// SPDX-License-Identifier: GPL-2.0 OR MIT /* * Copyright (C) 2020 Jason A. Donenfeld <[email protected]>. All Rights Reserved. * Copyright (c) 2016-2020 INRIA, CMU and Microsoft Corporation */ #include <crypto/curve25519.h> #include <crypto/internal/kpp.h> #include <linux/types.h> #include <linux/jump_label.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/scatterlist.h> #include <asm/cpufeature.h> #include <asm/processor.h> static __always_inline u64 eq_mask(u64 a, u64 b) { … } static __always_inline u64 gte_mask(u64 a, u64 b) { … } /* Computes the addition of four-element f1 with value in f2 * and returns the carry (if any) */ static inline u64 add_scalar(u64 *out, const u64 *f1, u64 f2) { … } /* Computes the field addition of two field elements */ static inline void fadd(u64 *out, const u64 *f1, const u64 *f2) { … } /* Computes the field subtraction of two field elements */ static inline void fsub(u64 *out, const u64 *f1, const u64 *f2) { … } /* Computes a field multiplication: out <- f1 * f2 * Uses the 8-element buffer tmp for intermediate results */ static inline void fmul(u64 *out, const u64 *f1, const u64 *f2, u64 *tmp) { … } /* Computes two field multiplications: * out[0] <- f1[0] * f2[0] * out[1] <- f1[1] * f2[1] * Uses the 16-element buffer tmp for intermediate results: */ static inline void fmul2(u64 *out, const u64 *f1, const u64 *f2, u64 *tmp) { … } /* Computes the field multiplication of four-element f1 with value in f2 * Requires f2 to be smaller than 2^17 */ static inline void fmul_scalar(u64 *out, const u64 *f1, u64 f2) { … } /* Computes p1 <- bit ? p2 : p1 in constant time */ static inline void cswap2(u64 bit, const u64 *p1, const u64 *p2) { … } /* Computes the square of a field element: out <- f * f * Uses the 8-element buffer tmp for intermediate results */ static inline void fsqr(u64 *out, const u64 *f, u64 *tmp) { … } /* Computes two field squarings: * out[0] <- f[0] * f[0] * out[1] <- f[1] * f[1] * Uses the 16-element buffer tmp for intermediate results */ static inline void fsqr2(u64 *out, const u64 *f, u64 *tmp) { … } static void point_add_and_double(u64 *q, u64 *p01_tmp1, u64 *tmp2) { … } static void point_double(u64 *nq, u64 *tmp1, u64 *tmp2) { … } static void montgomery_ladder(u64 *out, const u8 *key, u64 *init1) { … } static void fsquare_times(u64 *o, const u64 *inp, u64 *tmp, u32 n1) { … } static void finv(u64 *o, const u64 *i, u64 *tmp) { … } static void store_felem(u64 *b, u64 *f) { … } static void encode_point(u8 *o, const u64 *i) { … } static void curve25519_ever64(u8 *out, const u8 *priv, const u8 *pub) { … } /* The below constants were generated using this sage script: * * #!/usr/bin/env sage * import sys * from sage.all import * * def limbs(n): * n = int(n) * l = ((n >> 0) % 2^64, (n >> 64) % 2^64, (n >> 128) % 2^64, (n >> 192) % 2^64) * return "0x%016xULL, 0x%016xULL, 0x%016xULL, 0x%016xULL" % l * ec = EllipticCurve(GF(2^255 - 19), [0, 486662, 0, 1, 0]) * p_minus_s = (ec.lift_x(9) - ec.lift_x(1))[0] * print("static const u64 p_minus_s[] = { %s };\n" % limbs(p_minus_s)) * print("static const u64 table_ladder[] = {") * p = ec.lift_x(9) * for i in range(252): * l = (p[0] + p[2]) / (p[0] - p[2]) * print(("\t%s" + ("," if i != 251 else "")) % limbs(l)) * p = p * 2 * print("};") * */ static const u64 p_minus_s[] = …; static const u64 table_ladder[] = …; static void curve25519_ever64_base(u8 *out, const u8 *priv) { … } static __ro_after_init DEFINE_STATIC_KEY_FALSE(curve25519_use_bmi2_adx); void curve25519_arch(u8 mypublic[CURVE25519_KEY_SIZE], const u8 secret[CURVE25519_KEY_SIZE], const u8 basepoint[CURVE25519_KEY_SIZE]) { … } EXPORT_SYMBOL(…); void curve25519_base_arch(u8 pub[CURVE25519_KEY_SIZE], const u8 secret[CURVE25519_KEY_SIZE]) { … } EXPORT_SYMBOL(…); static int curve25519_set_secret(struct crypto_kpp *tfm, const void *buf, unsigned int len) { … } static int curve25519_generate_public_key(struct kpp_request *req) { … } static int curve25519_compute_shared_secret(struct kpp_request *req) { … } static unsigned int curve25519_max_size(struct crypto_kpp *tfm) { … } static struct kpp_alg curve25519_alg = …; static int __init curve25519_mod_init(void) { … } static void __exit curve25519_mod_exit(void) { … } module_init(…) …; module_exit(curve25519_mod_exit); MODULE_ALIAS_CRYPTO(…) …; MODULE_ALIAS_CRYPTO(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …; MODULE_AUTHOR(…) …;
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