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 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 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 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 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 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 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