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@xxxxxxxxxx> Reviewed-by: Eric Biggers <ebiggers@xxxxxxxxxx> Reviewed-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- crypto/Kconfig | 8 ++ crypto/Makefile | 1 + crypto/polyval-generic.c | 205 +++++++++++++++++++++++++++++++++++++++ crypto/tcrypt.c | 4 + crypto/testmgr.c | 6 ++ crypto/testmgr.h | 171 ++++++++++++++++++++++++++++++++ include/crypto/polyval.h | 17 ++++ 7 files changed, 412 insertions(+) create mode 100644 crypto/polyval-generic.c create mode 100644 include/crypto/polyval.h diff --git a/crypto/Kconfig b/crypto/Kconfig index 47752aaa16ff..00139845d76d 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -768,6 +768,14 @@ 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 diff --git a/crypto/Makefile b/crypto/Makefile index 6b3fe3df1489..561f901a91d4 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -169,6 +169,7 @@ 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 diff --git a/crypto/polyval-generic.c b/crypto/polyval-generic.c new file mode 100644 index 000000000000..bf2b03b7bfc0 --- /dev/null +++ b/crypto/polyval-generic.c @@ -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@xxxxxx> + * Copyright (c) 2009 Intel Corp. + * Author: Huang Ying <ying.huang@xxxxxxxxx> + * 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"); diff --git a/crypto/tcrypt.c b/crypto/tcrypt.c index fd671d0e2012..dd9cf216029b 100644 --- a/crypto/tcrypt.c +++ b/crypto/tcrypt.c @@ -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; diff --git a/crypto/testmgr.c b/crypto/testmgr.c index fbb12d7d78af..d807b200edf6 100644 --- a/crypto/testmgr.c +++ b/crypto/testmgr.c @@ -5284,6 +5284,12 @@ 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, diff --git a/crypto/testmgr.h b/crypto/testmgr.h index bf4ff97eeb37..c581e5405916 100644 --- a/crypto/testmgr.h +++ b/crypto/testmgr.h @@ -34929,4 +34929,175 @@ 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 */ diff --git a/include/crypto/polyval.h b/include/crypto/polyval.h new file mode 100644 index 000000000000..b14c38aa9166 --- /dev/null +++ b/include/crypto/polyval.h @@ -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 -- 2.36.1.124.g0e6072fb45-goog