Rework curve25519 library for modular design.

4 files changed, 100 insertions, 5 deletions

diff --git a/src/libcryptobox/curve25519/curve25519-donna-c64.c b/src/libcryptobox/curve25519/curve25519-donna-c64.c
index e6a5045ad..d98c385c2 100644
--- a/src/libcryptobox/curve25519/curve25519-donna-c64.c
+++ b/src/libcryptobox/curve25519/curve25519-donna-c64.c
@@ -477,9 +477,7 @@ static void crecip (felem out, const felem z)
 	/* 2^255 - 21 */fmul (out, t0, a);
 }
 
-int curve25519 (u8 *, const u8 *, const u8 *);
-
-int curve25519 (u8 *mypublic, const u8 *secret, const u8 *basepoint)
+int scalarmult_donna64 (u8 *mypublic, const u8 *secret, const u8 *basepoint)
 {
 	limb bp[5], x[5], z[5], zmone[5];
 	int i;
diff --git a/src/libcryptobox/curve25519/curve25519-donna.c b/src/libcryptobox/curve25519/curve25519-donna.c
index e6a50b87f..b3b59d860 100644
--- a/src/libcryptobox/curve25519/curve25519-donna.c
+++ b/src/libcryptobox/curve25519/curve25519-donna.c
@@ -891,10 +891,9 @@ static void crecip (limb *out, const limb *z)
 	/* 2^255 - 21 */fmul (out, t1, z11);
 }
 
-int curve25519 (u8 *mypublic, const u8 *secret, const u8 *basepoint)
+int scalarmult_donna32 (u8 *mypublic, const u8 *secret, const u8 *basepoint)
 {
 	limb bp[10], x[10], z[11], zmone[10];
-	int i;
 
 	fexpand (bp, basepoint);
 	cmult (x, z, secret, bp);
diff --git a/src/libcryptobox/curve25519/curve25519.c b/src/libcryptobox/curve25519/curve25519.c
new file mode 100644
index 000000000..1870d4987
--- /dev/null
+++ b/src/libcryptobox/curve25519/curve25519.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2015, Vsevolod Stakhov
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *	 * Redistributions of source code must retain the above copyright
+ *	   notice, this list of conditions and the following disclaimer.
+ *	 * Redistributions in binary form must reproduce the above copyright
+ *	   notice, this list of conditions and the following disclaimer in the
+ *	   documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY AUTHOR ''AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "cryptobox.h"
+#include "curve25519.h"
+#include "platform_config.h"
+
+extern unsigned long cpu_config;
+
+typedef struct curve25519_impl_s {
+	unsigned long cpu_flags;
+	const char *desc;
+
+	void (*scalarmult) (guint8 *mypublic,
+			const guint8 *secret,
+			const guint8 *basepoint);
+} curve25519_impl_t;
+
+#define CURVE25519_DECLARE(ext) \
+    void scalarmult_##ext(guint8 *mypublic, const guint8 *secret, const guint8 *basepoint)
+
+#define CURVE25519_IMPL(cpuflags, desc, ext) \
+    {(cpuflags), desc, scalarmult_##ext}
+
+#if defined(__LP64__)
+
+#if defined(HAVE_AVX)
+CURVE25519_DECLARE(avx);
+#define CURVE25519_AVX CURVE25519_IMPL(CPUID_AVX, "avx", avx)
+#endif
+
+#endif
+
+#if !defined(__LP64__)
+CURVE25519_DECLARE(donna32);
+#define CURVE25519_GENERIC CURVE25519_IMPL(0, "donna32", donna32)
+#else
+CURVE25519_DECLARE(donna64);
+#define CURVE25519_GENERIC CURVE25519_IMPL(0, "donna64", donna64)
+#endif
+
+static const curve25519_impl_t curve25519_list[] = {
+		CURVE25519_GENERIC,
+#if defined(CURVE25519_AVX)
+		CURVE25519_AVX,
+#endif
+};
+
+static const curve25519_impl_t *curve25519_opt = &curve25519_list[0];
+
+void
+curve25519_load (void)
+{
+	guint i;
+
+	if (cpu_config != 0) {
+		for (i = 0; i < G_N_ELEMENTS(curve25519_list); i++) {
+			if (curve25519_list[i].cpu_flags & cpu_config) {
+				curve25519_opt = &curve25519_list[i];
+				break;
+			}
+		}
+	}
+}
+
+int
+curve25519 (guchar *mypublic,
+		const guchar *secret,
+		const guchar *basepoint)
+{
+	curve25519_opt->scalarmult (mypublic, secret, basepoint);
+
+	return 0;
+}
+
diff --git a/src/libcryptobox/curve25519/curve25519.h b/src/libcryptobox/curve25519/curve25519.h
index 2d87e34cb..17fed4e53 100644
--- a/src/libcryptobox/curve25519/curve25519.h
+++ b/src/libcryptobox/curve25519/curve25519.h
@@ -6,5 +6,6 @@
 static const guchar curve25519_basepoint[32] = {9};
 
 int curve25519 (guchar *mypublic, const guchar *secret, const guchar *basepoint);
+void curve25519_load (void);
 
 #endif