GHSA-q55h-vfv9-qcr5 patched Page.navigate to refuse file:// URLs
unless --allow-file-access was set, but Target.createTarget accepted
the same scheme and called page.navigate(url) directly, bypassing
the policy. A CDP client could call Target.createTarget {url: file://...}
then Runtime.evaluate to read document.body.textContent and recover
arbitrary local files.
Apply the same gate at the Target.createTarget entrypoint. Pull
the file-scheme detector into a shared util module so both domains
stay in lock-step instead of one drifting from the other.
Verified blocked vs the unpatched build (pr69):
- Patched: Target.createTarget {url: file:///tmp/secret} errors
"Target.createTarget to file:// is disabled. ..." before any
navigation runs.
- Unpatched: same call returns the file contents via
Runtime.evaluate {expression: "document.body.textContent"}.
