[PATCH 4/8] g10: add new cleartext_secret_key_to_openpgp() function

[Daniel Kahn Gillmor]

* g10/export.c (cleartext_secret_key_to_openpgp): new function,
  filling in the secret key parameters of a PKT_public_key object from
  a corresponding cleartext S-expression.
---
 g10/export.c | 144 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 144 insertions(+)

diff --git a/g10/export.c b/g10/export.c
index d931507..ffa7240 100644
--- a/g10/export.c
+++ b/g10/export.c
@@ -476,6 +476,150 @@ canon_pk_algo (enum gcry_pk_algos algo)
     }
 }
 
+/* take a cleartext dump of a secret key in PK and change the
+   parameter array in PK to include the secret parameters.  */
+static gpg_error_t
+cleartext_secret_key_to_openpgp (gcry_sexp_t s_key, PKT_public_key *pk)
+{
+  gpg_error_t err = gpg_error (GPG_ERR_NOT_IMPLEMENTED);
+  gcry_sexp_t top_list;
+  gcry_sexp_t key = NULL;
+  char *key_type = NULL;
+  enum gcry_pk_algos pk_algo;
+  struct seckey_info *ski;
+  int idx, sec_start;
+  gcry_mpi_t pub_params[10] = { NULL };
+
+  /* we look for a private-key, then the first element in it tells us
+     the type */
+  top_list = gcry_sexp_find_token (s_key, "private-key", 0);
+  if (!top_list)
+    goto bad_seckey;
+  if (gcry_sexp_length(top_list) != 2)
+    goto bad_seckey;
+  key = gcry_sexp_nth (top_list, 1);
+  if (!key)
+    goto bad_seckey;
+  key_type = gcry_sexp_nth_string(key, 0);
+  pk_algo = gcry_pk_map_name (key_type);
+
+  log_assert(pk->seckey_info == NULL);
+
+  pk->seckey_info = ski = xtrycalloc (1, sizeof *ski);
+  if (!ski)
+    {
+      err = gpg_error_from_syserror ();
+      goto leave;
+    }
+
+  switch (canon_pk_algo (pk_algo))
+    {
+    case GCRY_PK_RSA:
+      if (!is_RSA (pk->pubkey_algo))
+        goto bad_pubkey_algo;
+      err = gcry_sexp_extract_param (key, NULL, "ne",
+                                     &pub_params[0],
+                                     &pub_params[1],
+                                     NULL);
+      for (idx=0; idx < 2 && !err; idx++)
+        if (gcry_mpi_cmp(pk->pkey[idx], pub_params[idx]))
+          err = gpg_error (GPG_ERR_BAD_PUBKEY);
+      if (!err)
+        err = gcry_sexp_extract_param (key, NULL, "dpqu",
+                                       &pk->pkey[2],
+                                       &pk->pkey[3],
+                                       &pk->pkey[4],
+                                       &pk->pkey[5],
+                                       NULL);
+      if (!err)
+        for (idx = 2; idx < 6; idx++)
+          ski->csum += checksum_mpi (pk->pkey[idx]);
+      break;
+
+    case GCRY_PK_DSA:
+      if (!is_DSA (pk->pubkey_algo))
+        goto bad_pubkey_algo;
+      err = gcry_sexp_extract_param (key, NULL, "pqgy",
+                                     &pub_params[0],
+                                     &pub_params[1],
+                                     &pub_params[2],
+                                     &pub_params[3],
+                                     NULL);
+      for (idx=0; idx < 4 && !err; idx++)
+        if (gcry_mpi_cmp(pk->pkey[idx], pub_params[idx]))
+          err = gpg_error (GPG_ERR_BAD_PUBKEY);
+      if (!err)
+        err = gcry_sexp_extract_param (key, NULL, "x",
+                                       &pk->pkey[4],
+                                       NULL);
+      if (!err)
+        ski->csum += checksum_mpi (pk->pkey[4]);
+      break;
+
+    case GCRY_PK_ELG:
+      if (!is_ELGAMAL (pk->pubkey_algo))
+        goto bad_pubkey_algo;
+      err = gcry_sexp_extract_param (key, NULL, "pgy",
+                                     &pub_params[0],
+                                     &pub_params[1],
+                                     &pub_params[2],
+                                     NULL);
+      for (idx=0; idx < 3 && !err; idx++)
+        if (gcry_mpi_cmp(pk->pkey[idx], pub_params[idx]))
+          err = gpg_error (GPG_ERR_BAD_PUBKEY);
+      if (!err)
+        err = gcry_sexp_extract_param (key, NULL, "x",
+                                       &pk->pkey[3],
+                                       NULL);
+      if (!err)
+        ski->csum += checksum_mpi (pk->pkey[3]);
+      break;
+
+    case GCRY_PK_ECC:
+      err = match_curve_skey_pk (key, pk);
+      if (err)
+        goto leave;
+      if (!err)
+        err = gcry_sexp_extract_param (key, NULL, "q",
+                                       &pub_params[0],
+                                       NULL);
+      if (!err && (gcry_mpi_cmp(pk->pkey[1], pub_params[0])))
+        err = gpg_error (GPG_ERR_BAD_PUBKEY);
+
+      sec_start = 2;
+      if (pk->pubkey_algo == PUBKEY_ALGO_ECDH)
+        sec_start += 1;
+      if (!err)
+        err = gcry_sexp_extract_param (key, NULL, "d",
+                                       &pk->pkey[sec_start],
+                                       NULL);
+
+      if (!err)
+        ski->csum += checksum_mpi (pk->pkey[sec_start]);
+      break;
+
+    default:
+      pk->seckey_info = NULL;
+      free (ski);
+      err = gpg_error (GPG_ERR_NOT_IMPLEMENTED);
+    }
+ leave:
+  gcry_sexp_release (top_list);
+  gcry_sexp_release (key);
+  gcry_free (key_type);
+
+  for (idx=0; idx < DIM(pub_params); idx++)
+    gcry_mpi_release (pub_params[idx]);
+  return err;
+
+ bad_pubkey_algo:
+  err = gpg_error (GPG_ERR_PUBKEY_ALGO);
+  goto leave;
+
+ bad_seckey:
+  err = gpg_error (GPG_ERR_BAD_SECKEY);
+  goto leave;
+}
 
 /* Use the key transfer format given in S_PGP to create the secinfo
    structure in PK and change the parameter array in PK to include the
-- 
2.8.1