Added anonymous diffie-hellman key exchange. It does not work yet, and

the whole code is mess.

1 files changed, 66 insertions, 12 deletions

diff --git a/lib/gnutls_dh.c b/lib/gnutls_dh.c
index a593b1a669..f7718dff40 100644
--- a/lib/gnutls_dh.c
+++ b/lib/gnutls_dh.c
@@ -1,5 +1,7 @@
 #include <defines.h>
-#include <gcrypt.h>
+#include <gnutls_int.h>
+
+/* Taken from gsti */
 
 static const uint8 diffie_hellman_group1_prime[130] = { 0x04, 0x00,
     0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC9, 0x0F, 0xDA, 0xA2,
@@ -15,23 +17,27 @@ static const uint8 diffie_hellman_group1_prime[130] = { 0x04, 0x00,
     0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF  };
 
 #if 0 
-     --Example--
-     you: X = g^x mod p;
+        --Example--
+     you:  X = g^x mod p;
      peer: Y = g^y mod p;
      
-       g = mpi_set_ui( NULL, 2 );
+     your_key = Y^x mod p;
+     his_key  = X^y mod p;
+     
      /* generate our secret and the public value for it */
-       X = calc_dh_secret( &x );
+       X = _gnutls_calc_dh_secret( &x );
      /* now we can calculate the shared secret */
-       key = calc_dh_key( Y, x );
+       key = _gnutls_calc_dh_key( Y, x);
        mpi_release( x );
+       mpi_release( g );
 #endif
 
 /****************
  * Choose a random value x and calculate e = g^x mod p.
  * Return: e and if ret_x is not NULL x.
+ * It also returns g and p.
  */
-MPI calc_dh_secret( MPI *ret_x )
+MPI _gnutls_calc_dh_secret( MPI *ret_x )
 {
     MPI e, g, x, prime;
     size_t n = sizeof diffie_hellman_group1_prime;
@@ -53,24 +59,72 @@ MPI calc_dh_secret( MPI *ret_x )
 	*ret_x = x;
     else
 	mpi_release(x);
-    mpi_release(g);
-    mpi_release(prime);
+	mpi_release(g);
+	mpi_release(prime);
     return e;
 }
 
+MPI __gnutls_calc_dh_secret( MPI *ret_x, MPI g, MPI prime )
+{
+    MPI e, x;
+
+    x = mpi_new( 200 );  /* FIXME: allocate in secure memory */
+    gcry_mpi_randomize( x, 200, GCRY_STRONG_RANDOM );
+    /* fixme: set high bit of x and select a larger one */
+
+    e = mpi_new(1024);
+    mpi_powm( e, g, x, prime );
+
+    if( ret_x )
+	*ret_x = x;
+    else
+	mpi_release(x);
+    return e;
+}
 
-MPI calc_dh_key( MPI f, MPI x )
+/* returns g and p */
+MPI _gnutls_get_dh_params( MPI *ret_p )
 {
-    MPI k, prime;
+    MPI g, prime;
     size_t n = sizeof diffie_hellman_group1_prime;
 
-    if( gcry_mpi_scan( &prime, GCRYMPI_FMT_STD,
+     if( gcry_mpi_scan( &prime, GCRYMPI_FMT_STD,
 		       diffie_hellman_group1_prime, &n ) )
 	abort();
 
+    g = mpi_set_ui( NULL, 2 );
+
+    if( ret_p )
+	*ret_p = prime;
+    else
+	mpi_release(prime);
+    return g;
+}
+
+
+MPI _gnutls_calc_dh_key( MPI f, MPI x )
+{
+    MPI k, prime;
+    size_t n = sizeof diffie_hellman_group1_prime;
+
     k = mpi_new( 1024 );  /* FIXME: allocate in secure memory */
+     if( gcry_mpi_scan( &prime, GCRYMPI_FMT_STD,
+		       diffie_hellman_group1_prime, &n ) )
+	abort();
+    /*dump_mpi(stderr, "prime=", prime );*/
+
     mpi_powm( k, f, x, prime );
     mpi_release(prime);
     return k;
 }
 
+MPI __gnutls_calc_dh_key( MPI f, MPI x, MPI prime )
+{
+    MPI k;
+
+    k = mpi_new( 1024 );  /* FIXME: allocate in secure memory */
+
+    mpi_powm( k, f, x, prime );
+    return k;
+}
+