fix: issue short-lived console tickets instead of JWTs in node_console MCP tool

LLM clients transcribing the console WebSocket URL into shell commands
reliably corrupted the ~200-char JWT embedded in it (dropped header
segment -> "MissingAlgorithmError: Missing 'alg' value in header" on
every connection attempt). The node_console tool now mints a short
random ticket ("gns3t_" + 16 urlsafe chars, 10 min TTL, multi-use)
stored server-side and bound to the node's console endpoints:

- new ConsoleTicketService (gns3server/services/console_tickets.py),
  in-memory store with lazy expiry sweeps
- get_current_active_user_from_websocket redeems tickets through the
  existing "token" query parameter, gated on websocket.path_params so a
  ticket only authenticates the console/ws and console/vnc routes of
  the node it was minted for; the JWT path is unchanged
- redemption reuses the existing user lookup, token_version revocation
  and is_active checks, so logging out invalidates outstanding tickets
- vnc_url no longer embeds the full session JWT
- the tool docstring now tells clients to run the returned command
  verbatim instead of reconstructing the URL
This commit is contained in:
YueGuobin 2026-08-29 01:00:12 +08:00
parent 2324dcd744
commit 6d6b5351fa
No known key found for this signature in database
9 changed files with 431 additions and 30 deletions

View File

@ -439,7 +439,7 @@ sequenceDiagram
### Console WebSocket
The `node_console` tool returns a WebSocket URL for connecting to a node's console. The URL includes a short-lived JWT (10 min) — reconnect if it expires. This endpoint is protocol-agnostic — it works for **telnet**, **ssh**, and **vnc** console types alike. The WebSocket simply proxies raw byte streams between the client and the compute node; protocol negotiation (e.g. SSH key exchange) happens on the compute side.
The `node_console` tool returns a WebSocket URL for connecting to a node's console. The URL includes a short-lived **console ticket** (10 min) — a short random string (`gns3t_…`, 22 chars) minted server-side and bound to that node's console endpoints. Tickets replaced the long JWT previously embedded here: LLM clients retyping the URL into shell commands reliably corrupted a ~200-char JWT, while a short ticket survives copying. Re-request the URL when the ticket expires (logging out also invalidates outstanding tickets). This endpoint is protocol-agnostic — it works for **telnet**, **ssh**, and **vnc** console types alike. The WebSocket simply proxies raw byte streams between the client and the compute node; protocol negotiation (e.g. SSH key exchange) happens on the compute side.
The WebSocket URL is constructed using the server's `_server_url()`, which resolves the host as follows:
@ -454,11 +454,11 @@ When `Server.host` is `0.0.0.0` (listen on all interfaces), the MCP server disco
If the configured host is already a specific IP or hostname (not `0.0.0.0`), it is used directly in the URL without modification.
Use `websocat` to connect from the command line:
Use `websocat` to connect from the command line (use the `command` returned by `node_console` verbatim — never reconstruct the URL by hand):
```bash
# The host in the URL is automatically resolved to a reachable address
websocat ws://192.168.1.3:3080/v3/projects/{project_id}/nodes/{node_id}/console/ws?token=<jwt>
websocat ws://192.168.1.3:3080/v3/projects/{project_id}/nodes/{node_id}/console/ws?token=<console_ticket>
```
### Source Files

View File

@ -58,7 +58,7 @@ graph LR
**URL**: `ws://{controller_host}:{port}/v3/projects/{project_id}/nodes/{node_id}/console/vnc?token={jwt_token}`
**Authentication**:
- JWT token via query parameter
- JWT token via query parameter, **or** a short-lived console ticket (`gns3t_…`, minted per node by the `node_console` MCP tool, valid 10 min, bound to this node's console endpoints)
- User must have `Node.Console` privilege
**WebSocket Subprotocols**:
@ -179,7 +179,7 @@ sequenceDiagram
1. **Authentication**:
- JWT token validation via `has_privilege_on_websocket("Node.Console")` dependency
- Token passed as query parameter: `?token={jwt}`
- Token passed as query parameter: `?token={jwt}`, or a console ticket (`gns3t_…`) redeemable only on the node it was minted for
2. **Authorization**:
- RBAC privilege check: `Node.Console`

View File

@ -53,7 +53,8 @@ from concurrent.futures import ThreadPoolExecutor
import hashlib
import logging
from gns3server.services import auth_service
from gns3server.services import auth_service, console_ticket_service
from gns3server.services.console_tickets import DEFAULT_TICKET_TTL
from gns3server.agent.gns3_copilot.gns3_client.connector import Gns3Connector
@ -416,12 +417,21 @@ def get_node_console_info_handler(params: dict[str, Any], gns3_ctx: dict[str, An
node = conn.http_call("get", f"{conn.base_url}/projects/{project_id}/nodes/{node_id}").json()
console_type = node.get("console_type", "unknown")
# Short-lived JWT for the WebSocket URL (10 min)
# Short-lived console ticket (10 min, multi-use, bound to this node's
# console endpoints). Deliberately a short random string instead of a JWT:
# LLM clients retype this URL into shell commands and reliably corrupted
# the ~200-char JWT previously embedded here (dropped header segment →
# "Missing 'alg' value in header" on the server).
username = gns3_ctx.get("jwt_username")
ws_token = auth_service.create_access_token(username, token_version=gns3_ctx.get("jwt_token_version", 0), expires_in=10) if username else None
ticket = console_ticket_service.mint(
username,
token_version=gns3_ctx.get("jwt_token_version", 0),
project_id=project_id,
node_id=node_id,
) if username else None
raw_url = f"{gns3_ctx['server_url']}/v3/projects/{project_id}/nodes/{node_id}/console/ws"
if ws_token:
raw_url += f"?token={ws_token}"
if ticket:
raw_url += f"?token={ticket}"
# Convert http scheme to ws for direct websocat usage
ws_url = raw_url.replace("https://", "wss://").replace("http://", "ws://")
@ -432,14 +442,15 @@ def get_node_console_info_handler(params: dict[str, Any], gns3_ctx: dict[str, An
"ws_url": ws_url,
"command": f"websocat -t --no-close {ws_url}",
}
if ws_token:
if ticket:
# Fingerprint of the minted token: compare it against what actually reached the
# server (logged on WebSocket auth rejection) to detect copy corruption, and
# re-request the URL once token_ttl_seconds has elapsed.
result["token_sha256_prefix"] = hashlib.sha256(ws_token.encode()).hexdigest()[:8]
result["token_ttl_seconds"] = 600
if console_type in ("vnc",):
result["vnc_url"] = f"/v3/projects/{project_id}/nodes/{node_id}/console/vnc?token={gns3_ctx['jwt_token']}"
result["token_sha256_prefix"] = hashlib.sha256(ticket.encode()).hexdigest()[:8]
result["token_ttl_seconds"] = DEFAULT_TICKET_TTL
if console_type in ("vnc",) and ticket:
# Same node binding covers the vnc endpoint (identical path params)
result["vnc_url"] = f"/v3/projects/{project_id}/nodes/{node_id}/console/vnc?token={ticket}"
return result

View File

@ -557,21 +557,19 @@ async def node_console(
) -> list[dict[str, Any]]:
"""Get WebSocket console connection info for a node.
Returns the WebSocket URL, console type (telnet/ssh/vnc), and other
connection details needed to interact with a node's console via WebSocket.
The URL includes a short-lived JWT (10 min) reconnect if it expires.
Returns the console type (telnet/ssh/vnc) and a ready-to-run websocat
command with a short-lived access token (10 min) already embedded.
Complete workflow:
1. Call this tool with project_id and node_id to get the WebSocket URL
2. Connect to the returned URL using websocat in text mode (-t):
> websocat -t --no-close "ws://<your-gns3-server-host>:3080/v3/projects/{project_id}/nodes/{node_id}/console/ws?token={jwt_token}"
3. Send device commands with \\r\\n line endings via heredoc:
> websocat -t --no-close "ws://..." <<< $'\\r\\nenable\\r\\nshow version\\r\\nexit\\r\\n'
4. Receive response: websocat receives and displays device output
Use 'timeout' to avoid connection hanging:
> timeout 10 websocat -t --no-close "ws://..." <<< $'commands\\r\\n'
IMPORTANT copy the returned values EXACTLY:
- Run the returned "command" string verbatim; it already contains the
full URL with token. NEVER construct or edit the URL yourself, and
NEVER copy the token by hand a mistyped token is rejected.
- The token expires after token_ttl_seconds (10 min): call this tool
again to get a fresh one; do not reuse an old URL.
Sending device commands after connecting:
> timeout 10 websocat -t --no-close "ws://..." <<< $'\\r\\nenable\\r\\nshow version\\r\\nexit\\r\\n'
Key points:
- Use \\r\\n (not \\n) to match console protocol line endings
- Use $'...' format for escape sequences in bash
- --no-close keeps the WebSocket open after stdin (heredoc) hits EOF, so

View File

@ -29,7 +29,9 @@ import gns3server.db.models as models
from gns3server.db.repositories.api_keys import ApiKeysRepository
from gns3server.db.repositories.users import UsersRepository
from gns3server.db.repositories.rbac import RbacRepository
from gns3server.services import auth_service
from gns3server.schemas.controller.tokens import TokenData
from gns3server.services import auth_service, console_ticket_service
from gns3server.services.console_tickets import TICKET_PREFIX
from .database import get_repository
log = logging.getLogger(__name__)
@ -149,7 +151,25 @@ async def get_current_active_user_from_websocket(
await websocket.accept(subprotocol=subprotocol)
try:
token_data = auth_service.get_token_data(token)
if token.startswith(TICKET_PREFIX):
# Console tickets ("gns3t_…"): short-lived credentials bound to one
# node's console endpoints, minted by the node_console MCP tool.
# redeem() confines them to the route matching their binding, so
# they cannot authenticate the notification/wireshark sockets that
# share this dependency.
ticket = console_ticket_service.redeem(token, websocket.path_params)
if ticket is None:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid or expired console ticket",
)
token_data = TokenData(
username=ticket.username,
token_version=ticket.token_version,
token_use="access",
)
else:
token_data = auth_service.get_token_data(token)
_reject_refresh_token(token_data)
user = await user_repo.get_user_by_username(token_data.username)

View File

@ -15,5 +15,7 @@
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from .authentication import AuthService
from .console_tickets import ConsoleTicketService
auth_service = AuthService()
console_ticket_service = ConsoleTicketService()

View File

@ -0,0 +1,115 @@
#
# Copyright (C) 2026 GNS3 Technologies Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
Short-lived console tickets.
A console ticket is a short random string ("gns3t_" + 16 urlsafe chars) that
replaces the long JWT previously embedded in console WebSocket URLs returned
to LLM clients, which reliably corrupted the ~200-char JWT when retyping it
into a shell command. The ticket carries no information itself the server
remembers what it maps to, which is what makes a 96-bit random string a
sufficient credential.
Tickets are bound to a single node's console endpoints (console/ws and
console/vnc share the same binding) and are multi-use within their TTL, so
console clients that reconnect after a drop keep working. Redeeming also
re-checks the minting user's token_version, so logging out invalidates
outstanding tickets just like it invalidates JWTs.
"""
import logging
import secrets
import time
from dataclasses import dataclass
from typing import Optional
log = logging.getLogger(__name__)
# Distinguishes tickets from JWTs (which contain dots) and API keys ("gns3_")
TICKET_PREFIX = "gns3t_"
DEFAULT_TICKET_TTL = 600 # seconds
@dataclass
class ConsoleTicket:
username: str
token_version: int
project_id: str
node_id: str
expires_at: float # time.monotonic() based
class ConsoleTicketService:
"""
In-memory store for console tickets.
Single-process asyncio app: minting (MCP tool handlers, via worker
threads) and redemption (WS auth dependency, event loop) share one dict.
dict get/set/del are atomic under the GIL and keys are random, so no
locking is needed. Tickets vanish on restart clients just request a
new one.
"""
def __init__(self) -> None:
self._tickets: dict[str, ConsoleTicket] = {}
def mint(
self,
username: str,
token_version: int,
project_id: str,
node_id: str,
ttl: int = DEFAULT_TICKET_TTL,
) -> str:
# 12 random bytes → 16 urlsafe chars (~96 bits); comfortably
# unguessable within the 10-minute window and short enough that
# LLM clients copy it without corruption.
ticket = TICKET_PREFIX + secrets.token_urlsafe(12)
self._sweep_expired()
self._tickets[ticket] = ConsoleTicket(
username=username,
token_version=token_version,
project_id=project_id,
node_id=node_id,
expires_at=time.monotonic() + ttl,
)
return ticket
def redeem(self, ticket: str, path_params: dict) -> Optional[ConsoleTicket]:
"""
Validate a ticket against the route it is being used on.
Returns the ticket record if valid, None otherwise. The route's path
parameters must match the ticket's binding, which confines a ticket
to the node's console endpoints — routes without a node_id path
parameter (notifications, web wireshark, ) always fail the binding.
"""
record = self._tickets.get(ticket)
if record is None:
return None
if time.monotonic() >= record.expires_at:
self._tickets.pop(ticket, None)
return None
if path_params.get("project_id") != record.project_id or path_params.get("node_id") != record.node_id:
return None
return record
def _sweep_expired(self) -> None:
now = time.monotonic()
for ticket in [t for t, record in self._tickets.items() if now >= record.expires_at]:
del self._tickets[ticket]

View File

@ -280,10 +280,38 @@ class TestNode:
def test_console(self, ctx):
from gns3server.agent.gns3_copilot.gns3_client.api_handlers import get_node_console_info_handler
from gns3server.services import console_ticket_service
with patch(f"{AH}._get_connector") as m:
m.return_value = _mock_conn({"console_url": "ws://host/console"})
result = get_node_console_info_handler({"project_id": "p1", "node_id": "n1"}, ctx)
assert "command" in result
# the URL embeds a short console ticket (not a JWT) redeemable for this node
assert "?token=gns3t_" in result["ws_url"]
ticket = result["ws_url"].split("token=")[1]
assert ticket in result["command"]
assert result["token_ttl_seconds"] == 600
assert len(result["token_sha256_prefix"]) == 8
redeemed = console_ticket_service.redeem(ticket, {"project_id": "p1", "node_id": "n1"})
assert redeemed is not None and redeemed.username == "admin"
assert "vnc_url" not in result # console_type is not vnc
def test_console_vnc_uses_same_ticket(self, ctx):
from gns3server.agent.gns3_copilot.gns3_client.api_handlers import get_node_console_info_handler
with patch(f"{AH}._get_connector") as m:
m.return_value = _mock_conn({"console_type": "vnc"})
result = get_node_console_info_handler({"project_id": "p1", "node_id": "n1"}, ctx)
ticket = result["ws_url"].split("token=")[1]
# one node-bound ticket covers both console endpoints (identical path params)
assert result["vnc_url"] == f"/v3/projects/p1/nodes/n1/console/vnc?token={ticket}"
def test_console_without_username_omits_token(self, ctx):
from gns3server.agent.gns3_copilot.gns3_client.api_handlers import get_node_console_info_handler
unauthenticated_ctx = {k: v for k, v in ctx.items() if k != "jwt_username"}
with patch(f"{AH}._get_connector") as m:
m.return_value = _mock_conn({"console_url": "ws://host/console"})
result = get_node_console_info_handler({"project_id": "p1", "node_id": "n1"}, unauthenticated_ctx)
assert "token=" not in result["ws_url"]
assert "token_sha256_prefix" not in result
@staticmethod
def _file_conn(text):

View File

@ -0,0 +1,227 @@
#
# Copyright (C) 2026 GNS3 Technologies Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import hashlib
from types import SimpleNamespace
from typing import List
import aiohttp
import pytest
from fastapi import FastAPI
from httpx import AsyncClient
from httpx_ws import aconnect_ws
from httpx_ws.transport import ASGIWebSocketTransport
from pydantic import SecretStr
from gns3server.config import Config
from gns3server.controller import Controller
from gns3server.controller.compute import Compute
from gns3server.controller.node import Node
from gns3server.controller.project import Project
from gns3server.services.console_tickets import (
ConsoleTicketService,
DEFAULT_TICKET_TTL,
TICKET_PREFIX,
)
from gns3server.services import console_ticket_service
from gns3server.utils.http_client import HTTPClient
from tests.api.routes.controller.test_nodes import FakeComputeConsoleWebSocket
class TestConsoleTicketService:
"""Unit tests for the in-memory ticket store (fresh instances, no app)."""
def test_mint_format(self) -> None:
service = ConsoleTicketService()
ticket = service.mint("admin", 1, "p1", "n1")
assert ticket.startswith(TICKET_PREFIX)
# 12 random bytes -> 16 urlsafe chars; shell-safe alphabet (no quoting hazards)
assert len(ticket) == len(TICKET_PREFIX) + 16
assert "." not in ticket # never confusable with a JWT
assert service.mint("admin", 1, "p1", "n1") != ticket
def test_redeem_valid_ticket_is_multi_use(self) -> None:
service = ConsoleTicketService()
ticket = service.mint("admin", 7, "p1", "n1")
path_params = {"project_id": "p1", "node_id": "n1"}
first = service.redeem(ticket, path_params)
second = service.redeem(ticket, path_params) # console clients reconnect, tickets stay usable
assert first is not None and second is not None
assert first.username == "admin"
assert first.token_version == 7
def test_redeem_rejects_wrong_binding(self) -> None:
service = ConsoleTicketService()
ticket = service.mint("admin", 0, "p1", "n1")
assert service.redeem(ticket, {"project_id": "p1", "node_id": "n2"}) is None
assert service.redeem(ticket, {"project_id": "p2", "node_id": "n1"}) is None
# routes without a node_id path parameter (notifications, wireshark…) never accept a ticket
assert service.redeem(ticket, {"project_id": "p1"}) is None
assert service.redeem(ticket, {}) is None
def test_redeem_rejects_unknown_ticket(self) -> None:
service = ConsoleTicketService()
assert service.redeem(TICKET_PREFIX + "doesnotexist", {"project_id": "p1", "node_id": "n1"}) is None
def test_expired_ticket_is_rejected_and_removed(self) -> None:
service = ConsoleTicketService()
ticket = service.mint("admin", 0, "p1", "n1", ttl=0)
assert service.redeem(ticket, {"project_id": "p1", "node_id": "n1"}) is None
assert ticket not in service._tickets
def test_mint_sweeps_expired_entries(self) -> None:
service = ConsoleTicketService()
stale = service.mint("admin", 0, "p1", "n1", ttl=0)
fresh = service.mint("admin", 0, "p1", "n2", ttl=DEFAULT_TICKET_TTL)
assert stale not in service._tickets
assert fresh in service._tickets
class TestConsoleTicketWebSocketAuth:
"""
Drive the console WebSocket auth dependency end-to-end through the real
routes (the shared service singleton is the one the dependency consults).
"""
pytestmark = pytest.mark.asyncio
@pytest.fixture(autouse=True)
def _reset_controller_singleton(self, controller):
# The project/compute fixtures register state on the shared Controller
# singleton; reset it after each test so files running later (e.g. the
# controller statistics endpoint) see a pristine controller regardless
# of test order — same reset the controller fixture applies at setup.
yield
Controller._instance = None
@pytest.fixture
def node(self, project: Project, compute: Compute) -> Node:
compute.host = "127.0.0.1"
compute.port = 3080
node = Node(project, compute, "test", node_type="vpcs")
project._nodes[node.id] = node
return node
@pytest.fixture
def compute_credentials(self) -> None:
server_config = Config.instance().settings.Server
server_config.compute_username = "admin"
server_config.compute_password = SecretStr("password")
@staticmethod
def _ws_client(app: FastAPI, base_client: AsyncClient) -> AsyncClient:
# base_client must be requested so the app gets the test-DB dependency
# override, but the WebSocket connection itself needs a function-local
# client: closing the WS transport from the class-scoped base_client
# teardown exits anyio cancel scopes in the wrong task.
return AsyncClient(base_url="http://test-api", transport=ASGIWebSocketTransport(app=app))
@staticmethod
def _forward_compute_ws(monkeypatch, messages: List[aiohttp.WSMessage]) -> FakeComputeConsoleWebSocket:
compute_ws = FakeComputeConsoleWebSocket(messages)
monkeypatch.setattr(
HTTPClient,
"get_client",
classmethod(lambda cls: SimpleNamespace(ws_connect=lambda *args, **kwargs: compute_ws))
)
return compute_ws
async def test_console_ws_accepts_valid_ticket(
self,
app: FastAPI,
base_client: AsyncClient,
compute_credentials,
project: Project,
node: Node,
monkeypatch
) -> None:
# admin is the seeded superadmin, so the RBAC privilege check is skipped
ticket = console_ticket_service.mint("admin", 0, project.id, node.id)
self._forward_compute_ws(monkeypatch, [
aiohttp.WSMessage(aiohttp.WSMsgType.TEXT, "device output", None),
])
async with self._ws_client(app, base_client) as client:
async with aconnect_ws(
f"/v3/projects/{project.id}/nodes/{node.id}/console/ws",
client,
params={"token": ticket}
) as ws:
# reaching the compute forwarding loop means ticket auth succeeded
assert await ws.receive_text() == "device output"
async def test_console_ws_rejects_ticket_bound_to_other_node(
self,
app: FastAPI,
base_client: AsyncClient,
project: Project,
node: Node
) -> None:
other_node = "00000000-0000-0000-0000-000000000000"
ticket = console_ticket_service.mint("admin", 0, project.id, other_node)
async with self._ws_client(app, base_client) as client:
async with aconnect_ws(
f"/v3/projects/{project.id}/nodes/{node.id}/console/ws",
client,
params={"token": ticket}
) as ws:
notification = await ws.receive_json()
assert notification["event"]["message"] == (
"Could not authenticate while connecting to controller WebSocket: "
"Invalid or expired console ticket "
f"(received token sha256 prefix: {hashlib.sha256(ticket.encode()).hexdigest()[:8]})"
)
async def test_console_ws_rejects_ticket_with_stale_token_version(
self,
app: FastAPI,
base_client: AsyncClient,
project: Project,
node: Node
) -> None:
# logging out bumps the user's token_version: outstanding tickets must die with it
ticket = console_ticket_service.mint("admin", 999, project.id, node.id)
async with self._ws_client(app, base_client) as client:
async with aconnect_ws(
f"/v3/projects/{project.id}/nodes/{node.id}/console/ws",
client,
params={"token": ticket}
) as ws:
notification = await ws.receive_json()
assert "Token has been revoked for 'admin'" in notification["event"]["message"]
async def test_ticket_rejected_on_non_console_websocket(
self,
app: FastAPI,
base_client: AsyncClient
) -> None:
# the controller notification stream shares the WS auth dependency but has
# no node binding: a console ticket must not authenticate it
ticket = console_ticket_service.mint("admin", 0, "p1", "n1")
async with self._ws_client(app, base_client) as client:
async with aconnect_ws("/v3/notifications/ws", client, params={"token": ticket}) as ws:
notification = await ws.receive_json()
assert "Invalid or expired console ticket" in notification["event"]["message"]