Files
hyperguild/ingestion/internal/api/ingestpath_root.go
mathiasandClaude Opus 5.5 8a91feb02b
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fix(ingestion): every brain/raw/ reader goes through an os.Root; symlinks are inert
raw/ is writable via Syncthing (a sendreceive folder shared with
flamingo, symlinks synced) and by the brain CronJobs, and several
readers followed symlinks out of it:

- /pending and brain_pending showed a symlink target's contents;
  brain_promote would copy it into wiki/ (then brain-sync to Gitea);
  brain_reject would copy it into raw/rejected/.
- The watcher, which needs no API call at all, ingested symlinked files
  (WalkDir yields them; extract.Text followed them). Not in the issue;
  found while fixing it.
- Ingest checked a path then reopened it by name (TOCTOU).

OpenRawRoot opens brain/raw as an os.Root and refuses a raw/ that is
itself a symlink. ListPending, PromoteNote and RejectNote read through
it and refuse anything not a regular file. extract.TextIn reads through
a root (temp copy for pdf/docmark); /ingest-path, brain_ingest and the
watcher use it, and the watcher archives via the root too, so a file
swapped for a symlink after a check still cannot lead out.

Refs #153

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-03 16:47:43 +02:00

68 lines
2.5 KiB
Go

package api
import (
"errors"
"os"
"github.com/mathiasbq/hyperguild/ingestion/internal/extract"
"path/filepath"
"strings"
)
// ErrOutsideIngestRoot is the one refusal for every bad ingest path. It never
// carries the underlying error: "no such file" versus "permission denied"
// would let a caller probe which server files exist (PR #152 review).
var ErrOutsideIngestRoot = errors.New("ingest path must be an existing file or directory inside brain/raw/")
// ResolveIngestPath confines a caller-supplied ingest path to brain/raw/, the
// inbox the watcher already owns (hyperguild#149). Relative paths resolve
// against that root; symlinks are evaluated before the containment check, so
// a link inside raw/ that points elsewhere is refused. The path must exist.
func ResolveIngestPath(brainDir, p string) (string, error) {
if strings.TrimSpace(p) == "" {
return "", ErrOutsideIngestRoot
}
// raw/ itself must be a real directory: if it were a symlink, containment
// inside it would mean nothing (hyperguild#153 item 4).
if fi, lerr := os.Lstat(filepath.Join(brainDir, "raw")); lerr != nil || fi.Mode()&os.ModeSymlink != 0 || !fi.IsDir() {
return "", ErrOutsideIngestRoot
}
root, err := filepath.EvalSymlinks(filepath.Join(brainDir, "raw"))
if err != nil {
return "", ErrOutsideIngestRoot
}
if !filepath.IsAbs(p) {
p = filepath.Join(root, p)
}
real, err := filepath.EvalSymlinks(filepath.Clean(p))
if err != nil {
return "", ErrOutsideIngestRoot
}
rel, err := filepath.Rel(root, real)
if err != nil || rel == ".." || strings.HasPrefix(rel, ".."+string(filepath.Separator)) || filepath.IsAbs(rel) {
return "", ErrOutsideIngestRoot
}
return real, nil
}
// ReadIngestFile extracts text from an ingest path already confined by
// ResolveIngestPath, reading it through the raw/ root rather than reopening
// the path by name (hyperguild#153 item 3): if the file is swapped for a
// symlink after the check, the read still cannot leave raw/.
func ReadIngestFile(brainDir, resolved string) (string, error) {
root, rawPath, err := OpenRawRoot(brainDir)
if err != nil {
return "", ErrOutsideIngestRoot
}
defer func() { _ = root.Close() }()
realRoot, err := filepath.EvalSymlinks(rawPath)
if err != nil {
return "", ErrOutsideIngestRoot
}
rel, err := filepath.Rel(realRoot, resolved)
if err != nil || rel == ".." || strings.HasPrefix(rel, ".."+string(filepath.Separator)) || filepath.IsAbs(rel) {
return "", ErrOutsideIngestRoot
}
return extract.TextIn(root, rel)
}