pubkey: Move sexp parsing for gcry_pk_getkey to the modules.

* cipher/pubkey-util.c: New.
(_gcry_pk_util_get_nbits): New.  Based on code from gcry_pk_genkey.
(_gcry_pk_util_get_rsa_use_e): Ditto.
* cipher/pubkey.c (gcry_pk_genkey): Strip most code and pass.
* cipher/rsa.c (rsa_generate): Remove args ALGO, NBITS and EVALUE.
Call new fucntions to get these values.
* cipher/dsa.c (dsa_generate): Remove args ALGO, NBITS and EVALUE.
Call _gcry_pk_util_get_nbits to get nbits.  Always parse genparms.
* cipher/elgamal.c (elg_generate): Ditto.
* cipher/ecc.c (ecc_generate): Ditto.

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

1 files changed, 127 insertions, 0 deletions

diff --git a/cipher/pubkey-util.c b/cipher/pubkey-util.c
new file mode 100644
index 00000000..ef0ef441
--- /dev/null
+++ b/cipher/pubkey-util.c
@@ -0,0 +1,127 @@
+/* pubkey-util.c - Supporting functions for all pubkey modules.
+ * Copyright (C) 1998, 1999, 2000, 2002, 2003, 2005,
+ *               2007, 2008, 2011 Free Software Foundation, Inc.
+ * Copyright (C) 2013  g10 Code GmbH
+ *
+ * This file is part of Libgcrypt.
+ *
+ * Libgcrypt is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * Libgcrypt is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "g10lib.h"
+#include "mpi.h"
+#include "cipher.h"
+#include "pubkey-internal.h"
+
+
+
+
+/* Get the "nbits" parameter from an s-expression of the format:
+ *
+ *   (algo
+ *     (parameter_name_1 ....)
+ *      ....
+ *     (parameter_name_n ....))
+ *
+ * Example:
+ *
+ *   (rsa
+ *     (nbits 4:2048))
+ *
+ * On success the value for nbits is stored at R_NBITS.  If no nbits
+ * parameter is found, the function returns success and stores 0 at
+ * R_NBITS.  For parsing errors the function returns an error code and
+ * stores 0 at R_NBITS.
+ */
+gpg_err_code_t
+_gcry_pk_util_get_nbits (gcry_sexp_t list, unsigned int *r_nbits)
+{
+  char buf[50];
+  const char *s;
+  size_t n;
+
+  *r_nbits = 0;
+
+  list = gcry_sexp_find_token (list, "nbits", 0);
+  if (!list)
+    return 0; /* No NBITS found.  */
+
+  s = gcry_sexp_nth_data (list, 1, &n);
+  if (!s || n >= DIM (buf) - 1 )
+    {
+      /* NBITS given without a cdr.  */
+      gcry_sexp_release (list);
+      return GPG_ERR_INV_OBJ;
+    }
+  memcpy (buf, s, n);
+  buf[n] = 0;
+  *r_nbits = (unsigned int)strtoul (buf, NULL, 0);
+  gcry_sexp_release (list);
+  return 0;
+}
+
+
+/* Get the optional "rsa-use-e" parameter from an s-expression of the
+ * format:
+ *
+ *   (algo
+ *     (parameter_name_1 ....)
+ *      ....
+ *     (parameter_name_n ....))
+ *
+ * Example:
+ *
+ *   (rsa
+ *     (nbits 4:2048)
+ *     (rsa-use-e 2:41))
+ *
+ * On success the value for nbits is stored at R_E.  If no rsa-use-e
+ * parameter is found, the function returns success and stores 65537 at
+ * R_E.  For parsing errors the function returns an error code and
+ * stores 0 at R_E.
+ */
+gpg_err_code_t
+_gcry_pk_util_get_rsa_use_e (gcry_sexp_t list, unsigned long *r_e)
+{
+  char buf[50];
+  const char *s;
+  size_t n;
+
+  *r_e = 0;
+
+  list = gcry_sexp_find_token (list, "rsa-use-e", 0);
+  if (!list)
+    {
+      *r_e = 65537; /* Not given, use the value generated by old versions. */
+      return 0;
+    }
+
+  s = gcry_sexp_nth_data (list, 1, &n);
+  if (!s || n >= DIM (buf) - 1 )
+    {
+      /* No value or value too large.  */
+      gcry_sexp_release (list);
+      return GPG_ERR_INV_OBJ;
+    }
+  memcpy (buf, s, n);
+  buf[n] = 0;
+  *r_e = strtoul (buf, NULL, 0);
+  gcry_sexp_release (list);
+  return 0;
+}