cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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curve25519-glue.c (3694B)

      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 * Based on public domain code from Daniel J. Bernstein and Peter Schwabe. This
      6 * began from SUPERCOP's curve25519/neon2/scalarmult.s, but has subsequently been
      7 * manually reworked for use in kernel space.
      8 */
      9
     10#include <asm/hwcap.h>
     11#include <asm/neon.h>
     12#include <asm/simd.h>
     13#include <crypto/internal/kpp.h>
     14#include <crypto/internal/simd.h>
     15#include <linux/types.h>
     16#include <linux/module.h>
     17#include <linux/init.h>
     18#include <linux/jump_label.h>
     19#include <linux/scatterlist.h>
     20#include <crypto/curve25519.h>
     21
     22asmlinkage void curve25519_neon(u8 mypublic[CURVE25519_KEY_SIZE],
     23				const u8 secret[CURVE25519_KEY_SIZE],
     24				const u8 basepoint[CURVE25519_KEY_SIZE]);
     25
     26static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
     27
     28void curve25519_arch(u8 out[CURVE25519_KEY_SIZE],
     29		     const u8 scalar[CURVE25519_KEY_SIZE],
     30		     const u8 point[CURVE25519_KEY_SIZE])
     31{
     32	if (static_branch_likely(&have_neon) && crypto_simd_usable()) {
     33		kernel_neon_begin();
     34		curve25519_neon(out, scalar, point);
     35		kernel_neon_end();
     36	} else {
     37		curve25519_generic(out, scalar, point);
     38	}
     39}
     40EXPORT_SYMBOL(curve25519_arch);
     41
     42void curve25519_base_arch(u8 pub[CURVE25519_KEY_SIZE],
     43			  const u8 secret[CURVE25519_KEY_SIZE])
     44{
     45	return curve25519_arch(pub, secret, curve25519_base_point);
     46}
     47EXPORT_SYMBOL(curve25519_base_arch);
     48
     49static int curve25519_set_secret(struct crypto_kpp *tfm, const void *buf,
     50				 unsigned int len)
     51{
     52	u8 *secret = kpp_tfm_ctx(tfm);
     53
     54	if (!len)
     55		curve25519_generate_secret(secret);
     56	else if (len == CURVE25519_KEY_SIZE &&
     57		 crypto_memneq(buf, curve25519_null_point, CURVE25519_KEY_SIZE))
     58		memcpy(secret, buf, CURVE25519_KEY_SIZE);
     59	else
     60		return -EINVAL;
     61	return 0;
     62}
     63
     64static int curve25519_compute_value(struct kpp_request *req)
     65{
     66	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
     67	const u8 *secret = kpp_tfm_ctx(tfm);
     68	u8 public_key[CURVE25519_KEY_SIZE];
     69	u8 buf[CURVE25519_KEY_SIZE];
     70	int copied, nbytes;
     71	u8 const *bp;
     72
     73	if (req->src) {
     74		copied = sg_copy_to_buffer(req->src,
     75					   sg_nents_for_len(req->src,
     76							    CURVE25519_KEY_SIZE),
     77					   public_key, CURVE25519_KEY_SIZE);
     78		if (copied != CURVE25519_KEY_SIZE)
     79			return -EINVAL;
     80		bp = public_key;
     81	} else {
     82		bp = curve25519_base_point;
     83	}
     84
     85	curve25519_arch(buf, secret, bp);
     86
     87	/* might want less than we've got */
     88	nbytes = min_t(size_t, CURVE25519_KEY_SIZE, req->dst_len);
     89	copied = sg_copy_from_buffer(req->dst, sg_nents_for_len(req->dst,
     90								nbytes),
     91				     buf, nbytes);
     92	if (copied != nbytes)
     93		return -EINVAL;
     94	return 0;
     95}
     96
     97static unsigned int curve25519_max_size(struct crypto_kpp *tfm)
     98{
     99	return CURVE25519_KEY_SIZE;
    100}
    101
    102static struct kpp_alg curve25519_alg = {
    103	.base.cra_name		= "curve25519",
    104	.base.cra_driver_name	= "curve25519-neon",
    105	.base.cra_priority	= 200,
    106	.base.cra_module	= THIS_MODULE,
    107	.base.cra_ctxsize	= CURVE25519_KEY_SIZE,
    108
    109	.set_secret		= curve25519_set_secret,
    110	.generate_public_key	= curve25519_compute_value,
    111	.compute_shared_secret	= curve25519_compute_value,
    112	.max_size		= curve25519_max_size,
    113};
    114
    115static int __init arm_curve25519_init(void)
    116{
    117	if (elf_hwcap & HWCAP_NEON) {
    118		static_branch_enable(&have_neon);
    119		return IS_REACHABLE(CONFIG_CRYPTO_KPP) ?
    120			crypto_register_kpp(&curve25519_alg) : 0;
    121	}
    122	return 0;
    123}
    124
    125static void __exit arm_curve25519_exit(void)
    126{
    127	if (IS_REACHABLE(CONFIG_CRYPTO_KPP) && elf_hwcap & HWCAP_NEON)
    128		crypto_unregister_kpp(&curve25519_alg);
    129}
    130
    131module_init(arm_curve25519_init);
    132module_exit(arm_curve25519_exit);
    133
    134MODULE_ALIAS_CRYPTO("curve25519");
    135MODULE_ALIAS_CRYPTO("curve25519-neon");
    136MODULE_LICENSE("GPL v2");