Draining skipped entries still left a hole: a tar entry whose header doesn't read as a regular file
(a socket or directory per its mode bits, say) can carry a body, and the tar reader decompresses it
to reach the next header without anything being charged or ctx being checked.
- compressed tars are now read through a reader that charges the budget for every byte the decoder
produces and checks ctx per read, so no skip path inside the tar reader gets around it
- entry content from that stream isn't charged a second time, and the per-entry drain is gone
- zip and plain tar are unchanged
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
The tree decompression budget was only spent as entry content was stored. A compressed tar reader
still decompresses whatever an entry leaves unread to reach the next header, so an excluded entry, a
file/directory clash, or the rest of one over the 2 GB per-entry cap decompressed with nothing charged
and no ctx check. A small `.tar.zst` could force hundreds of GB of work past the budget.
- in compressed tars the rest of every regular entry is now drained through the budget, with ctx
checked per chunk
- zip and plain tar are unchanged: they seek past skipped entries, so those cost nothing
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
the limiter bounds what's held *at once*, and each archive gives its bytes back when it's released. So a recursive bomb (42.zip shape) never trips a limit: every level fits on its own, and the scan just runs for effectively forever. Capping each archive at N× its own size wouldn't help either, since every level of such a bomb is high-ratio, so the work still grows about N-fold per level.
- each top-level archive gets one decompression budget of `max(100 × its size, 1 GiB)`, spent by every archive nested under it at any depth
- the budget is attached to the context when the walk enters a top-level archive, so `Extract` picks it up without a signature change
- once it's spent, the archive being extracted is truncated with a "possible decompression bomb" unknown and the walk moves on. The next top-level archive starts fresh
real trees (a war of jars, a layer of tarballs) expand a few times over, well under the ratio.
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
Alex Goodman
Keith Zantow
Keith Zantow