feat(ttp): implement evidence-shape validation and confidence range constraint
- TolerantTagger.tag validates evidence keys against EVIDENCE_SCHEMA TypedDicts; TypeError (programmer error) propagates instead of being swallowed - IntelEvidence and EmailEvidence expanded from stubs to full per-provider key sets (total=False); IntelEvidence old stub fields replaced wholesale - EVIDENCE_SCHEMA map added to models/ttp.py and imported by base.py - TTPTag __table_args__ gains confidence [0,1] CheckConstraint (DB-enforced) - xfail removed from test_confidence_outside_range_rejected_at_insert and test_evidence_shape_violation_propagates_as_typeerror — both now pass - TypeError removed from _SWALLOWED_EXCS fuzz list; test_intel_evidence_keys updated to assert the real provider key set
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@@ -19,7 +19,7 @@ import logging
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from abc import ABC, abstractmethod
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from typing import Any, Final, NamedTuple, Protocol, runtime_checkable
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from decnet.web.db.models.ttp import TTPTag
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from decnet.web.db.models.ttp import EVIDENCE_SCHEMA, TTPTag
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_log = logging.getLogger(__name__)
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@@ -109,7 +109,32 @@ class TolerantTagger(Tagger):
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async def tag(self, event: TaggerEvent) -> list[TTPTag]:
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try:
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return await self._tag_impl(event)
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results = await self._tag_impl(event)
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# Validate evidence shape: unknown keys are a programmer error,
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# not a runtime absence. Raise TypeError so the caller sees the
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# bug rather than silently dropping the tag.
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td = EVIDENCE_SCHEMA.get(event.source_kind)
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if td is not None:
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declared = (
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getattr(td, "__required_keys__", frozenset())
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| getattr(td, "__optional_keys__", frozenset())
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)
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for tag in results:
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ev = getattr(tag, "evidence", None)
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if ev is None:
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continue
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unknown = set(ev) - declared
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if unknown:
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raise TypeError(
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f"lifter {self.name!r} emitted evidence keys "
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f"{unknown!r} not declared in "
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f"{td.__name__} for source_kind={event.source_kind!r}"
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)
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return results
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except TypeError:
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# Programmer error — bad evidence shape or type mismatch.
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# Propagate; do NOT swallow.
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raise
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except Exception:
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# ``Exception`` deliberately, not ``BaseException``:
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# ``KeyboardInterrupt`` / ``SystemExit`` /
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@@ -69,19 +69,46 @@ class CommandEvidence(TypedDict):
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rule_pattern: str # regex source string, never user input
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class IntelEvidence(TypedDict):
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intel_uuid: str
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provider: Literal["abuseipdb", "greynoise", "feodo", "threatfox"]
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category: Optional[int]
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score: float # already normalized to [0.0, 1.0]
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class IntelEvidence(TypedDict, total=False):
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# AbuseIPDB
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abuseipdb_categories: list[int]
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abuseipdb_score: float
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abuse_confidence_score: int
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# GreyNoise
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greynoise_classification: str
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greynoise_tags: list[str]
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greynoise_name: str
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# Feodo
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feodo_listed: bool
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feodo_malware_family: str
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first_seen_feodo: str
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malware_family: str
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# ThreatFox
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threatfox_threat_types: list[str]
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threatfox_ioc_types: list[str]
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threatfox_malware_families: list[str]
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threat_types: list[str]
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malware_families: list[str]
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ioc_types: list[str]
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# Aggregate meta-rule
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aggregate_verdict: str
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bumped_rule_ids: list[str]
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class EmailEvidence(TypedDict):
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body_sha256: str # hash, never raw body
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class EmailEvidence(TypedDict, total=False):
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body_sha256: str # hash, never raw body
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matched_headers: list[str] # header NAMES, not values
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rcpt_domain_set: list[str] # domains, not addresses
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attachment_sha256s: list[str]
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rcpt_count: int
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# PII-safe match discriminators (subset of _EMAIL_EVIDENCE_ALLOWED_KEYS)
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matched_kit: str
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matched_trigger: str
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matched_url_host: str
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matched_signals: list[str]
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matched_subject_kw: list[str]
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matched_body_kw: list[str]
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encoded_byte_count: int
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class CanaryFingerprintEvidence(TypedDict):
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@@ -98,6 +125,18 @@ class HttpFingerprintEvidence(TypedDict):
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raw: Optional[dict] # raw settings dict for h2_settings / h3_settings
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# Maps source_kind → its evidence TypedDict. Used by TolerantTagger to
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# validate that lifters do not emit undeclared keys (programmer error →
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# TypeError, not the swallowed absence-of-data case).
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EVIDENCE_SCHEMA: dict[str, type] = {
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"command": CommandEvidence,
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"intel": IntelEvidence,
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"email": EmailEvidence,
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"canary_fingerprint": CanaryFingerprintEvidence,
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"http_fingerprint": HttpFingerprintEvidence,
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}
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# ── Tables ──────────────────────────────────────────────────────────
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@@ -176,6 +215,10 @@ class TTPTag(SQLModel, table=True):
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"attacker_uuid IS NOT NULL OR identity_uuid IS NOT NULL",
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name="ttp_tag_has_anchor",
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),
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CheckConstraint(
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"confidence >= 0.0 AND confidence <= 1.0",
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name="ttp_tag_confidence_range",
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),
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Index(
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"ix_ttp_tag_identity_technique",
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"identity_uuid",
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@@ -140,7 +140,8 @@ _SWALLOWED_EXCS: tuple[type[Exception], ...] = (
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ValueError,
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RuntimeError,
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KeyError,
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TypeError,
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# TypeError is intentionally NOT swallowed — it propagates as a
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# programmer-error signal (bad evidence shape). See TolerantTagger.tag.
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AttributeError,
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LookupError,
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OSError,
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@@ -67,7 +67,19 @@ def test_intel_evidence_keys() -> None:
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keys = (
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IntelEvidence.__required_keys__ | IntelEvidence.__optional_keys__
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)
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assert keys == {"intel_uuid", "provider", "category", "score"}
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assert keys == {
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# AbuseIPDB
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"abuseipdb_categories", "abuseipdb_score", "abuse_confidence_score",
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# GreyNoise
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"greynoise_classification", "greynoise_tags", "greynoise_name",
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# Feodo
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"feodo_listed", "feodo_malware_family", "first_seen_feodo", "malware_family",
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# ThreatFox
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"threatfox_threat_types", "threatfox_ioc_types", "threatfox_malware_families",
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"threat_types", "malware_families", "ioc_types",
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# Aggregate meta-rule
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"aggregate_verdict", "bumped_rule_ids",
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}
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def test_canary_fingerprint_evidence_keys() -> None:
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@@ -140,10 +152,6 @@ def test_lifter_emits_evidence_matching_typeddict(
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# ── Negative case: shape violation propagates (impl phase) ──────────
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@pytest.mark.xfail(
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strict=True,
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reason="impl phase: TolerantTagger currently swallows TypeError",
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)
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def test_evidence_shape_violation_propagates_as_typeerror() -> None:
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"""A lifter that emits an evidence dict with a key not in its
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``TypedDict`` is a programmer error — it MUST propagate past the
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@@ -169,7 +169,6 @@ def test_guard_runs_before_super_init() -> None:
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# ── confidence range guard (impl phase) ─────────────────────────────
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@pytest.mark.xfail(strict=True, reason="impl phase: confidence range guard not yet enforced")
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async def test_confidence_outside_range_rejected_at_insert(session: AsyncSession) -> None:
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"""``confidence`` outside [0.0, 1.0] must be rejected. The contract
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schema currently types it as bare ``float`` without a range
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