* filer: authorize TUS existing-session verbs against the validated stored target
Scope-check on TUS HEAD/PATCH/DELETE only populated a resource path for POST,
so a prefix-restricted token that learned another tenant's session id could act
on that session and land content at a TargetPath its own AllowedPrefixes forbid.
Split the filer JWT check into authenticateFilerJwt (signature and method) and
authorizeFilerJwtPaths (resource scope), and make the scope check fail closed:
a prefix-restricted token with no resolved resource path is denied instead of
authorized on signature alone. The TUS handler now authenticates first, reads
and validates the session once, authorizes the stored TargetPath, then operates
on that single pinned snapshot. readTusSessionInfo rejects a session whose id,
target or size is unusable, and getTusSession is split so the authorization
lookup no longer lists chunks.
* filer: reject non-canonical TUS upload ids
The uploads route took the first path component as the session id, so a trailing
path or other non-canonical spelling aliased one session under several URLs.
Require the id to be a canonical UUID, the only form the server mints, both at
routing and when reading a session's metadata, so one URL maps to one resource.
* filer: revalidate the pinned TUS session before completing an upload
Completion re-read chunks but not the session identity, so a PATCH finishing
after a concurrent DELETE or metadata replacement could still land at the id's
stored path. Before completing, confirm the session still exists and its target,
size and creation time are unchanged from the authorized snapshot; otherwise the
completion fails instead of writing to a path the request never authorized.
* filer: log TUS session lookup failures before returning not-found
readTusSessionInfo and loadTusSessionChunks failures answered "not found" with
no log line, so a transient filer or listing error was indistinguishable from a
genuinely missing session. Log the lookup at V(1) (a missing session is common
and benign) and the chunk-load error at Errorf (the session already resolved).
Chris Lu
fa549e9c83