infrasynth-backend-kit/infrasynth/security/altcha/services.py
jcv-dev 551b42eab5 feat: production-hardening pass across the kit
Close the gaps between the documented contract (API-STANDARD, TENANCY,
ENTITLEMENTS) and the implementation, and remove committed build artifacts.

Security:
- verify + process inbound webhooks (HMAC/handler verify, size limit,
  timestamp tolerance, idempotency via InboundEvent.external_id)
- real 2FA login flow (pre-auth challenge; tokens only after verify/recovery)
- wire HybridPermission into security/audit views; add API-key rotate and
  users/<id>/permissions|roles endpoints
- tenant-scoped throttling on by default; webhook replay protection
- verify MercadoPago webhook signatures
- login brute-force guard, configurable password policy, real ALTCHA PoW

Correctness:
- apply verified billing webhooks idempotently (subscription/entitlement/
  invoice/PaymentTransaction); scheduled payment lifecycle jobs
- capture audit update diffs automatically; add audit retention purge
- working notification retries, per-channel rate limits, log retention
- pluggable virus scanner, upload-size limit, pipeline toggle
- feature rollout %/environment targeting; settings-driven registrations
- workflow guards (instance cap, route depth, self-assignment, clone on re-entry)
- wire every previously-dead INFRASYNTH_* setting; drop truly dead ones

Delivery:
- README + CHANGELOG; CI format check + coverage gate
- keep test media out of the tree; untrack .coverage, __pycache__,
  egg-info, docs/ and invoice artifacts
2026-09-24 10:41:21 -05:00

74 lines
2.6 KiB
Python

import hashlib
import secrets
from datetime import timedelta
from django.utils import timezone
from infrasynth.shared.settings_utils import get_setting
from ..models import ALTCHAChallenge
class ALTCHAService:
"""Self-hosted proof-of-work challenge (anti-spam).
The client must find an integer ``number`` such that the SHA-256 of
``salt + number`` is divisible by ``difficulty``. Expected work is
``difficulty`` hashes, so the default of 10 000 is a strong-enough speed
bump while staying cheap for a real browser.
"""
def create_challenge(self) -> dict:
difficulty = int(get_setting("INFRASYNTH_SECURITY", "ALTCHA_DIFFICULTY", 10000))
expiry_seconds = int(get_setting("INFRASYNTH_SECURITY", "ALTCHA_CHALLENGE_EXPIRY_SECONDS", 300))
challenge_id = secrets.token_hex(32)
salt = secrets.token_hex(16)
expires_at = timezone.now() + timedelta(seconds=expiry_seconds)
ALTCHAChallenge.objects.create(
challenge_id=challenge_id,
salt=salt,
difficulty=difficulty,
expires_at=expires_at,
)
return {
"challenge_id": challenge_id,
"salt": salt,
"difficulty": difficulty,
"algorithm": "SHA-256",
}
def verify(self, challenge_id: str, solution: str, number) -> bool:
try:
number = int(number)
except (TypeError, ValueError):
return False
try:
challenge = ALTCHAChallenge.objects.get(challenge_id=challenge_id, is_verified=False)
except ALTCHAChallenge.DoesNotExist:
return False
if challenge.expires_at < timezone.now():
return False
expected = hashlib.sha256(f"{challenge.salt}{number}".encode()).hexdigest()
if not solution or solution != expected:
return False
if int(expected, 16) % challenge.difficulty != 0:
return False
challenge.is_verified = True
challenge.save(update_fields=["is_verified"])
return True
def compute_solution(self, salt: str, difficulty: int, *, max_iterations: int = 5_000_000) -> tuple[str, int]:
"""Reference solver (clients do this in JS; used in tests/tools)."""
difficulty = max(1, int(difficulty))
number = 0
while number < max_iterations:
h = hashlib.sha256(f"{salt}{number}".encode()).hexdigest()
if int(h, 16) % difficulty == 0:
return h, number
number += 1
raise RuntimeError("Could not find an ALTCHA solution within max_iterations.")