crypto: polyval - Add POLYVAL support

Add support for POLYVAL, an ε-Δ-universal hash function similar to
GHASH.  This patch only uses POLYVAL as a component to implement HCTR2
mode.  It should be noted that POLYVAL was originally specified for use
in AES-GCM-SIV (RFC 8452), but the kernel does not currently support
this mode.

POLYVAL is implemented as an shash algorithm.  The implementation is
modified from ghash-generic.c.

For more information on POLYVAL see:
Length-preserving encryption with HCTR2:
  https://eprint.iacr.org/2021/1441.pdf
AES-GCM-SIV: Nonce Misuse-Resistant Authenticated Encryption:
  https://datatracker.ietf.org/doc/html/rfc8452

Signed-off-by: Nathan Huckleberry <nhuck@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Nathan Huckleberry 2022-05-20 18:14:54 +00:00 committed by Herbert Xu
parent 17fee07a2a
commit f3c923a09c
7 changed files with 412 additions and 0 deletions

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@ -773,6 +773,14 @@ config CRYPTO_GHASH
GHASH is the hash function used in GCM (Galois/Counter Mode).
It is not a general-purpose cryptographic hash function.
config CRYPTO_POLYVAL
tristate
select CRYPTO_GF128MUL
select CRYPTO_HASH
help
POLYVAL is the hash function used in HCTR2. It is not a general-purpose
cryptographic hash function.
config CRYPTO_POLY1305
tristate "Poly1305 authenticator algorithm"
select CRYPTO_HASH

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@ -172,6 +172,7 @@ UBSAN_SANITIZE_jitterentropy.o = n
jitterentropy_rng-y := jitterentropy.o jitterentropy-kcapi.o
obj-$(CONFIG_CRYPTO_TEST) += tcrypt.o
obj-$(CONFIG_CRYPTO_GHASH) += ghash-generic.o
obj-$(CONFIG_CRYPTO_POLYVAL) += polyval-generic.o
obj-$(CONFIG_CRYPTO_USER_API) += af_alg.o
obj-$(CONFIG_CRYPTO_USER_API_HASH) += algif_hash.o
obj-$(CONFIG_CRYPTO_USER_API_SKCIPHER) += algif_skcipher.o

205
crypto/polyval-generic.c Normal file
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@ -0,0 +1,205 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* POLYVAL: hash function for HCTR2.
*
* Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
* Copyright (c) 2009 Intel Corp.
* Author: Huang Ying <ying.huang@intel.com>
* Copyright 2021 Google LLC
*/
/*
* Code based on crypto/ghash-generic.c
*
* POLYVAL is a keyed hash function similar to GHASH. POLYVAL uses a different
* modulus for finite field multiplication which makes hardware accelerated
* implementations on little-endian machines faster. POLYVAL is used in the
* kernel to implement HCTR2, but was originally specified for AES-GCM-SIV
* (RFC 8452).
*
* For more information see:
* Length-preserving encryption with HCTR2:
* https://eprint.iacr.org/2021/1441.pdf
* AES-GCM-SIV: Nonce Misuse-Resistant Authenticated Encryption:
* https://datatracker.ietf.org/doc/html/rfc8452
*
* Like GHASH, POLYVAL is not a cryptographic hash function and should
* not be used outside of crypto modes explicitly designed to use POLYVAL.
*
* This implementation uses a convenient trick involving the GHASH and POLYVAL
* fields. This trick allows multiplication in the POLYVAL field to be
* implemented by using multiplication in the GHASH field as a subroutine. An
* element of the POLYVAL field can be converted to an element of the GHASH
* field by computing x*REVERSE(a), where REVERSE reverses the byte-ordering of
* a. Similarly, an element of the GHASH field can be converted back to the
* POLYVAL field by computing REVERSE(x^{-1}*a). For more information, see:
* https://datatracker.ietf.org/doc/html/rfc8452#appendix-A
*
* By using this trick, we do not need to implement the POLYVAL field for the
* generic implementation.
*
* Warning: this generic implementation is not intended to be used in practice
* and is not constant time. For practical use, a hardware accelerated
* implementation of POLYVAL should be used instead.
*
*/
#include <asm/unaligned.h>
#include <crypto/algapi.h>
#include <crypto/gf128mul.h>
#include <crypto/polyval.h>
#include <crypto/internal/hash.h>
#include <linux/crypto.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
struct polyval_tfm_ctx {
struct gf128mul_4k *gf128;
};
struct polyval_desc_ctx {
union {
u8 buffer[POLYVAL_BLOCK_SIZE];
be128 buffer128;
};
u32 bytes;
};
static void copy_and_reverse(u8 dst[POLYVAL_BLOCK_SIZE],
const u8 src[POLYVAL_BLOCK_SIZE])
{
u64 a = get_unaligned((const u64 *)&src[0]);
u64 b = get_unaligned((const u64 *)&src[8]);
put_unaligned(swab64(a), (u64 *)&dst[8]);
put_unaligned(swab64(b), (u64 *)&dst[0]);
}
static int polyval_setkey(struct crypto_shash *tfm,
const u8 *key, unsigned int keylen)
{
struct polyval_tfm_ctx *ctx = crypto_shash_ctx(tfm);
be128 k;
if (keylen != POLYVAL_BLOCK_SIZE)
return -EINVAL;
gf128mul_free_4k(ctx->gf128);
BUILD_BUG_ON(sizeof(k) != POLYVAL_BLOCK_SIZE);
copy_and_reverse((u8 *)&k, key);
gf128mul_x_lle(&k, &k);
ctx->gf128 = gf128mul_init_4k_lle(&k);
memzero_explicit(&k, POLYVAL_BLOCK_SIZE);
if (!ctx->gf128)
return -ENOMEM;
return 0;
}
static int polyval_init(struct shash_desc *desc)
{
struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
memset(dctx, 0, sizeof(*dctx));
return 0;
}
static int polyval_update(struct shash_desc *desc,
const u8 *src, unsigned int srclen)
{
struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
const struct polyval_tfm_ctx *ctx = crypto_shash_ctx(desc->tfm);
u8 *pos;
u8 tmp[POLYVAL_BLOCK_SIZE];
int n;
if (dctx->bytes) {
n = min(srclen, dctx->bytes);
pos = dctx->buffer + dctx->bytes - 1;
dctx->bytes -= n;
srclen -= n;
while (n--)
*pos-- ^= *src++;
if (!dctx->bytes)
gf128mul_4k_lle(&dctx->buffer128, ctx->gf128);
}
while (srclen >= POLYVAL_BLOCK_SIZE) {
copy_and_reverse(tmp, src);
crypto_xor(dctx->buffer, tmp, POLYVAL_BLOCK_SIZE);
gf128mul_4k_lle(&dctx->buffer128, ctx->gf128);
src += POLYVAL_BLOCK_SIZE;
srclen -= POLYVAL_BLOCK_SIZE;
}
if (srclen) {
dctx->bytes = POLYVAL_BLOCK_SIZE - srclen;
pos = dctx->buffer + POLYVAL_BLOCK_SIZE - 1;
while (srclen--)
*pos-- ^= *src++;
}
return 0;
}
static int polyval_final(struct shash_desc *desc, u8 *dst)
{
struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
const struct polyval_tfm_ctx *ctx = crypto_shash_ctx(desc->tfm);
if (dctx->bytes)
gf128mul_4k_lle(&dctx->buffer128, ctx->gf128);
copy_and_reverse(dst, dctx->buffer);
return 0;
}
static void polyval_exit_tfm(struct crypto_tfm *tfm)
{
struct polyval_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
gf128mul_free_4k(ctx->gf128);
}
static struct shash_alg polyval_alg = {
.digestsize = POLYVAL_DIGEST_SIZE,
.init = polyval_init,
.update = polyval_update,
.final = polyval_final,
.setkey = polyval_setkey,
.descsize = sizeof(struct polyval_desc_ctx),
.base = {
.cra_name = "polyval",
.cra_driver_name = "polyval-generic",
.cra_priority = 100,
.cra_blocksize = POLYVAL_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct polyval_tfm_ctx),
.cra_module = THIS_MODULE,
.cra_exit = polyval_exit_tfm,
},
};
static int __init polyval_mod_init(void)
{
return crypto_register_shash(&polyval_alg);
}
static void __exit polyval_mod_exit(void)
{
crypto_unregister_shash(&polyval_alg);
}
subsys_initcall(polyval_mod_init);
module_exit(polyval_mod_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("POLYVAL hash function");
MODULE_ALIAS_CRYPTO("polyval");
MODULE_ALIAS_CRYPTO("polyval-generic");

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@ -1730,6 +1730,10 @@ static int do_test(const char *alg, u32 type, u32 mask, int m, u32 num_mb)
ret += tcrypt_test("ccm(sm4)");
break;
case 57:
ret += tcrypt_test("polyval");
break;
case 100:
ret += tcrypt_test("hmac(md5)");
break;

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@ -5342,6 +5342,12 @@ static const struct alg_test_desc alg_test_descs[] = {
.suite = {
.hash = __VECS(poly1305_tv_template)
}
}, {
.alg = "polyval",
.test = alg_test_hash,
.suite = {
.hash = __VECS(polyval_tv_template)
}
}, {
.alg = "rfc3686(ctr(aes))",
.test = alg_test_skcipher,

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@ -34944,4 +34944,175 @@ static const struct cipher_testvec aes_xctr_tv_template[] = {
};
/*
* Test vectors generated using https://github.com/google/hctr2
*
* To ensure compatibility with RFC 8452, some tests were sourced from
* https://datatracker.ietf.org/doc/html/rfc8452
*/
static const struct hash_testvec polyval_tv_template[] = {
{ // From RFC 8452
.key = "\x31\x07\x28\xd9\x91\x1f\x1f\x38"
"\x37\xb2\x43\x16\xc3\xfa\xb9\xa0",
.plaintext = "\x65\x78\x61\x6d\x70\x6c\x65\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x48\x65\x6c\x6c\x6f\x20\x77\x6f"
"\x72\x6c\x64\x00\x00\x00\x00\x00"
"\x38\x00\x00\x00\x00\x00\x00\x00"
"\x58\x00\x00\x00\x00\x00\x00\x00",
.digest = "\xad\x7f\xcf\x0b\x51\x69\x85\x16"
"\x62\x67\x2f\x3c\x5f\x95\x13\x8f",
.psize = 48,
.ksize = 16,
},
{ // From RFC 8452
.key = "\xd9\xb3\x60\x27\x96\x94\x94\x1a"
"\xc5\xdb\xc6\x98\x7a\xda\x73\x77",
.plaintext = "\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00",
.digest = "\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00",
.psize = 16,
.ksize = 16,
},
{ // From RFC 8452
.key = "\xd9\xb3\x60\x27\x96\x94\x94\x1a"
"\xc5\xdb\xc6\x98\x7a\xda\x73\x77",
.plaintext = "\x01\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x40\x00\x00\x00\x00\x00\x00\x00",
.digest = "\xeb\x93\xb7\x74\x09\x62\xc5\xe4"
"\x9d\x2a\x90\xa7\xdc\x5c\xec\x74",
.psize = 32,
.ksize = 16,
},
{ // From RFC 8452
.key = "\xd9\xb3\x60\x27\x96\x94\x94\x1a"
"\xc5\xdb\xc6\x98\x7a\xda\x73\x77",
.plaintext = "\x01\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x02\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x03\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x80\x01\x00\x00\x00\x00\x00\x00",
.digest = "\x81\x38\x87\x46\xbc\x22\xd2\x6b"
"\x2a\xbc\x3d\xcb\x15\x75\x42\x22",
.psize = 64,
.ksize = 16,
},
{ // From RFC 8452
.key = "\xd9\xb3\x60\x27\x96\x94\x94\x1a"
"\xc5\xdb\xc6\x98\x7a\xda\x73\x77",
.plaintext = "\x01\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x02\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x03\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x04\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x02\x00\x00\x00\x00\x00\x00",
.digest = "\x1e\x39\xb6\xd3\x34\x4d\x34\x8f"
"\x60\x44\xf8\x99\x35\xd1\xcf\x78",
.psize = 80,
.ksize = 16,
},
{ // From RFC 8452
.key = "\xd9\xb3\x60\x27\x96\x94\x94\x1a"
"\xc5\xdb\xc6\x98\x7a\xda\x73\x77",
.plaintext = "\x01\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x02\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x03\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x04\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x05\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00"
"\x08\x00\x00\x00\x00\x00\x00\x00"
"\x00\x02\x00\x00\x00\x00\x00\x00",
.digest = "\xff\xcd\x05\xd5\x77\x0f\x34\xad"
"\x92\x67\xf0\xa5\x99\x94\xb1\x5a",
.psize = 96,
.ksize = 16,
},
{ // Random ( 1)
.key = "\x90\xcc\xac\xee\xba\xd7\xd4\x68"
"\x98\xa6\x79\x70\xdf\x66\x15\x6c",
.plaintext = "",
.digest = "\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00",
.psize = 0,
.ksize = 16,
},
{ // Random ( 1)
.key = "\xc1\x45\x71\xf0\x30\x07\x94\xe7"
"\x3a\xdd\xe4\xc6\x19\x2d\x02\xa2",
.plaintext = "\xc1\x5d\x47\xc7\x4c\x7c\x5e\x07"
"\x85\x14\x8f\x79\xcc\x73\x83\xf7"
"\x35\xb8\xcb\x73\x61\xf0\x53\x31"
"\xbf\x84\xde\xb6\xde\xaf\xb0\xb8"
"\xb7\xd9\x11\x91\x89\xfd\x1e\x4c"
"\x84\x4a\x1f\x2a\x87\xa4\xaf\x62"
"\x8d\x7d\x58\xf6\x43\x35\xfc\x53"
"\x8f\x1a\xf6\x12\xe1\x13\x3f\x66"
"\x91\x4b\x13\xd6\x45\xfb\xb0\x7a"
"\xe0\x8b\x8e\x99\xf7\x86\x46\x37"
"\xd1\x22\x9e\x52\xf3\x3f\xd9\x75"
"\x2c\x2c\xc6\xbb\x0e\x08\x14\x29"
"\xe8\x50\x2f\xd8\xbe\xf4\xe9\x69"
"\x4a\xee\xf7\xae\x15\x65\x35\x1e",
.digest = "\x00\x4f\x5d\xe9\x3b\xc0\xd6\x50"
"\x3e\x38\x73\x86\xc6\xda\xca\x7f",
.psize = 112,
.ksize = 16,
},
{ // Random ( 1)
.key = "\x37\xbe\x68\x16\x50\xb9\x4e\xb0"
"\x47\xde\xe2\xbd\xde\xe4\x48\x09",
.plaintext = "\x87\xfc\x68\x9f\xff\xf2\x4a\x1e"
"\x82\x3b\x73\x8f\xc1\xb2\x1b\x7a"
"\x6c\x4f\x81\xbc\x88\x9b\x6c\xa3"
"\x9c\xc2\xa5\xbc\x14\x70\x4c\x9b"
"\x0c\x9f\x59\x92\x16\x4b\x91\x3d"
"\x18\x55\x22\x68\x12\x8c\x63\xb2"
"\x51\xcb\x85\x4b\xd2\xae\x0b\x1c"
"\x5d\x28\x9d\x1d\xb1\xc8\xf0\x77"
"\xe9\xb5\x07\x4e\x06\xc8\xee\xf8"
"\x1b\xed\x72\x2a\x55\x7d\x16\xc9"
"\xf2\x54\xe7\xe9\xe0\x44\x5b\x33"
"\xb1\x49\xee\xff\x43\xfb\x82\xcd"
"\x4a\x70\x78\x81\xa4\x34\x36\xe8"
"\x4c\x28\x54\xa6\x6c\xc3\x6b\x78"
"\xe7\xc0\x5d\xc6\x5d\x81\xab\x70"
"\x08\x86\xa1\xfd\xf4\x77\x55\xfd"
"\xa3\xe9\xe2\x1b\xdf\x99\xb7\x80"
"\xf9\x0a\x4f\x72\x4a\xd3\xaf\xbb"
"\xb3\x3b\xeb\x08\x58\x0f\x79\xce"
"\xa5\x99\x05\x12\x34\xd4\xf4\x86"
"\x37\x23\x1d\xc8\x49\xc0\x92\xae"
"\xa6\xac\x9b\x31\x55\xed\x15\xc6"
"\x05\x17\x37\x8d\x90\x42\xe4\x87"
"\x89\x62\x88\x69\x1c\x6a\xfd\xe3"
"\x00\x2b\x47\x1a\x73\xc1\x51\xc2"
"\xc0\x62\x74\x6a\x9e\xb2\xe5\x21"
"\xbe\x90\xb5\xb0\x50\xca\x88\x68"
"\xe1\x9d\x7a\xdf\x6c\xb7\xb9\x98"
"\xee\x28\x62\x61\x8b\xd1\x47\xf9"
"\x04\x7a\x0b\x5d\xcd\x2b\x65\xf5"
"\x12\xa3\xfe\x1a\xaa\x2c\x78\x42"
"\xb8\xbe\x7d\x74\xeb\x59\xba\xba",
.digest = "\xae\x11\xd4\x60\x2a\x5f\x9e\x42"
"\x89\x04\xc2\x34\x8d\x55\x94\x0a",
.psize = 256,
.ksize = 16,
},
};
#endif /* _CRYPTO_TESTMGR_H */

17
include/crypto/polyval.h Normal file
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@ -0,0 +1,17 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Common values for the Polyval hash algorithm
*
* Copyright 2021 Google LLC
*/
#ifndef _CRYPTO_POLYVAL_H
#define _CRYPTO_POLYVAL_H
#include <linux/types.h>
#include <linux/crypto.h>
#define POLYVAL_BLOCK_SIZE 16
#define POLYVAL_DIGEST_SIZE 16
#endif