Adds AEAD support to the TLS stack, currently supporting AES-GCM. Brings fixes
for TLS record fragmentation, enforcing TLS versions < 1.2 and proper signature
scheme support indication.
While a hardcoded 1.2 version is fine when we offer that in Client Hello, we
should include the actually offered version if it has been reduced before
starting the exchange.
Fixes fragment reassembling if a buffer contains more than one record, but
the last record contains a partial TLS record header. Thanks to Nick Saunders
and Jamil Nimeh for identifying this issue and providing a fix for it.
To better separate the code path for different TLS versions and modes of
operation, we introduce a TLS AEAD abstraction. We provide three implementations
using traditional transforms, and get prepared for TLS AEAD modes.
The salt, or often called implicit nonce, varies between AEAD algorithms and
their use in protocols. For IKE and ESP, GCM uses 4 bytes, while CCM uses
3 bytes. With TLS, however, AEAD mode uses 4 bytes for both GCM and CCM.
Our GCM backends currently support 4 bytes and CCM 3 bytes only. This is fine
until we go for CCM mode support in TLS, which requires 4 byte nonces.
Limits cached OCSP verification to responses signed by the CA, a directly
delegated signer or a pre-installed OCSP responder certificate. Disables
auth config merge for revocation trust-chain strength checkin, as it breaks
CA constraints in some scenarios.
To avoid considering each cached OCSP response and evaluating its trustchain,
we limit the certificates considered for OCSP signing to:
- The issuing CA of the checked certificate
- A directly delegated signer by the same CA, having the OCSP signer constraint
- Any locally installed (trusted) certificate having the OCSP signer constraint
The first two options cover the requirements from RFC 6960 2.6. For
compatibility with non-conforming CAs, we allow the third option as exception,
but require the installation of such certificates locally.
This behavior was introduced with 6840a6fb to avoid key/signature strength
checking for the revocation trustchain as we do it for end entity certificates.
Unfortunately this breaks CA constraint checking under certain conditions, as
we merge additional intermediate/CA certificates to the auth config.
As key/signature strength checking of the revocation trustchain is a rather
exotic requirement we drop support for that to properly enforce CA constraints.
The DH transform is optional for ESP/AH proposals. The initiator can
include NONE (0) in its proposal to indicate that while it prefers to
do a DH exchange, the responder may still decide to not do so.
Fixes#532.
(Re-)Introduces X.509 Attribute Certificate support in IKE, and cleans up the
x509 AC parser/generator. ACs may be stored locally or exchanged in IKEv2
CERT payloads, Attribute Authorities must be installed locally. pki --acert
issues Attribute Certificates and replaces the removed openac utility.
This validator checks for any attribute certificate it can find for validated
end entity certificates and tries to extract group membership information
used for connection authorization rules.
Andreas Steffen