Class: Contrast::Agent::Protect::Rule::DefaultScanner Deprecated

Inherits:
Object
  • Object
show all
Defined in:
lib/contrast/agent/protect/rule/default_scanner.rb

Overview

Deprecated.

RUBY-356: this class and those that extend it are being phased out in favor of the more performant code in the Service.

The base class used to determine if a user input crosses a token boundary or state, indicating a successful attack using SQL or NoSQL Injection.

Constant Summary collapse

OPERATOR_PATTERN = 
%r{[+=*^/%><!-]}.cs__freeze

Instance Method Summary collapse

Instance Method Details

#crosses_boundary(query, index, input) ⇒ Object

Potential states :STATE_INSIDE_TOKEN :STATE_INSIDE_NUMBER :STATE_EXPECTING_TOKEN :STATE_INSIDE_DOUBLEQUOTE :STATE_INSIDE_SINGLEQUOTE :STATE_INSIDE_STRING_ESCAPE_BLOCK :STATE_INSIDE_LINE_COMMENT # inside a comment that will continue to the end of the line :STATE_INSIDE_BLOCK_COMMENT # inside a commend that will end with a closing tag :STATE_SKIP_NEXT_CHARACTER



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 21

def crosses_boundary query, index, input
  last_boundary = 0
  token_boundaries(query).each do |boundary|
    if boundary > index
      return last_boundary, boundary if boundary < index + input.length

      break
    end
    last_boundary = boundary
  end
  nil
end

#double_quote?(query, index) ⇒ Boolean 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 180

def double_quote? query, index
  return false unless index >= 0 && index < query.length

  query[index] == Contrast::Utils::ObjectShare::DOUBLE_QUOTE
end

#double_quote_escape_in_double_quote? ⇒ Boolean

Indicates if ‘“”’ inside of double quotes is the equivalent of ‘"’ We assume no by default



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 260

def double_quote_escape_in_double_quote?
  false
end

#end_block_comment?(char, index, query) ⇒ Boolean

Is the current character / sequence of characters the end of a block comment We assume ‘*/’ ends the comment by default



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 251

def end_block_comment? char, index, query
  return false unless char == Contrast::Utils::ObjectShare::ASTERISK
  return false unless (query.length - 2) >= index

  query[index + 1] == Contrast::Utils::ObjectShare::SLASH
end

#escape_char?(char) ⇒ Boolean

Is the character provided an escape character? By default, we’ll assume



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 272

def escape_char? char
  char == Contrast::Utils::ObjectShare::BACK_SLASH
end

#escape_sequence_end?(_char) ⇒ Boolean

Is this the end of a string escape sequence? Since escape sequences aren’t supported, the answer is always false



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 284

def escape_sequence_end? _char
  false
end

#escape_sequence_start?(_char) ⇒ Boolean

Is this the start of a string escape sequence? Since escape sequences aren’t supported, the answer is always false



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 278

def escape_sequence_start? _char
  false
end

#find_block_comment_boundary(query, index) ⇒ Object 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 203

def find_block_comment_boundary query, index
  idx = index
  while idx < query.length
    char = query[idx]
    break if end_block_comment?(char, idx, query)

    idx += 1
  end
  idx
end

#find_escape_sequence_boundary(query, index) ⇒ Object 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 192

def find_escape_sequence_boundary query, index
  idx = index
  while idx < query.length
    char = query[idx]
    break if escape_sequence_end?(char)

    idx += 1
  end
  idx
end

#find_new_line_boundary(query, index) ⇒ Object 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 214

def find_new_line_boundary query, index
  idx = index
  while idx < query.length
    char = query[idx]
    break if char == Contrast::Utils::ObjectShare::NEW_LINE
    break if char == Contrast::Utils::ObjectShare::RETURN

    idx += 1
  end
  idx
end

#operator?(char) ⇒ Boolean 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 227

def operator? char
  char.match?(OPERATOR_PATTERN)
end

#process_double_quote(boundaries, char, index, query) ⇒ Object 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 146

def process_double_quote boundaries, char, index, query
  if escape_char?(char)
    :STATE_SKIP_NEXT_CHARACTER
  elsif escape_sequence_start?(char)
    :STATE_INSIDE_STRING_ESCAPE_BLOCK
  elsif char == Contrast::Utils::ObjectShare::DOUBLE_QUOTE
    if double_quote_escape_in_double_quote? && double_quote?(query, index + 1)
      :STATE_SKIP_NEXT_CHARACTER
    else
      boundaries << index
      :STATE_EXPECTING_TOKEN
    end
  else
    :STATE_INSIDE_DOUBLEQUOTE
  end
end

#process_expecting_token(boundaries, char, index, query) ⇒ Object 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 89

def process_expecting_token boundaries, char, index, query
  if char == Contrast::Utils::ObjectShare::SINGLE_QUOTE
    boundaries << index
    :STATE_INSIDE_SINGLEQUOTE
  elsif char == Contrast::Utils::ObjectShare::DOUBLE_QUOTE
    boundaries << index
    :STATE_INSIDE_DOUBLEQUOTE
  elsif char.match?(Contrast::Utils::ObjectShare::DIGIT_REGEXP)
    boundaries << index
    :STATE_INSIDE_NUMBER
  elsif start_line_comment?(char, index, query)
    boundaries << index
    :STATE_INSIDE_LINE_COMMENT
  elsif start_block_comment?(char, index, query)
    boundaries << index
    :STATE_INSIDE_BLOCK_COMMENT
  elsif char.match?(Contrast::Utils::ObjectShare::NOT_WHITE_SPACE_REGEXP)
    boundaries << index
    :STATE_INSIDE_TOKEN
  else
    :STATE_EXPECTING_TOKEN
  end
end

#process_inside_token(boundaries, char, index, query) ⇒ Object 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 113

def process_inside_token boundaries, char, index, query
  if char == Contrast::Utils::ObjectShare::SINGLE_QUOTE
    boundaries << index
    :STATE_INSIDE_SINGLEQUOTE
  elsif char == Contrast::Utils::ObjectShare::DOUBLE_QUOTE
    boundaries << index
    :STATE_INSIDE_DOUBLEQUOTE
  elsif start_line_comment?(char, index, query)
    boundaries << index
    :STATE_INSIDE_LINE_COMMENT
  elsif start_block_comment?(char, index, query)
    boundaries << index
    :STATE_INSIDE_BLOCK_COMMENT
  elsif operator?(char)
    boundaries << index
    :STATE_EXPECTING_TOKEN
  elsif char.match?(Contrast::Utils::ObjectShare::WHITE_SPACE_REGEXP)
    boundaries << index
    :STATE_EXPECTING_TOKEN
  else
    :STATE_INSIDE_TOKEN
  end
end

#process_number(boundaries, char, index, _query) ⇒ Object 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 137

def process_number boundaries, char, index, _query
  if char.match?(Contrast::Utils::ObjectShare::DIGIT_REGEXP) || char == Contrast::Utils::ObjectShare::PERIOD
    :STATE_INSIDE_NUMBER
  else
    boundaries << index
    :STATE_EXPECTING_TOKEN
  end
end

#process_single_quote(boundaries, char, index, query) ⇒ Object 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 163

def process_single_quote boundaries, char, index, query
  if escape_char?(char)
    :STATE_SKIP_NEXT_CHARACTER
  elsif escape_sequence_start?(char)
    :STATE_INSIDE_STRING_ESCAPE_BLOCK
  elsif char == Contrast::Utils::ObjectShare::SINGLE_QUOTE
    if singe_quote_escape_in_singe_quote? && single_quote?(query, index + 1)
      :STATE_SKIP_NEXT_CHARACTER
    else
      boundaries << index
      :STATE_EXPECTING_TOKEN
    end
  else
    :STATE_INSIDE_SINGLEQUOTE
  end
end

#process_state(boundaries, current_state, char, index, query) ⇒ Object 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 74

def process_state boundaries, current_state, char, index, query
  case current_state
  when :STATE_EXPECTING_TOKEN
    process_expecting_token(boundaries, char, index, query)
  when :STATE_INSIDE_NUMBER
    process_number(boundaries, char, index, query)
  when :STATE_INSIDE_TOKEN
    process_inside_token(boundaries, char, index, query)
  when :STATE_INSIDE_DOUBLEQUOTE
    process_double_quote(boundaries, char, index, query)
  when :STATE_INSIDE_SINGLEQUOTE
    process_single_quote(boundaries, char, index, query)
  end
end

#scan_token_boundaries(query) ⇒ Object 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 38

def scan_token_boundaries query
  boundaries = []
  return boundaries unless query && !query.empty?

  state = :STATE_EXPECTING_TOKEN
  index = 0

  while index < query.length
    char = query[index]

    previous_state = state

    state = process_state(boundaries, state, char, index, query)

    case state
    when :STATE_SKIP_NEXT_CHARACTER
      index += 1
      state = previous_state
    when :STATE_INSIDE_STRING_ESCAPE_BLOCK
      index = find_escape_sequence_boundary(query, index + 1)
      state = previous_state
    when :STATE_INSIDE_BLOCK_COMMENT
      index = find_block_comment_boundary(query, index + 2)
      index += 1
      state = previous_state
      boundaries << index
    when :STATE_INSIDE_LINE_COMMENT
      index = find_new_line_boundary(query, index + 1)
      state = previous_state
      boundaries << index
    end
    index += 1
  end
  boundaries
end

#singe_quote_escape_in_singe_quote? ⇒ Boolean

Indicates if “”” inside of single quotes is the equivalent of “'” We assume yes by default



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 266

def singe_quote_escape_in_singe_quote?
  true
end

#single_quote?(query, index) ⇒ Boolean 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 186

def single_quote? query, index
  return false unless index >= 0 && index < query.length

  query[index] == Contrast::Utils::ObjectShare::SINGLE_QUOTE
end

#start_block_comment?(char, index, query) ⇒ Boolean

Is the current character / sequence of characters the start of a block comment We assume ‘/*’ starts the comment by default



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 242

def start_block_comment? char, index, query
  return false unless char == Contrast::Utils::ObjectShare::SLASH
  return false unless (query.length - 2) >= index

  query[index + 1] == Contrast::Utils::ObjectShare::ASTERISK
end

#start_line_comment?(char, index, query) ⇒ Boolean

@note: Any class extending this module should override these methods as needed Are the current and subsequent characters both ‘-’ ?



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 233

def start_line_comment? char, index, query
  return false unless char == Contrast::Utils::ObjectShare::DASH
  return false unless (query.length - 2) >= index

  query[index + 1] == Contrast::Utils::ObjectShare::DASH
end

#token_boundaries(query) ⇒ Object 



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# File 'lib/contrast/agent/protect/rule/default_scanner.rb', line 34

def token_boundaries query
  @_token_boundaries ||= scan_token_boundaries(query)
end