1 // SPDX-License-Identifier: GPL-2.0 OR MIT
2 /*
3 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
4 *
5 * This is an implementation of the Curve25519 ECDH algorithm, using either an
6 * architecture-optimized implementation or a generic implementation. The
7 * generic implementation is either 32-bit, or 64-bit with 128-bit integers,
8 * depending on what is supported by the target compiler.
9 *
10 * Information: https://cr.yp.to/ecdh.html
11 */
12
13 #include <crypto/curve25519.h>
14 #include <crypto/utils.h>
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18
19 static const u8 curve25519_null_point[CURVE25519_KEY_SIZE] __aligned(32) = { 0 };
20 static const u8 curve25519_base_point[CURVE25519_KEY_SIZE] __aligned(32) = { 9 };
21
22 #ifdef CONFIG_CRYPTO_LIB_CURVE25519_ARCH
23 #include "curve25519.h" /* $(SRCARCH)/curve25519.h */
24 #else
curve25519_arch(u8 mypublic[CURVE25519_KEY_SIZE],const u8 secret[CURVE25519_KEY_SIZE],const u8 basepoint[CURVE25519_KEY_SIZE])25 static void curve25519_arch(u8 mypublic[CURVE25519_KEY_SIZE],
26 const u8 secret[CURVE25519_KEY_SIZE],
27 const u8 basepoint[CURVE25519_KEY_SIZE])
28 {
29 curve25519_generic(mypublic, secret, basepoint);
30 }
31
curve25519_base_arch(u8 pub[CURVE25519_KEY_SIZE],const u8 secret[CURVE25519_KEY_SIZE])32 static void curve25519_base_arch(u8 pub[CURVE25519_KEY_SIZE],
33 const u8 secret[CURVE25519_KEY_SIZE])
34 {
35 curve25519_generic(pub, secret, curve25519_base_point);
36 }
37 #endif
38
39 bool __must_check
curve25519(u8 mypublic[CURVE25519_KEY_SIZE],const u8 secret[CURVE25519_KEY_SIZE],const u8 basepoint[CURVE25519_KEY_SIZE])40 curve25519(u8 mypublic[CURVE25519_KEY_SIZE],
41 const u8 secret[CURVE25519_KEY_SIZE],
42 const u8 basepoint[CURVE25519_KEY_SIZE])
43 {
44 curve25519_arch(mypublic, secret, basepoint);
45 return crypto_memneq(mypublic, curve25519_null_point,
46 CURVE25519_KEY_SIZE);
47 }
48 EXPORT_SYMBOL(curve25519);
49
50 bool __must_check
curve25519_generate_public(u8 pub[CURVE25519_KEY_SIZE],const u8 secret[CURVE25519_KEY_SIZE])51 curve25519_generate_public(u8 pub[CURVE25519_KEY_SIZE],
52 const u8 secret[CURVE25519_KEY_SIZE])
53 {
54 if (unlikely(!crypto_memneq(secret, curve25519_null_point,
55 CURVE25519_KEY_SIZE)))
56 return false;
57 curve25519_base_arch(pub, secret);
58 return crypto_memneq(pub, curve25519_null_point, CURVE25519_KEY_SIZE);
59 }
60 EXPORT_SYMBOL(curve25519_generate_public);
61
62 #ifdef curve25519_mod_init_arch
curve25519_mod_init(void)63 static int __init curve25519_mod_init(void)
64 {
65 curve25519_mod_init_arch();
66 return 0;
67 }
68 subsys_initcall(curve25519_mod_init);
69
curve25519_mod_exit(void)70 static void __exit curve25519_mod_exit(void)
71 {
72 }
73 module_exit(curve25519_mod_exit);
74 #endif
75
76 MODULE_LICENSE("GPL v2");
77 MODULE_DESCRIPTION("Curve25519 algorithm");
78 MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");
79