The automatically reseeding implementations of HMAC-DRBG would panic if called with a desired non-zero output length cleanly divisible by 65_536, the maximum number of output bytes that can be generated before reseeding has to happen.

Impact

An application relying on libcrux-hmac-drgb to provide randomness of byte length a non-zero integer multiple of 65_536 in a single call to fill_bytes would panic.

Any calls with output buffer lengths not cleanly divisible by 65_536 are not affected.

Mitigation

With release the release of version 0.0.2 of libcrux-hmac-drbg this bug has been fixed and reseeding DRBG implementations can be used with arbitrary output lengths.

We recommend users upgrade to libcrux-hmac-drbg version 0.0.2.