Both halves of the path a download writes to arrived from the frontend
unchecked. `start_download` and the queue pump built their target as
`PathBuf::from(target_dir).join(file_path)`, and `mark_download_completed`
stored a frontend-supplied `file_path` on the row verbatim — the same
column that is later read back into `std::fs::remove_file` when a
download is deleted. A correct sanitiser already existed and
`download_item_and_start` used it, but `download_item` is a command in
its own right, so calling it directly routed the guard around.
The guard moves inside. `confine_to_root` folds `..` away lexically and
requires the result to sit inside the storage root, modelled on
`media_server::resolve_path` — the check comes after the join because
`Path::join` drops the base when the joined half is absolute, so an
absolute `file_path` is obeyed rather than folded. `confine_queued_path`
sanitises a queued path per component (so the already-safe name
`download_item_and_start` passes in is not sanitised into a second,
different one) and confines it. Applied in `download_item`, at both join
sites, and to what `mark_download_completed` writes.
Every path the app builds for itself is returned unchanged, including
the absolute ones `download_series`/`download_season` produce from
`${targetDir}/videos`, so no existing row or file on disk is orphaned.
The pump fails an offending row rather than skipping it, because the
pump re-queries and would otherwise not terminate.
Not a live vulnerability: reaching these commands with hostile input
needs script execution in a webview whose CSP is `script-src 'self'`.
This is hardening and consistency.
TRACES: DR-211 | UT-205
dtourolle
da6b039b29