Files
MileVault/milevault_export/backend/app/api/auth.py
T
owain e5feeb1178
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Add explicit "link passkey to my account" flow
Signing in by passkey on a fresh install created a new empty account because
the seeded admin has no email to match on. Add canonical SSO-style linking: an
authenticated user starts an OIDC flow whose `state` is a signed, short-lived
"link to user N" token (purpose=pocketid-link). The callback detects that state
and attaches the returned identity to that account instead of creating/matching
one — no reliance on emails lining up, and no group gating (the initiator is
already authorised; this is identity linking, not access control).

- auth.py: _make_link_state/_decode_link_state, GET /pocketid/link-url, callback
  handles state (rejects if the passkey is already on another account →
  auth_error=passkey_in_use). Expose has_passkey on /auth/me.
- Profile: "Passkey sign-in" section for all users — shows linked state or a
  "Link a passkey to this account" button; success banner on return.
- Login: messages for passkey_in_use / link_failed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-08 17:11:30 +01:00

276 lines
11 KiB
Python

from fastapi import APIRouter, Depends, HTTPException, status
from fastapi.security import OAuth2PasswordRequestForm
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from pydantic import BaseModel
from typing import Optional
from datetime import timedelta
from jose import jwt, JWTError
import httpx
from app.core.database import get_db
from app.core.security import verify_password, create_access_token, get_current_user
from app.core.config import settings
from app.models.user import User
router = APIRouter()
# Marks a short-lived OIDC `state` token as an account-link request (as opposed
# to a normal sign-in), so the callback attaches the passkey to a known user
# instead of creating/looking-up by identity.
LINK_STATE_PURPOSE = "pocketid-link"
def _make_link_state(user_id: int) -> str:
"""Signed, short-lived token carrying 'link this passkey to user_id' intent."""
return create_access_token(
{"sub": str(user_id), "purpose": LINK_STATE_PURPOSE},
expires_delta=timedelta(minutes=10),
)
def _decode_link_state(state: Optional[str]) -> Optional[int]:
"""Return the user id from a valid link-state token, else None."""
if not state:
return None
try:
payload = jwt.decode(state, settings.secret_key, algorithms=[settings.algorithm])
if payload.get("purpose") != LINK_STATE_PURPOSE:
return None
return int(payload["sub"])
except (JWTError, KeyError, TypeError, ValueError):
return None
async def _config_admin(db: AsyncSession):
"""The admin row that holds instance-wide PocketID settings.
Settings live on an admin user row, but there can be more than one admin.
Prefer the admin that actually has an issuer configured; otherwise fall back
to the lowest-id admin. Without this, an unordered LIMIT 1 could return an
admin with no config and make PocketID look disabled / gating inconsistent.
"""
result = await db.execute(
select(User)
.where(User.is_admin == True, User.pocketid_issuer.isnot(None))
.order_by(User.id)
.limit(1)
)
admin = result.scalar_one_or_none()
if admin is None:
result = await db.execute(
select(User).where(User.is_admin == True).order_by(User.id).limit(1)
)
admin = result.scalar_one_or_none()
return admin
async def _get_pocketid_config(db: AsyncSession):
"""Get PocketID config from DB (admin user) falling back to env vars."""
admin = await _config_admin(db)
issuer = (admin and admin.pocketid_issuer) or settings.pocketid_issuer
client_id = (admin and admin.pocketid_client_id) or settings.pocketid_client_id
client_secret = (admin and admin.pocketid_client_secret) or settings.pocketid_client_secret
return issuer, client_id, client_secret
async def _get_allowed_group(db: AsyncSession):
"""Group a PocketID user must belong to in order to sign in (None = allow all)."""
admin = await _config_admin(db)
group = (admin and admin.pocketid_allowed_group) or settings.pocketid_allowed_group
return (group or "").strip() or None
async def _unique_username(db: AsyncSession, base: str) -> str:
"""Return `base`, or `base-2`, `base-3`, … until it is not already taken."""
base = (base or "user").strip() or "user"
candidate = base
n = 1
while True:
existing = await db.execute(select(User).where(User.username == candidate))
if existing.scalar_one_or_none() is None:
return candidate
n += 1
candidate = f"{base}-{n}"
class Token(BaseModel):
access_token: str
token_type: str
user_id: int
username: str
is_admin: bool
class UserOut(BaseModel):
id: int
username: str
email: Optional[str]
is_admin: bool
has_passkey: bool = False
class Config:
from_attributes = True
@router.post("/token", response_model=Token)
async def login(
form_data: OAuth2PasswordRequestForm = Depends(),
db: AsyncSession = Depends(get_db),
):
result = await db.execute(select(User).where(User.username == form_data.username))
user = result.scalar_one_or_none()
if not user or not user.hashed_password:
raise HTTPException(status_code=400, detail="Invalid credentials")
if not verify_password(form_data.password, user.hashed_password):
raise HTTPException(status_code=400, detail="Invalid credentials")
token = create_access_token({"sub": str(user.id)})
return Token(access_token=token, token_type="bearer",
user_id=user.id, username=user.username, is_admin=user.is_admin)
@router.get("/me", response_model=UserOut)
async def get_me(current_user: User = Depends(get_current_user)):
return UserOut(
id=current_user.id,
username=current_user.username,
email=current_user.email,
is_admin=current_user.is_admin,
has_passkey=current_user.pocketid_sub is not None,
)
@router.get("/pocketid/available")
async def pocketid_available(db: AsyncSession = Depends(get_db)):
issuer, client_id, _ = await _get_pocketid_config(db)
return {"available": bool(issuer and client_id)}
@router.get("/pocketid/login-url")
async def pocketid_login_url(db: AsyncSession = Depends(get_db)):
issuer, client_id, _ = await _get_pocketid_config(db)
if not issuer or not client_id:
raise HTTPException(status_code=404, detail="PocketID not configured")
from urllib.parse import urlencode
params = {
"client_id": client_id,
"redirect_uri": f"{settings.base_url}/api/auth/pocketid/callback",
"response_type": "code",
"scope": "openid profile email groups",
}
return {"url": f"{issuer}/authorize?{urlencode(params)}"}
@router.get("/pocketid/link-url")
async def pocketid_link_url(
db: AsyncSession = Depends(get_db),
current_user: User = Depends(get_current_user),
):
"""Authenticated user starts an OIDC flow to attach a passkey to THEIR account.
The `state` carries a signed 'link to this user' token so the callback links
the returned identity instead of creating/matching a new account.
"""
issuer, client_id, _ = await _get_pocketid_config(db)
if not issuer or not client_id:
raise HTTPException(status_code=404, detail="PocketID not configured")
from urllib.parse import urlencode
params = {
"client_id": client_id,
"redirect_uri": f"{settings.base_url}/api/auth/pocketid/callback",
"response_type": "code",
"scope": "openid profile email groups",
"state": _make_link_state(current_user.id),
}
return {"url": f"{issuer}/authorize?{urlencode(params)}"}
@router.get("/pocketid/callback")
async def pocketid_callback(code: str, state: Optional[str] = None, db: AsyncSession = Depends(get_db)):
issuer, client_id, client_secret = await _get_pocketid_config(db)
if not issuer:
raise HTTPException(status_code=404, detail="PocketID not configured")
async with httpx.AsyncClient() as client:
resp = await client.post(
f"{issuer}/api/oidc/token",
data={"grant_type": "authorization_code", "code": code,
"redirect_uri": f"{settings.base_url}/api/auth/pocketid/callback",
"client_id": client_id, "client_secret": client_secret},
)
if resp.status_code != 200:
print(f"PocketID token exchange failed ({resp.status_code}): {resp.text}")
raise HTTPException(status_code=400, detail="Token exchange failed")
tokens = resp.json()
userinfo_resp = await client.get(
f"{issuer}/api/oidc/userinfo",
headers={"Authorization": f"Bearer {tokens['access_token']}"},
)
userinfo = userinfo_resp.json()
from fastapi.responses import RedirectResponse
sub = userinfo.get("sub")
email = userinfo.get("email")
preferred_username = userinfo.get("preferred_username") or email
# ── Explicit account-link flow ──────────────────────────────────────────
# Initiated by an already-authenticated user from their profile. Attach the
# passkey to that account. No group gating here: this is identity linking,
# not access control, and the initiator is already an authorised user.
link_user_id = _decode_link_state(state)
if link_user_id is not None:
result = await db.execute(select(User).where(User.pocketid_sub == sub))
holder = result.scalar_one_or_none()
if holder and holder.id != link_user_id:
# This passkey is already attached to a different account.
return RedirectResponse(url="/login?auth_error=passkey_in_use")
result = await db.execute(select(User).where(User.id == link_user_id))
target = result.scalar_one_or_none()
if target is None:
return RedirectResponse(url="/login?auth_error=link_failed")
target.pocketid_sub = sub
if not target.email and email:
dup = await db.execute(
select(User).where(User.email == email, User.id != target.id)
)
if dup.scalar_one_or_none() is None:
target.email = email
return RedirectResponse(url="/profile?linked=1")
# Group gating: if an allowed group is configured, the user must be in it.
allowed_group = await _get_allowed_group(db)
if allowed_group:
groups = userinfo.get("groups") or []
if allowed_group not in groups:
return RedirectResponse(url="/login?auth_error=not_authorized")
# 1) Existing passkey identity → use it.
result = await db.execute(select(User).where(User.pocketid_sub == sub))
user = result.scalar_one_or_none()
# 2) No passkey identity yet, but an account with this email exists and is
# not already linked to a different passkey → link them (preserves data).
if not user and email:
result = await db.execute(select(User).where(User.email == email))
existing = result.scalar_one_or_none()
if existing and existing.pocketid_sub is None:
existing.pocketid_sub = sub
user = existing
# 3) Otherwise provision a new account with a collision-safe username.
if not user:
base = preferred_username or (email.split("@")[0] if email else "user")
username = await _unique_username(db, base)
# Only set email if no other account already claims it (unique column).
email_taken = False
if email:
dup = await db.execute(select(User).where(User.email == email))
email_taken = dup.scalar_one_or_none() is not None
user = User(username=username, email=None if email_taken else email, pocketid_sub=sub)
db.add(user)
await db.flush()
token = create_access_token({"sub": str(user.id)})
return RedirectResponse(url=f"/?token={token}")