Editorial changes and allow building with old libgcrypts.

Changed order of some conditional to make to put the special case into
the true branch.  Indentation changes.  Minor other changes to make the
ECC code more similar to the rest of our code.

It builds but many sefltests still fail.  Need to fix that before
using it with an ECDH enabled libgcrypt.

[/]
2011-01-21  Werner Koch  <[email protected]>

	* configure.ac: Need Libgcrypt 1.4.6 due to AESWRAP.
	(HAVE_GCRY_PK_ECDH): Add new test.

[agent/]
2011-01-21  Werner Koch  <[email protected]>

	* cvt-openpgp.c (GCRY_PK_ECDH) [!HAVE_GCRY_PK_ECDH]: New.

[include/]
2011-01-21  Werner Koch  <[email protected]>

	* cipher.h (GCRY_PK_USAGE_CERT): Remove compatibility macros
	because we now require libgcrypt 1.4.6.
	(GCRY_PK_ECDH): Add replacement.

1 files changed, 58 insertions, 54 deletions

diff --git a/g10/pubkey-enc.c b/g10/pubkey-enc.c
index 24411e8a1..ddca41ec4 100644
--- a/g10/pubkey-enc.c
+++ b/g10/pubkey-enc.c
@@ -218,68 +218,72 @@ get_it (PKT_pubkey_enc *enc, DEK *dek, PKT_public_key *sk, u32 *keyid)
     log_printhex ("DEK frame:", frame, nframe);
   n = 0;
 
-  if( sk->pubkey_algo != PUBKEY_ALGO_ECDH )  {
-    if (!card)
-      {
-        if (n + 7 > nframe)
-          {
-            err = gpg_error (G10ERR_WRONG_SECKEY);
-            goto leave;
-          }
-        if (frame[n] == 1 && frame[nframe - 1] == 2)
-          {
-            log_info (_("old encoding of the DEK is not supported\n"));
-            err = gpg_error (G10ERR_CIPHER_ALGO);
-            goto leave;
-          }
-        if (frame[n] != 2) /* Something went wrong.  */
-          {
-            err = gpg_error (G10ERR_WRONG_SECKEY);
-            goto leave;
-          }
-        for (n++; n < nframe && frame[n]; n++) /* Skip the random bytes.  */
-          ;
-        n++; /* Skip the zero byte.  */
-      }
-  }
-  else  {
-    gcry_mpi_t shared_mpi;
-    gcry_mpi_t decoded;
-
-    /* at the beginning the frame is the bytes of shared point MPI */
-     
-    err = gcry_mpi_scan (&shared_mpi, GCRYMPI_FMT_USG, frame, nframe, NULL);
-    if (err)  {
-      log_fatal ("mpi_scan failed: %s\n", gpg_strerror (err));
-      goto leave;
-    }
+  if (sk->pubkey_algo == PUBKEY_ALGO_ECDH)
+    {
+      gcry_mpi_t shared_mpi;
+      gcry_mpi_t decoded;
+      
+      /* At the beginning the frame are the bytes of shared point MPI.  */
+      err = gcry_mpi_scan (&shared_mpi, GCRYMPI_FMT_USG, frame, nframe, NULL);
+      if (err)
+        {
+          log_fatal ("mpi_scan failed: %s\n", gpg_strerror (err));
+          goto leave;
+        }
 
-    err = pk_ecdh_decrypt (&decoded, fp, enc->data[1]/*encr data as an MPI*/, shared_mpi, sk->pkey);
-    mpi_release( shared_mpi );
-    if( err )
-      goto leave;
+      err = pk_ecdh_decrypt (&decoded, fp, enc->data[1]/*encr data as an MPI*/,
+                             shared_mpi, sk->pkey);
+      mpi_release (shared_mpi);
+      if(err)
+        goto leave;
 
-    /* reuse nframe, which size is sufficient to include the session key */
-    err = gcry_mpi_print (GCRYMPI_FMT_USG, frame, nframe, &nframe, decoded);
-    mpi_release( decoded );
-    if( err )
-      goto leave;
+      /* Reuse NFRAME, which size is sufficient to include the session key.  */
+      err = gcry_mpi_print (GCRYMPI_FMT_USG, frame, nframe, &nframe, decoded);
+      mpi_release (decoded);
+      if (err)
+        goto leave;
 
-    /* Now the frame is the bytes decrypted but padded session key  */
+      /* Now the frame are the bytes decrypted but padded session key.  */
 
-    /* Allow double padding for the benefit of DEK size concealment.
-     * Higher than this is wasteful.  
-     */
-    if( frame[nframe-1] > 8*2 || nframe <= 8 )  {
-      err = G10ERR_WRONG_SECKEY; goto leave; 
+      /* Allow double padding for the benefit of DEK size concealment.
+         Higher than this is wasteful. */
+      if (frame[nframe-1] > 8*2 || nframe <= 8)
+        {
+          err = gpg_error (GPG_ERR_WRONG_SECKEY);
+          goto leave; 
+        }
+      nframe -= frame[nframe-1]; /* Remove padding.  */
+      assert (n); /* (used just below) */
+    }
+  else
+    {
+      if (!card)
+        {
+          if (n + 7 > nframe)
+            {
+              err = gpg_error (GPG_ERR_WRONG_SECKEY);
+              goto leave;
+            }
+          if (frame[n] == 1 && frame[nframe - 1] == 2)
+            {
+              log_info (_("old encoding of the DEK is not supported\n"));
+              err = gpg_error (GPG_ERR_CIPHER_ALGO);
+              goto leave;
+            }
+          if (frame[n] != 2) /* Something went wrong.  */
+            {
+              err = gpg_error (GPG_ERR_WRONG_SECKEY);
+              goto leave;
+            }
+          for (n++; n < nframe && frame[n]; n++) /* Skip the random bytes.  */
+            ;
+          n++; /* Skip the zero byte.  */
+        }
     }
-    nframe -= frame[nframe-1];	/* remove padding */
-    assert( n==0 );	/* used just bellow */
-  }
 
   if (n + 4 > nframe)
     {
-      err = gpg_error (G10ERR_WRONG_SECKEY);
+      err = gpg_error (GPG_ERR_WRONG_SECKEY);
       goto leave;
     }