import clean BK tree at cset 1.3670

1 files changed, 158 insertions, 0 deletions

diff --git a/packages/teleport/files/crypt.c b/packages/teleport/files/crypt.c
index e69de29bb2..359c5ee99a 100644
--- a/packages/teleport/files/crypt.c
+++ b/packages/teleport/files/crypt.c
@@ -0,0 +1,158 @@
+/*
+ * Copyright (C) 2003 Philip Blundell <philb@gnu.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <glib.h>
+#include <assert.h>
+
+#include "libdisplaymigration/auth.h"
+#include "libdisplaymigration/crypt.h"
+
+static gcry_mpi_t
+mpi_from_sexp (gcry_sexp_t r, char *tag)
+{
+  gcry_sexp_t s = gcry_sexp_find_token (r, tag, 0);
+  return gcry_sexp_nth_mpi (s, 1, GCRYMPI_FMT_USG);
+}
+
+static char *
+hex_from_mpi (gcry_mpi_t m)
+{
+  char *buf;
+  gcry_mpi_aprint (GCRYMPI_FMT_HEX, (void *)&buf, NULL, m);
+  return buf;
+}
+
+void
+displaymigration_crypt_create_hash (char *display, char *challenge, size_t len, char *result)
+{
+  size_t dlen = strlen (display);
+  gchar *buf = g_malloc (dlen + 1 + len);
+  strcpy (buf, display);
+  memcpy (buf + dlen + 1, challenge, len);
+  gcry_md_hash_buffer (GCRY_MD_SHA1, result, buf, len + dlen + 1);
+  g_free (buf);
+}
+
+static int
+do_encode_md (const unsigned char *digest, size_t digestlen, int algo,
+              unsigned int nbits, gcry_mpi_t *r_val)
+{
+  int nframe = (nbits+7) / 8;
+  unsigned char *frame;
+  int i, n;
+  unsigned char asn[100];
+  size_t asnlen;
+
+  asnlen = sizeof(asn);
+  if (gcry_md_algo_info (algo, GCRYCTL_GET_ASNOID, asn, &asnlen))
+    return -1;
+
+  if (digestlen + asnlen + 4  > nframe )
+    return -1;
+  
+  /* We encode the MD in this way:
+   *
+   *	   0  1 PAD(n bytes)   0  ASN(asnlen bytes)  MD(len bytes)
+   *
+   * PAD consists of FF bytes.
+   */
+  frame = g_malloc (nframe);
+  n = 0;
+  frame[n++] = 0;
+  frame[n++] = 1; /* block type */
+  i = nframe - digestlen - asnlen -3 ;
+  assert ( i > 1 );
+  memset ( frame+n, 0xff, i ); n += i;
+  frame[n++] = 0;
+  memcpy ( frame+n, asn, asnlen ); n += asnlen;
+  memcpy ( frame+n, digest, digestlen ); n += digestlen;
+  assert ( n == nframe );
+      
+  gcry_mpi_scan (r_val, GCRYMPI_FMT_USG, frame, nframe, &nframe);
+  g_free (frame);
+  return 0;
+}
+
+gboolean
+displaymigration_crypt_sign_hash (struct rsa_key *k, char *hash, gchar **result)
+{
+  gcry_mpi_t mpi;
+  gcry_sexp_t data, sig, key;
+  int rc;
+  char *hex;
+
+  do_encode_md (hash, 20, GCRY_MD_SHA1, 1024, &mpi);
+
+  if (gcry_sexp_build (&data, NULL, "(data (value %m))", mpi))
+    return FALSE;
+ 
+  gcry_mpi_release (mpi);
+
+  if (gcry_sexp_build (&key, NULL, "(private-key (rsa (n %m) (e %m) (d %m) (p %m) (q %m) (u %m)))",
+		       k->n, k->e, k->d, k->p, k->q, k->u))
+    {
+      gcry_sexp_release (data);
+      return FALSE;
+    }
+  
+  rc = gcry_pk_sign (&sig, data, key);
+
+  gcry_sexp_release (data);
+  gcry_sexp_release (key);
+
+  if (rc)
+    return FALSE;
+
+  mpi = mpi_from_sexp (sig, "s");
+  hex = hex_from_mpi (mpi);
+  *result = g_strdup (hex);
+  gcry_free (hex);
+  gcry_mpi_release (mpi);
+  gcry_sexp_release (sig);
+
+  return TRUE;
+}
+
+gboolean
+displaymigration_crypt_check_signature (struct rsa_key *k, char *hash, char *sigbuf)
+{
+  gcry_mpi_t mpi, mpi2;
+  gcry_sexp_t data, sig, key;
+  int rc;
+
+  do_encode_md (hash, 20, GCRY_MD_SHA1, 1024, &mpi);
+
+  gcry_sexp_build (&data, NULL, "(data (value %m))", mpi);
+  
+  gcry_mpi_release (mpi);
+
+  gcry_sexp_build (&key, NULL, "(public-key (rsa (n %m) (e %m)))", k->n, k->e);
+
+  if (gcry_mpi_scan (&mpi2, GCRYMPI_FMT_HEX, sigbuf, 0, NULL))
+    {
+      gcry_sexp_release (data);
+      return FALSE;
+    }
+
+  gcry_sexp_build (&sig, NULL, "(sig-val (rsa (s %m)))", mpi2);
+
+  rc = gcry_pk_verify (sig, data, key);
+
+  gcry_sexp_release (data);
+  gcry_sexp_release (key);
+  gcry_sexp_release (sig);
+  gcry_mpi_release (mpi2);
+
+  if (rc)
+    return FALSE;
+
+  return TRUE;
+}