gpg: Support decryption of the new AEAD packet
* common/openpgpdefs.h (aead_algo_t): New. (pkttype_t): Add PKT_ENCRYPTED_AEAD. * g10/decrypt-data.c (struct decode_filter_context_s): Add fields for AEAD. (aead_set_nonce_and_ad): New. (aead_checktag): New. (decrypt_data): Support AEAD. (aead_underflow): New. (aead_decode_filter): New. * g10/dek.h (DEK): Add field use_aead. Turn use_mdc, algo_info_printed, and symmetric into bit flags. * g10/mainproc.c (struct mainproc_context): Add field seen_pkt_encrypted_aead. (release_list): Clear it. (have_seen_pkt_encrypted_aead): New. (symkey_decrypt_seskey): Support AEAD. (proc_symkey_enc): Ditto. (proc_encrypted): Ditto. (proc_plaintext): Ditto. * g10/misc.c (MY_GCRY_CIPHER_MODE_EAX): New. (openpgp_aead_test_algo): New. (openpgp_aead_algo_name): New. (openpgp_aead_algo_info): New. * g10/packet.h (PKT_symkey_enc): Add field use_aead. (PKT_user_id): Add field flags.aead (PKT_public_key): Ditto. (PKT_encrypted): Add fields for AEAD. * g10/parse-packet.c (parse): Handle PKT_ENCRYPTED_AEAD. (parse_symkeyenc): Support AEAD. (parse_encrypted): Ditto. (dump_sig_subpkt): Dump AEAD preference packet. (parse_encrypted_aead): New.
This patch allows to decrypt data encrypted using the new AEAD
mechanism as specified in rfc4880bis. Although preferences are used
to enable this new mode, it is useful to have at least a decryption
option in case a user switches between GnuPG 2.2 and newer versions.
The new AEAD mechanism is much faster than the current CFB+MDC and
thus 2.2 will allow faster decryption of symmetric only decryption.
This patch is based on the current master (2.3) code base and includes
a few other patches. In particular
commit 44be675b759d27bac310c2de8bae1b7882a26b65
(gpg: More check for symmetric key encryption.)
is included.
- Signed-off-by: Werner Koch <wk@gnupg.org>