Commit Graph
2 Commits
Author SHA1 Message Date
mathiasandClaude Opus 5.5 87fa28e2c8 fix(update,session): brain_update and session_log confine caller paths (#169)
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Review round 1 on PR #170 found two more handlers with the #169 class of
bug (verified by execution):

- brain_update resolved its caller path with resolveWithin, a lexical
  containment check: any brain file could be superseded
  (classification.yaml, raw/, sessions/), and a final symlink was
  written through. UpdateNote now resolves like brain_edit
  (notes.Resolve, ScopeNotes: knowledge/ and wiki/ .md notes), and reads
  and rewrites through brainfs (ReadRegular, WriteRegular).
- session_log joined the caller's session_id onto the sessions dir and
  opened it O_CREATE|O_APPEND: an id with path segments created or
  appended a .jsonl file anywhere the pod could write. The id must now
  be a plain name (^[A-Za-z0-9_][A-Za-z0-9._-]{0,127}$, which every live
  session file matches), and the open adds O_NOFOLLOW|O_NONBLOCK. Read
  checks the id too.
- Tunnel tests: the .txt case now names an existing file (it failed on
  "missing" before), the symlink test adds an in-brain target, and the
  FIFO comment no longer claims the handle check is the only guard.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-04 22:38:08 +02:00
mathiasandClaude Opus 5.5 9eb3d2456d fix(tunnel): brain_tunnel cannot write outside the wiki or through symlinks
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brain_tunnel passes caller-supplied source and target paths to
WriteTunnel, which checked only the first segments ("wiki/<wing>/...")
and joined them onto the brain dir. "wiki/b/x/../../../../tmp/f.md"
resolved outside the brain, and appendSeeAlso read and rewrote that file
(verified by execution): any MCP token holder could append to any
existing file the pod user can write, inside the brain (raw/, sessions/,
classification.yaml) or outside it.

- checkNotePath: only a clean, local wiki/.../<slug>.md path, with no
  ".", ".." or empty segments.
- Both notes are read and rewritten through brainfs. New
  brainfs.WriteRegular: never creates; Lstat through the root, open with
  O_NOFOLLOW|O_NONBLOCK, and require the opened handle to be the same
  regular file (os.SameFile). os.Root.OpenFile follows an in-root final
  symlink even with O_NOFOLLOW (verified on go1.27), so the flag alone
  does not refuse it.
- The source is no longer rewritten when the target is refused.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-04 22:23:45 +02:00