fix(node): bound and tighten the chat link-preview SSRF surface

2026-09-01T17:09:20Z

The link-preview fetch is an outbound request to an address a member chose. safe_url() already blocked non-public addresses and re-checked each redirect hop; this adds the parts that were missing: - Rate limit. `_do_link_preview_request` was reachable by any member with no ceiling, so a member — or a hub minting tokens for many accounts — could drive unbounded outbound HTTP from the operator's machine (amplification / DoS / on-demand IP disclosure to arbitrary hosts). Now bounded per connection (15) and node-wide (60) over a 60 s window; only a real fetch counts, a cache hit is free, and over the ceiling the reply is a plain `ok: false` (bare link), not cached. - Port allowlist. safe_url() passed `parts.port` straight through, so a member could aim the node at `http://:`. Restricted to {80, 443, 8080, 8443} — every real OpenGraph page, none of SSH / mail / DB / cache / search / admin ports. - DNS rebinding. The connection's actual peer address is now re-checked against the public-address rule (`_reject_if_rebound`), so a name that resolves clean and then to something internal does not get its body read. Best-effort (no `network_stream` extension, no check); a full literal-pin is noted as remaining hardening. - Decompression bomb. `_downscale` now refuses an image whose header dimensions exceed ~40 MP before convert()/thumbnail() decode it. Third security review, finding M3. Co-Authored-By: Claude Sonnet 5 Claude-Session: https://claude.ai/code/session_011pG75yGK3NthNfyjH74omG

feat(chat): link previews for pasted URLs

2026-08-28T01:43:19Z

Paste an http(s) link in a group's chat and it unfurls into an OpenGraph card — title, description, site name, and image — the way WhatsApp/Signal/ Slack do it. The fetch is the node's, never the browser's or the hub's. The browser cannot: a strict img-src/connect-src and CORS block it, and a direct fetch would leak every reader's IP to the linked host on each render. The hub must not touch group content (draft-v6 §2.5). The node already fetches third-party metadata for the Videos and Music apps, over the same authorised path. Flow mirrors media_meta_req: the client sends `link_preview_req {url}`, the node replies `link_preview_resp` with the card fields (or `ok: false`), and any OG image is stored under its blake3 in the existing media_cache thumb store — the client then fetches it via the normal file_req path, exactly like a poster. Nothing durable is added: the card text lives in a bounded in-memory TTL cache on the node (draft-v6 §2.7 — enrichment on demand, the asking device caches), and MNP goes 0.11 → 0.12 (additive: an older node logs "unknown type" and the client shows the bare link). Because the URL is chosen by a *member* and triggers an outbound request from the operator's machine, `linkpreview.safe_url` is an SSRF gate: http(s) only, no credentials, and every resolved address must be globally routable — no loopback, private, link-local, multicast or reserved range, cloud-metadata included. Redirects are followed by hand so each hop is re-checked. Residual, documented in the module: DNS rebinding between the check and connect, closed properly by pinning the checked IP — a follow-up. Also fixes a long-standing chat annoyance the preview cards made worse: opening the Chat tab landed a screen or two above the newest message because the scroll-to-bottom ran before attachment thumbnails and (now) preview cards had loaded and grown the content. A ResizeObserver keeps the view pinned to the bottom through late content growth, and does nothing once the reader scrolls up. Tests: test_linkpreview.py (the SSRF gate and the OpenGraph parse, incl. redirect re-validation and image downscaling) and test_link_preview_request.py (reply shape, the media_cache image round-trip, the result cache). Co-Authored-By: Claude Sonnet 5 Claude-Session: https://claude.ai/code/session_018gKJ85aZyvEwarXMFzFEwi

meshbay.git/packages/meshbay-node/src/meshbay_node/linkpreview.py, branch 0.16

fix(node): bound and tighten the chat link-preview SSRF surface

feat(chat): link previews for pasted URLs