Two webchat hardening fixes:
- Session listing no longer pulls every system-owned conversation into
memory. listSessions/pageSessions went through listConversations(owner)
whose `username IN (owner, system)` loaded all IM/cron rows just to show
one visitor's handful of threads. New listWebchatConversations(username)
queries only the visitor's own rows; the channel prefix is matched
in-memory with a literal startsWith (so a '_'/'%' in the api key's first
8 chars can't act as a LIKE wildcard).
- Upload now enforces a per-conversation quota (file count + total bytes,
both configurable) so a visitor can't fill the disk with many
individually-under-cap files. Pairs with the existing staging TTL sweep.
WebChat had no file support: the /stream body carried only text, and
agent-produced files had no visitor-reachable download path (the JWT
/chat/files endpoint is unreachable for API-key visitors).
Add webchat-authenticated file transfer, reusing MessageContentPart +
the existing upload dir + agent multimodal injection:
- WebChatFileService: validate (size cap, extension whitelist, filename
sanitize), store under the conversation's upload dir, stage by opaque
fileId, traversal-safe resolve. Untrusted-uploader hardening lives here.
- POST /upload (multipart) and GET /files, both authed by API key +
visitor token with a server-derived conversationId (never client paths).
Downloads send non-images as attachment + X-Content-Type-Options:nosniff.
- /stream gains attachmentIds; the server resolves each id from the
staging registry (client metadata is never trusted), builds parts, and
persists them on the user message so the agent's multimodal/file tools
pick them up from history — same path as the JWT web chat.
- Strip server-side file paths from the visitor-facing message view
(listMessageViewsExternal + includePath flag) so the filesystem layout
is not disclosed.
Refs matevip/mateclaw#342
