Commit 26609a21 authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
Browse files

crypto: nhpoly1305 - add NHPoly1305 support 



Add a generic implementation of NHPoly1305, an ε-almost-∆-universal hash
function used in the Adiantum encryption mode.

CONFIG_NHPOLY1305 is not selectable by itself since there won't be any
real reason to enable it without also enabling Adiantum support.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Acked-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 1b6fd3d5

crypto/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -496,6 +496,11 @@ config CRYPTO_KEYWRAP 
	  Support for key wrapping (NIST SP800-38F / RFC3394) without

	  padding.



config CRYPTO_NHPOLY1305

	tristate

	select CRYPTO_HASH

	select CRYPTO_POLY1305



comment "Hash modes"



config CRYPTO_CMAC

crypto/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -85,6 +85,7 @@ obj-$(CONFIG_CRYPTO_LRW) += lrw.o 
obj-$(CONFIG_CRYPTO_XTS) += xts.o

obj-$(CONFIG_CRYPTO_CTR) += ctr.o

obj-$(CONFIG_CRYPTO_KEYWRAP) += keywrap.o

obj-$(CONFIG_CRYPTO_NHPOLY1305) += nhpoly1305.o

obj-$(CONFIG_CRYPTO_GCM) += gcm.o

obj-$(CONFIG_CRYPTO_CCM) += ccm.o

obj-$(CONFIG_CRYPTO_CHACHA20POLY1305) += chacha20poly1305.o

crypto/nhpoly1305.c

0 → 100644
+254 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * NHPoly1305 - ε-almost-∆-universal hash function for Adiantum

 *

 * Copyright 2018 Google LLC

 */



/*

 * "NHPoly1305" is the main component of Adiantum hashing.

 * Specifically, it is the calculation

 *

 *	H_M ← Poly1305_{K_M}(NH_{K_N}(pad_{128}(M)))

 *

 * from the procedure in section A.5 of the Adiantum paper [1].  It is an

 * ε-almost-∆-universal (εA∆U) hash function for equal-length inputs over

 * Z/(2^{128}Z), where the "∆" operation is addition.  It hashes 1024-byte

 * chunks of the input with the NH hash function [2], reducing the input length

 * by 32x.  The resulting NH digests are evaluated as a polynomial in

 * GF(2^{130}-5), like in the Poly1305 MAC [3].  Note that the polynomial

 * evaluation by itself would suffice to achieve the εA∆U property; NH is used

 * for performance since it's over twice as fast as Poly1305.

 *

 * This is *not* a cryptographic hash function; do not use it as such!

 *

 * [1] Adiantum: length-preserving encryption for entry-level processors

 *     (https://eprint.iacr.org/2018/720.pdf)

 * [2] UMAC: Fast and Secure Message Authentication

 *     (https://fastcrypto.org/umac/umac_proc.pdf)

 * [3] The Poly1305-AES message-authentication code

 *     (https://cr.yp.to/mac/poly1305-20050329.pdf)

 */



#include <asm/unaligned.h>

#include <crypto/algapi.h>

#include <crypto/internal/hash.h>

#include <crypto/nhpoly1305.h>

#include <linux/crypto.h>

#include <linux/kernel.h>

#include <linux/module.h>



static void nh_generic(const u32 *key, const u8 *message, size_t message_len,

		       __le64 hash[NH_NUM_PASSES])

{

	u64 sums[4] = { 0, 0, 0, 0 };



	BUILD_BUG_ON(NH_PAIR_STRIDE != 2);

	BUILD_BUG_ON(NH_NUM_PASSES != 4);



	while (message_len) {

		u32 m0 = get_unaligned_le32(message + 0);

		u32 m1 = get_unaligned_le32(message + 4);

		u32 m2 = get_unaligned_le32(message + 8);

		u32 m3 = get_unaligned_le32(message + 12);



		sums[0] += (u64)(u32)(m0 + key[ 0]) * (u32)(m2 + key[ 2]);

		sums[1] += (u64)(u32)(m0 + key[ 4]) * (u32)(m2 + key[ 6]);

		sums[2] += (u64)(u32)(m0 + key[ 8]) * (u32)(m2 + key[10]);

		sums[3] += (u64)(u32)(m0 + key[12]) * (u32)(m2 + key[14]);

		sums[0] += (u64)(u32)(m1 + key[ 1]) * (u32)(m3 + key[ 3]);

		sums[1] += (u64)(u32)(m1 + key[ 5]) * (u32)(m3 + key[ 7]);

		sums[2] += (u64)(u32)(m1 + key[ 9]) * (u32)(m3 + key[11]);

		sums[3] += (u64)(u32)(m1 + key[13]) * (u32)(m3 + key[15]);

		key += NH_MESSAGE_UNIT / sizeof(key[0]);

		message += NH_MESSAGE_UNIT;

		message_len -= NH_MESSAGE_UNIT;

	}



	hash[0] = cpu_to_le64(sums[0]);

	hash[1] = cpu_to_le64(sums[1]);

	hash[2] = cpu_to_le64(sums[2]);

	hash[3] = cpu_to_le64(sums[3]);

}



/* Pass the next NH hash value through Poly1305 */

static void process_nh_hash_value(struct nhpoly1305_state *state,

				  const struct nhpoly1305_key *key)

{

	BUILD_BUG_ON(NH_HASH_BYTES % POLY1305_BLOCK_SIZE != 0);



	poly1305_core_blocks(&state->poly_state, &key->poly_key, state->nh_hash,

			     NH_HASH_BYTES / POLY1305_BLOCK_SIZE);

}



/*

 * Feed the next portion of the source data, as a whole number of 16-byte

 * "NH message units", through NH and Poly1305.  Each NH hash is taken over

 * 1024 bytes, except possibly the final one which is taken over a multiple of

 * 16 bytes up to 1024.  Also, in the case where data is passed in misaligned

 * chunks, we combine partial hashes; the end result is the same either way.

 */

static void nhpoly1305_units(struct nhpoly1305_state *state,

			     const struct nhpoly1305_key *key,

			     const u8 *src, unsigned int srclen, nh_t nh_fn)

{

	do {

		unsigned int bytes;



		if (state->nh_remaining == 0) {

			/* Starting a new NH message */

			bytes = min_t(unsigned int, srclen, NH_MESSAGE_BYTES);

			nh_fn(key->nh_key, src, bytes, state->nh_hash);

			state->nh_remaining = NH_MESSAGE_BYTES - bytes;

		} else {

			/* Continuing a previous NH message */

			__le64 tmp_hash[NH_NUM_PASSES];

			unsigned int pos;

			int i;



			pos = NH_MESSAGE_BYTES - state->nh_remaining;

			bytes = min(srclen, state->nh_remaining);

			nh_fn(&key->nh_key[pos / 4], src, bytes, tmp_hash);

			for (i = 0; i < NH_NUM_PASSES; i++)

				le64_add_cpu(&state->nh_hash[i],

					     le64_to_cpu(tmp_hash[i]));

			state->nh_remaining -= bytes;

		}

		if (state->nh_remaining == 0)

			process_nh_hash_value(state, key);

		src += bytes;

		srclen -= bytes;

	} while (srclen);

}



int crypto_nhpoly1305_setkey(struct crypto_shash *tfm,

			     const u8 *key, unsigned int keylen)

{

	struct nhpoly1305_key *ctx = crypto_shash_ctx(tfm);

	int i;



	if (keylen != NHPOLY1305_KEY_SIZE)

		return -EINVAL;



	poly1305_core_setkey(&ctx->poly_key, key);

	key += POLY1305_BLOCK_SIZE;



	for (i = 0; i < NH_KEY_WORDS; i++)

		ctx->nh_key[i] = get_unaligned_le32(key + i * sizeof(u32));



	return 0;

}

EXPORT_SYMBOL(crypto_nhpoly1305_setkey);



int crypto_nhpoly1305_init(struct shash_desc *desc)

{

	struct nhpoly1305_state *state = shash_desc_ctx(desc);



	poly1305_core_init(&state->poly_state);

	state->buflen = 0;

	state->nh_remaining = 0;

	return 0;

}

EXPORT_SYMBOL(crypto_nhpoly1305_init);



int crypto_nhpoly1305_update_helper(struct shash_desc *desc,

				    const u8 *src, unsigned int srclen,

				    nh_t nh_fn)

{

	struct nhpoly1305_state *state = shash_desc_ctx(desc);

	const struct nhpoly1305_key *key = crypto_shash_ctx(desc->tfm);

	unsigned int bytes;



	if (state->buflen) {

		bytes = min(srclen, (int)NH_MESSAGE_UNIT - state->buflen);

		memcpy(&state->buffer[state->buflen], src, bytes);

		state->buflen += bytes;

		if (state->buflen < NH_MESSAGE_UNIT)

			return 0;

		nhpoly1305_units(state, key, state->buffer, NH_MESSAGE_UNIT,

				 nh_fn);

		state->buflen = 0;

		src += bytes;

		srclen -= bytes;

	}



	if (srclen >= NH_MESSAGE_UNIT) {

		bytes = round_down(srclen, NH_MESSAGE_UNIT);

		nhpoly1305_units(state, key, src, bytes, nh_fn);

		src += bytes;

		srclen -= bytes;

	}



	if (srclen) {

		memcpy(state->buffer, src, srclen);

		state->buflen = srclen;

	}

	return 0;

}

EXPORT_SYMBOL(crypto_nhpoly1305_update_helper);



int crypto_nhpoly1305_update(struct shash_desc *desc,

			     const u8 *src, unsigned int srclen)

{

	return crypto_nhpoly1305_update_helper(desc, src, srclen, nh_generic);

}

EXPORT_SYMBOL(crypto_nhpoly1305_update);



int crypto_nhpoly1305_final_helper(struct shash_desc *desc, u8 *dst, nh_t nh_fn)

{

	struct nhpoly1305_state *state = shash_desc_ctx(desc);

	const struct nhpoly1305_key *key = crypto_shash_ctx(desc->tfm);



	if (state->buflen) {

		memset(&state->buffer[state->buflen], 0,

		       NH_MESSAGE_UNIT - state->buflen);

		nhpoly1305_units(state, key, state->buffer, NH_MESSAGE_UNIT,

				 nh_fn);

	}



	if (state->nh_remaining)

		process_nh_hash_value(state, key);



	poly1305_core_emit(&state->poly_state, dst);

	return 0;

}

EXPORT_SYMBOL(crypto_nhpoly1305_final_helper);



int crypto_nhpoly1305_final(struct shash_desc *desc, u8 *dst)

{

	return crypto_nhpoly1305_final_helper(desc, dst, nh_generic);

}

EXPORT_SYMBOL(crypto_nhpoly1305_final);



static struct shash_alg nhpoly1305_alg = {

	.base.cra_name		= "nhpoly1305",

	.base.cra_driver_name	= "nhpoly1305-generic",

	.base.cra_priority	= 100,

	.base.cra_ctxsize	= sizeof(struct nhpoly1305_key),

	.base.cra_module	= THIS_MODULE,

	.digestsize		= POLY1305_DIGEST_SIZE,

	.init			= crypto_nhpoly1305_init,

	.update			= crypto_nhpoly1305_update,

	.final			= crypto_nhpoly1305_final,

	.setkey			= crypto_nhpoly1305_setkey,

	.descsize		= sizeof(struct nhpoly1305_state),

};



static int __init nhpoly1305_mod_init(void)

{

	return crypto_register_shash(&nhpoly1305_alg);

}



static void __exit nhpoly1305_mod_exit(void)

{

	crypto_unregister_shash(&nhpoly1305_alg);

}



module_init(nhpoly1305_mod_init);

module_exit(nhpoly1305_mod_exit);



MODULE_DESCRIPTION("NHPoly1305 ε-almost-∆-universal hash function");

MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("Eric Biggers <ebiggers@google.com>");

MODULE_ALIAS_CRYPTO("nhpoly1305");

MODULE_ALIAS_CRYPTO("nhpoly1305-generic");

crypto/testmgr.c

+6 −0
Original line number Diff line number Diff line
@@ -3311,6 +3311,12 @@ static const struct alg_test_desc alg_test_descs[] = { 
				.dec = __VECS(morus640_dec_tv_template),

			}

		}

	}, {

		.alg = "nhpoly1305",

		.test = alg_test_hash,

		.suite = {

			.hash = __VECS(nhpoly1305_tv_template)

		}

	}, {

		.alg = "ofb(aes)",

		.test = alg_test_skcipher,

crypto/testmgr.h

+1236 −4

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