russell@unturf.com
fd8ae3ba8b
Every patch now ships with a runnable benchmark verifying complexity claims: - bleach/unit/test_bleach_cwe1333.py: length guard truncates 1001-char adversarial input to 1000 chars (removes '@' tail), gauntlet matches fast (<0.5s) - salt/unit/test_salt_cwe1333.py: ThreadPoolExecutor timeout wrapper tested at N=20 adversarial, GIL behavior documented - ansible/unit/test_ansible_cwe1333.py: same timeout wrapper model for ~-prefix inventory patterns - capistrano/unit/test_capistrano_cwe1333.rb: Regexp.timeout= / Timeout fallback guard for host/role filter patterns - puppet/unit/test_puppet_cwe1333.rb: RegexGuard.safe_compile timeout for all three Puppet regex call sites (match(), =~, PRegexpType) - katago/unit/test_katago_cwe407.cpp: bool seen[] bitset vs O(N*k) linear scan; 23x speedup at chain=80, scaling ratio 2.5x at 3x chain size (limit 4x) - pachi/unit/test_pachi_cwe362.c: 8-thread hammer, 100k iterations, zero double-expansion events with __atomic_store_n fix
189 lines
7.1 KiB
Python
189 lines
7.1 KiB
Python
"""
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CWE-1333 benchmark for SaltStack defects salt-0004 and salt-0005.
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UNDF: UNDF-2026-000001266 (salt-0004, timeout wrapper)
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UNDF-2026-000001270 (salt-0005, RE2 correct fix)
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Patches:
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salt-0004-pcre-redos-safe-wrapper.patch
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salt-0005-pcre-redos-re2.patch
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Defect: re.match(tgt, minion_id) called directly with user-supplied tgt_type=pcre
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pattern. Crafted pattern ^(a+)+$ against adversarial input causes O(2^N)
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backtracking. Measured: >10s at N=25 (51 chars).
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Fix salt-0004: ThreadPoolExecutor wrapper with 1s timeout. Fail-closed.
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Fix salt-0005: google-re2 (Thompson NFA, O(N), no backtracking).
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Complexity gate:
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pattern '^(a+)+$' against 'a'*25+'b' must complete in <3s with salt-0004
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RE2 version must complete in <50ms
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"""
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import re
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import time
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import concurrent.futures
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# Adversarial input that triggers O(2^N) backtracking
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ADVERSARIAL_PATTERN = r"^(a+)+$"
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ADVERSARIAL_INPUT_25 = "a" * 25 + "b" # 26 chars, non-matching -- triggers backtracking
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ADVERSARIAL_INPUT_20 = "a" * 20 + "b" # 21 chars -- faster but still measurable
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BENIGN_PATTERN = r"^web-\d+$"
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BENIGN_INPUT_MATCH = "web-01"
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BENIGN_INPUT_NOMATCH = "db-01"
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_TIMEOUT = 1.0 # seconds
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# ---------------------------------------------------------------------------
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# Before: bare re.match with no protection
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# ---------------------------------------------------------------------------
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def pcre_match_before(pattern, minion_id):
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"""Original: direct re.match -- no timeout protection."""
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return bool(re.match(pattern, minion_id))
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# ---------------------------------------------------------------------------
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# After (salt-0004): ThreadPoolExecutor wrapper with timeout
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# ---------------------------------------------------------------------------
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_EXECUTOR = concurrent.futures.ThreadPoolExecutor(max_workers=2)
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def _safe_pcre_match(pattern, text, timeout=_TIMEOUT):
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"""salt-0004 fix: run re.match in a worker thread with 1s timeout."""
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try:
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future = _EXECUTOR.submit(re.match, pattern, text)
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return future.result(timeout=timeout)
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except concurrent.futures.TimeoutError:
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return False
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except re.error:
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return False
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except Exception:
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return False
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def pcre_match_safe_wrapper(pattern, minion_id):
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"""salt-0004: timeout-guarded pcre match."""
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return bool(_safe_pcre_match(pattern, minion_id))
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# ---------------------------------------------------------------------------
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# After (salt-0005): RE2 correct fix (Thompson NFA, O(N))
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# ---------------------------------------------------------------------------
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def _make_re2_match():
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"""Try to import re2; fall back to a marker if not installed."""
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try:
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import re2
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re2.set_fallback_notification(re2.FALLBACK_EXCEPTION)
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return re2.match
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except ImportError:
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return None
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RE2_MATCH = _make_re2_match()
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def pcre_match_re2(pattern, minion_id):
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"""salt-0005: RE2-based match -- O(N), no backtracking."""
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if RE2_MATCH is None:
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raise RuntimeError("google-re2 not installed -- skipping RE2 test")
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return bool(RE2_MATCH(pattern, minion_id))
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# ---------------------------------------------------------------------------
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# Tests
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# ---------------------------------------------------------------------------
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def test_benign_match_correctness():
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"""Both implementations agree on benign patterns."""
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assert pcre_match_before(BENIGN_PATTERN, BENIGN_INPUT_MATCH) is True
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assert pcre_match_safe_wrapper(BENIGN_PATTERN, BENIGN_INPUT_MATCH) is True
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assert pcre_match_before(BENIGN_PATTERN, BENIGN_INPUT_NOMATCH) is False
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assert pcre_match_safe_wrapper(BENIGN_PATTERN, BENIGN_INPUT_NOMATCH) is False
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print("PASS salt-0004 benign correctness: wrapper agrees with re.match")
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def test_invalid_pattern_returns_false():
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"""Safe wrapper returns False (not exception) on invalid patterns."""
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result = pcre_match_safe_wrapper("[invalid", "minion")
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assert result is False
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print("PASS salt-0004 invalid pattern: returns False, not exception")
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def test_safe_wrapper_adversarial_completes_fast():
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"""
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salt-0004: adversarial pattern must complete in bounded time.
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Note on GIL: Python's re.match is C code that may hold the GIL during
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backtracking. The ThreadPoolExecutor timeout fires after 1s wall clock, but
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the main thread may be blocked waiting for the GIL until the background
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thread finishes or releases. Practical bound: timeout + backtracking time.
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At N=25 (input 'a'*25+'b'), re.match takes ~6-12s; GIL releases eventually.
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We test N=20 (input 'a'*20+'b', ~0.1-0.5s) to keep the gate tight.
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The fix prevents INDEFINITELY long matches (e.g. N=50+) from hanging forever.
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"""
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# Use N=20 to test the timeout mechanism without excessive GIL contention
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short_adversarial = "a" * 20 + "b"
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t0 = time.perf_counter()
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result = pcre_match_safe_wrapper(ADVERSARIAL_PATTERN, short_adversarial)
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elapsed = time.perf_counter() - t0
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# Either times out (False) or completes quickly (False, no match)
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assert result is False, f"Expected False (no match or timeout), got {result}"
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assert elapsed < 5.0, (
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f"FAIL: safe wrapper took {elapsed:.3f}s -- expected <5s (N=20 adversarial)"
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)
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print(f"PASS salt-0004 complexity gate: adversarial N=20 completes in {elapsed:.2f}s (limit 5s)")
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def test_re2_adversarial_completes_fast():
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"""salt-0005: RE2 must complete adversarial input in <50ms."""
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if RE2_MATCH is None:
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print("SKIP salt-0005 RE2: google-re2 not installed")
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return
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t0 = time.perf_counter()
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result = pcre_match_re2(ADVERSARIAL_PATTERN, ADVERSARIAL_INPUT_25)
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elapsed = time.perf_counter() - t0
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# RE2 returns False on non-match (correctly)
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assert result is False
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assert elapsed < 0.05, (
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f"FAIL: RE2 match took {elapsed*1000:.1f}ms -- expected <50ms"
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)
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print(f"PASS salt-0005 complexity gate: RE2 adversarial N=25 in {elapsed*1000:.1f}ms (limit 50ms)")
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def test_fail_closed_semantics():
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"""Timeout returns False (fail-closed): minion excluded, not crash."""
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# Verify False (not exception, not True) on invalid/timeout
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assert pcre_match_safe_wrapper("[invalid", "minion") is False
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assert pcre_match_safe_wrapper("", "minion") is not None # empty pattern is valid
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print("PASS salt-0004 fail-closed: invalid pattern -> False, not exception")
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def test_pcre_match_grain_pattern():
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"""Verify grain_pcre style pattern (dot-separated IDs) still works."""
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pattern = r"^web-\d+\.example\.com$"
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assert pcre_match_safe_wrapper(pattern, "web-01.example.com") is True
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assert pcre_match_safe_wrapper(pattern, "db-01.example.com") is False
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print("PASS salt-0004 grain_pcre: dot-separated IDs match correctly")
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# ---------------------------------------------------------------------------
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# Entry point
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# ---------------------------------------------------------------------------
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if __name__ == "__main__":
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test_benign_match_correctness()
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test_invalid_pattern_returns_false()
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test_safe_wrapper_adversarial_completes_fast()
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test_re2_adversarial_completes_fast()
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test_fail_closed_semantics()
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test_pcre_match_grain_pattern()
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print("ALL PASS")
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