Sigstore Timestamp Authority allocates excessive memory during request parsing

Impact

Excessive memory allocation

Function api.ParseJSONRequest currently splits (via a call to strings.Split) an optionally-provided OID (which is untrusted data) on periods. Similarly, function api.getContentType splits the Content-Type header (which is also untrusted data) on an application string.

As a result, in the face of a malicious request with either an excessively long OID in the payload containing many period characters or a malformed Content-Type header, a call to api.ParseJSONRequest or api.getContentType incurs allocations of O(n) bytes (where n stands for the length of the function's argument). Relevant weakness: CWE-405: Asymmetric Resource Consumption (Amplification)

Patches

Upgrade to v2.0.3.

Workarounds

There are no workarounds with the service itself. If the service is behind a load balancer, configure the load balancer to reject excessively large requests.