gpg: First take on PKT_ENCRYPTED_AEAD.

* common/openpgpdefs.h (PKT_ENCRYPTED_AEAD): New const.
* g10/dek.h (DEK): Increase size of use_aead to 4 bits.
* g10/filter.h (cipher_filter_context_t):  Add new fields for AEAD.
* g10/packet.h (PKT_encrypted): Add fields aead_algo, cipher_algo, and
chunkbyte.
* g10/build-packet.c (do_encrypted_aead): New.
(build_packet): Call it.
* g10/parse-packet.c (dump_sig_subpkt): Handle SIGSUBPKT_PREF_AEAD.
(parse_one_sig_subpkt, can_handle_critical): Ditto.
(parse_encrypted): Clear new PKT_ENCRYPTED fields.
(parse_encrypted_aead): New.
(parse): Call it.
* g10/gpg.c (main): Take care of --rfc4880bis option when checking
compliance.
* g10/cipher-aead.c: Replace the stub by real code.
* g10/decrypt-data.c (decode_filter_ctx_t): Add fields for use with
AEAD.
(aead_set_nonce): New.
(aead_set_ad): New.
(decrypt_data): Support AEAD.
(aead_underflow): New.
(aead_decode_filter): New.
* g10/encrypt.c (use_aead): Make that new fucntion work.
(encrypt_simple): Use default_aead_algo() instead of EAX.
* g10/mainproc.c (proc_encrypted): Support AEAD.
(do_proc_packets): Support PKT_ENCRYPTED_AEAD.
--

This code has seen only a very few manual tests.  Encrypting always
uses a 64k chunks and decryption has not been tested with larger
chunks.  Those small chunks make debugging much faster.

Tests can be done using:

  gpg --rfc4880bis --pinentry-mode=loopback --passphrase abc \
      --force-aead --aead-algo ocb --s2k-mode 0 --cipher AES \
      -v -z 0 --status-fd 2 -c <INFILE >OUTFILE

and

  gpg --rfc4880bis --pinentry-mode=loopback --passphrase=abc \
      --status-fd 2 -v -d <INFILE >OUTFILE

Signed-off-by: Werner Koch <wk@gnupg.org>

1 files changed, 8 insertions, 5 deletions

diff --git a/g10/encrypt.c b/g10/encrypt.c
index 01feb4a7d..856849799 100644
--- a/g10/encrypt.c
+++ b/g10/encrypt.c
@@ -123,7 +123,7 @@ use_aead (pk_list_t pk_list, int algo)
       return 0;
     }
 
-  can_use = openpgp_cipher_get_algo_blklen (algo) != 16;
+  can_use = openpgp_cipher_get_algo_blklen (algo) == 16;
 
   /* With --force-mdc we clearly do not want AEAD.  */
   if (opt.force_mdc)
@@ -133,12 +133,15 @@ use_aead (pk_list_t pk_list, int algo)
   if (opt.force_aead)
     {
       if (!can_use)
-        log_info ("Warning: request to use AEAD ignored for cipher '%s'\n",
-                  openpgp_cipher_algo_name (algo));
+        {
+          log_info ("Warning: request to use AEAD ignored for cipher '%s'\n",
+                    openpgp_cipher_algo_name (algo));
+          return 0;
+        }
       return 1;
     }
 
-  /* AEAD does noly work with 128 bit cipher blocklength.  */
+  /* AEAD does only work with 128 bit cipher blocklength.  */
   if (!can_use)
     return 0;
 
@@ -307,7 +310,7 @@ encrypt_simple (const char *filename, int mode, int use_seskey)
                  openpgp_cipher_algo_name (cfx.dek->algo));
 
       if (use_aead (NULL, cfx.dek->algo))
-        cfx.dek->use_aead = 1;
+        cfx.dek->use_aead = default_aead_algo ();
       else
         cfx.dek->use_mdc = !!use_mdc (NULL, cfx.dek->algo);
     }