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-generic.c (2233B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2
      3#include <crypto/curve25519.h>
      4#include <crypto/internal/kpp.h>
      5#include <crypto/kpp.h>
      6#include <linux/module.h>
      7#include <linux/scatterlist.h>
      8
      9static int curve25519_set_secret(struct crypto_kpp *tfm, const void *buf,
     10				 unsigned int len)
     11{
     12	u8 *secret = kpp_tfm_ctx(tfm);
     13
     14	if (!len)
     15		curve25519_generate_secret(secret);
     16	else if (len == CURVE25519_KEY_SIZE &&
     17		 crypto_memneq(buf, curve25519_null_point, CURVE25519_KEY_SIZE))
     18		memcpy(secret, buf, CURVE25519_KEY_SIZE);
     19	else
     20		return -EINVAL;
     21	return 0;
     22}
     23
     24static int curve25519_compute_value(struct kpp_request *req)
     25{
     26	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
     27	const u8 *secret = kpp_tfm_ctx(tfm);
     28	u8 public_key[CURVE25519_KEY_SIZE];
     29	u8 buf[CURVE25519_KEY_SIZE];
     30	int copied, nbytes;
     31	u8 const *bp;
     32
     33	if (req->src) {
     34		copied = sg_copy_to_buffer(req->src,
     35					   sg_nents_for_len(req->src,
     36							    CURVE25519_KEY_SIZE),
     37					   public_key, CURVE25519_KEY_SIZE);
     38		if (copied != CURVE25519_KEY_SIZE)
     39			return -EINVAL;
     40		bp = public_key;
     41	} else {
     42		bp = curve25519_base_point;
     43	}
     44
     45	curve25519_generic(buf, secret, bp);
     46
     47	/* might want less than we've got */
     48	nbytes = min_t(size_t, CURVE25519_KEY_SIZE, req->dst_len);
     49	copied = sg_copy_from_buffer(req->dst, sg_nents_for_len(req->dst,
     50								nbytes),
     51				     buf, nbytes);
     52	if (copied != nbytes)
     53		return -EINVAL;
     54	return 0;
     55}
     56
     57static unsigned int curve25519_max_size(struct crypto_kpp *tfm)
     58{
     59	return CURVE25519_KEY_SIZE;
     60}
     61
     62static struct kpp_alg curve25519_alg = {
     63	.base.cra_name		= "curve25519",
     64	.base.cra_driver_name	= "curve25519-generic",
     65	.base.cra_priority	= 100,
     66	.base.cra_module	= THIS_MODULE,
     67	.base.cra_ctxsize	= CURVE25519_KEY_SIZE,
     68
     69	.set_secret		= curve25519_set_secret,
     70	.generate_public_key	= curve25519_compute_value,
     71	.compute_shared_secret	= curve25519_compute_value,
     72	.max_size		= curve25519_max_size,
     73};
     74
     75static int curve25519_init(void)
     76{
     77	return crypto_register_kpp(&curve25519_alg);
     78}
     79
     80static void curve25519_exit(void)
     81{
     82	crypto_unregister_kpp(&curve25519_alg);
     83}
     84
     85subsys_initcall(curve25519_init);
     86module_exit(curve25519_exit);
     87
     88MODULE_ALIAS_CRYPTO("curve25519");
     89MODULE_ALIAS_CRYPTO("curve25519-generic");
     90MODULE_LICENSE("GPL");