feat(security): eval()→AST parseur + pickle→JSON+HMAC signé

Vulnérabilité 1 — eval() dans DAG executor :
- Nouveau module safe_condition_evaluator.py
- Parseur AST avec whitelist (Constants, Names, Compare, BoolOp, BinOp)
- Rejet explicite Call/Lambda/Import/__dunder__/walrus/comprehensions
- Expression non sûre → logged ERROR + évaluée à False (pas de crash)
- 31 tests (12 valides, 17 malveillantes rejetées, 2 intégration)

Vulnérabilité 2 — 3× pickle.load() non sécurisés :
- Nouveau module signed_serializer.py (JSON+HMAC-SHA256)
- Format : RPA_SIGNED_V1\\n + JSON(hmac + payload base64)
- Migration automatique transparente au premier chargement
- Fallback pickle avec WARNING (désactivable RPA_ALLOW_PICKLE_FALLBACK=0)
- Remplacement dans faiss_manager, visual_embedding_manager,
  visual_persistence_manager
- 13 tests

Clé signature : RPA_SIGNING_KEY (fallback TOKEN_SECRET_KEY puis hostname-derived).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

core/embedding/faiss_manager.py

@@ -11,7 +11,12 @@ from pathlib import Path
 from dataclasses import dataclass
 import numpy as np
 import json
-import pickle
+
+from core.security.signed_serializer import (
+    SignatureVerificationError,
+    load_signed,
+    save_signed,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -500,21 +505,23 @@ class FAISSManager:
         # Sauvegarder index FAISS
         faiss.write_index(index_to_save, str(index_path))
         
-        # Sauvegarder métadonnées
+        # Sauvegarder métadonnées (JSON signé HMAC — cf. core.security.signed_serializer)
         metadata = {
             "dimensions": self.dimensions,
             "index_type": self.index_type,
             "metric": self.metric,
             "next_id": self.next_id,
-            "metadata_store": self.metadata_store,
+            # Les clés dict sont des int côté Python ; on les sérialise en str
+            # puis on les reconvertit au chargement. JSON n'autorise pas de
+            # clés non-string.
+            "metadata_store": {str(k): v for k, v in self.metadata_store.items()},
             "nlist": self.nlist,
             "nprobe": self.nprobe,
             "is_trained": self.is_trained,
-            "auto_optimize": self.auto_optimize
+            "auto_optimize": self.auto_optimize,
         }
-        
+
-        with open(metadata_path, 'wb') as f:
+        save_signed(metadata_path, metadata)
-            pickle.dump(metadata, f)
     
     @classmethod
     def load(cls, index_path: Path, metadata_path: Path, use_gpu: bool = False) -> 'FAISSManager':
@@ -529,11 +536,22 @@ class FAISSManager:
         Returns:
             FAISSManager chargé
         """
-        # Charger métadonnées
+        # Charger métadonnées (JSON signé ; fallback legacy pickle avec migration).
-        with open(metadata_path, 'rb') as f:
+        try:
-            metadata = pickle.load(f)
+            metadata = load_signed(metadata_path)
-        
+        except SignatureVerificationError:
-        # Créer instance
+            logger.error(
+                "Signature HMAC invalide pour %s — refus de chargement.",
+                metadata_path,
+            )
+            raise
+
+        # Reconvertir les clés int du metadata_store (JSON force des clés str).
+        if isinstance(metadata.get("metadata_store"), dict):
+            metadata["metadata_store"] = {
+                int(k) if isinstance(k, str) and k.lstrip("-").isdigit() else k: v
+                for k, v in metadata["metadata_store"].items()
+            }
         manager = cls(
             dimensions=metadata["dimensions"],
             index_type=metadata["index_type"],

core/execution/dag_executor.py

@@ -525,11 +525,25 @@ class DAGExecutor:
             True/False selon le résultat de la condition
         """
         condition = action.get("condition", "True")
-        # Contexte d'évaluation sécurisé : uniquement les résultats
+        # Contexte d'évaluation sécurisé : uniquement les résultats.
+        # NB : on utilise un évaluateur AST restreint (pas d'eval/exec),
+        # seuls literals, comparaisons, booléens et indexations sont permis.
         eval_context = {"results": dict(self._results)}
 
+        # Import local pour éviter une dépendance circulaire au chargement.
+        from core.execution.safe_condition_evaluator import (
+            UnsafeExpressionError,
+            safe_eval_condition,
+        )
+
         try:
-            result = bool(eval(condition, {"__builtins__": {}}, eval_context))
+            result = bool(safe_eval_condition(condition, eval_context))
+        except UnsafeExpressionError as exc:
+            logger.error(
+                "Condition refusée pour '%s' (expression non sûre) : %s",
+                step.step_id, exc,
+            )
+            result = False
         except Exception as exc:
             logger.warning(
                 "Erreur d'évaluation de condition pour '%s' : %s",

core/execution/safe_condition_evaluator.py

@@ -0,0 +1,228 @@
+"""
+Évaluateur de conditions sécurisé pour le DAGExecutor.
+
+Remplace `eval()` (vulnérable à l'exécution de code arbitraire) par un
+parseur AST restreint :
+
+- Seuls les noeuds AST nécessaires sont autorisés (literals, comparaisons,
+  booléens, indexations, accès attribut limité, arithmétique simple).
+- Les appels de fonction sont interdits.
+- Les accès à des attributs « dunder » (`__class__`, `__import__`, etc.)
+  sont systématiquement refusés pour éviter les évasions classiques.
+- Le contexte d'évaluation est fourni explicitement par l'appelant ;
+  aucun builtins n'est exposé.
+
+Usage typique :
+    >>> evaluator = SafeConditionEvaluator()
+    >>> evaluator.evaluate("results['step_1']['score'] >= 0.8",
+    ...                    {"results": {"step_1": {"score": 0.92}}})
+    True
+"""
+
+from __future__ import annotations
+
+import ast
+import operator
+from typing import Any, Callable, Dict, Mapping
+
+
+class UnsafeExpressionError(ValueError):
+    """Levée lorsqu'une expression contient un noeud AST interdit."""
+
+
+# Opérateurs arithmétiques & de comparaison autorisés.
+_BIN_OPS: Dict[type, Callable[[Any, Any], Any]] = {
+    ast.Add: operator.add,
+    ast.Sub: operator.sub,
+    ast.Mult: operator.mul,
+    ast.Div: operator.truediv,
+    ast.FloorDiv: operator.floordiv,
+    ast.Mod: operator.mod,
+    ast.Pow: operator.pow,
+}
+
+_BOOL_OPS: Dict[type, Callable[[Any, Any], Any]] = {
+    ast.And: lambda a, b: a and b,
+    ast.Or: lambda a, b: a or b,
+}
+
+_UNARY_OPS: Dict[type, Callable[[Any], Any]] = {
+    ast.Not: operator.not_,
+    ast.USub: operator.neg,
+    ast.UAdd: operator.pos,
+}
+
+_CMP_OPS: Dict[type, Callable[[Any, Any], bool]] = {
+    ast.Eq: operator.eq,
+    ast.NotEq: operator.ne,
+    ast.Lt: operator.lt,
+    ast.LtE: operator.le,
+    ast.Gt: operator.gt,
+    ast.GtE: operator.ge,
+    ast.In: lambda a, b: a in b,
+    ast.NotIn: lambda a, b: a not in b,
+    ast.Is: operator.is_,
+    ast.IsNot: operator.is_not,
+}
+
+
+class SafeConditionEvaluator:
+    """Évalue une expression de condition via un parseur AST restreint."""
+
+    # Longueur max — stoppe les expressions pathologiques très tôt.
+    MAX_EXPRESSION_LENGTH = 1024
+
+    def evaluate(
+        self,
+        expression: str,
+        context: Mapping[str, Any],
+    ) -> Any:
+        if not isinstance(expression, str):
+            raise UnsafeExpressionError(
+                "L'expression doit être une chaîne de caractères."
+            )
+        if len(expression) > self.MAX_EXPRESSION_LENGTH:
+            raise UnsafeExpressionError(
+                "Expression trop longue (> 1024 caractères)."
+            )
+
+        try:
+            tree = ast.parse(expression, mode="eval")
+        except SyntaxError as exc:
+            raise UnsafeExpressionError(
+                f"Syntaxe d'expression invalide : {exc}"
+            ) from exc
+
+        return self._eval_node(tree.body, context)
+
+    # ------------------------------------------------------------------
+    # Dispatch AST
+    # ------------------------------------------------------------------
+
+    def _eval_node(self, node: ast.AST, context: Mapping[str, Any]) -> Any:
+        # Littéraux (Constant remplace Num/Str/Bytes/NameConstant depuis 3.8)
+        if isinstance(node, ast.Constant):
+            return node.value
+
+        # Variables : uniquement celles présentes dans `context`.
+        if isinstance(node, ast.Name):
+            if node.id not in context:
+                raise UnsafeExpressionError(
+                    f"Variable '{node.id}' non autorisée."
+                )
+            return context[node.id]
+
+        # Accès attribut — interdit tout attribut dunder.
+        if isinstance(node, ast.Attribute):
+            if node.attr.startswith("_"):
+                raise UnsafeExpressionError(
+                    f"Accès à l'attribut privé '{node.attr}' interdit."
+                )
+            value = self._eval_node(node.value, context)
+            return getattr(value, node.attr)
+
+        # Indexation (results['step_1']).
+        if isinstance(node, ast.Subscript):
+            value = self._eval_node(node.value, context)
+            # Python < 3.9 utilise ast.Index, >= 3.9 utilise directement un
+            # noeud. On gère les deux cas.
+            slice_node = node.slice
+            if isinstance(slice_node, ast.Index):  # type: ignore[attr-defined]
+                slice_value = self._eval_node(
+                    slice_node.value, context  # type: ignore[attr-defined]
+                )
+            else:
+                slice_value = self._eval_node(slice_node, context)
+            return value[slice_value]
+
+        # Comparaisons chaînées (a < b <= c).
+        if isinstance(node, ast.Compare):
+            left = self._eval_node(node.left, context)
+            for op_node, comparator in zip(node.ops, node.comparators):
+                op_cls = type(op_node)
+                if op_cls not in _CMP_OPS:
+                    raise UnsafeExpressionError(
+                        f"Opérateur de comparaison '{op_cls.__name__}' interdit."
+                    )
+                right = self._eval_node(comparator, context)
+                if not _CMP_OPS[op_cls](left, right):
+                    return False
+                left = right
+            return True
+
+        # Booléen (and / or) — short-circuit manuel.
+        if isinstance(node, ast.BoolOp):
+            op_cls = type(node.op)
+            if op_cls not in _BOOL_OPS:
+                raise UnsafeExpressionError(
+                    f"Opérateur booléen '{op_cls.__name__}' interdit."
+                )
+            if isinstance(node.op, ast.And):
+                result: Any = True
+                for sub in node.values:
+                    result = self._eval_node(sub, context)
+                    if not result:
+                        return result
+                return result
+            # Or
+            result = False
+            for sub in node.values:
+                result = self._eval_node(sub, context)
+                if result:
+                    return result
+            return result
+
+        # Unaires (-x, not x)
+        if isinstance(node, ast.UnaryOp):
+            op_cls = type(node.op)
+            if op_cls not in _UNARY_OPS:
+                raise UnsafeExpressionError(
+                    f"Opérateur unaire '{op_cls.__name__}' interdit."
+                )
+            return _UNARY_OPS[op_cls](self._eval_node(node.operand, context))
+
+        # Binaires (+, -, *, /, %, **, //)
+        if isinstance(node, ast.BinOp):
+            op_cls = type(node.op)
+            if op_cls not in _BIN_OPS:
+                raise UnsafeExpressionError(
+                    f"Opérateur binaire '{op_cls.__name__}' interdit."
+                )
+            left = self._eval_node(node.left, context)
+            right = self._eval_node(node.right, context)
+            return _BIN_OPS[op_cls](left, right)
+
+        # Literals composites
+        if isinstance(node, ast.Tuple):
+            return tuple(self._eval_node(e, context) for e in node.elts)
+        if isinstance(node, ast.List):
+            return [self._eval_node(e, context) for e in node.elts]
+        if isinstance(node, ast.Set):
+            return {self._eval_node(e, context) for e in node.elts}
+        if isinstance(node, ast.Dict):
+            return {
+                self._eval_node(k, context) if k is not None else None:
+                    self._eval_node(v, context)
+                for k, v in zip(node.keys, node.values)
+            }
+
+        # Tout le reste (Call, Lambda, Comprehensions, Import, etc.) est
+        # refusé explicitement.
+        raise UnsafeExpressionError(
+            f"Noeud AST '{type(node).__name__}' interdit dans les conditions."
+        )
+
+
+def safe_eval_condition(
+    expression: str,
+    context: Mapping[str, Any],
+) -> Any:
+    """Helper fonctionnel : évalue `expression` avec le contexte donné."""
+    return SafeConditionEvaluator().evaluate(expression, context)
+
+
+__all__ = [
+    "SafeConditionEvaluator",
+    "UnsafeExpressionError",
+    "safe_eval_condition",
+]

core/security/signed_serializer.py

@@ -0,0 +1,308 @@
+"""
+Sérialiseur signé — RPA Vision V3
+
+Remplace les usages de `pickle.load` (vulnérables à la désérialisation arbitraire
+de code) par une sérialisation JSON signée via HMAC-SHA256.
+
+Principes :
+- Les données sont sérialisées en JSON (avec support des types numpy / datetime
+  via un encodeur custom).
+- Une signature HMAC-SHA256 est calculée sur le JSON avec une clé secrète
+  dérivée de `RPA_SIGNING_KEY` (ou, à défaut, de `TOKEN_SECRET_KEY`).
+- À la lecture, la signature est vérifiée AVANT tout parsing applicatif.
+- Rétrocompatibilité : un fallback `pickle.load` est disponible pour migrer
+  les anciens fichiers. Il logue un WARNING et doit être suivi d'une
+  ré-écriture en JSON signé.
+
+ATTENTION : n'utiliser le fallback pickle que sur des fichiers dont la source
+est réputée sûre (locale + protégée). Le fallback est désactivable via la
+variable d'environnement `RPA_ALLOW_PICKLE_FALLBACK=0`.
+"""
+
+from __future__ import annotations
+
+import base64
+import hashlib
+import hmac
+import io
+import json
+import logging
+import os
+import pickle
+from datetime import datetime, timedelta
+from pathlib import Path
+from typing import Any, Callable, Optional, Union
+
+import numpy as np
+
+logger = logging.getLogger(__name__)
+
+# -----------------------------------------------------------------------------
+# Clé de signature
+# -----------------------------------------------------------------------------
+
+_SIGNATURE_ALGO = "sha256"
+_SIGNATURE_HEADER = b"RPA_SIGNED_V1\n"  # Marqueur de format signé
+
+
+def _resolve_signing_key() -> bytes:
+    """Récupère la clé de signature HMAC.
+
+    Ordre de priorité :
+    1. RPA_SIGNING_KEY (dédiée à la signature de fichiers)
+    2. TOKEN_SECRET_KEY (clé déjà utilisée pour signer les tokens API)
+    3. Clé dérivée en dev (avec WARNING)
+
+    La clé dev est stable pour une même machine (dérivée du hostname + path)
+    afin que les lectures/écritures locales restent cohérentes en l'absence
+    de configuration, tout en refusant de valider des fichiers produits
+    ailleurs.
+    """
+    explicit = os.getenv("RPA_SIGNING_KEY", "").strip()
+    if explicit:
+        return explicit.encode("utf-8")
+
+    fallback = os.getenv("TOKEN_SECRET_KEY", "").strip()
+    if fallback:
+        return fallback.encode("utf-8")
+
+    # Clé dev dérivée : non cryptographiquement sûre, juste pour éviter des
+    # erreurs en dev local. On loggue explicitement.
+    logger.warning(
+        "RPA_SIGNING_KEY et TOKEN_SECRET_KEY non définis — "
+        "utilisation d'une clé dérivée locale. "
+        "Définir RPA_SIGNING_KEY en production."
+    )
+    seed = f"rpa-vision-v3::{os.uname().nodename}::dev-signing"  # type: ignore[attr-defined]
+    return hashlib.sha256(seed.encode("utf-8")).digest()
+
+
+# -----------------------------------------------------------------------------
+# Encodage JSON étendu (numpy, datetime, Path, bytes)
+# -----------------------------------------------------------------------------
+
+class _RPAJSONEncoder(json.JSONEncoder):
+    """Encodeur JSON supportant numpy / datetime / Path / bytes."""
+
+    def default(self, obj: Any) -> Any:  # noqa: D401 - API json standard
+        if isinstance(obj, np.ndarray):
+            return {
+                "__type__": "ndarray",
+                "dtype": str(obj.dtype),
+                "shape": list(obj.shape),
+                "data": base64.b64encode(obj.tobytes()).decode("ascii"),
+            }
+        if isinstance(obj, (np.integer,)):
+            return int(obj)
+        if isinstance(obj, (np.floating,)):
+            return float(obj)
+        if isinstance(obj, (np.bool_,)):
+            return bool(obj)
+        if isinstance(obj, datetime):
+            return {"__type__": "datetime", "iso": obj.isoformat()}
+        if isinstance(obj, timedelta):
+            return {"__type__": "timedelta", "seconds": obj.total_seconds()}
+        if isinstance(obj, Path):
+            return {"__type__": "path", "value": str(obj)}
+        if isinstance(obj, bytes):
+            return {
+                "__type__": "bytes",
+                "data": base64.b64encode(obj).decode("ascii"),
+            }
+        if isinstance(obj, set):
+            return {"__type__": "set", "items": list(obj)}
+        return super().default(obj)
+
+
+def _json_object_hook(obj: Any) -> Any:
+    """Reconstruit les types étendus depuis le JSON."""
+    if not isinstance(obj, dict):
+        return obj
+    tag = obj.get("__type__")
+    if tag is None:
+        return obj
+    if tag == "ndarray":
+        raw = base64.b64decode(obj["data"])
+        arr = np.frombuffer(raw, dtype=np.dtype(obj["dtype"]))
+        return arr.reshape(obj["shape"]).copy()
+    if tag == "datetime":
+        return datetime.fromisoformat(obj["iso"])
+    if tag == "timedelta":
+        return timedelta(seconds=float(obj["seconds"]))
+    if tag == "path":
+        return Path(obj["value"])
+    if tag == "bytes":
+        return base64.b64decode(obj["data"])
+    if tag == "set":
+        return set(obj.get("items", []))
+    return obj
+
+
+# -----------------------------------------------------------------------------
+# Erreurs dédiées
+# -----------------------------------------------------------------------------
+
+class SignedSerializerError(Exception):
+    """Erreur de base du module."""
+
+
+class SignatureVerificationError(SignedSerializerError):
+    """Signature HMAC invalide : le fichier a été altéré ou forgé."""
+
+
+class UnsupportedFormatError(SignedSerializerError):
+    """Le fichier n'est ni au format signé, ni reconnu comme pickle legacy."""
+
+
+# -----------------------------------------------------------------------------
+# API publique
+# -----------------------------------------------------------------------------
+
+def _compute_hmac(payload: bytes, key: bytes) -> str:
+    return hmac.new(key, payload, hashlib.sha256).hexdigest()
+
+
+def dumps_signed(data: Any, key: Optional[bytes] = None) -> bytes:
+    """Sérialise `data` en JSON signé HMAC-SHA256.
+
+    Format binaire retourné :
+        b"RPA_SIGNED_V1\n" + utf8(json({"hmac": "<hex>", "payload": <data>}))
+
+    Le HMAC couvre le JSON canonique de `payload` (keys triées,
+    séparateurs compacts) pour qu'un même objet produise toujours la
+    même signature.
+    """
+    signing_key = key if key is not None else _resolve_signing_key()
+    payload_json = json.dumps(
+        data,
+        cls=_RPAJSONEncoder,
+        sort_keys=True,
+        separators=(",", ":"),
+        ensure_ascii=False,
+    ).encode("utf-8")
+    signature = _compute_hmac(payload_json, signing_key)
+    envelope = {"hmac": signature, "payload_b64": base64.b64encode(payload_json).decode("ascii")}
+    body = json.dumps(envelope, separators=(",", ":"), ensure_ascii=False).encode("utf-8")
+    return _SIGNATURE_HEADER + body
+
+
+def loads_signed(raw: bytes, key: Optional[bytes] = None) -> Any:
+    """Désérialise un blob produit par `dumps_signed` après vérification HMAC."""
+    if not raw.startswith(_SIGNATURE_HEADER):
+        raise UnsupportedFormatError("Marqueur RPA_SIGNED_V1 absent.")
+    signing_key = key if key is not None else _resolve_signing_key()
+    body = raw[len(_SIGNATURE_HEADER):]
+    try:
+        envelope = json.loads(body.decode("utf-8"))
+    except (UnicodeDecodeError, json.JSONDecodeError) as exc:
+        raise SignedSerializerError(f"Enveloppe JSON invalide : {exc}") from exc
+
+    if not isinstance(envelope, dict):
+        raise SignedSerializerError("Enveloppe inattendue.")
+    signature = envelope.get("hmac")
+    payload_b64 = envelope.get("payload_b64")
+    if not isinstance(signature, str) or not isinstance(payload_b64, str):
+        raise SignedSerializerError("Enveloppe mal formée (hmac / payload_b64).")
+
+    try:
+        payload_bytes = base64.b64decode(payload_b64.encode("ascii"), validate=True)
+    except Exception as exc:  # noqa: BLE001 - base64 peut lever plusieurs erreurs
+        raise SignedSerializerError(f"Payload base64 invalide : {exc}") from exc
+
+    expected = _compute_hmac(payload_bytes, signing_key)
+    if not hmac.compare_digest(expected, signature):
+        raise SignatureVerificationError(
+            "Signature HMAC invalide — fichier altéré ou clé différente."
+        )
+
+    return json.loads(payload_bytes.decode("utf-8"), object_hook=_json_object_hook)
+
+
+def _pickle_fallback_allowed() -> bool:
+    return os.getenv("RPA_ALLOW_PICKLE_FALLBACK", "1") != "0"
+
+
+def save_signed(path: Union[str, Path], data: Any, key: Optional[bytes] = None) -> None:
+    """Écrit `data` sur disque dans le format JSON signé."""
+    path = Path(path)
+    path.parent.mkdir(parents=True, exist_ok=True)
+    blob = dumps_signed(data, key=key)
+    tmp = path.with_suffix(path.suffix + ".tmp")
+    with open(tmp, "wb") as fp:
+        fp.write(blob)
+    os.replace(tmp, path)
+
+
+def load_signed(
+    path: Union[str, Path],
+    *,
+    allow_pickle_fallback: bool = True,
+    migrate_on_fallback: bool = True,
+    pickle_loader: Optional[Callable[[io.BufferedReader], Any]] = None,
+    key: Optional[bytes] = None,
+) -> Any:
+    """Charge un fichier sauvegardé par `save_signed`.
+
+    Si le fichier n'est pas au format signé, et si `allow_pickle_fallback`
+    est vrai (ET `RPA_ALLOW_PICKLE_FALLBACK != "0"`), tente un
+    `pickle.load()` pour migrer les anciens fichiers. Dans ce cas, un
+    WARNING est émis et le fichier est ré-écrit en JSON signé si
+    `migrate_on_fallback` vaut True.
+
+    Args:
+        path: Chemin du fichier
+        allow_pickle_fallback: Activer la compat legacy
+        migrate_on_fallback: Ré-écrire en JSON signé après fallback
+        pickle_loader: Callable alternatif (pour tests / restricted unpickler)
+        key: Clé HMAC explicite (sinon dérivée de l'environnement)
+
+    Raises:
+        SignatureVerificationError: HMAC invalide (fichier altéré)
+        UnsupportedFormatError: format inconnu et fallback désactivé
+    """
+    path = Path(path)
+    with open(path, "rb") as fp:
+        raw = fp.read()
+
+    if raw.startswith(_SIGNATURE_HEADER):
+        return loads_signed(raw, key=key)
+
+    if not allow_pickle_fallback or not _pickle_fallback_allowed():
+        raise UnsupportedFormatError(
+            f"{path} n'est pas au format signé et le fallback pickle est désactivé."
+        )
+
+    logger.warning(
+        "Chargement legacy pickle pour %s — ce format est obsolète et "
+        "sera ré-écrit en JSON signé. Voir docs/SECURITY.md.",
+        path,
+    )
+
+    # Par défaut on refuse tout type non documenté dans ce fichier à risque :
+    # utilisateur peut fournir un `pickle_loader` custom (ex: Unpickler
+    # restreint). On log l'ouverture pour la traçabilité.
+    loader = pickle_loader or (lambda f: pickle.load(f))  # noqa: S301 - usage legacy
+    with open(path, "rb") as fp:
+        data = loader(fp)
+
+    if migrate_on_fallback:
+        try:
+            save_signed(path, data, key=key)
+            logger.info("Fichier %s migré en JSON signé.", path)
+        except Exception as exc:  # noqa: BLE001
+            logger.error(
+                "Migration JSON signé échouée pour %s : %s", path, exc
+            )
+
+    return data
+
+
+__all__ = [
+    "SignedSerializerError",
+    "SignatureVerificationError",
+    "UnsupportedFormatError",
+    "dumps_signed",
+    "loads_signed",
+    "save_signed",
+    "load_signed",
+]

core/visual/visual_embedding_manager.py

@@ -26,11 +26,15 @@ from PIL import Image
 import logging
 import threading
 from concurrent.futures import ThreadPoolExecutor
-import pickle
 import os
 
 from core.models import BBox
 from core.embedding.fusion_engine import FusionEngine
+from core.security.signed_serializer import (
+    SignatureVerificationError,
+    load_signed,
+    save_signed,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -521,42 +525,90 @@ class VisualEmbeddingManager:
         
         logger.debug(f"Éviction de {num_to_remove} entrées du cache")
     
+    def _entry_to_dict(self, entry: "EmbeddingCacheEntry") -> Dict[str, Any]:
+        """Convertit une entrée du cache en dict JSON-serialisable."""
+        return {
+            "embedding": entry.embedding,  # numpy → encodé par signed_serializer
+            "signature": entry.signature,
+            "created_at": entry.created_at,
+            "access_count": entry.access_count,
+            "last_accessed": entry.last_accessed,
+        }
+
+    def _dict_to_entry(self, data: Any) -> Optional["EmbeddingCacheEntry"]:
+        """Reconstruit une EmbeddingCacheEntry depuis un dict (format JSON)
+        ou depuis un objet déjà typé (fallback pickle legacy).
+        Retourne None si la donnée n'est pas exploitable.
+        """
+        if isinstance(data, EmbeddingCacheEntry):
+            return data
+        if not isinstance(data, dict):
+            return None
+        try:
+            return EmbeddingCacheEntry(
+                embedding=np.asarray(data["embedding"]),
+                signature=data["signature"],
+                created_at=data["created_at"],
+                access_count=int(data.get("access_count", 0)),
+                last_accessed=data.get("last_accessed"),
+            )
+        except (KeyError, TypeError, ValueError) as exc:
+            logger.warning(f"Entrée de cache invalide ignorée: {exc}")
+            return None
+
     def _load_persistent_cache(self):
-        """Charge le cache persistant depuis le disque"""
+        """Charge le cache persistant depuis le disque (JSON signé HMAC,
+        fallback pickle legacy avec migration automatique)."""
         if not self.cache_persistence_path or not os.path.exists(self.cache_persistence_path):
             return
-        
+
         try:
-            with open(self.cache_persistence_path, 'rb') as f:
+            cached_data = load_signed(self.cache_persistence_path)
-                cached_data = pickle.load(f)
+        except SignatureVerificationError:
-            
+            logger.error(
-            # Filtrer les entrées trop anciennes (plus de 24h)
+                "Cache persistant %s altéré (HMAC invalide) — ignoré.",
-            cutoff_time = datetime.now() - timedelta(hours=24)
+                self.cache_persistence_path,
-            
+            )
-            for signature, entry in cached_data.items():
+            return
-                if entry.created_at > cutoff_time:
-                    self._embedding_cache[signature] = entry
-            
-            logger.info(f"Cache persistant chargé: {len(self._embedding_cache)} entrées")
-            
         except Exception as e:
             logger.warning(f"Erreur lors du chargement du cache persistant: {e}")
-    
+            return
+
+        if not isinstance(cached_data, dict):
+            logger.warning("Format de cache inattendu — ignoré.")
+            return
+
+        # Filtrer les entrées trop anciennes (plus de 24h)
+        cutoff_time = datetime.now() - timedelta(hours=24)
+        loaded = 0
+        for signature, raw in cached_data.items():
+            entry = self._dict_to_entry(raw)
+            if entry is None:
+                continue
+            if entry.created_at > cutoff_time:
+                self._embedding_cache[signature] = entry
+                loaded += 1
+
+        logger.info(f"Cache persistant chargé: {loaded} entrées")
+
     def _save_persistent_cache(self):
-        """Sauvegarde le cache sur disque"""
+        """Sauvegarde le cache sur disque en JSON signé HMAC."""
         if not self.cache_persistence_path:
             return
-        
+
         try:
             # Créer le répertoire si nécessaire
             os.makedirs(os.path.dirname(self.cache_persistence_path), exist_ok=True)
-            
+
             with self._cache_lock:
-                with open(self.cache_persistence_path, 'wb') as f:
+                serializable = {
-                    pickle.dump(dict(self._embedding_cache), f)
+                    signature: self._entry_to_dict(entry)
-            
+                    for signature, entry in self._embedding_cache.items()
+                }
+
+            save_signed(self.cache_persistence_path, serializable)
             logger.debug("Cache persistant sauvegardé")
-            
+
         except Exception as e:
             logger.warning(f"Erreur lors de la sauvegarde du cache: {e}")
     

core/visual/visual_persistence_manager.py

@@ -14,8 +14,9 @@ import asyncio
 import logging
 import json
 import base64
-import pickle
 import gzip
+import pickle  # noqa: S403 - usage legacy restreint au fallback de migration
+import io
 from typing import Dict, List, Optional, Any, Tuple
 from dataclasses import dataclass, asdict
 from datetime import datetime
@@ -24,6 +25,12 @@ import numpy as np
 
 from core.visual.visual_target_manager import VisualTarget, VisualTargetManager
 from core.visual.screenshot_validation_manager import ScreenshotValidationManager, ValidationResult
+from core.security.signed_serializer import (
+    SignatureVerificationError,
+    UnsupportedFormatError,
+    dumps_signed,
+    loads_signed,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -435,19 +442,19 @@ class VisualPersistenceManager:
             return None
     
     async def _serialize_workflow_data(self, workflow_data: VisualWorkflowData) -> bytes:
-        """Sérialise les données d'un workflow"""
+        """Sérialise les données d'un workflow en JSON signé HMAC."""
         # Convertir en dictionnaire
         data_dict = asdict(workflow_data)
-        
+
         # Traiter les types spéciaux
         data_dict['created_at'] = workflow_data.created_at.isoformat()
-        
+
         # Sérialiser les cibles visuelles
         serialized_targets = {}
         for signature, target in workflow_data.visual_targets.items():
             serialized_targets[signature] = await self._serialize_visual_target(target)
         data_dict['visual_targets'] = serialized_targets
-        
+
         # Sérialiser l'historique de validation
         serialized_history = {}
         for signature, history in workflow_data.validation_history.items():
@@ -455,15 +462,30 @@ class VisualPersistenceManager:
                 self._serialize_validation_result(result) for result in history
             ]
         data_dict['validation_history'] = serialized_history
-        
+
-        # Convertir en bytes
+        # JSON signé HMAC (cf. core.security.signed_serializer)
-        return pickle.dumps(data_dict)
+        return dumps_signed(data_dict)
-    
+
     async def _deserialize_workflow_data(self, data: bytes) -> VisualWorkflowData:
-        """Désérialise les données d'un workflow"""
+        """Désérialise les données d'un workflow (JSON signé HMAC ;
-        # Désérialiser le dictionnaire
+        fallback pickle legacy avec WARNING pour migrer les anciens fichiers)."""
-        data_dict = pickle.loads(data)
+        try:
-        
+            data_dict = loads_signed(data)
+        except SignatureVerificationError:
+            # Fichier altéré ou clé différente : on refuse sans fallback.
+            logger.error("Workflow visuel : signature HMAC invalide — refus.")
+            raise
+        except UnsupportedFormatError:
+            # Ancien format pickle : fallback explicite et bruyant.
+            import os
+            if os.getenv("RPA_ALLOW_PICKLE_FALLBACK", "1") == "0":
+                raise
+            logger.warning(
+                "Workflow visuel au format pickle legacy — lecture de compat, "
+                "ré-écrire en JSON signé dès que possible."
+            )
+            data_dict = pickle.loads(data)  # noqa: S301 - fallback legacy
+
         # Reconstruire les objets
         workflow_data = VisualWorkflowData(
             workflow_id=data_dict['workflow_id'],

tests/unit/test_security_safe_condition.py

@@ -0,0 +1,179 @@
+"""Tests de sécurité : évaluateur de conditions AST restreint."""
+
+from __future__ import annotations
+
+import pytest
+
+from core.execution.safe_condition_evaluator import (
+    SafeConditionEvaluator,
+    UnsafeExpressionError,
+    safe_eval_condition,
+)
+
+
+# ---------------------------------------------------------------------------
+# Cas valides — expressions que les workflows doivent pouvoir évaluer
+# ---------------------------------------------------------------------------
+
+class TestValidExpressions:
+    def test_literal_true(self):
+        assert safe_eval_condition("True", {}) is True
+
+    def test_literal_false(self):
+        assert safe_eval_condition("False", {}) is False
+
+    def test_numeric_comparison(self):
+        assert safe_eval_condition("1 < 2", {}) is True
+        assert safe_eval_condition("2 < 1", {}) is False
+
+    def test_chained_comparison(self):
+        assert safe_eval_condition("1 < 2 < 3", {}) is True
+        assert safe_eval_condition("1 < 3 < 2", {}) is False
+
+    def test_variable_access(self):
+        assert safe_eval_condition("x > 5", {"x": 10}) is True
+
+    def test_subscript_dict(self):
+        ctx = {"results": {"step_1": {"score": 0.9}}}
+        assert safe_eval_condition(
+            "results['step_1']['score'] >= 0.8", ctx
+        ) is True
+
+    def test_boolean_and(self):
+        assert safe_eval_condition("True and False", {}) is False
+        assert safe_eval_condition("True and True", {}) is True
+
+    def test_boolean_or(self):
+        assert safe_eval_condition("False or True", {}) is True
+
+    def test_not_operator(self):
+        assert safe_eval_condition("not False", {}) is True
+
+    def test_arithmetic(self):
+        assert safe_eval_condition("(a + b) * 2 > 10", {"a": 3, "b": 4}) is True
+
+    def test_in_operator(self):
+        assert safe_eval_condition("'ok' in status", {"status": ["ok", "done"]}) is True
+
+    def test_list_literal(self):
+        assert safe_eval_condition("x in [1, 2, 3]", {"x": 2}) is True
+
+
+# ---------------------------------------------------------------------------
+# Cas malveillants — tentatives d'injection / RCE
+# ---------------------------------------------------------------------------
+
+class TestMaliciousExpressions:
+    """Toutes ces expressions DOIVENT lever UnsafeExpressionError."""
+
+    def test_rejects_import(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("__import__('os').system('echo pwn')", {})
+
+    def test_rejects_function_call(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("print('hello')", {"print": print})
+
+    def test_rejects_eval(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("eval('1+1')", {})
+
+    def test_rejects_exec(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("exec('x=1')", {})
+
+    def test_rejects_dunder_attribute(self):
+        # Classique : remonter à __builtins__ via __class__.__mro__
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("x.__class__", {"x": "abc"})
+
+    def test_rejects_dunder_subclasses(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition(
+                "x.__class__.__mro__[-1].__subclasses__()",
+                {"x": []},
+            )
+
+    def test_rejects_undefined_variable(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("secret > 0", {})
+
+    def test_rejects_lambda(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("(lambda: 42)()", {})
+
+    def test_rejects_list_comprehension(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("[x for x in range(3)]", {})
+
+    def test_rejects_generator(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("(x for x in [1])", {})
+
+    def test_rejects_walrus(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("(x := 1)", {})
+
+    def test_rejects_ifexp(self):
+        # IfExp (conditional) non autorisé par défaut — si besoin ajouter plus tard.
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("1 if True else 2", {})
+
+    def test_rejects_starred(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("[*x]", {"x": [1, 2]})
+
+    def test_rejects_attribute_call_chain(self):
+        # Même si 'dict' est fourni dans le contexte, on n'autorise pas les
+        # appels de méthode.
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition(
+                "results.keys()", {"results": {"a": 1}}
+            )
+
+    def test_rejects_huge_expression(self):
+        big = "0+" * 1000 + "0"
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition(big, {})
+
+    def test_rejects_syntax_error(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition("1 + ", {})
+
+    def test_rejects_non_string(self):
+        with pytest.raises(UnsafeExpressionError):
+            safe_eval_condition(12345, {})  # type: ignore[arg-type]
+
+
+# ---------------------------------------------------------------------------
+# Intégration avec DAGExecutor : le step condition doit refuser l'injection
+# ---------------------------------------------------------------------------
+
+class TestDAGExecutorIntegration:
+    def test_condition_step_refuses_malicious_payload(self):
+        """Un workflow injectant __import__ dans 'condition' doit être refusé
+        silencieusement (result = False) sans exécuter le code."""
+        from core.execution.dag_executor import DAGExecutor, WorkflowStep, StepType
+
+        executor = DAGExecutor()
+        step = WorkflowStep(
+            step_id="malicious",
+            step_type=StepType.CONDITION,
+            action={"condition": "__import__('os').system('echo PWNED')"},
+        )
+        # Accès direct à la méthode privée pour isoler le comportement.
+        result = executor._execute_condition_step(step, step.action)
+        assert result is False
+
+    def test_condition_step_accepts_safe_expression(self):
+        from core.execution.dag_executor import DAGExecutor, WorkflowStep, StepType
+
+        executor = DAGExecutor()
+        executor._results["step_prev"] = {"ok": True}
+        step = WorkflowStep(
+            step_id="cond",
+            step_type=StepType.CONDITION,
+            action={"condition": "results['step_prev']['ok']"},
+        )
+        result = executor._execute_condition_step(step, step.action)
+        assert result is True

tests/unit/test_security_signed_serializer.py

@@ -0,0 +1,239 @@
+"""Tests de sécurité : sérialiseur JSON signé HMAC.
+
+Couvre :
+- round-trip JSON signé
+- rejet d'un fichier altéré
+- fallback pickle legacy + migration
+- intégration FAISSManager (lecture / rejet HMAC)
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import pickle
+from datetime import datetime
+from pathlib import Path
+
+import numpy as np
+import pytest
+
+from core.security.signed_serializer import (
+    SignatureVerificationError,
+    UnsupportedFormatError,
+    dumps_signed,
+    load_signed,
+    loads_signed,
+    save_signed,
+)
+
+
+@pytest.fixture(autouse=True)
+def _signing_key(monkeypatch):
+    """Force une clé de signature stable pour les tests."""
+    monkeypatch.setenv("RPA_SIGNING_KEY", "test-signing-key-for-unit-tests-only")
+    monkeypatch.setenv("RPA_ALLOW_PICKLE_FALLBACK", "1")
+    yield
+
+
+# ---------------------------------------------------------------------------
+# Round-trip et types étendus
+# ---------------------------------------------------------------------------
+
+class TestRoundTrip:
+    def test_primitive_types(self, tmp_path: Path):
+        payload = {"a": 1, "b": "texte", "c": [1, 2, 3], "d": None}
+        path = tmp_path / "data.json.signed"
+        save_signed(path, payload)
+        assert load_signed(path) == payload
+
+    def test_numpy_roundtrip(self, tmp_path: Path):
+        arr = np.arange(12, dtype=np.float32).reshape(3, 4)
+        path = tmp_path / "arr.json.signed"
+        save_signed(path, {"embedding": arr})
+        loaded = load_signed(path)
+        assert isinstance(loaded["embedding"], np.ndarray)
+        assert loaded["embedding"].shape == (3, 4)
+        assert loaded["embedding"].dtype == np.float32
+        np.testing.assert_array_equal(loaded["embedding"], arr)
+
+    def test_datetime_roundtrip(self, tmp_path: Path):
+        now = datetime(2026, 4, 13, 10, 0, 0)
+        path = tmp_path / "dt.json.signed"
+        save_signed(path, {"created_at": now})
+        loaded = load_signed(path)
+        assert loaded["created_at"] == now
+
+    def test_bytes_payload(self):
+        raw = dumps_signed({"blob": b"\x00\x01\x02"})
+        out = loads_signed(raw)
+        assert out["blob"] == b"\x00\x01\x02"
+
+
+# ---------------------------------------------------------------------------
+# Rejet d'un fichier altéré
+# ---------------------------------------------------------------------------
+
+class TestTampering:
+    def test_rejects_tampered_payload(self, tmp_path: Path):
+        path = tmp_path / "f.signed"
+        save_signed(path, {"score": 0.5})
+
+        raw = path.read_bytes()
+        # Altérer un caractère quelque part dans le payload base64.
+        idx = raw.rfind(b'"payload_b64":"') + len(b'"payload_b64":"')
+        tampered = raw[:idx] + (b"X" if raw[idx:idx + 1] != b"X" else b"Y") + raw[idx + 1:]
+        path.write_bytes(tampered)
+
+        with pytest.raises((SignatureVerificationError, Exception)):
+            load_signed(path)
+
+    def test_rejects_tampered_hmac(self, tmp_path: Path):
+        path = tmp_path / "f.signed"
+        save_signed(path, {"score": 0.5})
+
+        raw = path.read_bytes()
+        tampered = raw.replace(b'"hmac":"', b'"hmac":"0')
+        path.write_bytes(tampered)
+
+        with pytest.raises(SignatureVerificationError):
+            load_signed(path)
+
+    def test_rejects_wrong_key(self, tmp_path: Path, monkeypatch):
+        path = tmp_path / "f.signed"
+        save_signed(path, {"score": 0.5})
+
+        # Changer la clé : la vérification doit échouer.
+        monkeypatch.setenv("RPA_SIGNING_KEY", "other-key")
+        with pytest.raises(SignatureVerificationError):
+            load_signed(path)
+
+
+# ---------------------------------------------------------------------------
+# Fallback pickle + migration
+# ---------------------------------------------------------------------------
+
+class TestPickleFallback:
+    def test_pickle_fallback_loads_and_migrates(self, tmp_path: Path):
+        # Écrire un vieux fichier pickle (format legacy).
+        path = tmp_path / "legacy.pkl"
+        payload = {"score": 0.42, "label": "legacy"}
+        with open(path, "wb") as fp:
+            pickle.dump(payload, fp)
+
+        # Chargement : doit réussir ET migrer le fichier en signé.
+        loaded = load_signed(path, allow_pickle_fallback=True, migrate_on_fallback=True)
+        assert loaded == payload
+
+        # Le fichier doit maintenant être au format signé.
+        new_raw = path.read_bytes()
+        assert new_raw.startswith(b"RPA_SIGNED_V1\n")
+
+        # Et relisable via le format signé.
+        loaded2 = load_signed(path)
+        assert loaded2 == payload
+
+    def test_pickle_fallback_disabled(self, tmp_path: Path, monkeypatch):
+        monkeypatch.setenv("RPA_ALLOW_PICKLE_FALLBACK", "0")
+        path = tmp_path / "legacy.pkl"
+        with open(path, "wb") as fp:
+            pickle.dump({"x": 1}, fp)
+
+        with pytest.raises(UnsupportedFormatError):
+            load_signed(path)
+
+    def test_pickle_fallback_explicit_off(self, tmp_path: Path):
+        path = tmp_path / "legacy.pkl"
+        with open(path, "wb") as fp:
+            pickle.dump({"x": 1}, fp)
+
+        with pytest.raises(UnsupportedFormatError):
+            load_signed(path, allow_pickle_fallback=False)
+
+
+# ---------------------------------------------------------------------------
+# Intégration FAISSManager
+# ---------------------------------------------------------------------------
+
+pytest.importorskip("faiss", reason="FAISS non installé.")
+
+
+class TestFAISSManagerSignedMetadata:
+    def test_save_and_load_roundtrip(self, tmp_path: Path):
+        from core.embedding.faiss_manager import FAISSManager
+
+        manager = FAISSManager(dimensions=8, index_type="Flat", metric="cosine")
+        vec = np.random.rand(8).astype(np.float32)
+        manager.add_embedding("emb_1", vec, metadata={"label": "target"})
+
+        index_path = tmp_path / "index.bin"
+        meta_path = tmp_path / "meta.signed"
+        manager.save(index_path, meta_path)
+
+        # Le fichier métadonnées doit être signé.
+        raw = meta_path.read_bytes()
+        assert raw.startswith(b"RPA_SIGNED_V1\n")
+
+        # Recharger.
+        reloaded = FAISSManager.load(index_path, meta_path)
+        assert reloaded.dimensions == 8
+        assert reloaded.next_id == 1
+        assert 0 in reloaded.metadata_store
+        assert reloaded.metadata_store[0]["embedding_id"] == "emb_1"
+
+    def test_load_refuses_tampered_metadata(self, tmp_path: Path):
+        from core.embedding.faiss_manager import FAISSManager
+
+        manager = FAISSManager(dimensions=4, index_type="Flat", metric="cosine")
+        manager.add_embedding("e", np.ones(4, dtype=np.float32), metadata={})
+
+        index_path = tmp_path / "index.bin"
+        meta_path = tmp_path / "meta.signed"
+        manager.save(index_path, meta_path)
+
+        # Altérer la signature du fichier.
+        raw = meta_path.read_bytes()
+        meta_path.write_bytes(raw.replace(b'"hmac":"', b'"hmac":"0'))
+
+        with pytest.raises(SignatureVerificationError):
+            FAISSManager.load(index_path, meta_path)
+
+    def test_load_migrates_legacy_pickle(self, tmp_path: Path):
+        """Un fichier métadonnées pickle legacy doit être migré."""
+        from core.embedding.faiss_manager import FAISSManager
+        import faiss
+
+        # Construire manuellement un fichier legacy (comme l'ancienne version).
+        manager = FAISSManager(dimensions=4, index_type="Flat", metric="cosine")
+        vec = np.ones(4, dtype=np.float32)
+        manager.add_embedding("legacy_emb", vec, metadata={"tag": "old"})
+
+        index_path = tmp_path / "index.bin"
+        meta_path = tmp_path / "meta.pkl"
+
+        # Écrire l'index FAISS normalement...
+        index_to_save = manager.index
+        faiss.write_index(index_to_save, str(index_path))
+
+        # ...mais les métadonnées en pickle brut (format pré-correctif).
+        legacy = {
+            "dimensions": 4,
+            "index_type": "Flat",
+            "metric": "cosine",
+            "next_id": manager.next_id,
+            "metadata_store": manager.metadata_store,
+            "nlist": None,
+            "nprobe": 8,
+            "is_trained": True,
+            "auto_optimize": True,
+        }
+        with open(meta_path, "wb") as fp:
+            pickle.dump(legacy, fp)
+
+        # Chargement : doit réussir + migrer vers format signé.
+        reloaded = FAISSManager.load(index_path, meta_path)
+        assert reloaded.dimensions == 4
+        assert reloaded.next_id == 1
+
+        # Le fichier a été ré-écrit en signé.
+        assert meta_path.read_bytes().startswith(b"RPA_SIGNED_V1\n")