diff options
Diffstat (limited to 'packages/meshbay-node/src/meshbay_node/transport')
4 files changed, 65 insertions, 25 deletions
diff --git a/packages/meshbay-node/src/meshbay_node/transport/webrtc/admin.py b/packages/meshbay-node/src/meshbay_node/transport/webrtc/admin.py index f42d8e8..daaee62 100644 --- a/packages/meshbay-node/src/meshbay_node/transport/webrtc/admin.py +++ b/packages/meshbay-node/src/meshbay_node/transport/webrtc/admin.py @@ -5,6 +5,7 @@ import base64 import os import time +import msgpack from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PublicKey from meshbay_common import MNP_VERSION from meshbay_common.adminop import ( @@ -42,6 +43,16 @@ from meshbay_common.adminop import ( from meshbay_common.crypto import pk_to_b64 from meshbay_common.protocol import MNP +# What one connection may have waiting for a signature. Anyone authenticated can +# ask for a challenge — the signature is what is checked, and it comes later — so +# without a bound a member who never answers makes the node keep every request, +# payload and all, for the life of the connection (§13.5b). A person signs one +# operation at a time; a handful covers a settings page saving several at once. +MAX_PENDING_ADMIN_OPS = 8 +# The subject and payload of one pending operation, packed. A path is at most a +# few KiB, and the largest field a legitimate request carries is a directory list. +MAX_ADMIN_OP_BYTES = 64 * 1024 + # Which executor runs each signed operation once its signature has been # checked. Every one runs as a task of the session. _ADMIN_EXECUTORS = { @@ -98,8 +109,22 @@ class AdminMixin: (e.g. root management from a NodePage connection). """ gid = group_id if group_id is not None else (self._group_id or "") + now = time.time() + for op_id, pending in list(self._admin_ops.items()): + if now - pending["ts"] > ADMIN_CHALLENGE_TTL: + del self._admin_ops[op_id] + if len(self._admin_ops) >= MAX_PENDING_ADMIN_OPS: + self._send({"type": "error", "detail": "Too many operations waiting for a " + "signature", "code": "too_many_pending"}) + self._audit("admin_pending_flood", op) + return + if len(msgpack.packb([subject, payload or {}], use_bin_type=True)) \ + > MAX_ADMIN_OP_BYTES: + self._send({"type": "error", "detail": "Request too large", + "code": "too_large"}) + return nonce = os.urandom(32) - ts = int(time.time()) + ts = int(now) op_id = base64.b64encode(os.urandom(16)).decode() self._admin_ops[op_id] = { "op": op, "subject": subject, "nonce": nonce, "ts": ts, diff --git a/packages/meshbay-node/src/meshbay_node/transport/webrtc/admission.py b/packages/meshbay-node/src/meshbay_node/transport/webrtc/admission.py index b02e59a..e678a13 100644 --- a/packages/meshbay-node/src/meshbay_node/transport/webrtc/admission.py +++ b/packages/meshbay-node/src/meshbay_node/transport/webrtc/admission.py @@ -8,7 +8,12 @@ import time from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PublicKey from meshbay_common import MNP_VERSION -from meshbay_common.adminop import OP_INVITE_CANCEL, OP_INVITE_CREATE, OP_INVITE_LINK_CREATE +from meshbay_common.adminop import ( + OP_INVITE_CANCEL, + OP_INVITE_CREATE, + OP_INVITE_LINK_CREATE, + invite_create_subject, +) from meshbay_common.crypto import wrap_gek_aes from meshbay_common.device import ( DEVICE_TTL, @@ -71,11 +76,13 @@ class AdmissionMixin: }) return - self._issue_admin_challenge(OP_INVITE_CREATE, invitee_id, { - "group_id": group_id, - "user_id": invitee_id, - "username": str(msg.get("username", ""))[:64], - }) + username = str(msg.get("username", ""))[:64] + self._issue_admin_challenge( + OP_INVITE_CREATE, invite_create_subject(invitee_id, username), { + "group_id": group_id, + "user_id": invitee_id, + "username": username, + }) def _do_invite_link_create(self, msg: dict) -> None: """ diff --git a/packages/meshbay-node/src/meshbay_node/transport/webrtc/apps/video_meta.py b/packages/meshbay-node/src/meshbay_node/transport/webrtc/apps/video_meta.py index 834bac4..a9b35dc 100644 --- a/packages/meshbay-node/src/meshbay_node/transport/webrtc/apps/video_meta.py +++ b/packages/meshbay-node/src/meshbay_node/transport/webrtc/apps/video_meta.py @@ -11,6 +11,7 @@ from meshbay_common.adminop import ( OP_TMDB_ENABLED, OP_TMDB_OVERRIDE, OP_TMDB_REMATCH, + tmdb_config_subject, ) from meshbay_common.protocol import MNP @@ -60,12 +61,12 @@ class VideoMetaMixin: if not self._has_admin_authority(): self._send({"type": "error", "detail": "No authorized key for this"}) return - # The subject is the signed, audited, human-shown string — it must - # never contain the token itself (it would end up in the audit log - # in plaintext). The actual token travels only in `payload`, which - # is node-side context, never re-sent or re-verified from the wire. - # The language is not a secret, so it travels in the subject itself. - subject = f"custom_token={'yes' if token else 'no'},language={language or 'default'}" + # The subject is the signed, audited string, so it must never contain + # the token itself (it would end up in the audit log in plaintext); it + # carries the token's SHA-256 instead, which binds the signature to this + # token without writing it down. `None` (unchanged) and `""` (clear) + # stay distinct, for the token and the language alike. + subject = tmdb_config_subject(token, language) self._issue_admin_challenge( OP_TMDB_CONFIG, subject, payload={"token": token, "language": language}, diff --git a/packages/meshbay-node/src/meshbay_node/transport/webrtc/node_ops.py b/packages/meshbay-node/src/meshbay_node/transport/webrtc/node_ops.py index 9d58d8c..f7bbbfa 100644 --- a/packages/meshbay-node/src/meshbay_node/transport/webrtc/node_ops.py +++ b/packages/meshbay-node/src/meshbay_node/transport/webrtc/node_ops.py @@ -14,6 +14,8 @@ from meshbay_common.adminop import ( OP_ROOT_UPDATE, OP_SET_SCAN_SETTINGS, OP_TRANSFER_LIMITS, + group_attach_subject, + root_add_subject, ) from meshbay_common.protocol import MNP @@ -246,10 +248,11 @@ class NodeOpsMixin: # is ignored rather than obeyed: on load it forces every other root # read-only, which is the model the RO/RW one replaced. A second # writable directory is `root_add` with `writable`. + writable = bool(msg.get("writable", True)) + # The directory being exposed is signed, not only the group's name. self._issue_admin_challenge( - OP_GROUP_ATTACH, name, - payload={"name": name, "shared_dir": shared_dir, - "writable": bool(msg.get("writable", True))}, + OP_GROUP_ATTACH, group_attach_subject(name, shared_dir, writable), + payload={"name": name, "shared_dir": shared_dir, "writable": writable}, group_id="") async def _admin_exec_group_attach( @@ -342,16 +345,20 @@ class NodeOpsMixin: if not self._has_admin_authority(): self._send({"type": "error", "detail": "No authorized key for this"}) return + payload = { + "group_id": target_group, "path": path, + "name": str(msg.get("name", ""))[:128], + "kind": str(msg.get("kind", "generic"))[:16], + "writable": bool(msg.get("writable", msg.get("upload", False))), + "removable": bool(msg.get("removable", False)), + } + # Everything the executor acts on is signed — `writable` decides whether + # every member may write there. The group is in the transcript itself. self._issue_admin_challenge( - OP_ROOT_ADD, path, - payload={ - "group_id": target_group, "path": path, - "name": str(msg.get("name", ""))[:128], - "kind": str(msg.get("kind", "generic"))[:16], - "writable": bool(msg.get("writable", msg.get("upload", False))), - "removable": bool(msg.get("removable", False)), - }, - group_id=target_group) + OP_ROOT_ADD, + root_add_subject(path, payload["name"], payload["kind"], + payload["writable"], payload["removable"]), + payload=payload, group_id=target_group) async def _admin_exec_root_add( self, pending: dict, transcript: bytes, sig: bytes, |