Fixed the ECC interface to Libgcrypt to be ABI compatible with the previous version.

Quite some changes were needed but in the end we have less code than
before.  Instead of trying to do everything with MPIs and pass them
back and forth between Libgcrypt and GnuPG, we know use the
S-expression based interface and make heavy use of our opaque MPI
feature.

Encryption, decryption, signing and verification work with
self-generared keys.

Import and export does not yet work; thus it was not possible to check
the test keys at https://sites.google.com/site/brainhub/pgpecckeys .

1 files changed, 6 insertions, 45 deletions

diff --git a/g10/build-packet.c b/g10/build-packet.c
index 122ef15e7..1cdf9616c 100644
--- a/g10/build-packet.c
+++ b/g10/build-packet.c
@@ -157,8 +157,8 @@ build_packet( IOBUF out, PACKET *pkt )
 /*
  * Write the mpi A to OUT.
  */
-static int
-mpi_write (iobuf_t out, gcry_mpi_t a)
+gpg_error_t
+gpg_mpi_write (iobuf_t out, gcry_mpi_t a)
 {
   int rc;
 
@@ -191,45 +191,6 @@ mpi_write (iobuf_t out, gcry_mpi_t a)
 }
 
 
-/*
- * Write a special size+body mpi A, to OUT.  The format of the content
- * of the MPI is one byte LEN, following by LEN bytes.
- */
-gpg_error_t
-write_size_body_mpi (iobuf_t out, gcry_mpi_t a)
-{
-  gpg_error_t err;
-  byte buffer[256]; /* Fixed buffer for a public parameter, max possible */
-  size_t nbytes = (mpi_get_nbits (a)+7)/8;
-
-  if (nbytes > sizeof(buffer))
-    {
-      log_error("mpi with size+body is too large (%u bytes)\n", nbytes);
-      return gpg_error (GPG_ERR_TOO_LARGE);
-    }
-
-  err = gcry_mpi_print (GCRYMPI_FMT_USG, buffer, sizeof(buffer), &nbytes, a);
-  if (err)
-    {
-      log_error ("failed to exported size+body mpi\n");
-      return err;
-    }
-  if (nbytes < 2 || buffer[0] != nbytes-1)
-    {
-      if (nbytes > 2)
-        log_error ("internal size mismatch in mpi size+body: "
-                   "%02x != %02x (other bytes: %02x %02x ... %02x %02x)\n",
-                   buffer[0], nbytes-1, buffer[1], buffer[2], buffer[nbytes-2],
-                   buffer[nbytes-1]);
-      else
-        log_error ("internal size mismatch in mpi size+body: "
-                   "only %d bytes\n", nbytes);
-      return gpg_error (GPG_ERR_INV_DATA);
-  }
-  return iobuf_write (out, buffer, nbytes);
-}
-
-
 /* Calculate the length of a packet described by PKT.  */
 u32
 calc_packet_length( PACKET *pkt )
@@ -341,7 +302,7 @@ do_key (iobuf_t out, int ctb, PKT_public_key *pk)
 
   for (i=0; i < npkey; i++ )
     {
-      err = mpi_write (a, pk->pkey[i]);
+      err = gpg_mpi_write (a, pk->pkey[i]);
       if (err)
         goto leave;
     }
@@ -436,7 +397,7 @@ do_key (iobuf_t out, int ctb, PKT_public_key *pk)
         {
           /* Non-protected key. */
           for ( ; i < nskey; i++ )
-            if ( (err = mpi_write (a, pk->pkey[i])))
+            if ( (err = gpg_mpi_write (a, pk->pkey[i])))
               goto leave;
           write_16 (a, ski->csum );
         }
@@ -512,7 +473,7 @@ do_pubkey_enc( IOBUF out, int ctb, PKT_pubkey_enc *enc )
     write_fake_data( a, enc->data[0] );
 
   for (i=0; i < n && !rc ; i++ )
-    rc = mpi_write (a, enc->data[i]);
+    rc = gpg_mpi_write (a, enc->data[i]);
 
   if (!rc)
     {
@@ -1170,7 +1131,7 @@ do_signature( IOBUF out, int ctb, PKT_signature *sig )
   if ( !n )
     write_fake_data( a, sig->data[0] );
   for (i=0; i < n && !rc ; i++ )
-    rc = mpi_write(a, sig->data[i] );
+    rc = gpg_mpi_write (a, sig->data[i] );
 
   if (!rc)
     {