Class: Scryer::Rules::SqlInjectionRule

Inherits:
Scryer::Rule show all
Defined in:
lib/scryer/rules/sql_injection_rule.rb

Overview

Flags ActiveRecord finder/query methods called with a string argument that contains interpolation (#...) — the classic Rails SQL injection pattern, e.g. Order.where("status = '#{params[:status]}'"). Parameterized/hash forms (where(status: params[:status]), where("status = ?", params[:status])) are safe and not flagged.

Constant Summary collapse

QUERY_METHODS = 
%w[
  where find_by find_by! order pluck select group having
  find_by_sql calculate exists? count
].freeze

Instance Attribute Summary

Attributes inherited from Scryer::Rule

#file, #sexp, #source

Instance Method Summary collapse

Methods inherited from Scryer::Rule

inherited, #initialize

Constructor Details

This class inherits a constructor from Scryer::Rule

Instance Method Details

#scan ⇒ Object 



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# File 'lib/scryer/rules/sql_injection_rule.rb', line 19

def scan
  findings = []

  Ast.each_node(sexp) do |node|
    next unless Ast.tagged?(node, :method_add_arg, :command, :command_call)

    receiver_and_name = Ast.call_name(inner_call_node(node))
    next unless receiver_and_name

    _receiver, method_name = receiver_and_name
    next unless QUERY_METHODS.include?(method_name)

    args = Ast.call_arguments(node)
    next if args.empty?

    first_arg = args.first
    next unless Ast.string_literal_has_interpolation?(first_arg)

    line = Ast.line_of(first_arg) || Ast.line_of(node)
    findings << finding(
      line: line,
      message: "`#{method_name}` is called with a string built via interpolation, " \
               "which lets user-controlled input change the SQL executed.",
      suggested_fix: "Use a parameterized form instead, e.g. " \
                      "`#{method_name}(\"column = ?\", value)` or the hash form " \
                      "`#{method_name}(column: value)` — both let Active Record escape " \
                      "the value safely instead of interpolating it directly into SQL."
    )
  end

  findings
end