RUSTSEC-2024-0345

There is a denial-of-service vulnerability in sequoia-openpgp, our crate providing a low-level interface to our OpenPGP implementation. When triggered, the process will enter an infinite loop.

Many thanks to Andrew Gallagher for disclosing the issue to us.

## Impact

Any software directly or indirectly using the interface `sequoia_openpgp::cert::raw::RawCertParser`. Notably, this includes all software using the `sequoia_cert_store` crate.

## Details

The `RawCertParser` does not advance the input stream when encountering unsupported cert (primary key) versions, resulting in an infinite loop.

The fix introduces a new raw-cert-specific `cert::raw::Error::UnuspportedCert`.

## Affected software

- sequoia-openpgp 1.13.0 - sequoia-openpgp 1.14.0 - sequoia-openpgp 1.15.0 - sequoia-openpgp 1.16.0 - sequoia-openpgp 1.17.0 - sequoia-openpgp 1.18.0 - sequoia-openpgp 1.19.0 - sequoia-openpgp 1.20.0 - Any software built against a vulnerable version of sequoia-openpgp which is directly or indirectly using the interface `sequoia_openpgp::cert::raw::RawCertParser`. Notably, this includes all software using the `sequoia_cert_store` crate.