server.rs logged previews of attacker-controlled strings with raw byte
slicing: `&text[..text.len().min(200)]` for a malformed CDP frame (inside a
`warn!`, which is active at the worker's default log level) and the same for
an intercepted event JSON. `&s[..n]` panics when byte `n` falls inside a
multi-byte UTF-8 character, so a single WebSocket frame that is invalid JSON,
>=201 bytes, with a multi-byte char straddling byte 200 panics the CDP
processor task — an unauthenticated one-frame crash. page.rs had the same
pattern (behind --verbose debug logging) for evaluated JS expressions.
Add truncate_on_char_boundary (str::floor_char_boundary is still unstable) and
route all four sites through it. Regression test constructs the exact 'a'*199 +
'€' input, asserts the old raw slice panics (via catch_unwind) and the helper
truncates on the boundary instead.
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"}.
Andrey Mnatsakanov