msd-core/scripts/prompt-injection-scan.sh

#!/usr/bin/env bash
# prompt-injection-scan.sh — Scan files for prompt injection patterns
#
# Usage:
#   scripts/prompt-injection-scan.sh --diff origin/main   # CI mode: scan changed .md files
#   scripts/prompt-injection-scan.sh --file path/to/file   # Scan a single file
#   scripts/prompt-injection-scan.sh --dir agents/          # Scan all files in a directory
#
# Exit codes:
#   0 = clean
#   1 = findings detected
#   2 = usage error
set -euo pipefail

# ─── Patterns ────────────────────────────────────────────────────────────────
# Each pattern is a POSIX extended regex. Keep alphabetized by category.
#
# Left-boundary prefix `(^|[^[:alnum:]])`: several trigger words are also
# suffixes of ordinary English words or camelCase identifiers (fact/impact/
# contract/artifact/interact all end in "act"; retrieval/medieval end in
# "eval"; blueprint/reprint/fingerprint end in "print"; describeFunction/
# wrapFunction end in "Function"; Jordan/Sudan end in "dan"), so an
# unanchored keyword matches as a false-positive substring. `\b` is a GNU
# grep extension and this script must also run under BSD/macOS grep, so the
# boundary is spelled out as `(^|[^[:alnum:]])` instead. This never narrows
# real detections: a genuine attack phrase is always preceded by start-of-
# line, whitespace, or punctuation, never by another alnum character glued
# directly onto the keyword. Only patterns whose leading keyword is provably
# not a real-word suffix are left unanchored (#3175 audit).

PATTERNS=(
  # Instruction override
  'ignore[[:space:]]+(all[[:space:]]+)?(previous|prior|above|earlier|preceding)[[:space:]]+(instructions|prompts|rules|directives|context)'
  'disregard[[:space:]]+(all[[:space:]]+)?(previous|prior|above)[[:space:]]+(instructions|prompts|rules)'
  'forget[[:space:]]+(all[[:space:]]+)?(previous|prior|above)[[:space:]]+(instructions|prompts|rules|context)'
  'override[[:space:]]+(all[[:space:]]+)?(system|previous|safety)[[:space:]]+(instructions|prompts|rules|checks|filters|guards)'
  'override[[:space:]]+(system|safety|security)[[:space:]]'

  # Role manipulation
  'you[[:space:]]+are[[:space:]]+now[[:space:]]+(a|an|my)[[:space:]]'
  'from[[:space:]]+now[[:space:]]+on[[:space:]]+(you|pretend|act|behave)'
  'pretend[[:space:]]+(you[[:space:]]+are|to[[:space:]]+be)[[:space:]]'
  '(^|[^[:alnum:]])act[[:space:]]+as[[:space:]]+(a|an|if|my)[[:space:]]'
  'roleplay[[:space:]]+as[[:space:]]'
  'assume[[:space:]]+the[[:space:]]+role[[:space:]]+of[[:space:]]'

  # System prompt extraction
  'output[[:space:]]+(your|the)[[:space:]]+(system[[:space:]]+)?(prompt|instructions)'
  'reveal[[:space:]]+(your|the)[[:space:]]+(system[[:space:]]+)?(prompt|instructions)'
  'show[[:space:]]+me[[:space:]]+(your|the)[[:space:]]+(system[[:space:]]+)?(prompt|instructions)'
  '(^|[^[:alnum:]])print[[:space:]]+(your|the)[[:space:]]+(system[[:space:]]+)?(prompt|instructions)'
  'what[[:space:]]+(is|are)[[:space:]]+(your|the)[[:space:]]+(system[[:space:]]+)?(prompt|instructions)'
  'repeat[[:space:]]+(your|the|all)[[:space:]]+(system[[:space:]]+)?(prompt|instructions|rules)'

  # Fake message boundaries
  '</?system>'
  '</?assistant>'
  '</?human>'
  '\[SYSTEM\]'
  '\[/SYSTEM\]'
  '\[INST\]'
  '\[/INST\]'
  '<<SYS>>'
  '<</SYS>>'

  # Tool call injection / code execution in markdown
  #
  # The quote-or-apostrophe class below is spelled ["'"'"'"] (a literal `'`
  # via bash's close-quote/escape/reopen idiom), not `["\x27]` — `\x27` is a
  # GNU-grep-only hex escape; BSD/macOS grep treats it as four literal
  # characters (", \, x, 2, 7) and never matches an actual apostrophe, so
  # `eval('...')` (single-quoted) silently went undetected on macOS while
  # passing on GNU-grep CI runners. Found auditing #3175; fixed here since it
  # is the same unanchored/portability defect class as the boundary fix.
  '(^|[^[:alnum:]])eval[[:space:]]*\([[:space:]]*["'"'"']'
  'exec[[:space:]]*\([[:space:]]*["'"'"']'
  '(^|[^[:alnum:]])Function[[:space:]]*\([[:space:]]*["'"'"'].*return'

  # Jailbreak / DAN patterns
  'do[[:space:]]+anything[[:space:]]+now'
  '(^|[^[:alnum:]])DAN[[:space:]]+mode'
  'developer[[:space:]]+mode[[:space:]]+(enabled|output|activated)'
  'jailbreak'
  'bypass[[:space:]]+(safety|content|security)[[:space:]]+(filter|check|rule|guard)'
)

# ─── Allowlist ───────────────────────────────────────────────────────────────
# Files that legitimately discuss injection patterns (security docs, tests, this script)
ALLOWLIST=(
  'scripts/prompt-injection-scan.sh'
  'scripts/base64-scan.sh'
  'scripts/secret-scan.sh'
  'tests/security-scan.security.test.cjs'
  'tests/security.test.cjs'
  'tests/prompt-injection-scan.security.test.cjs'
  'tests/verify.test.cjs'
  'gsd-core/bin/lib/security.cjs'
  'hooks/gsd-prompt-guard.js'
  'hooks/gsd-read-injection-scanner.js'
  'tests/read-injection-scanner.security.test.cjs'
  'tests/read-injection-scanner.property.test.cjs'
  'tests/security-prompt-injection.security.test.cjs'
  'tests/list-seeds.test.cjs'
  'tests/fixtures/adversarial/security/'
  'SECURITY.md'
  # These files contain intentional injection examples / security-model prose
  # and are not attack vectors — they explain/demonstrate injection patterns.
  'TEST-EXAMPLES.md'
  'explanation/security-model.md'
  # The untrusted-input boundary reference quotes injection phrases
  # ("ignore previous instructions", "you are now…") as examples agents must
  # NOT comply with — it is the defense, not an attack vector.
  'references/untrusted-input-boundary.md'
  # Security regression tests for input validators — fixtures must contain
  # real injection payloads to prove the validator rejects them. See
  # DEFECT.PROMPT-INJECTION-SCAN-COLLISION in CONTEXT.md.
  'tests/windsurf-conversion.test.cjs'
  # RuleTester fixtures for the local/no-unguarded-nonportable-exec ESLint rule
  # contain shell-exec command strings (exec("sh -c …"), execFileSync('bash',['-c',…]))
  # as test DATA the rule must lint — not attack vectors. ADR-1703 Phase 3 (#1720).
  'tests/no-unguarded-nonportable-exec.rule.test.cjs'
  # RuleTester fixtures for the local/no-bare-npm-exec ESLint rule contain npm
  # exec command strings (execFileSync('npm', ['install'])) as test DATA the rule
  # must lint — not attack vectors. ADR-1703 Phase 4 (#1726).
  'tests/no-bare-npm-exec.rule.test.cjs'
  # #2547 — the Kimi field-shadowing regression proves gsd-prompt-guard still
  # SCANS the reconstructed edit[].new content when a model-supplied new_string
  # tries to shadow it. The fixture must be a real injection phrase or the test
  # asserts nothing: it is the payload the guard is required to catch, carried
  # as test DATA. Same class as the read-injection-scanner suites above.
  'tests/kimi-payload-field-shadowing.security.test.cjs'
)

is_allowlisted() {
  local file="$1"
  for allowed in "${ALLOWLIST[@]}"; do
    if [[ "$file" == *"$allowed"* ]]; then
      return 0
    fi
  done
  return 1
}

# ─── File Collection ─────────────────────────────────────────────────────────

collect_files() {
  local mode="$1"
  shift

  case "$mode" in
    --diff)
      local base="${1:-origin/main}"
      # Get changed files in the diff, filter to scannable extensions
      git diff --name-only --diff-filter=ACMR "$base"...HEAD 2>/dev/null \
        | grep -E '\.(md|cjs|js|json|yml|yaml|sh)$' || true
      ;;
    --file)
      if [[ -f "$1" ]]; then
        echo "$1"
      else
        echo "Error: file not found: $1" >&2
        exit 2
      fi
      ;;
    --dir)
      local dir="$1"
      if [[ ! -d "$dir" ]]; then
        echo "Error: directory not found: $dir" >&2
        exit 2
      fi
      find "$dir" -type f \( -name '*.md' -o -name '*.cjs' -o -name '*.js' -o -name '*.json' -o -name '*.yml' -o -name '*.yaml' -o -name '*.sh' \) \
        ! -path '*/node_modules/*' ! -path '*/.git/*' ! -path '*/dist/*' 2>/dev/null || true
      ;;
    --stdin)
      cat
      ;;
    *)
      echo "Usage: $0 --diff [base] | --file <path> | --dir <path> | --stdin" >&2
      exit 2
      ;;
  esac
}

# ─── Scanner ─────────────────────────────────────────────────────────────────

scan_file() {
  local file="$1"
  local found=0

  if is_allowlisted "$file"; then
    return 0
  fi

  for pattern in "${PATTERNS[@]}"; do
    # Use grep -iE for case-insensitive extended regex
    # -n for line numbers, -c for count mode first to check
    local matches
    matches=$(grep -inE -e "$pattern" "$file" 2>/dev/null || true)
    if [[ -n "$matches" ]]; then
      if [[ $found -eq 0 ]]; then
        echo "FAIL: $file"
        found=1
      fi
      echo "$matches" | while IFS= read -r line; do
        echo "  $line"
      done
    fi
  done

  return $found
}

# ─── Main ────────────────────────────────────────────────────────────────────

main() {
  if [[ $# -eq 0 ]]; then
    echo "Usage: $0 --diff [base] | --file <path> | --dir <path>" >&2
    exit 2
  fi

  local mode="$1"
  shift

  local files
  files=$(collect_files "$mode" "$@")

  if [[ -z "$files" ]]; then
    echo "prompt-injection-scan: no files to scan"
    exit 0
  fi

  local total=0
  local failed=0

  while IFS= read -r file; do
    [[ -z "$file" ]] && continue
    total=$((total + 1))
    if ! scan_file "$file"; then
      failed=$((failed + 1))
    fi
  done <<< "$files"

  echo ""
  echo "prompt-injection-scan: scanned $total files, $failed with findings"

  if [[ $failed -gt 0 ]]; then
    exit 1
  fi
  exit 0
}

main "$@"