From: "ko1 (Koichi Sasada)" <redmine@...>
Date: 2013-02-22T09:08:42+09:00
Subject: [ruby-core:52651] [ruby-trunk - Feature #7795] Symbol.defined? and/or to_existing_symbol


Issue #7795 has been updated by ko1 (Koichi Sasada).

Assignee set to matz (Yukihiro Matsumoto)


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Feature #7795: Symbol.defined? and/or to_existing_symbol
https://bugs.ruby-lang.org/issues/7795#change-36737

Author: Student (Nathan Zook)
Status: Open
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: next minor


I'm pulling this out from deep in the discussions of issue http://bugs.ruby-lang.org/issues/7791, Let Symbols be Garbage Collected.

The problem is that the extreme utility of symbols makes them enticed to use, which results in a DOS vulnerability.  My proposal is to add either of a pair of methods that would make it easy to defend against a DOS along these lines.

#1) Symbol.defined?

In existing code, it would might like this:
class Symbol
  def self.defined?(string)
   all_symbols.any?{|sym| sym.to_s == string}
  end
end 

#2) to_existing_sym.  This would be defined in the same places as to_sym, but would through an argument error if the symbol did not already exist.



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