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authorJason A. Donenfeld <Jason@zx2c4.com>2018-02-21 19:19:50 +0100
committerJason A. Donenfeld <Jason@zx2c4.com>2018-02-21 21:07:14 +0100
commit9d7505bcded3abdba703cd4a3d1b4ea719e4a491 (patch)
treebce4528550d1f3b5e622969b63f3dab208ae6ce5
parentallowedips: fix comment style (diff)
downloadWireGuard-master.zip
WireGuard-master.tar.xz
contrib: embedded-wg-library: add key generation functionsHEADmaster
-rw-r--r--contrib/examples/embeddable-wg-library/test.c6
-rw-r--r--contrib/examples/embeddable-wg-library/wireguard.c197
-rw-r--r--contrib/examples/embeddable-wg-library/wireguard.h3
3 files changed, 204 insertions, 2 deletions
diff --git a/contrib/examples/embeddable-wg-library/test.c b/contrib/examples/embeddable-wg-library/test.c
index aad24de..8d4aae3 100644
--- a/contrib/examples/embeddable-wg-library/test.c
+++ b/contrib/examples/embeddable-wg-library/test.c
@@ -50,9 +50,11 @@ int main(int argc, char *argv[])
.first_peer = &new_peer,
.last_peer = &new_peer
};
+ wg_key temp_private_key;
- wg_key_from_base64(new_device.private_key, "SFLKy56SOiFoAvQDSCBRrH/nyYonuAQnyr/JTQRPDlU=");
- wg_key_from_base64(new_peer.public_key, "aNoLvvCfgbtTf4f2Eb/CWVNvIc5AJt/4C4pKrxMUZlM=");
+ wg_generate_private_key(temp_private_key);
+ wg_generate_public_key(new_peer.public_key, temp_private_key);
+ wg_generate_private_key(new_device.private_key);
if (wg_add_device(new_device.name) < 0) {
perror("Unable to add device");
diff --git a/contrib/examples/embeddable-wg-library/wireguard.c b/contrib/examples/embeddable-wg-library/wireguard.c
index 692d285..b728126 100644
--- a/contrib/examples/embeddable-wg-library/wireguard.c
+++ b/contrib/examples/embeddable-wg-library/wireguard.c
@@ -19,6 +19,8 @@
#include <sys/socket.h>
#include <time.h>
#include <unistd.h>
+#include <fcntl.h>
+#include <assert.h>
#include "wireguard.h"
@@ -1575,3 +1577,198 @@ int wg_key_from_base64(wg_key key, const wg_key_b64_string base64)
out:
return -errno;
}
+
+typedef int64_t fe[16];
+
+static __attribute__((noinline)) void memzero_explicit(void *s, size_t count)
+{
+ memset(s, 0, count);
+ __asm__ __volatile__("": :"r"(s) :"memory");
+}
+
+static void carry(fe o)
+{
+ int i;
+ int64_t c;
+
+ for (i = 0; i < 16; ++i) {
+ o[i] += (1LL << 16);
+ c = o[i] >> 16;
+ o[(i + 1) * (i < 15)] += c - 1 + 37 * (c - 1) * (i == 15);
+ o[i] -= c << 16;
+ }
+
+ memzero_explicit(&c, sizeof(c));
+}
+
+static 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;
+ }
+
+ memzero_explicit(&t, sizeof(t));
+ memzero_explicit(&c, sizeof(c));
+ memzero_explicit(&b, sizeof(b));
+}
+
+static 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;
+ }
+
+ memzero_explicit(m, sizeof(m));
+ memzero_explicit(t, sizeof(t));
+ memzero_explicit(&b, sizeof(b));
+}
+
+static 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 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 void multmod(fe o, const fe a, const fe b)
+{
+ int64_t i, j, 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);
+
+ memzero_explicit(t, sizeof(t));
+}
+
+static 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));
+
+ memzero_explicit(c, sizeof(c));
+}
+
+static void normalize_key(uint8_t *z)
+{
+ z[31] = (z[31] & 127) | 64;
+ z[0] &= 248;
+}
+
+void wg_generate_public_key(wg_key public_key, const wg_key private_key)
+{
+ int i, r;
+ uint8_t z[32];
+ fe a = { 1 }, b = { 9 }, c = { 0 }, d = { 1 }, e, f;
+
+ memcpy(z, private_key, sizeof(z));
+ normalize_key(z);
+
+ 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, (const fe){ 0xdb41, 1 });
+ add(a, a, d);
+ multmod(c, c, a);
+ multmod(a, d, f);
+ multmod(d, b, (const fe){ 9 });
+ multmod(b, e, e);
+ cswap(a, b, r);
+ cswap(c, d, r);
+ }
+ invert(c, c);
+ multmod(a, a, c);
+ pack(public_key, a);
+
+ memzero_explicit(&r, sizeof(r));
+ memzero_explicit(z, sizeof(z));
+ memzero_explicit(a, sizeof(a));
+ memzero_explicit(b, sizeof(b));
+ memzero_explicit(c, sizeof(c));
+ memzero_explicit(d, sizeof(d));
+ memzero_explicit(e, sizeof(e));
+ memzero_explicit(f, sizeof(f));
+}
+
+void wg_generate_private_key(wg_key private_key)
+{
+ wg_generate_preshared_key(private_key);
+ normalize_key(private_key);
+}
+
+void wg_generate_preshared_key(wg_key preshared_key)
+{
+ ssize_t ret;
+ int fd;
+
+#if defined(__NR_getrandom)
+ ret = syscall(__NR_getrandom, preshared_key, sizeof(wg_key), 0);
+ if (ret == sizeof(wg_key))
+ return;
+#endif
+ fd = open("/dev/urandom", O_RDONLY);
+ assert(fd >= 0);
+ ret = read(fd, preshared_key, sizeof(wg_key));
+ close(fd);
+ assert(ret == sizeof(wg_key));
+}
diff --git a/contrib/examples/embeddable-wg-library/wireguard.h b/contrib/examples/embeddable-wg-library/wireguard.h
index 350de7d..53d9d5d 100644
--- a/contrib/examples/embeddable-wg-library/wireguard.h
+++ b/contrib/examples/embeddable-wg-library/wireguard.h
@@ -90,5 +90,8 @@ char *wg_list_device_names(void); /* first\0second\0third\0forth\0last\0\0 */
void wg_key_to_base64(wg_key_b64_string base64, const wg_key key);
int wg_key_from_base64(wg_key key, const wg_key_b64_string base64);
bool wg_key_is_zero(const wg_key key);
+void wg_generate_public_key(wg_key public_key, const wg_key private_key);
+void wg_generate_private_key(wg_key private_key);
+void wg_generate_preshared_key(wg_key preshared_key);
#endif