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authorJeroen Leenarts <jeroen.leenarts@gmail.com>2018-08-22 08:47:20 +0200
committerRoopesh Chander <roop@roopc.net>2018-10-27 15:13:01 +0530
commit834c9ae7ce795fe731db4e894f04c121b50ab00f (patch)
tree81c09a362ff6c4c97f1f621b2013bf6b476cca1a /WireGuard/WireGuard/Crypto
parentTunnel creation: Hide 'Exclude private IPs' switch till the feature is ready (diff)
downloadwireguard-apple-834c9ae7ce795fe731db4e894f04c121b50ab00f.tar.xz
wireguard-apple-834c9ae7ce795fe731db4e894f04c121b50ab00f.zip
Crypto: Add key generation functions
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'WireGuard/WireGuard/Crypto')
-rw-r--r--WireGuard/WireGuard/Crypto/x25519.c177
-rw-r--r--WireGuard/WireGuard/Crypto/x25519.h7
2 files changed, 184 insertions, 0 deletions
diff --git a/WireGuard/WireGuard/Crypto/x25519.c b/WireGuard/WireGuard/Crypto/x25519.c
new file mode 100644
index 00000000..b198ae04
--- /dev/null
+++ b/WireGuard/WireGuard/Crypto/x25519.c
@@ -0,0 +1,177 @@
+/* SPDX-License-Identifier: GPL-2.0+
+ *
+ * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * Curve25519 ECDH functions, based on TweetNaCl but cleaned up.
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include <CommonCrypto/CommonRandom.h>
+
+#include "x25519.h"
+
+typedef int64_t fe[16];
+
+static inline void carry(fe o)
+{
+ int i;
+
+ for (i = 0; i < 16; ++i) {
+ o[(i + 1) % 16] += (i == 15 ? 38 : 1) * (o[i] >> 16);
+ o[i] &= 0xffff;
+ }
+}
+
+static inline void cswap(fe p, fe q, int b)
+{
+ int i;
+ int64_t t, c = ~(b - 1);
+
+ for (i = 0; i < 16; ++i) {
+ t = c & (p[i] ^ q[i]);
+ p[i] ^= t;
+ q[i] ^= t;
+ }
+}
+
+static inline void pack(uint8_t *o, const fe n)
+{
+ int i, j, b;
+ fe m, t;
+
+ memcpy(t, n, sizeof(t));
+ carry(t);
+ carry(t);
+ carry(t);
+ for (j = 0; j < 2; ++j) {
+ m[0] = t[0] - 0xffed;
+ for (i = 1; i < 15; ++i) {
+ m[i] = t[i] - 0xffff - ((m[i - 1] >> 16) & 1);
+ m[i - 1] &= 0xffff;
+ }
+ m[15] = t[15] - 0x7fff - ((m[14] >> 16) & 1);
+ b = (m[15] >> 16) & 1;
+ m[14] &= 0xffff;
+ cswap(t, m, 1 - b);
+ }
+ for (i = 0; i < 16; ++i) {
+ o[2 * i] = t[i] & 0xff;
+ o[2 * i + 1] = t[i] >> 8;
+ }
+}
+
+static inline void unpack(fe o, const uint8_t *n)
+{
+ int i;
+
+ for (i = 0; i < 16; ++i)
+ o[i] = n[2 * i] + ((int64_t)n[2 * i + 1] << 8);
+ o[15] &= 0x7fff;
+}
+
+static inline void add(fe o, const fe a, const fe b)
+{
+ int i;
+
+ for (i = 0; i < 16; ++i)
+ o[i] = a[i] + b[i];
+}
+
+static inline void subtract(fe o, const fe a, const fe b)
+{
+ int i;
+
+ for (i = 0; i < 16; ++i)
+ o[i] = a[i] - b[i];
+}
+
+static inline void multmod(fe o, const fe a, const fe b)
+{
+ int i, j;
+ int64_t t[31] = { 0 };
+
+ for (i = 0; i < 16; ++i) {
+ for (j = 0; j < 16; ++j)
+ t[i + j] += a[i] * b[j];
+ }
+ for (i = 0; i < 15; ++i)
+ t[i] += 38 * t[i + 16];
+ memcpy(o, t, sizeof(fe));
+ carry(o);
+ carry(o);
+}
+
+static inline void invert(fe o, const fe i)
+{
+ fe c;
+ int a;
+
+ memcpy(c, i, sizeof(c));
+ for (a = 253; a >= 0; --a) {
+ multmod(c, c, c);
+ if (a != 2 && a != 4)
+ multmod(c, c, i);
+ }
+ memcpy(o, c, sizeof(fe));
+}
+
+static void curve25519_shared_secret(uint8_t shared_secret[32], const uint8_t private_key[32], const uint8_t public_key[32])
+{
+ static const fe a24 = { 0xdb41, 1 };
+ uint8_t z[32];
+ int64_t r;
+ int i;
+ fe a = { 1 }, b, c = { 0 }, d = { 1 }, e, f, x;
+
+ memcpy(z, private_key, sizeof(z));
+
+ z[31] = (z[31] & 127) | 64;
+ z[0] &= 248;
+
+ unpack(x, public_key);
+ memcpy(b, x, sizeof(b));
+
+ for (i = 254; i >= 0; --i) {
+ r = (z[i >> 3] >> (i & 7)) & 1;
+ cswap(a, b, r);
+ cswap(c, d, r);
+ add(e, a, c);
+ subtract(a, a, c);
+ add(c, b, d);
+ subtract(b, b, d);
+ multmod(d, e, e);
+ multmod(f, a, a);
+ multmod(a, c, a);
+ multmod(c, b, e);
+ add(e, a, c);
+ subtract(a, a, c);
+ multmod(b, a, a);
+ subtract(c, d, f);
+ multmod(a, c, a24);
+ add(a, a, d);
+ multmod(c, c, a);
+ multmod(a, d, f);
+ multmod(d, b, x);
+ multmod(b, e, e);
+ cswap(a, b, r);
+ cswap(c, d, r);
+ }
+ invert(c, c);
+ multmod(a, a, c);
+ pack(shared_secret, a);
+}
+
+void curve25519_derive_public_key(uint8_t public_key[32], const uint8_t private_key[32])
+{
+ static const uint8_t basepoint[32] = { 9 };
+
+ curve25519_shared_secret(public_key, private_key, basepoint);
+}
+
+void curve25519_generate_private_key(uint8_t private_key[32])
+{
+ CCRandomGenerateBytes(private_key, 32);
+ private_key[31] = (private_key[31] & 127) | 64;
+ private_key[0] &= 248;
+}
diff --git a/WireGuard/WireGuard/Crypto/x25519.h b/WireGuard/WireGuard/Crypto/x25519.h
new file mode 100644
index 00000000..7d8440dd
--- /dev/null
+++ b/WireGuard/WireGuard/Crypto/x25519.h
@@ -0,0 +1,7 @@
+#ifndef X25519_H
+#define X25519_H
+
+void curve25519_derive_public_key(unsigned char public_key[32], const unsigned char private_key[32]);
+void curve25519_generate_private_key(unsigned char private_key[32]);
+
+#endif