Each of these asks the allocator for tens of gigabytes, or runs for hours, from
a file of a few kilobytes to a few megabytes. An allocation failure is an abort,
so no panic guard can report it and the user's unsaved work is gone.
- IGES composite curves (102) name their children by pointer, and a tree whose
every node names the same child twice fans out to 2^30 leaf visits under the
depth cap. Count the entities visited and the segments produced against one
budget, since a node that yields no segment trips no bound on the output, and
refuse a composite curve that contains itself.
- IGES directory entries could all name the same parameter range, each
materialising it as its own string and token list. Keep the total text
proportional to the parameter section the file carries.
- STEP knot multiplicities were expanded into one value each before the knot
count was compared with the control points: 20 million knots of multiplicity
64 built a 10 GB vector only to be rejected. Check the sum first.
- One STEP face could list any number of boundary loops, each cloning its edge
handles into a new wire that the face extent then samples. Cap the loops and
the edges they hold; 100,000 bounds went from 2.1 GB to an immediate error.
Also guard the IGES translation, which was the one importer stage outside every
panic guard, keep the vertex-sewing bucket key clear of the overflow its
neighbour lookup caused for coordinates near f64's range, and count how often a
loop passes each vertex once instead of once per edge.
Fixes#146
Co-Authored-By: Claude Opus 5 <[email protected]>
(cherry picked from commit c32792b71c76d74348ad5002d8d2da870937e58e)
Matt
b5fb86f245