feat(sso): replace local auth with Keycloak OIDC callback flow

backend/app/api/auth.py

@@ -1,43 +1,60 @@
-from fastapi import APIRouter, Depends, HTTPException, Response, status
+from fastapi import APIRouter, Depends, HTTPException, Request, Response, status
+from fastapi.responses import RedirectResponse
 from sqlalchemy.orm import Session
+from authlib.integrations.starlette_client import OAuthError
 from app import models, schemas
-from app.auth import create_access_token, get_current_user, hash_password, verify_password
-from app.database import get_db
+from app.auth import create_access_token, get_current_user, oauth
+from app.database import get_db, settings
 
 router = APIRouter()
 
-
-@router.post("/register", response_model=schemas.UserOut, status_code=201)
-def register(body: schemas.UserCreate, db: Session = Depends(get_db)) -> models.User:
-    if db.query(models.User).filter(models.User.username == body.username).first():
-        raise HTTPException(status_code=400, detail="Username already registered")
-    if db.query(models.User).filter(models.User.email == body.email).first():
-        raise HTTPException(status_code=400, detail="Email already registered")
-    user = models.User(
-        username=body.username,
-        email=body.email,
-        hashed_password=hash_password(body.password),
-    )
-    db.add(user)
-    db.commit()
-    db.refresh(user)
-    return user
+FIREWALL_ADMINS_GROUP = "firewall admins"
 
 
-@router.post("/login")
-def login(body: schemas.LoginRequest, response: Response, db: Session = Depends(get_db)) -> dict:
-    user = db.query(models.User).filter(models.User.username == body.username).first()
-    if not user or not verify_password(body.password, user.hashed_password):
-        raise HTTPException(status_code=401, detail="Invalid credentials")
-    token = create_access_token(user.id)
+@router.get("/oidc/login")
+async def oidc_login(request: Request) -> RedirectResponse:
+    return await oauth.keycloak.authorize_redirect(request, settings.keycloak_redirect_uri)
+
+
+@router.get("/oidc/callback")
+async def oidc_callback(request: Request, db: Session = Depends(get_db)) -> RedirectResponse:
+    try:
+        token = await oauth.keycloak.authorize_access_token(request)
+    except OAuthError as e:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(e))
+
+    userinfo = token.get("userinfo") or {}
+    groups = userinfo.get("groups", [])
+    if FIREWALL_ADMINS_GROUP not in groups:
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Not in firewall admins group")
+
+    sub = userinfo["sub"]
+    email = userinfo.get("email", "")
+    username = userinfo.get("preferred_username", sub)
+
+    user = db.query(models.User).filter(models.User.keycloak_sub == sub).first()
+    if not user:
+        user = models.User(
+            keycloak_sub=sub,
+            email=email,
+            username=username,
+            hashed_password=None,
+            is_active=True,
+        )
+        db.add(user)
+        db.commit()
+        db.refresh(user)
+
+    access_token = create_access_token(user.id)
+    response = RedirectResponse(url="/", status_code=status.HTTP_302_FOUND)
     response.set_cookie(
         key="access_token",
-        value=token,
+        value=access_token,
         httponly=True,
         samesite="lax",
         max_age=3600,
     )
-    return {"message": "Logged in"}
+    return response
 
 
 @router.post("/logout")

backend/app/auth.py

@@ -1,21 +1,23 @@
 from datetime import datetime, timedelta, timezone
 from typing import Optional
 from jose import JWTError, jwt
-from passlib.context import CryptContext
+from authlib.integrations.starlette_client import OAuth
 from fastapi import Cookie, HTTPException, status, Depends
 from sqlalchemy.orm import Session
 from app.database import get_db, settings
 from app import models
 
-pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
-
-
-def hash_password(password: str) -> str:
-    return pwd_context.hash(password)
-
-
-def verify_password(plain: str, hashed: str) -> bool:
-    return pwd_context.verify(plain, hashed)
+oauth = OAuth()
+oauth.register(
+    name="keycloak",
+    client_id=settings.keycloak_client_id,
+    client_secret=settings.keycloak_client_secret,
+    server_metadata_url=(
+        f"{settings.keycloak_url}/realms/{settings.keycloak_realm}"
+        "/.well-known/openid-configuration"
+    ),
+    client_kwargs={"scope": "openid email profile"},
+)
 
 
 def create_access_token(user_id: int) -> str:

backend/app/main.py

@@ -1,9 +1,12 @@
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
+from starlette.middleware.sessions import SessionMiddleware
 from app.api import auth, configs, zones, interfaces, policies, rules, masq
+from app.database import settings
 
 app = FastAPI(title="Shorefront", version="0.1.0")
 
+app.add_middleware(SessionMiddleware, secret_key=settings.jwt_secret_key)
 app.add_middleware(
     CORSMiddleware,
     allow_origins=["http://localhost:5173", "http://localhost:80"],