fix: corrige 6 bugs mineurs (BUG-035 a BUG-040)

backend/auth/middleware.py

@@ -4,6 +4,7 @@
 
 import logging
 import os
+import sys
 
 from fastapi import Depends, HTTPException, Request
 from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
@@ -17,6 +18,9 @@ logger = logging.getLogger("obsigate.auth.middleware")
 
 security = HTTPBearer(auto_error=False)
 
+#: Hosts considered safe to bind without authentication (loopback only).
+_LOOPBACK_HOSTS = {"127.0.0.1", "::1", "localhost", "0:0:0:0:0:0:0:1"}
+
 
 def is_auth_enabled() -> bool:
     """Check if authentication is enabled via environment variable.
@@ -26,6 +30,34 @@ def is_auth_enabled() -> bool:
     return os.environ.get("OBSIGATE_AUTH_ENABLED", "true").lower() != "false"
 
 
+def is_insecure_mode_allowed() -> bool:
+    """True when the operator explicitly accepts running without auth (BUG-037)."""
+    return os.environ.get("OBSIGATE_ALLOW_INSECURE", "false").lower() in ("1", "true", "yes", "on")
+
+
+def bind_host_from_argv(argv: list[str] | None = None) -> str | None:
+    """Extract the ``--host`` value from the process arguments (uvicorn), if any.
+
+    Returns ``None`` when no explicit host is passed (uvicorn then defaults to
+    loopback ``127.0.0.1``).
+    """
+    args = sys.argv if argv is None else argv
+    for i, arg in enumerate(args):
+        if arg == "--host" and i + 1 < len(args):
+            return args[i + 1]
+        if arg.startswith("--host="):
+            return arg.split("=", 1)[1]
+    return None
+
+
+def is_loopback_host(host: str | None) -> bool:
+    """True when *host* is a loopback address (or unset → uvicorn default)."""
+    if not host:
+        return True
+    normalized = host.strip().strip("[]").lower()
+    return normalized in _LOOPBACK_HOSTS
+
+
 def get_current_user(
     request: Request,
     credentials: HTTPAuthorizationCredentials | None = Depends(security),

backend/auth/password.py

@@ -1,14 +1,21 @@
 # backend/auth/password.py
 # Argon2id password hashing — OWASP 2024 recommended algorithm.
-# Parameters: time_cost=2, memory_cost=64MB, parallelism=2
+# Parameters (BUG-038): time_cost=2, memory_cost=19 MiB, parallelism=1
+# (OWASP current recommendation for Argon2id). The previous 64 MiB setting
+# allowed memory exhaustion under concurrent login attempts.
 
 from argon2 import PasswordHasher
 from argon2.exceptions import VerificationError, VerifyMismatchError
 
+#: Argon2id cost parameters (OWASP 2024: m=19456 KiB, t=2, p=1).
+ARGON2_TIME_COST = 2
+ARGON2_MEMORY_COST_KIB = 19456  # 19 MiB
+ARGON2_PARALLELISM = 1
+
 ph = PasswordHasher(
-    time_cost=2,
-    memory_cost=65536,  # 64 MB
-    parallelism=2,
+    time_cost=ARGON2_TIME_COST,
+    memory_cost=ARGON2_MEMORY_COST_KIB,
+    parallelism=ARGON2_PARALLELISM,
     hash_len=32,
     salt_len=16,
 )

backend/auth/router.py

@@ -124,31 +124,32 @@ async def auth_status():
 async def login(body: LoginRequest, response: Response, request: Request):
     """Authenticate a user. Returns access token and sets refresh cookie.
 
-    Implements timing-safe responses to prevent user enumeration:
-    a failed login with an unknown user takes the same time as one
-    with a known user (dummy hash is computed).
+    Implements timing-safe responses to prevent user enumeration: a failed
+    login with an unknown user takes the same time as one with a known user
+    (dummy hash is computed). BUG-039: unknown, inactive, locked and
+    per-account rate-limited accounts all answer the same ``401`` so the HTTP
+    status can never reveal whether an account exists.
     """
+    client_ip = get_client_ip(request)
+
+    # IP-based rate limiting (10 failures / 15 min per IP). It is not
+    # account-specific, so a 429 here cannot be used to enumerate accounts.
+    if is_rate_limited(client_ip):
+        raise HTTPException(429, "Trop de tentatives depuis cette adresse IP (15min)")
+
     user = get_user(body.username)
 
-    if not user:
+    # BUG-039: uniform 401 + equivalent timing for every account-state outcome.
+    if not user or not user.get("active"):
         # Timing-safe: simulate hash computation to prevent user enumeration
         hash_password("dummy_timing_protection")
         raise HTTPException(401, "Identifiants invalides")
 
-    if not user.get("active"):
-        raise HTTPException(403, "Compte désactivé")
-
-    # IP-based rate limiting (10 failures / 15 min per IP)
-    client_ip = get_client_ip(request)
-    if is_rate_limited(client_ip):
-        raise HTTPException(429, "Trop de tentatives depuis cette adresse IP (15min)")
-
     # BUG-031: per-account budget still applies when the attacker rotates IPs.
-    if is_account_rate_limited(body.username):
-        raise HTTPException(429, "Trop de tentatives sur ce compte (15min)")
-
-    if is_locked(body.username):
-        raise HTTPException(429, "Compte temporairement verrouillé (15min)")
+    # Kept indistinguishable from a wrong password (BUG-039).
+    if is_account_rate_limited(body.username) or is_locked(body.username):
+        hash_password("dummy_timing_protection")
+        raise HTTPException(401, "Identifiants invalides")
 
     if not verify_password(body.password, user["password_hash"]):
         attempts = record_login_failure(body.username)