Class: Rules::GithubScriptInjection

Inherits:
Base
  • Object
show all
Includes:
GuardPatterns
Defined in:
lib/rules/github_script_injection.rb

Constant Summary collapse

DANGEROUS_EXPR_PATTERN = 
/\$\{\{\s*(#{DANGEROUS_CONTEXTS.map { |c| Regexp.escape(c) }.join('|')})/
INPUT_EXPR_PATTERN = 
/\$\{\{\s*((?:inputs|github\.event\.inputs)\.[^\s}]+)/

Constants included from GuardPatterns

Rules::GuardPatterns::DANGEROUS_CONTEXTS, Rules::GuardPatterns::JOB_PROPERTIES, Rules::GuardPatterns::SAFE_TRIGGERS

Instance Method Summary collapse

Methods included from GuardPatterns

#guarded_by_safe_event?, #safe_trigger_only?, #strip_inline_comment

Instance Method Details

#check(workflow) ⇒ Object 



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# File 'lib/rules/github_script_injection.rb', line 14

def check(workflow)
    findings = []
    safe_triggers = safe_trigger_only?(workflow)

    workflow.raw_lines.each_with_index do |line, idx|
        line_num = idx + 1
        next if line.strip.start_with?('#')
        next unless in_github_script_block?(workflow, line_num)

        has_dangerous = line.match?(DANGEROUS_EXPR_PATTERN)
        has_input = line.match?(INPUT_EXPR_PATTERN)
        next unless has_dangerous || has_input

        guarded = guarded_by_safe_event?(workflow, line_num)

        # INPUT expressions (inputs.*) are user-controlled even on
        # safe-trigger-only workflows, so they always fire.
        if has_input
            match = line.match(INPUT_EXPR_PATTERN)
            if match
                findings << finding(workflow,
                    line: line_num,
                    code: line.strip,
                    message: "Attacker-controllable expression \${{ #{match[1]} }} in actions/github-script — JavaScript injection risk",
                    fix: "Pass input via env: block and reference as process.env.VAR"
                )
            end
        end

        # DANGEROUS expressions respect both safe_trigger_only? and
        # event guards — they are only exploitable from unsafe triggers.
        if has_dangerous && !safe_triggers && !guarded
            match = line.match(DANGEROUS_EXPR_PATTERN)
            if match
                findings << finding(workflow,
                    line: line_num,
                    code: line.strip,
                    message: "Attacker-controllable expression \${{ #{match[1]} }} in actions/github-script — JavaScript injection risk",
                    fix: "Use context.payload instead: context.payload.pull_request.title"
                )
            end
        end
    end

    findings
end

#description ⇒ Object 



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# File 'lib/rules/github_script_injection.rb', line 8

def description = "Attacker-controllable ${{ }} expression in actions/github-script"

#name ⇒ Object 



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# File 'lib/rules/github_script_injection.rb', line 7

def name = "github-script-injection"

#severity ⇒ Object 



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# File 'lib/rules/github_script_injection.rb', line 9

def severity = :critical