diff options
Diffstat (limited to 'packages/meshbay-node/src/meshbay_node/transport/webrtc_server.py')
| -rw-r--r-- | packages/meshbay-node/src/meshbay_node/transport/webrtc_server.py | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/packages/meshbay-node/src/meshbay_node/transport/webrtc_server.py b/packages/meshbay-node/src/meshbay_node/transport/webrtc_server.py index af41061..298b3cd 100644 --- a/packages/meshbay-node/src/meshbay_node/transport/webrtc_server.py +++ b/packages/meshbay-node/src/meshbay_node/transport/webrtc_server.py @@ -29,6 +29,7 @@ import hashlib import hmac import logging import os +import re import struct import tempfile import time @@ -146,6 +147,32 @@ log = logging.getLogger(__name__) CHUNK_SIZE = 1024 * 1024 MAX_MSG = 64 * 1024 * 1024 +# Per-account blobs (docs/playlists.md §4.3). These are an unbounded write +# primitive pointed at somebody else's disk, so every one of them is checked — +# and every check **refuses**, never truncates. A truncating cap silently loses +# tracks, which is the one failure the whole playlist design exists to prevent. +# +# The numbers are sized against the measured shape: ~300 bytes per track before +# compression, deflate worth about three on a payload this repetitive. A 1 MB +# body is therefore roughly ten thousand tracks in one playlist, and the +# manifest holds names and revisions only. +USER_BLOB_MANIFEST_MAX = 64 * 1024 +USER_BLOB_BODY_MAX = 1024 * 1024 +USER_BLOB_ACCOUNT_MAX = 8 * 1024 * 1024 + +# "playlists" is the manifest; "playlist:<id>" is one playlist's tracks. A +# pattern rather than a set, because the ids are client-generated — but a +# pattern, not anything at all, or the table becomes a key/value store for +# whatever a client feels like writing. +# +# The character class is deliberately wider than a UUID: the reserved id is the +# word "favorites" (docs/playlists.md §5.1), so a hex-only pattern refuses the +# one playlist every account has. It stays narrow enough to carry no structure +# of its own — no "/", no ".", no second ":" — so a kind can never be read as a +# path or as anything but one name in one namespace. +_USER_BLOB_KIND_RE = re.compile( + r"^(playlists|playlist:[A-Za-z0-9_-]{1,64})$") + # Chat link-preview results, kept in memory only (draft-v6 §2.7: the node # produces enrichment on demand and keeps nothing durable — the asking device # caches). Bounded and time-limited so a busy group cannot grow it without end @@ -682,6 +709,14 @@ class WebRTCPeerSession: self._spawn(self._do_keypair_bundle_store(msg)) elif mtype == MNP.KEYPAIR_BUNDLE_DELETE: self._spawn(self._do_keypair_bundle_delete()) + elif mtype == MNP.USER_BLOB_STORE: + self._spawn(self._do_user_blob_store(msg)) + elif mtype == MNP.USER_BLOB_FETCH: + self._spawn(self._do_user_blob_fetch(msg)) + elif mtype == MNP.USER_BLOB_LIST: + self._spawn(self._do_user_blob_list()) + elif mtype == MNP.USER_BLOB_DELETE: + self._spawn(self._do_user_blob_delete(msg)) elif mtype == MNP.STREAM_REQUEST: sem = self._ctx.get("_transcode_sem") log.info("stream: req file=%s credits=%s slots_free=%s prev=%s", @@ -1136,6 +1171,113 @@ class WebRTCPeerSession: "detail": "keypair_bundle_stored", }) + # ── Per-account blobs (playlists, docs/playlists.md §8.2) ──────────────── + # + # The node stores bytes it cannot read and hands them back. `self._user_id` + # comes from the authenticated session and never from the message: a + # `user_id` in the body would let any member of this group read or + # overwrite any other member's blob, which is finding C5 one size down. + + def _user_blob_kind(self, msg: dict) -> str | None: + """The validated `kind`, or None having already refused.""" + kind = msg.get("kind") + if not isinstance(kind, str) or not _USER_BLOB_KIND_RE.match(kind): + self._send({"type": "error", "detail": "Unknown blob kind"}) + return None + return kind + + def _user_blob_store_ok(self): + store = self._ctx.get("bundle_store") + if not store: + self._send({"type": "error", "detail": "Bundle store not available"}) + return None + if not self._user_id: + self._send({"type": "error", "detail": "Not authenticated"}) + return None + return store + + async def _do_user_blob_store(self, msg: dict) -> None: + store = self._user_blob_store_ok() + if not store: + return + kind = self._user_blob_kind(msg) + if not kind: + return + + blob = msg.get("blob_enc") + if not isinstance(blob, (bytes, bytearray)) or not blob: + self._send({"type": "error", "detail": "Missing blob_enc"}) + return + blob = bytes(blob) + + rev = msg.get("rev") + if not isinstance(rev, int) or rev < 0: + self._send({"type": "error", "detail": "Missing rev"}) + return + + limit = (USER_BLOB_MANIFEST_MAX if kind == "playlists" + else USER_BLOB_BODY_MAX) + if len(blob) > limit: + # A stated reason, not a bare error: the client turns this into a + # sentence the reader can act on ("this playlist is too large"), + # and a refusal nobody can read is a support case. + self._send({"type": "error", + "detail": f"Blob too large ({len(blob)} > {limit})"}) + return + + # What the account already uses, minus whatever this call replaces. + used = await store.user_blob_total_bytes(self._user_id) + existing = await store.fetch_user_blob(self._user_id, kind) + if existing: + used -= len(existing["blob_enc"]) + if used + len(blob) > USER_BLOB_ACCOUNT_MAX: + self._send({"type": "error", + "detail": f"Account blob quota exceeded " + f"({used + len(blob)} > {USER_BLOB_ACCOUNT_MAX})"}) + return + + await store.store_user_blob(self._user_id, kind, rev, blob) + self._audit("user_blob_store", f"{kind} rev={rev} bytes={len(blob)}") + self._send({"type": "ack", "v": MNP_VERSION, "detail": "user_blob_stored"}) + + async def _do_user_blob_fetch(self, msg: dict) -> None: + store = self._user_blob_store_ok() + if not store: + return + kind = self._user_blob_kind(msg) + if not kind: + return + row = await store.fetch_user_blob(self._user_id, kind) + self._audit("user_blob_fetch", kind) + self._send({ + "type": MNP.USER_BLOB_RESP, "v": MNP_VERSION, "kind": kind, + # A kind this account has never written is `null`, not an error: + # "no playlist here yet" is the ordinary state of a fresh node and + # the client must not read it as a failure. + "rev": row["rev"] if row else None, + "blob_enc": row["blob_enc"] if row else None, + }) + + async def _do_user_blob_list(self) -> None: + store = self._user_blob_store_ok() + if not store: + return + blobs = await store.list_user_blobs(self._user_id) + self._send({"type": MNP.USER_BLOB_LIST_RESP, "v": MNP_VERSION, + "blobs": blobs}) + + async def _do_user_blob_delete(self, msg: dict) -> None: + store = self._user_blob_store_ok() + if not store: + return + kind = self._user_blob_kind(msg) + if not kind: + return + removed = await store.delete_user_blob(self._user_id, kind) + self._audit("user_blob_delete", kind) + self._send({"type": "ack", "v": MNP_VERSION, + "detail": "user_blob_deleted" if removed else "user_blob_absent"}) + # ── Pairing and join (H3, M3) ──────────────────────────────────────────── def _join_refuse(self, reason: str, audit_detail: str = "") -> None: |