[PATCH 1/1] Add SM4 symmetric cipher algorithm
Jussi Kivilinna
jussi.kivilinna at iki.fi
Tue Jun 9 19:59:51 CEST 2020
Hello,
Patch looks mostly good. I have add few comments below.
On 8.6.2020 14.00, Tianjia Zhang via Gcrypt-devel wrote:
> * cipher/Makefile.am (EXTRA_libcipher_la_SOURCES): Add sm4.c.
> * cipher/cipher.c (cipher_list, cipher_list_algo301):
> Add _gcry_cipher_spec_sm4.
> * cipher/sm4.c: New.
> * configure.ac (available_ciphers): Add sm4.
> * src/cipher.h: Add declarations for SM4.
> * src/gcrypt.h.in (gcry_cipher_algos): Add algorithm ID for SM4.
> * tests/basic.c (check_ciphers): Add sm4 check.
Please also add GCRY_MAC_CMAC_SM4 support in mac.c/mac-cmac.c.
>
> Signed-off-by: Tianjia Zhang <tianjia.zhang at linux.alibaba.com>
> ---
> cipher/Makefile.am | 1 +
> cipher/cipher.c | 8 ++
> cipher/sm4.c | 270 +++++++++++++++++++++++++++++++++++++++++++++
> configure.ac | 7 ++
> src/cipher.h | 1 +
> src/gcrypt.h.in | 3 +-
> tests/basic.c | 3 +
> 7 files changed, 292 insertions(+), 1 deletion(-)
> create mode 100644 cipher/sm4.c
>
> diff --git a/cipher/Makefile.am b/cipher/Makefile.am
> index ef83cc74..56661dcd 100644
> --- a/cipher/Makefile.am
> +++ b/cipher/Makefile.am
> @@ -107,6 +107,7 @@ EXTRA_libcipher_la_SOURCES = \
> scrypt.c \
> seed.c \
> serpent.c serpent-sse2-amd64.S \
> + sm4.c \
> serpent-avx2-amd64.S serpent-armv7-neon.S \
> sha1.c sha1-ssse3-amd64.S sha1-avx-amd64.S sha1-avx-bmi2-amd64.S \
> sha1-avx2-bmi2-amd64.S sha1-armv7-neon.S sha1-armv8-aarch32-ce.S \
> diff --git a/cipher/cipher.c b/cipher/cipher.c
> index edcb421a..dfb083a0 100644
> --- a/cipher/cipher.c
> +++ b/cipher/cipher.c
> @@ -87,6 +87,9 @@ static gcry_cipher_spec_t * const cipher_list[] =
> #endif
> #if USE_CHACHA20
> &_gcry_cipher_spec_chacha20,
> +#endif
> +#if USE_SM4
> + &_gcry_cipher_spec_sm4,
> #endif
> NULL
> };
> @@ -202,6 +205,11 @@ static gcry_cipher_spec_t * const cipher_list_algo301[] =
> &_gcry_cipher_spec_gost28147_mesh,
> #else
> NULL,
> +#endif
> +#if USE_SM4
> + &_gcry_cipher_spec_sm4,
> +#else
> + NULL,
> #endif
> };
>
> diff --git a/cipher/sm4.c b/cipher/sm4.c
> new file mode 100644
> index 00000000..a1bdca10
> --- /dev/null
> +++ b/cipher/sm4.c
> @@ -0,0 +1,270 @@
> +/* sm4.c - SM4 Cipher Algorithm
> + * Copyright (C) 2020 Alibaba Group.
> + * Copyright (C) 2020 Tianjia Zhang
> + *
> + * This file is part of Libgcrypt.
> + *
> + * Libgcrypt is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU Lesser General Public License as
> + * published by the Free Software Foundation; either version 2.1 of
> + * the License, or (at your option) any later version.
> + *
> + * Libgcrypt is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this program; if not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <config.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +
> +#include "types.h" /* for byte and u32 typedefs */
> +#include "bithelp.h"
> +#include "g10lib.h"
> +#include "cipher.h"
> +
> +typedef struct
> +{
> + u32 rkey_enc[32];
> + u32 rkey_dec[32];
> +} SM4_context;
> +
> +static const u32 fk[4] = {
> + 0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
> +};
> +
> +static const byte sbox[256] = {
> + 0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7,
> + 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
> + 0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3,
> + 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
> + 0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a,
> + 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62,
> + 0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95,
> + 0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
> + 0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba,
> + 0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
> + 0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b,
> + 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35,
> + 0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2,
> + 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
> + 0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52,
> + 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
> + 0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5,
> + 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1,
> + 0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55,
> + 0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
> + 0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60,
> + 0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
> + 0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f,
> + 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51,
> + 0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f,
> + 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
> + 0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd,
> + 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
> + 0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e,
> + 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84,
> + 0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20,
> + 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48
> +};
> +
> +static const u32 ck[] = {
> + 0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
> + 0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
> + 0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
> + 0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
> + 0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
> + 0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
> + 0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
> + 0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
> +};
> +
> +static u32 sm4_t_non_lin_sub(u32 x)
> +{
> + int i;
> + byte *b = (byte *)&x;
> +
> + for (i = 0; i < 4; ++i)
> + b[i] = sbox[b[i]];
> +
> + return x;
> +}
> +
> +static u32 sm4_key_lin_sub(u32 x)
> +{
> + return x ^ rol(x, 13) ^ rol(x, 23);
> +}
> +
> +static u32 sm4_enc_lin_sub(u32 x)
> +{
> + return x ^ rol(x, 2) ^ rol(x, 10) ^ rol(x, 18) ^ rol(x, 24);
> +}
> +
> +static u32 sm4_key_sub(u32 x)
> +{
> + return sm4_key_lin_sub(sm4_t_non_lin_sub(x));
> +}
> +
> +static u32 sm4_enc_sub(u32 x)
> +{
> + return sm4_enc_lin_sub(sm4_t_non_lin_sub(x));
> +}
> +
> +static u32 sm4_round(const u32 *x, const u32 rk)
> +{
> + return x[0] ^ sm4_enc_sub(x[1] ^ x[2] ^ x[3] ^ rk);
> +}
> +
> +static gcry_err_code_t
> +sm4_expand_key (SM4_context *ctx, const u32 *key, const unsigned keylen)
> +{
> + u32 rk[4], t;
> + int i;
> +
> + if (keylen != 16)
> + return GPG_ERR_INV_KEYLEN;
> +
> + for (i = 0; i < 4; ++i)
> + rk[i] = be_bswap32(key[i]) ^ fk[i];
> +
> + for (i = 0; i < 32; ++i)
> + {
> + t = rk[0] ^ sm4_key_sub(rk[1] ^ rk[2] ^ rk[3] ^ ck[i]);
> + ctx->rkey_enc[i] = t;
> + rk[0] = rk[1];
> + rk[1] = rk[2];
> + rk[2] = rk[3];
> + rk[3] = t;
> + }
> +
> + for (i = 0; i < 32; ++i)
> + ctx->rkey_dec[i] = ctx->rkey_enc[31 - i];
> +
> + return 0;
> +}
> +
> +static gcry_err_code_t
> +sm4_setkey (void *context, const byte *key, const unsigned keylen,
> + gcry_cipher_hd_t hd)
> +{
> + SM4_context *ctx = context;
> + (void)hd;
> + return sm4_expand_key (ctx, (const u32 *)key, keylen);
Casting byte pointer to word pointer here. 'key' here might not be
aligned 4 bytes and can then cause seg-fault in 'sm4_expand_key' on
architectures that do not handle unaligned memory accesses
automatically.
It's better to change 'sm4_expand_key' take 'key' as byte pointer
and use 'buf_get_be32' for reading from it.
> +}
> +
> +static void
> +sm4_do_crypt (const u32 *rk, u32 *out, const u32 *in)
Likewise, better to use byte pointer for 'out' and 'in' here and
use 'buf_get_be32' and 'buf_put_be32' for reading and writing.
> +{
> + u32 x[4], t;
> + int i;
> +
> + for (i = 0; i < 4; ++i)
> + x[i] = be_bswap32(in[i]);
> +
> + for (i = 0; i < 32; ++i)
> + {
> + t = sm4_round(x, rk[i]);
> + x[0] = x[1];
> + x[1] = x[2];
> + x[2] = x[3];
> + x[3] = t;
> + }
> +
> + for (i = 0; i < 4; ++i)
> + out[i] = be_bswap32(x[3 - i]);
> +}
> +
> +static unsigned int
> +sm4_encrypt (void *context, byte *outbuf, const byte *inbuf)
> +{
> + SM4_context *ctx = context;
> +
> + sm4_do_crypt (ctx->rkey_enc, (u32 *)outbuf, (const u32 *)inbuf);
> + return 0;
> +}
> +
> +static unsigned int
> +sm4_decrypt (void *context, byte *outbuf, const byte *inbuf)
> +{
> + SM4_context *ctx = context;
> +
> + sm4_do_crypt (ctx->rkey_dec, (u32 *)outbuf, (const u32 *)inbuf);
> + return 0;
> +}
Encrypt/decrypt functions should return 'stack burn' depth in bytes.
Good estimate for this is size of variables + size of arguments +
size of call return pointer. So in this case, "4*6+sizeof(void*)*4".
> +
> +static const char *
> +sm4_selftest (void)
> +{
> + SM4_context ctx;
> + byte scratch[16];
> +
> + static const byte plaintext[16] = {
> + 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF,
> + 0xFE, 0xDC, 0xBA, 0x98, 0x76, 0x54, 0x32, 0x10,
> + };
> + static const byte key[16] = {
> + 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF,
> + 0xFE, 0xDC, 0xBA, 0x98, 0x76, 0x54, 0x32, 0x10,
> + };
> + static const byte ciphertext[16] = {
> + 0x68, 0x1E, 0xDF, 0x34, 0xD2, 0x06, 0x96, 0x5E,
> + 0x86, 0xB3, 0xE9, 0x4F, 0x53, 0x6E, 0x42, 0x46
> + };
> +
> + sm4_setkey (&ctx, key, sizeof (key), NULL);
> + sm4_encrypt (&ctx, scratch, plaintext);
> + if (memcmp (scratch, ciphertext, sizeof (ciphertext)))
> + return "SM4 test encryption failed.";
> + sm4_decrypt (&ctx, scratch, scratch);
> + if (memcmp (scratch, plaintext, sizeof (plaintext)))
> + return "SM4 test decryption failed.";
> +
> + return NULL;
> +}
> +
> +static gpg_err_code_t
> +run_selftests (int algo, int extended, selftest_report_func_t report)
> +{
> + const char *what;
> + const char *errtxt;
> +
> + (void)extended;
> +
> + if (algo != GCRY_CIPHER_SM4)
> + return GPG_ERR_CIPHER_ALGO;
> +
> + what = "selftest";
> + errtxt = sm4_selftest ();
> + if (errtxt)
> + goto failed;
> +
> + return 0;
> +
> + failed:
> + if (report)
> + report ("cipher", GCRY_CIPHER_SM4, what, errtxt);
> + return GPG_ERR_SELFTEST_FAILED;
> +}
> +
> +static gcry_cipher_oid_spec_t sm4_oids[] =
> + {
> + { "1.2.156.10197.1.104.1", GCRY_CIPHER_MODE_ECB },
> + { "1.2.156.10197.1.104.2", GCRY_CIPHER_MODE_CBC },
> + { "1.2.156.10197.1.104.3", GCRY_CIPHER_MODE_OFB },
> + { "1.2.156.10197.1.104.4", GCRY_CIPHER_MODE_CFB },
> + { NULL }
> + };
> +
> +gcry_cipher_spec_t _gcry_cipher_spec_sm4 =
> + {
> + GCRY_CIPHER_SM4, {0, 0},
> + "SM4", NULL, sm4_oids, 16, 128,
> + sizeof (SM4_context),
> + sm4_setkey, sm4_encrypt, sm4_decrypt,
> + NULL, NULL,
> + run_selftests
> + };
> diff --git a/configure.ac b/configure.ac
> index 3bf0179e..472758b5 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -212,6 +212,7 @@ LIBGCRYPT_CONFIG_HOST="$host"
> # Definitions for symmetric ciphers.
> available_ciphers="arcfour blowfish cast5 des aes twofish serpent rfc2268 seed"
> available_ciphers="$available_ciphers camellia idea salsa20 gost28147 chacha20"
> +available_ciphers="$available_ciphers sm4"
> enabled_ciphers=""
>
> # Definitions for public-key ciphers.
> @@ -2533,6 +2534,12 @@ if test "$found" = "1" ; then
> fi
> fi
>
> +LIST_MEMBER(sm4, $enabled_ciphers)
> +if test "$found" = "1" ; then
> + GCRYPT_CIPHERS="$GCRYPT_CIPHERS sm4.lo"
> + AC_DEFINE(USE_SM4, 1, [Defined if this module should be included])
> +fi
> +
> LIST_MEMBER(dsa, $enabled_pubkey_ciphers)
> if test "$found" = "1" ; then
> GCRYPT_PUBKEY_CIPHERS="$GCRYPT_PUBKEY_CIPHERS dsa.lo"
> diff --git a/src/cipher.h b/src/cipher.h
> index 20ccb8c5..c49bbda5 100644
> --- a/src/cipher.h
> +++ b/src/cipher.h
> @@ -302,6 +302,7 @@ extern gcry_cipher_spec_t _gcry_cipher_spec_salsa20r12;
> extern gcry_cipher_spec_t _gcry_cipher_spec_gost28147;
> extern gcry_cipher_spec_t _gcry_cipher_spec_gost28147_mesh;
> extern gcry_cipher_spec_t _gcry_cipher_spec_chacha20;
> +extern gcry_cipher_spec_t _gcry_cipher_spec_sm4;
>
> /* Declarations for the digest specifications. */
> extern gcry_md_spec_t _gcry_digest_spec_crc32;
> diff --git a/src/gcrypt.h.in b/src/gcrypt.h.in
> index c0132189..9ddef17b 100644
> --- a/src/gcrypt.h.in
> +++ b/src/gcrypt.h.in
> @@ -946,7 +946,8 @@ enum gcry_cipher_algos
> GCRY_CIPHER_SALSA20R12 = 314,
> GCRY_CIPHER_GOST28147 = 315,
> GCRY_CIPHER_CHACHA20 = 316,
> - GCRY_CIPHER_GOST28147_MESH = 317 /* GOST 28247 with optional CryptoPro keymeshing */
> + GCRY_CIPHER_GOST28147_MESH = 317, /* GOST 28247 with optional CryptoPro keymeshing */
> + GCRY_CIPHER_SM4 = 318
> };
>
> /* The Rijndael algorithm is basically AES, so provide some macros. */
> diff --git a/tests/basic.c b/tests/basic.c
> index 2dee1bee..6f2945a5 100644
> --- a/tests/basic.c
> +++ b/tests/basic.c
> @@ -9444,6 +9444,9 @@ check_ciphers (void)
> #if USE_GOST28147
> GCRY_CIPHER_GOST28147,
> GCRY_CIPHER_GOST28147_MESH,
> +#endif
> +#if USE_SM4
> + GCRY_CIPHER_SM4,
> #endif
> 0
> };
>
It would be nice to have some extra test-vectors in basic.c for
common cipher modes with SM4. There's few such vectors at following
Internet-Draft that could be used:
https://tools.ietf.org/html/draft-ribose-cfrg-sm4-10#appendix-A.2
-Jussi
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