver.__send__(method, *args)
rescue NoMethodError => e
raise unless e.receiver == receiver
raise MethodCallError, "Unable to call #{method.inspect} on #{receiver.inspect}, perhaps it is a class using marshal compat, which is not visible in ruby? #{e}"
end
def formatted_stack
formatted = []
@stack[0, @stack_idx].each do |e|
if e.is_a?(Integer)
if formatted.last == "ivar_"
formatted[-1] = "ivar_#{e}"
else
formatted << "[#{e}]"
end
else
formatted << e
end
end
formatted
end
class Error < StandardError
end
class UnpermittedSymbolError < Error
def initialize(symbol:, stack:)
@symbol = symbol
@stack = stack
super "Attempting to load unpermitted symbol #{symbol.inspect} @ #{stack.join "."}"
end
end
class UnpermittedIvarError < Error
def initialize(symbol:, klass:, stack:)
@symbol = symbol
@klass = klass
@stack = stack
super "Attempting to set unpermitted ivar #{symbol.inspect} on object of class #{klass} @ #{stack.join "."}"
end
end
class UnpermittedClassError < Error
def initialize(name:, stack:)
@name = name
@stack = stack
super "Attempting to load unpermitted class #{name.inspect} @ #{stack.join "."}"
end
end
class UnsupportedError < Error
def initialize(message, stack:)
super "#{message} @ #{stack.join "."}"
end
end
class FormatError < Error
end
class MethodCallError < Error
end
end
end
end