# Pattern Search

PatternSearch uses sift, written in Go, to perform the pattern matching.

This scanner can flag anti-patterns found in a codebase or require that certain strings be present. This might be useful for preventing the use of dangerous methods like eval() in Ruby (which might allow for RCE) or dangerouslySetInnerHTML in React (which might allow for XSS). By default, all found patterns are added to the info section of the report. If a found pattern is forbidden, this scanner will fail and the message will be show to the developer in the report to give additional context on why this was an issue. A required pattern must be found in order for the scan to pass.

# Configuration

The scanner also allows the options below. These options can be set globally and per-match. In addition, the exclude_ options can be used together.

Option	Type	Description
`exclude_extension` and `include_extension`	`Array`	for excluding and including file extensions, respectively. While these options can be combined, exclusions take precedence when extensions conflict (are both included and excluded) in declarations.
`exclude_directory`	`Array`	for excluding directories whose name matches GLOB. It appears that sift does not support `/`s in the directory name.
`exclude_filepaths`	`Array`	for excluding file paths. Note the file paths must be regular paths, not GLOB, and cannot include regular expressions.
`not_followed_within`	`Array`	for only showing matches not followed by PATTERN within NUM lines. The value must have the format `NUM:PATTERN`. Use 0 for excluding on the same line.
`files`	`Array`	for search only files whose name matches GLOB.

# Sample Configuration for Scanner

salus.yml
scanner_configs:
  PatternSearch:
    matches:
      - regex: dangerouslySetInnerHTML
        message: Do not use dangerouslySetInnerHTML to render user controlled input.
        forbidden: true
        exclude_directory:
          - node_modules
        exclude_filepaths:
          - file1.rb
          - subdir/file1.rb
        include_extension:
          - js
          - erb
          - html
          - htm
        not_followed_within: 0:my_pattern
        files:
          - a.js
          - b.js
      - regex: "# Threat Model"
        message: All repos must contain a documented threat model.
        required: true
        exclude_extension:
          - rb
          - js