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Brakeman::CheckSQL

This check tests for find calls which do not use Rails' auto SQL escaping

For example:

Project.find(:all, :conditions => "name = '" + params[:name] + "'")

Project.find(:all, :conditions => "name = '#{params[:name]}'")

User.find_by_sql("SELECT * FROM projects WHERE name = '#{params[:name]}'")

Public Instance Methods

check_by_sql_arguments(arg) click to toggle source

find_by_sql and count_by_sql can take either a straight SQL string or an array with values to bind.

# File lib/brakeman/checks/check_sql.rb, line 319
def check_by_sql_arguments arg
  return unless sexp? arg

  #This is kind of unnecessary, because unsafe_sql? will handle an array
  #correctly, but might be better to be explicit.
  if array? arg
    unsafe_sql? arg[1]
  else
    unsafe_sql? arg
  end
end
check_call(exp) click to toggle source

Check call for string building

# File lib/brakeman/checks/check_sql.rb, line 525
def check_call exp
  return unless call? exp

  if unsafe = check_for_string_building(exp)
    unsafe
  elsif call? exp.target
    check_call exp.target
  else
    nil
  end
end
check_find_arguments(arg) click to toggle source

The 'find' methods accept a number of different types of parameters:

* The first argument might be :all, :first, or :last
* The first argument might be an integer ID or an array of IDs
* The second argument might be a hash of options, some of which are
  dangerous and some of which are not
* The second argument might contain SQL fragments as values
* The second argument might contain properly parameterized SQL fragments in arrays
* The second argument might contain improperly parameterized SQL fragments in arrays

This method should only be passed the second argument.

# File lib/brakeman/checks/check_sql.rb, line 253
def check_find_arguments arg
  if not sexp? arg or node_type? arg, :lit, :string, :str, :true, :false, :nil
    return nil
  end

  unsafe_sql? arg
end
check_for_limit_or_offset_vulnerability(options) click to toggle source

Prior to Rails 2.1.1, the :offset and :limit parameters were not escaping input properly.

www.rorsecurity.info/2008/09/08/sql-injection-issue-in-limit-and-offset-parameter/

# File lib/brakeman/checks/check_sql.rb, line 541
def check_for_limit_or_offset_vulnerability options
  return false if @rails_version.nil? or @rails_version >= "2.1.1" or not hash? options

  if hash_access(options, :limit) or hash_access(options, :offset)
    return true
  end

  false
end
check_for_string_building(exp) click to toggle source
# File lib/brakeman/checks/check_sql.rb, line 484
def check_for_string_building exp
  return unless call? exp

  target = exp.target
  method = exp.method

  if string? target or string? exp.first_arg
    if STRING_METHODS.include? method
      return exp
    end
  elsif STRING_METHODS.include? method and call? target
    unsafe_sql? target
  end
end
check_hash_keys(exp) click to toggle source

Check hash keys for user input. (Seems unlikely, but if a user can control the column names queried, that could be bad)

# File lib/brakeman/checks/check_sql.rb, line 362
def check_hash_keys exp
  hash_iterate(exp) do |key, value|
    unless symbol? key
      if unsafe_key = unsafe_sql?(value)
        return unsafe_key
      end
    end
  end

  false
end
check_hash_values(exp) click to toggle source

Checks hash values associated with these keys:

* conditions
* order
* having
* joins
* select
* from
* lock
# File lib/brakeman/checks/check_sql.rb, line 457
def check_hash_values exp
  hash_iterate(exp) do |key, value|
    if symbol? key
      unsafe = case key.value
               when :conditions, :having, :select
                 check_query_arguments value
               when :order, :group
                 check_order_arguments value
               when :joins
                 check_joins_arguments value
               when :lock
                 check_lock_arguments value
               when :from
                 unsafe_sql? value
               else
                 nil
               end

      return unsafe if unsafe
    end
  end

  false
end
check_joins_arguments(arg) click to toggle source

joins can take a string, hash of associations, or an array of both(?) We only care about the possible string values.

# File lib/brakeman/checks/check_sql.rb, line 333
def check_joins_arguments arg
  return unless sexp? arg and not node_type? arg, :hash, :string, :str

  if array? arg
    arg.each do |a|
      if unsafe = check_joins_arguments(a)
        return unsafe
      end
    end

    nil
  else
    unsafe_sql? arg
  end
end
check_lock_arguments(arg) click to toggle source

Model#lock essentially only cares about strings. But those strings can be any SQL fragment. This does not apply to all databases. (For those who do not support it, the lock method does nothing).

# File lib/brakeman/checks/check_sql.rb, line 352
def check_lock_arguments arg
  return unless sexp? arg and not node_type? arg, :hash, :array, :string, :str

  unsafe_sql? arg, :ignore_hash
end
check_order_arguments(args) click to toggle source

Checks each argument to order/reorder/group for possible SQL. Anything used with these methods is passed in verbatim.

# File lib/brakeman/checks/check_sql.rb, line 301
def check_order_arguments args
  return unless sexp? args

  if node_type? args, :arglist
    args.each do |arg|
      if unsafe_arg = unsafe_sql?(arg)
        return unsafe_arg
      end
    end

    nil
  else
    unsafe_sql? args
  end
end
check_query_arguments(arg) click to toggle source
# File lib/brakeman/checks/check_sql.rb, line 271
def check_query_arguments arg
  return unless sexp? arg
  first_arg = arg[1]

  if node_type? arg, :arglist
    if arg.length > 2 and node_type? first_arg, :string_interp, :dstr
      # Model.where("blah = ?", blah)
      return check_string_interp first_arg
    else
      arg = first_arg
    end
  end

  if request_value? arg
    # Model.where(params[:where])
    arg
  elsif hash? arg
    #This is generally going to be a hash of column names and values, which
    #would escape the values. But the keys _could_ be user input.
    check_hash_keys arg
  elsif node_type? arg, :lit, :str
    nil
  else
    #Hashes are safe...but we check above for hash, so...?
    unsafe_sql? arg, :ignore_hash
  end
end
check_rails_version_for_cve_2012_2660() click to toggle source
# File lib/brakeman/checks/check_sql.rb, line 94
def check_rails_version_for_cve_2012_2660
  if version_between?("2.0.0", "2.3.14") || version_between?("3.0.0", "3.0.12") || version_between?("3.1.0", "3.1.4") || version_between?("3.2.0", "3.2.3")
    warn :warning_type => 'SQL Injection',
      :message => 'All versions of Rails before 3.0.13, 3.1.5, and 3.2.5 contain a SQL Query Generation Vulnerability: CVE-2012-2660; Upgrade to 3.2.5, 3.1.5, 3.0.13',
      :confidence => CONFIDENCE[:high],
      :file => gemfile_or_environment,
      :link_path => "https://groups.google.com/d/topic/rubyonrails-security/8SA-M3as7A8/discussion"
  end
end
check_rails_version_for_cve_2012_2661() click to toggle source
# File lib/brakeman/checks/check_sql.rb, line 104
def check_rails_version_for_cve_2012_2661
  if version_between?("3.0.0", "3.0.12") || version_between?("3.1.0", "3.1.4") || version_between?("3.2.0", "3.2.3")
    warn :warning_type => 'SQL Injection',
      :message => 'All versions of Rails before 3.0.13, 3.1.5, and 3.2.5 contain a SQL Injection Vulnerability: CVE-2012-2661; Upgrade to 3.2.5, 3.1.5, 3.0.13',
      :confidence => CONFIDENCE[:high],
      :file => gemfile_or_environment,
      :link_path => "https://groups.google.com/d/topic/rubyonrails-security/dUaiOOGWL1k/discussion"
  end
end
check_rails_version_for_cve_2012_2695() click to toggle source
# File lib/brakeman/checks/check_sql.rb, line 114
def check_rails_version_for_cve_2012_2695
  if version_between?("2.0.0", "2.3.14") || version_between?("3.0.0", "3.0.13") || version_between?("3.1.0", "3.1.5") || version_between?("3.2.0", "3.2.5")
    warn :warning_type => 'SQL Injection',
      :message => 'All versions of Rails before 3.0.14, 3.1.6, and 3.2.6 contain SQL Injection Vulnerabilities: CVE-2012-2694 and CVE-2012-2695; Upgrade to 3.2.6, 3.1.6, 3.0.14',
      :confidence => CONFIDENCE[:high],
      :file => gemfile_or_environment,
      :link_path => "https://groups.google.com/d/topic/rubyonrails-security/l4L0TEVAz1k/discussion"
  end
end
check_scope_arguments(call) click to toggle source
# File lib/brakeman/checks/check_sql.rb, line 261
def check_scope_arguments call
  scope_arg = call.second_arg #first arg is name of scope

  if node_type? scope_arg, :iter
    unsafe_sql? scope_arg.block
  else
    unsafe_sql? scope_arg
  end
end
check_string_interp(arg) click to toggle source

Check an interpolated string for dangerous values.

This method assumes values interpolated into strings are unsafe by default, unless safe_value? explicitly returns true.

# File lib/brakeman/checks/check_sql.rb, line 378
def check_string_interp arg
  arg.each do |exp|
    if node_type?(exp, :string_eval, :evstr) and not safe_value? exp.value
      return exp.value
    end
  end

  nil
end
constantize_call?(result) click to toggle source

Look for something like this:

params[:x].constantize.find('something')

s(:call,
  s(:call,
    s(:call,
      s(:call, nil, :params, s(:arglist)),
      :[],
      s(:arglist, s(:lit, :x))),
    :constantize,
    s(:arglist)),
  :find,
  s(:arglist, s(:str, "something")))
# File lib/brakeman/checks/check_sql.rb, line 565
def constantize_call? result
  call = result[:call]
  call? call.target and call.target.method == :constantize
end
find_dangerous_value(exp, ignore_hash) click to toggle source

Check exp for dangerous values. Used by unsafe_sql?

# File lib/brakeman/checks/check_sql.rb, line 405
def find_dangerous_value exp, ignore_hash
  case exp.node_type
  when :lit, :str, :const, :colon2, :true, :false, :nil
    nil
  when :array
    #Assume this is an array like
    #
    #  ["blah = ? AND thing = ?", ...]
    #
    #and check first value

    unsafe_sql? exp[1]
  when :string_interp, :dstr
    check_string_interp exp
  when :hash
    check_hash_values exp unless ignore_hash
  when :if
    unsafe_sql? exp.then_clause or unsafe_sql? exp.else_clause
  when :call
    unless IGNORE_METHODS_IN_SQL.include? exp.method
      if has_immediate_user_input? exp or has_immediate_model? exp
        exp
      else
        check_call exp
      end
    end
  when :or
    if unsafe = (unsafe_sql?(exp.lhs) || unsafe_sql?(exp.rhs))
      return unsafe
    else
      nil
    end
  when :block, :rlist
    unsafe_sql? exp.last
  else
    if has_immediate_user_input? exp or has_immediate_model? exp
      exp
    else
      nil
    end
  end
end
find_scope_calls() click to toggle source

Find calls to named_scope() or scope() in models RP 3 TODO

# File lib/brakeman/checks/check_sql.rb, line 57
def find_scope_calls
  scope_calls = []

  if version_between? "2.1.0", "3.0.9"
    active_record_models.each do |name, model|
      if model[:options][:named_scope]
        model[:options][:named_scope].each do |args|
          call = make_call(nil, :named_scope, args).line(args.line)
          scope_calls << { :call => call, :location => [:class, name ], :method => :named_scope }
        end
      end
     end
  elsif version_between? "3.1.0", "3.9.9"
    active_record_models.each do |name, model|
      if model[:options][:scope]
        model[:options][:scope].each do |args|
          second_arg = args[2]

          next unless sexp? second_arg

          if second_arg.node_type == :iter and node_type? second_arg.block, :block, :call
            process_scope_with_block name, args
          elsif second_arg.node_type == :call
            call = second_arg
            scope_calls << { :call => call, :location => [:class, name ], :method => call.method }
          else
            call = make_call(nil, :scope, args).line(args.line)
            scope_calls << { :call => call, :location => [:class, name ], :method => :scope }
          end
        end
      end
    end
  end

  scope_calls
end
process_result(result) click to toggle source

Process possible SQL injection sites:

Model#find

Model#(named_)scope

Model#(find|count)_by_sql

Model#all

  Rails 3

Model#(where|having)
Model#(order|group)

  Find Options Hash

Dangerous keys that accept SQL:

* conditions
* order
* having
* joins
* select
* from
* lock
# File lib/brakeman/checks/check_sql.rb, line 171
def process_result result
  return if duplicate? result or result[:call].original_line

  call = result[:call]
  method = call.method

  dangerous_value = case method
                    when :find
                      check_find_arguments call.second_arg
                    when :exists?
                      check_find_arguments call.first_arg
                    when :named_scope, :scope
                      check_scope_arguments call
                    when :find_by_sql, :count_by_sql
                      check_by_sql_arguments call.first_arg
                    when :calculate
                      check_find_arguments call.third_arg
                    when :last, :first, :all
                      check_find_arguments call.first_arg
                    when :average, :count, :maximum, :minimum, :sum
                      if call.length > 5
                        unsafe_sql?(call.first_arg) or check_find_arguments(call.last_arg)
                      else
                        check_find_arguments call.last_arg
                      end
                    when :where, :having
                      check_query_arguments call.arglist
                    when :order, :group, :reorder
                      check_order_arguments call.arglist
                    when :joins
                      check_joins_arguments call.first_arg
                    when :from, :select
                      unsafe_sql? call.first_arg
                    when :lock
                      check_lock_arguments call.first_arg
                    else
                      Brakeman.debug "Unhandled SQL method: #{method}"
                    end

  if dangerous_value
    add_result result

    if input = include_user_input?(dangerous_value)
      confidence = CONFIDENCE[:high]
      user_input = input.match
    else
      confidence = CONFIDENCE[:med]
      user_input = dangerous_value
    end

    warn :result => result,
      :warning_type => "SQL Injection",
      :message => "Possible SQL injection",
      :user_input => user_input,
      :confidence => confidence
  end

  if check_for_limit_or_offset_vulnerability call.last_arg
    if include_user_input? call.last_arg
      confidence = CONFIDENCE[:high]
    else
      confidence = CONFIDENCE[:low]
    end

    warn :result => result,
      :warning_type => "SQL Injection",
      :message => "Upgrade to Rails >= 2.1.2 to escape :limit and :offset. Possible SQL injection",
      :confidence => confidence
  end
end
process_scope_with_block(model_name, args) click to toggle source
# File lib/brakeman/checks/check_sql.rb, line 124
def process_scope_with_block model_name, args
  scope_name = args[1][1]
  block = args[-1][-1]

  #Search lambda for calls to query methods
  if block.node_type == :block
    find_calls = Brakeman::FindAllCalls.new tracker

    find_calls.process_source block, model_name, scope_name

    find_calls.calls.each do |call|
      if @sql_targets.include? call[:method]
        process_result call
      end
    end
  elsif block.node_type == :call
    process_result :target => block.target, :method => block.method, :call => block, :location => [:class, model_name, scope_name]
  end
end
run_check() click to toggle source
# File lib/brakeman/checks/check_sql.rb, line 16
def run_check
  @rails_version = tracker.config[:rails_version]

  @sql_targets = [:all, :average, :calculate, :count, :count_by_sql, :exists?,
    :find, :find_by_sql, :first, :last, :maximum, :minimum, :sum]

  if tracker.options[:rails3]
    @sql_targets.concat [:from, :group, :having, :joins, :lock, :order, :reorder, :select, :where]
  end

  Brakeman.debug "Finding possible SQL calls on models"
  calls = tracker.find_call :targets => active_record_models.keys,
    :methods => @sql_targets,
    :chained => true

  Brakeman.debug "Finding possible SQL calls with no target"
  calls.concat tracker.find_call(:target => nil, :method => @sql_targets)

  Brakeman.debug "Finding possible SQL calls using constantized()"
  calls.concat tracker.find_call(:method => @sql_targets).select { |result| constantize_call? result }

  Brakeman.debug "Finding calls to named_scope or scope"
  calls.concat find_scope_calls

  Brakeman.debug "Checking version of Rails for CVE-2012-2660"
  check_rails_version_for_cve_2012_2660

  Brakeman.debug "Checking version of Rails for CVE-2012-2661"
  check_rails_version_for_cve_2012_2661

  Brakeman.debug "Checking version of Rails for CVE-2012-2695"
  check_rails_version_for_cve_2012_2695

  Brakeman.debug "Processing possible SQL calls"
  calls.each do |c|
    process_result c
  end
end
safe_value?(exp) click to toggle source
# File lib/brakeman/checks/check_sql.rb, line 505
def safe_value? exp
  return true unless sexp? exp

  case exp.node_type
  when :str, :lit, :const, :colon2, :nil, :true, :false
    true
  when :call
    IGNORE_METHODS_IN_SQL.include? exp.method
  when :if
    safe_value? exp.then_clause and safe_value? exp.else_clause
  when :block, :rlist
    safe_value? exp.last
  when :or
    safe_value? exp.lhs and safe_value? exp.rhs
  else
    false
  end
end
unsafe_sql?(exp, ignore_hash = false) click to toggle source

Checks the given expression for unsafe SQL values. If an unsafe value is found, returns that value (may be the given exp or a subexpression).

Otherwise, returns false/nil.

# File lib/brakeman/checks/check_sql.rb, line 392
def unsafe_sql? exp, ignore_hash = false
  return unless sexp? exp

  dangerous_value = find_dangerous_value exp, ignore_hash

  if safe_value? dangerous_value
    false
  else
    dangerous_value
  end
end

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