Two places built a path from a name somebody else supplied and checked only
for slashes.
The mirror refused "a/b" as a model name but took "..", which is a single
path element too: a fetch for model ".." wrote beside the mirror root rather
than inside it. Model, version and file names now have to be one element
that does not start with a dot — the mirror's own checksum files are dotted
— on the fetch path and the API alike.
The agent took the engine version from the control plane as given and made
a directory of it under /opt/llmgw/engines, and a RemoveAll before replacing
one. A version of "../x" would have done both outside the install root, as
root. The agent now installs only versions that look like one — letters,
digits and ._+- — whatever the control plane sent.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>