some cleanups in Diffie Hellman key exchange

1 files changed, 97 insertions, 8 deletions

diff --git a/lib/gnutls_dh.c b/lib/gnutls_dh.c
index 3a821c1ef8..3137de71c3 100644
--- a/lib/gnutls_dh.c
+++ b/lib/gnutls_dh.c
@@ -28,6 +28,7 @@
 #define DH_G_1024 2
 #define DH_G_4096 5
 #define DH_G_2048 5
+#define DH_G_3072 13
 
 static const uint8 diffie_hellman_group1_prime[130] = { 0x04, 0x00,
 	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC9, 0x0F, 0xDA, 0xA2,
@@ -121,6 +122,64 @@ const uint8 diffie_hellman_prime_4096[512] = {
 	0x7f
 };
 
+/* prime - 3072 bits */
+const uint8 diffie_hellman_prime_3072[384] = { 
+	0xd5, 0x6e, 0xc8, 0x1f, 0xe9, 0x80, 0x9e, 
+	0x56, 0x35, 0x6d, 0x6d, 0xdb, 0xfa, 0x47, 
+	0x75, 0xcd, 0xfa, 0x32, 0x52, 0x1a, 0xc8, 
+	0xad, 0xee, 0xb0, 0xdb, 0xb7, 0x07, 0x58, 
+	0xa6, 0x42, 0xfe, 0x59, 0xfb, 0xce, 0xe8, 
+	0x12, 0x63, 0x09, 0x9f, 0x5d, 0x15, 0x25, 
+	0x49, 0xf2, 0x61, 0x83, 0xd8, 0x5c, 0x81, 
+	0xdd, 0x4c, 0x26, 0xe6, 0x24, 0xce, 0x6a, 
+	0xa5, 0x07, 0x80, 0x1c, 0x3d, 0x94, 0xd1, 
+	0x5d, 0x73, 0xbd, 0x26, 0x48, 0x22, 0x25, 
+	0xdd, 0x2f, 0x64, 0xe5, 0xed, 0xb3, 0xa9, 
+	0x94, 0xb3, 0x96, 0x88, 0x5d, 0x06, 0x41, 
+	0x80, 0xf8, 0xe1, 0x3c, 0x8f, 0xa9, 0x5b, 
+	0x44, 0x7e, 0x32, 0xbd, 0x62, 0x37, 0xe1, 
+	0xde, 0x18, 0xe8, 0x12, 0x7d, 0x28, 0x7d, 
+	0x5c, 0xcf, 0xa9, 0x16, 0x0f, 0xdc, 0xc1, 
+	0x92, 0xe0, 0x43, 0xac, 0xd0, 0x25, 0x37, 
+	0x8e, 0x5d, 0x4d, 0x26, 0x46, 0xbc, 0xc5, 
+	0x22, 0x05, 0x29, 0x41, 0x53, 0x2f, 0x7a, 
+	0x95, 0xa8, 0x36, 0xed, 0x85, 0xac, 0xf3, 
+	0xde, 0x0c, 0xbe, 0xa9, 0xfa, 0xc4, 0xa6, 
+	0x0b, 0x23, 0xfc, 0x7c, 0x77, 0xdc, 0x7c, 
+	0x94, 0x9b, 0x7c, 0xe0, 0x3b, 0xa1, 0x66, 
+	0x78, 0x85, 0x99, 0x5a, 0xba, 0x26, 0xa3, 
+	0xac, 0x97, 0xd4, 0x3a, 0x33, 0xee, 0xa3, 
+	0x96, 0xe0, 0x16, 0xdf, 0x61, 0xe7, 0x1f, 
+	0x35, 0xa5, 0x47, 0x54, 0x51, 0xce, 0x93, 
+	0x40, 0x6f, 0x40, 0x86, 0x3b, 0x17, 0x12, 
+	0xd3, 0x4d, 0x2e, 0xb3, 0x04, 0xf8, 0x8b, 
+	0x30, 0xb1, 0x27, 0xd7, 0xeb, 0xde, 0xd7, 
+	0xa9, 0x06, 0xfe, 0x6b, 0x59, 0x8c, 0x5d, 
+	0x9f, 0x93, 0x1f, 0x12, 0x65, 0xe6, 0xa6, 
+	0xeb, 0x5d, 0x4b, 0x9a, 0x16, 0x85, 0xce, 
+	0x18, 0x16, 0x5a, 0x5c, 0x3c, 0xeb, 0xc0, 
+	0xe1, 0x58, 0x64, 0x06, 0x38, 0x1c, 0x66, 
+	0x90, 0x4a, 0x30, 0xbe, 0x82, 0xe9, 0x9b, 
+	0x40, 0x2e, 0x6a, 0x91, 0x4f, 0x48, 0xc2, 
+	0x82, 0x40, 0xe9, 0xcd, 0x87, 0x77, 0x24, 
+	0xa7, 0xdc, 0x26, 0x05, 0x18, 0x9c, 0x8b, 
+	0x0e, 0x84, 0x29, 0x57, 0x76, 0x66, 0x7d, 
+	0x1e, 0x39, 0xc2, 0xf6, 0x2f, 0xbb, 0xeb, 
+	0x6e, 0x58, 0x3b, 0x11, 0x70, 0x75, 0xdb, 
+	0xe9, 0xf8, 0xcb, 0xd4, 0x4c, 0x84, 0xb3, 
+	0xcb, 0x66, 0x81, 0x4e, 0x93, 0xd9, 0x2f, 
+	0xc5, 0x60, 0x53, 0x69, 0x6e, 0xf3, 0x8e, 
+	0xa5, 0x6a, 0xa0, 0x96, 0xae, 0x31, 0xb6, 
+	0x12, 0x91, 0x0e, 0xc4, 0xc9, 0xd0, 0x50, 
+	0xf7, 0xbc, 0xe7, 0x78, 0xc9, 0x97, 0x02, 
+	0x26, 0x6a, 0xe3, 0x9a, 0x16, 0x63, 0xa2, 
+	0x5e, 0x1d, 0x4e, 0x71, 0x52, 0xb4, 0x73, 
+	0x31, 0x27, 0x6c, 0x46, 0xe4, 0x67, 0x02, 
+	0xde, 0x34, 0x7e, 0x24, 0x3b, 0xb9, 0xfe, 
+	0x08, 0x7e, 0xe9, 0x0a, 0xdc, 0xe7, 0xc2, 
+	0xa6, 0xa6, 0xb3, 0x7d, 0xe0, 0xa2, 0xe7, 
+	0x6d, 0x2e, 0x33, 0xed, 0x47, 0xf7
+};
 
 /* prime - 2048 bits */
 const uint8 diffie_hellman_prime_2048[256] = { 
@@ -180,14 +239,25 @@ const uint8 diffie_hellman_prime_2048[256] = {
 	gnutls_mpi_release(g);
 */
 
-#define X_SIZE 512
+
+/* This function should return a resonable size for X
+ * (DH secret key). The input is the number of bits of 
+ * the modulus.
+ * FIXME: This function is not correct
+ */
+static int get_x_size( int bits) {
+	if (bits <= 2048) return 512;
+	if (bits <= 4096) return 768;
+	return 1024;
+}
 
 MPI gnutls_calc_dh_secret(MPI * ret_x, MPI g, MPI prime)
 {
 	MPI e, x;
-
-	x = gcry_mpi_new(X_SIZE);	/* FIXME: allocate in secure memory */
-	gcry_mpi_randomize(x, X_SIZE, GCRY_STRONG_RANDOM);
+	int x_size = get_x_size( gcry_mpi_get_nbits(prime));
+	
+	x = gcry_mpi_new(x_size);	/* FIXME: allocate in secure memory */
+	gcry_mpi_randomize(x, x_size, GCRY_STRONG_RANDOM);
 	/* fixme: set high bit of x and select a larger one */
 
 	e = gcry_mpi_alloc_like(prime);
@@ -200,16 +270,19 @@ MPI gnutls_calc_dh_secret(MPI * ret_x, MPI g, MPI prime)
 	return e;
 }
 
-/* returns g and p */
+/* returns g and p, depends on the requested bits.
+ * We only support limited key sizes.
+ */
 MPI gnutls_get_dh_params(MPI * ret_p, int bits)
 {
 	MPI g, prime;
 	size_t n;
 	
 	if (bits >= 4096) bits = 4096;
-	else if (bits>=2048) bits=2048;
-	else if (bits>=1024) bits=1024;
-	else bits=1024;
+	else if (bits<=1024) bits=1024;
+	else if (bits<=2048) bits=2048;
+	else if (bits<=3072) bits=3072;
+	else if (bits<=4096) bits=4096;
 	
 	switch (bits) {
 	case 1024:
@@ -244,6 +317,22 @@ MPI gnutls_get_dh_params(MPI * ret_p, int bits)
 		else
 			gcry_mpi_release(prime);
 		return g;
+	case 3072:
+		n = sizeof diffie_hellman_prime_3072;
+
+		if (gcry_mpi_scan(&prime, GCRYMPI_FMT_USG,
+			  diffie_hellman_prime_3072, &n)) {
+			gnutls_assert();
+			abort();
+		}
+
+		g = gcry_mpi_set_ui(NULL, DH_G_3072);
+
+		if (ret_p)
+			*ret_p = prime;
+		else
+			gcry_mpi_release(prime);
+		return g;
 	case 4096:
 		n = sizeof diffie_hellman_prime_4096;