Affected: crates.io: hickory-proto

When a TSIG record is decoded from the DNS wire format, its MAC length and "other data" length are checked against the end of the record data. If a check failed, the error value was built from `end_idx - decoder.index()`. For a malformed record the decoder can already be past `end_idx`, so this unsigned subtraction underflows.

In builds with overflow checks enabled (the `dev` profile by default) the underflow panics, so a peer that sends a crafted TSIG record can crash the process. In builds without overflow checks the result wraps and is only used in the returned error.

The fix returns a plain "insufficient bytes" error without the subtraction. It is in 0.26.2.