Class: Ronin::Fuzzing::Mutator

Inherits:
Object
  • Object
show all
Defined in:
lib/ronin/fuzzing/mutator.rb

Overview

Fuzzer class that permutates over every mutation of a String, given mutation rules.

Since:

  • 0.5.0

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(rules) ⇒ Mutator

Initialize the Mutator.

Raises:

  • (TypeError)

    A mutation pattern was not a Regexp, String or Symbol. A mutation substitution was not a Symbol or Enumerable.

Since:

  • 0.5.0


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# File 'lib/ronin/fuzzing/mutator.rb', line 54

def initialize(rules)
  @rules = {}
  
  rules.each do |pattern,mutation|
    pattern = case pattern
              when Regexp
                pattern
              when String
                Regexp.new(Regexp.escape(pattern))
              when Symbol
                Regexp.const_get(pattern.to_s.upcase)
              else
                raise(TypeError,"cannot convert #{pattern.inspect} to a Regexp")
              end

    mutation = case mutation
               when Enumerable
                 mutation
               when Symbol
                 Ronin::Fuzzing[mutation]
               else
                 raise(TypeError,"mutation #{mutation.inspect} must be a Symbol or Enumerable")
               end

    @rules[pattern] = mutation
  end
end

Instance Attribute Details

#rulesObject (readonly)

Mutation rules

Since:

  • 0.5.0


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# File 'lib/ronin/fuzzing/mutator.rb', line 42

def rules
  @rules
end

Instance Method Details

#each(string) {|mutant| ... } ⇒ Enumerator

Permutes over every possible mutation of the String.

Yields:

  • (mutant)

    The given block will be yielded every possible mutant String.

Yield Parameters:

  • mutant (String)

    A mutated String.

Since:

  • 0.5.0


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# File 'lib/ronin/fuzzing/mutator.rb', line 97

def each(string)
  return enum_for(__method__,string) unless block_given?

  matches = Set[]

  @rules.each do |pattern,mutation|
    scanner = StringScanner.new(string)

    while scanner.scan_until(pattern)
      length   = scanner.matched_size
      index    = scanner.pos - length
      original = scanner.matched

      mutator = Combinatorics::Generator.new do |g|
        mutation.each do |mutate|
          g.yield case mutate
                  when Proc
                    mutate.call(original)
                  when Integer
                    mutate.chr
                  else
                    mutate.to_s
                  end
        end
      end

      matches << [index, length, mutator]
    end
  end

  matches.powerset do |submatches|
    # ignore the empty Set
    next if submatches.empty?

    # sort the submatches by index
    submatches = submatches.sort_by { |index,length,mutator| index }
    sets       = []
    prev_index = 0

    submatches.each do |index,length,mutator|
      # add the previous substring to the set of Strings
      if index > prev_index
        sets << [string[prev_index,index - prev_index]]
      end

      # add the mutator to the set of Strings
      sets << mutator

      prev_index = index + length
    end

    # add the remaining substring to the set of Strings
    if prev_index < string.length
      sets << [string[prev_index..-1]]
    end

    sets.comprehension { |strings| yield strings.join }
  end

  return nil
end