gpg: Rework ECC support and add experimental support for Ed25519.

* agent/findkey.c (key_parms_from_sexp): Add algo name "ecc".
(agent_is_dsa_key): Ditto.
(agent_is_eddsa_key): New.  Not finished, though.
* agent/pksign.c (do_encode_eddsa): New.
(agent_pksign_do): Use gcry_log_debug functions.
* agent/protect.c (agent_protect): Parse a flags parameter.
* g10/keygen.c (gpg_curve_to_oid): Move to ...
* common/openpgp-oid.c (openpgp_curve_to_oid): here and rename.
(oid_ed25519): New.
(openpgp_oid_is_ed25519): New.
(openpgp_oid_to_curve): New.
* common/t-openpgp-oid.c (test_openpgp_oid_is_ed25519): New.
* g10/build-packet.c (gpg_mpi_write): Write the length header also for
opaque MPIs.
(gpg_mpi_write_nohdr): New.
(do_key): Use gpg_mpi_write_nohdr depending on algorithm.
(do_pubkey_enc): Ditto.
* g10/ecdh.c (pk_ecdh_encrypt_with_shared_point): Use
gpg_mpi_write_nohdr.
* g10/export.c (transfer_format_to_openpgp):
* g10/keygen.c (ecckey_from_sexp): Return the error.
(gen_ecc): Repalce arg NBITS by CURVE.
(read_parameter_file): Add keywords "Key-Curve" and "Subkey-Curve".
(ask_curve): New.
(generate_keypair, generate_subkeypair): Use ask_curve.
(do_generate_keypair): Also pass curve name.
* g10/keylist.c (list_keyblock_print, list_keyblock_colon): Print
curve name.
* g10/parse-packet.c (mpi_read): Remove workaround for
Libcgrypt < 1.5.
(parse_key): Fix ECC case.  Print the curve name.
* g10/pkglue.c (mpi_from_sexp): Rename to get_mpi_from_sexp.
(pk_verify, pk_check_secret_key): Add special case for Ed25519.
* g10/seskey.c (encode_md_value): Ditto.
* g10/sign.c (do_sign, hash_for, sign_file): Ditto.
--

Be warned that this code is subject to further changes and that the
format will very likely change before a release.  There are also known
bugs and missing code.

Signed-off-by: Werner Koch <[email protected]>

1 files changed, 13 insertions, 14 deletions

diff --git a/g10/parse-packet.c b/g10/parse-packet.c
index 9c0436231..3b2698fcb 100644
--- a/g10/parse-packet.c
+++ b/g10/parse-packet.c
@@ -140,22 +140,13 @@ mpi_read (iobuf_t inp, unsigned int *ret_nread, int secure)
       nread++;
     }
 
-  if (nread >= 2 && !(buf[0] << 8 | buf[1]))
-    {
-      /* Libgcrypt < 1.5.0 accidently rejects zero-length (i.e. zero)
-         MPIs.  We fix this here.  */
-      a = gcry_mpi_new (0);
-    }
-  else
-    {
-      if (gcry_mpi_scan (&a, GCRYMPI_FMT_PGP, buf, nread, &nread))
-	a = NULL;
-    }
+  if (gcry_mpi_scan (&a, GCRYMPI_FMT_PGP, buf, nread, &nread))
+    a = NULL;
 
  leave:
   gcry_free (buf);
   if (nread > *ret_nread)
-    log_bug ("mpi larger than packet");
+    log_bug ("mpi larger than packet (%zu/%u)", nread, *ret_nread);
   else
     *ret_nread = nread;
   return a;
@@ -1999,8 +1990,8 @@ parse_key (IOBUF inp, int pkttype, unsigned long pktlen,
     {
       for (i = 0; i < npkey; i++)
         {
-          if ((algorithm == PUBKEY_ALGO_ECDSA
-               || algorithm == PUBKEY_ALGO_ECDH) && (i==0 || i == 2))
+          if ((algorithm == PUBKEY_ALGO_ECDSA && (i == 0))
+              || (algorithm == PUBKEY_ALGO_ECDH) && (i == 0 || i == 2))
             {
               size_t n;
 	      err = read_size_body (inp, pktlen, &n, pk->pkey+i);
@@ -2020,6 +2011,14 @@ parse_key (IOBUF inp, int pkttype, unsigned long pktlen,
             {
               es_fprintf (listfp, "\tpkey[%d]: ", i);
               mpi_print (listfp, pk->pkey[i], mpi_print_mode);
+              if ((algorithm == PUBKEY_ALGO_ECDSA
+                   || algorithm == PUBKEY_ALGO_ECDH) && i==0)
+                {
+                  char *curve = openpgp_oid_to_str (pk->pkey[0]);
+                  es_fprintf (listfp, " %s (%s)",
+                              openpgp_oid_to_curve (curve), curve);
+                  xfree (curve);
+                }
               es_putc ('\n', listfp);
             }
         }