From 429a7dfb16438645cbb7c7fec0eb30e54823d5dc Mon Sep 17 00:00:00 2001
From: Leo Vasanko <leo@git>
Date: Wed, 18 Oct 2023 01:06:27 +0300
Subject: [PATCH] Implemented login page and new jwt-based sessions. Watching
 cleanup.

---
 cista/app.py      |  22 +++++----
 cista/auth.py     | 117 ++++++++++++++++++++++++++++++++++++++++++++++
 cista/config.py   |  47 -------------------
 cista/session.py  |  32 +++++++++++++
 cista/watching.py |   6 +--
 pyproject.toml    |   1 +
 6 files changed, 166 insertions(+), 59 deletions(-)
 create mode 100644 cista/auth.py
 create mode 100644 cista/session.py

diff --git a/cista/app.py b/cista/app.py
index a5272e5..9217c43 100644
--- a/cista/app.py
+++ b/cista/app.py
@@ -1,18 +1,21 @@
-import asyncio
 from importlib.resources import files
 
 import msgspec
-from sanic import Sanic
+from html5tagger import E
+from sanic import Sanic, redirect
 from sanic.log import logger
 from sanic.response import html
 
-from . import watching
+from . import session, watching
+from .auth import authbp
+from .config import config
 from .fileio import ROOT, FileServer
 from .protocol import ErrorMsg, FileRange, StatusMsg
 
 app = Sanic("cista")
 fileserver = FileServer()
 watching.register(app, "/api/watch")
+app.blueprint(authbp)
 
 def asend(ws, msg):
     return ws.send(msg if isinstance(msg, bytes) else msgspec.json.encode(msg).decode())
@@ -27,7 +30,14 @@ async def stop_fileserver(app, _):
 
 @app.get("/")
 async def index_page(request):
+    s = config.public or session.get(request)
+    print("Main session", s)
+    if not s:
+        return redirect("/login")
     index = files("cista").joinpath("static", "index.html").read_text()
+    flash = request.cookies.flash
+    if flash:
+        index += str(E.div(flash, id="flash"))
     return html(index)
 
 app.static("/files", ROOT, use_content_range=True, stream_large_files=True, directory_view=True)
@@ -59,12 +69,6 @@ async def upload(request, ws):
             logger.exception(repr(res), e)
             return
 
-@app.websocket("/ws")
-async def ws(request, ws):
-    while True:
-        data = await ws.recv()
-        await ws.send(data)
-
 @app.websocket('/api/download')
 async def download(request, ws):
     alink = fileserver.alink
diff --git a/cista/auth.py b/cista/auth.py
new file mode 100644
index 0000000..691be43
--- /dev/null
+++ b/cista/auth.py
@@ -0,0 +1,117 @@
+import hmac
+import re
+from time import time
+from unicodedata import normalize
+
+import argon2
+import msgspec
+from html5tagger import Document
+from sanic import Blueprint, html, json, redirect
+
+from . import session
+from .config import User, config
+
+_argon = argon2.PasswordHasher()
+_droppyhash = re.compile(r'^([a-f0-9]{64})\$([a-f0-9]{8})$')
+
+def _pwnorm(password):
+    return normalize('NFC', password).strip().encode()
+
+def login(username: str, password: str):
+    un = _pwnorm(username)
+    pw = _pwnorm(password)
+    try:
+        u = config.users[un.decode()]
+    except KeyError:
+        raise ValueError("Invalid username")
+    # Verify password
+    need_rehash = False
+    if not u.hash:
+        raise ValueError("Account disabled")
+    if (m := _droppyhash.match(u.hash)) is not None:
+        h, s = m.groups()
+        h2 = hmac.digest(pw + s.encode() + un, b"", "sha256").hex()
+        if not hmac.compare_digest(h, h2):
+            raise ValueError("Invalid password")
+        # Droppy hashes are weak, do a hash update
+        need_rehash = True
+    else:
+        try:
+            _argon.verify(u.hash, pw)
+        except Exception:
+            raise ValueError("Invalid password")
+        if _argon.check_needs_rehash(u.hash):
+            need_rehash = True
+    # Login successful
+    if need_rehash:
+        u.set_password(password)
+    now = int(time())
+    u.lastSeen = now
+    return u
+
+def set_password(user: User, password: str):
+    user.hash = _argon.hash(_pwnorm(password))
+
+class LoginResponse(msgspec.Struct):
+    user: str = ""
+    privileged: bool = False
+    error: str = ""
+
+authbp = Blueprint("auth")
+
+@authbp.get("/login")
+async def login_page(request):
+    doc = Document("Cista Login")
+    with doc.div(id="login"):
+        with doc.form(method="POST", autocomplete="on"):
+            doc.h1("Login")
+            doc.input(name="username", placeholder="Username", autocomplete="username").br
+            doc.input(type="password", name="password", placeholder="Password", autocomplete="current-password").br
+            doc.input(type="submit", value="Login")
+        s = session.get(request)
+        if s:
+            name = s["username"]
+            with doc.form(method="POST", action="/logout"):
+                doc.input(type="submit", value=f"Logout {name}")
+    flash = request.cookies.flash
+    if flash:
+        doc.p(flash)
+    res = html(doc)
+    if flash:
+        res.cookies.delete_cookie("flash")
+    if s is False:
+        session.delete(res)
+    return res
+
+@authbp.post("/login")
+async def login_post(request):
+    json_format = request.headers.content_type == "application/json"
+    if json_format:
+        username = request.json["username"]
+        password = request.json["password"]
+    else:
+        print(request.form)
+        username = request.form["username"][0]
+        password = request.form["password"][0]
+    if not username or not password:
+        raise ValueError("Missing username or password")
+    user = login(username, password)
+
+    if json_format:
+        res = json({
+            "status": "authenticated",
+            "user": username,
+            "privileged": user.privileged,
+        })
+    else:
+        res = redirect("/")
+        res.cookies.add_cookie("flash", "Logged in",     host_prefix=True, max_age=5)
+    session.create(res, username)
+    return res
+
+@authbp.post("/logout")
+async def logout_post(request):
+    res = redirect("/")
+    session.delete(res)
+    res.cookies.add_cookie("flash", "Logged out",host_prefix=True, max_age=5)
+    return res
diff --git a/cista/config.py b/cista/config.py
index d2c7938..5a944ac 100644
--- a/cista/config.py
+++ b/cista/config.py
@@ -1,26 +1,19 @@
 from __future__ import annotations
 
-import hmac
-import re
 import secrets
 from functools import wraps
 from hashlib import sha256
 from pathlib import Path, PurePath
 from time import time
-from unicodedata import normalize
 
-import argon2
 import msgspec
 
-_argon = argon2.PasswordHasher()
-_droppyhash = re.compile(r'^([a-f0-9]{64})\$([a-f0-9]{8})$')
 
 class Config(msgspec.Struct):
     path: Path = Path.cwd()
     secret: str = secrets.token_hex(12)
     public: bool = False
     users: dict[str, User] = {}
-    sessions: dict[str, Session] = {}
     links: dict[str, Link] = {}
 
 class User(msgspec.Struct, omit_defaults=True):
@@ -28,13 +21,6 @@ class User(msgspec.Struct, omit_defaults=True):
     hash: str = ""
     lastSeen: int = 0
 
-    def set_password(self, password: str):
-        self.hash = _argon.hash(_pwnorm(password))
-
-class Session(msgspec.Struct):
-    username: str
-    lastSeen: int
-
 class Link(msgspec.Struct, omit_defaults=True):
     location: str
     creator: str = ""
@@ -54,39 +40,6 @@ def derived_secret(*params, len=8) -> bytes:
     # Output a bytes of the desired length
     return sha256(combined).digest()[:len]
 
-def _pwnorm(password):
-    return normalize('NFC', password).strip().encode()
-
-def login(username: str, password: str):
-    un = _pwnorm(username)
-    pw = _pwnorm(password)
-    try:
-        u = config.users[un.decode()]
-    except KeyError:
-        raise ValueError("Invalid username")
-    # Verify password
-    if not u.hash:
-        raise ValueError("Account disabled")
-    if (m := _droppyhash.match(u.hash)) is not None:
-        h, s = m.groups()
-        h2 = hmac.digest(pw + s.encode() + un, b"", "sha256").hex()
-        if not hmac.compare_digest(h, h2):
-            raise ValueError("Invalid password")
-        # Droppy hashes are weak, do a hash update
-        u.set_password(password)
-    else:
-        try:
-            _argon.verify(u.hash, pw)
-        except Exception:
-            raise ValueError("Invalid password")
-        if _argon.check_needs_rehash(u.hash):
-            u.set_password(password)
-    # Login successful
-    now = int(time())
-    u.lastSeen = now
-    sid = secrets.token_urlsafe(12)
-    config.sessions[sid] = Session(username, now)
-    return u, sid
 
 def enc_hook(obj):
     if isinstance(obj, PurePath):
diff --git a/cista/session.py b/cista/session.py
new file mode 100644
index 0000000..3cc9d4f
--- /dev/null
+++ b/cista/session.py
@@ -0,0 +1,32 @@
+from time import time
+
+import jwt
+
+from .config import derived_secret
+
+session_secret = derived_secret("session")
+max_age = 60  # Seconds since last login
+
+def get(request):
+    try:
+        return jwt.decode(request.cookies.s, session_secret, algorithms=["HS256"])
+    except Exception as e:
+        s = None
+        return False if "s" in request.cookies else None
+
+def create(res, username, **kwargs):
+    data = {
+        "exp": int(time()) + max_age,
+        "username": username,
+        **kwargs,
+    }
+    s = jwt.encode(data, session_secret)
+    res.cookies.add_cookie("s", s, host_prefix=True, httponly=True, max_age=max_age)
+
+def update(res, s, **kwargs):
+    s.update(kwargs)
+    s = jwt.encode(s, session_secret)
+    res.cookies.add_cookie("s", s, host_prefix=True, httponly=True, max_age=max(1, s["exp"] - int(time())))
+
+def delete(res):
+    res.cookies.delete_cookie("s", host_prefix=True)
diff --git a/cista/watching.py b/cista/watching.py
index 087432e..896f8b3 100644
--- a/cista/watching.py
+++ b/cista/watching.py
@@ -1,11 +1,11 @@
 import asyncio
 import secrets
-from pathlib import Path, PurePosixPath
 import threading
-from watchdog.events import FileSystemEventHandler
-from watchdog.observers import Observer
+from pathlib import Path, PurePosixPath
 
 import msgspec
+from watchdog.events import FileSystemEventHandler
+from watchdog.observers import Observer
 
 from . import config
 from .fileio import ROOT
diff --git a/pyproject.toml b/pyproject.toml
index 498a599..0fe66c8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -17,6 +17,7 @@ dependencies = [
     "argon2-cffi",
     "msgspec",
     "pathvalidate",
+    "pyjwt",
     "sanic",
     "tomli_w",
     "watchdog",