resolve_under_root and resolve_dataset_path previously returned absolute
paths unchanged, so an authenticated client could supply
save_directory="/tmp/escape" (or any other absolute path) and have the
exporter drop adapter files anywhere the server user could write. This
turned up during a recent audit pass where an authenticated POST to
/api/export/export/lora with save_directory="/tmp/lora_escape_test"
returned 200 and wrote adapter_model.safetensors, adapter_config.json,
and tokenizer files under /tmp.
The fix is two-layered:
storage_roots.py adds an _assert_contained(resolved, root) helper that
runs after path resolution and rejects any result whose realpath does
not sit under realpath(root). resolve_under_root now rejects '..'
segments and null bytes outright, and only accepts absolute inputs when
they are already inside the configured root (internal call sites that
re-resolve a stored absolute path stay idempotent;
worker.py:resolve_output_dir(output_dir) etc. continue to work).
resolve_dataset_path picks up the same containment rule, scoped to the
three dataset roots.
models/export.py adds field_validator("save_directory", mode="before")
to ExportCommonOptions and ExportGGUFRequest so bad input fails fast at
422 with a clear message rather than a 500 deep inside the resolver.
The validator rejects empty/whitespace, null bytes, control chars,
strings longer than 255 chars, absolute paths, and '..' segments.
routes/export.py:_export_details now returns os.path.relpath(output_path,
exports_root()) so the Export Complete dialog and /api/models/loras no
longer leak the absolute install prefix to the UI; the basename is
used as a last-resort fallback.
Verified end to end:
- POST /api/export/export/lora {"save_directory":"/tmp/foo"} -> 422
"save_directory must be a name or relative path under the export
root; absolute paths are rejected". /tmp/foo is not created.
- "../../etc/escape" -> 422 "may not contain '..' segments".
- save_directory="my_subdir" -> still accepted (400 only because the
test had no checkpoint loaded yet, not because of validation).
- Internal idempotent re-resolve via resolve_export_dir(absolute path
that is already under exports_root) returns the same path unchanged.
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