[PATCH 1/2] crypto: introduce SM4 symmetric cipher algorithm

[Gilad Ben-Yossef]

Introduce the SM4 cipher algorithms (OSCCA GB/T 32907-2016).

SM4 (GBT.32907-2016) is a cryptographic standard issued by the
Organization of State Commercial Administration of China (OSCCA)
as an authorized cryptographic algorithms for the use within China.

SMS4 was originally created for use in protecting wireless
networks, and is mandated in the Chinese National Standard for
Wireless LAN WAPI (Wired Authentication and Privacy Infrastructure)
(GB.15629.11-2003).

Signed-off-by: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>
---
 crypto/Kconfig       |  25 ++++++
 crypto/Makefile      |   1 +
 crypto/sm4_generic.c | 244 +++++++++++++++++++++++++++++++++++++++++++++++++++
 include/crypto/sm4.h |  28 ++++++
 4 files changed, 298 insertions(+)
 create mode 100644 crypto/sm4_generic.c
 create mode 100644 include/crypto/sm4.h

diff --git a/crypto/Kconfig b/crypto/Kconfig
index de693e0..4b8df3a 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1475,6 +1475,31 @@ config CRYPTO_SERPENT_AVX2_X86_64
 	  See also:
 	  <http://www.cl.cam.ac.uk/~rja14/serpent.html>
 
+config CRYPTO_SM4
+	tristate "SM4 cipher algorithm"
+	select CRYPTO_ALGAPI
+	help
+	  SM4 cipher algorithms (OSCCA GB/T 32907-2016).
+
+	  SM4 (GBT.32907-2016) is a cryptographic standard issued by the
+	  Organization of State Commercial Administration of China (OSCCA)
+	  as an authorized cryptographic algorithms for the use within China.
+
+	  SMS4 was originally created for use in protecting wireless
+	  networks, and is mandated in the Chinese National Standard for
+	  Wireless LAN WAPI (Wired Authentication and Privacy Infrastructure)
+	  (GB.15629.11-2003).
+
+	  The latest SM4 standard (GBT.32907-2016) was proposed by OSCCA and
+	  standardized through TC 260 of the Standardization Administration
+	  of the People's Republic of China (SAC).
+
+	  The input, output, and key of SMS4 are each 128 bits.
+
+	  See also: <https://eprint.iacr.org/2008/329.pdf>
+
+	  If unsure, say N.
+
 config CRYPTO_SPECK
 	tristate "Speck cipher algorithm"
 	select CRYPTO_ALGAPI
diff --git a/crypto/Makefile b/crypto/Makefile
index 04517b2..eb4d9cd 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -100,6 +100,7 @@ obj-$(CONFIG_CRYPTO_SERPENT) += serpent_generic.o
 CFLAGS_serpent_generic.o := $(call cc-option,-fsched-pressure)  # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79149
 obj-$(CONFIG_CRYPTO_AES) += aes_generic.o
 CFLAGS_aes_generic.o := $(call cc-option,-fno-code-hoisting) # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83356
+obj-$(CONFIG_CRYPTO_SM4) += sm4_generic.o
 obj-$(CONFIG_CRYPTO_AES_TI) += aes_ti.o
 obj-$(CONFIG_CRYPTO_CAMELLIA) += camellia_generic.o
 obj-$(CONFIG_CRYPTO_CAST_COMMON) += cast_common.o
diff --git a/crypto/sm4_generic.c b/crypto/sm4_generic.c
new file mode 100644
index 0000000..f537a27
--- /dev/null
+++ b/crypto/sm4_generic.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * SM4 Cipher Algorithm.
+ *
+ * Copyright (C) 2018 ARM Limited or its affiliates.
+ * All rights reserved.
+ */
+
+#include <crypto/sm4.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/crypto.h>
+#include <asm/byteorder.h>
+#include <asm/unaligned.h>
+
+static const u32 fk[4] = {
+	0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
+};
+
+static const u8 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;
+	u8 *b = (u8 *)&x;
+
+	for (i = 0; i < 4; ++i)
+		b[i] = sbox[b[i]];
+
+	return x;
+}
+
+static u32 sm4_key_lin_sub(u32 x)
+{
+	return x ^ rol32(x, 13) ^ rol32(x, 23);
+
+}
+
+static u32 sm4_enc_lin_sub(u32 x)
+{
+	return x ^ rol32(x, 2) ^ rol32(x, 10) ^ rol32(x, 18) ^ rol32(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);
+}
+
+
+/**
+ * crypto_sm4_expand_key - Expands the SM4 key as described in GB/T 32907-2016
+ * @ctx:	The location where the computed key will be stored.
+ * @in_key:	The supplied key.
+ * @key_len:	The length of the supplied key.
+ *
+ * Returns 0 on success. The function fails only if an invalid key size (or
+ * pointer) is supplied.
+ */
+int crypto_sm4_expand_key(struct crypto_sm4_ctx *ctx, const u8 *in_key,
+			  unsigned int key_len)
+{
+	u32 rk[4], t;
+	const u32 *key = (u32 *)in_key;
+	int i;
+
+	if (key_len != SM4_KEY_SIZE)
+		return -EINVAL;
+
+	for (i = 0; i < 4; ++i)
+		rk[i] = get_unaligned_be32(&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;
+}
+EXPORT_SYMBOL_GPL(crypto_sm4_expand_key);
+
+/**
+ * crypto_sm4_set_key - Set the AES key.
+ * @tfm:	The %crypto_tfm that is used in the context.
+ * @in_key:	The input key.
+ * @key_len:	The size of the key.
+ *
+ * Returns 0 on success, on failure the %CRYPTO_TFM_RES_BAD_KEY_LEN flag in tfm
+ * is set. The function uses crypto_sm4_expand_key() to expand the key.
+ * &crypto_sm4_ctx _must_ be the private data embedded in @tfm which is
+ * retrieved with crypto_tfm_ctx().
+ */
+int crypto_sm4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
+		       unsigned int key_len)
+{
+	struct crypto_sm4_ctx *ctx = crypto_tfm_ctx(tfm);
+	u32 *flags = &tfm->crt_flags;
+	int ret;
+
+	ret = crypto_sm4_expand_key(ctx, in_key, key_len);
+	if (!ret)
+		return 0;
+
+	*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+	return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(crypto_sm4_set_key);
+
+static void sm4_do_crypt(const u32 *rk, u32 *out, const u32 *in)
+{
+	u32 x[4], i, t;
+
+	for (i = 0; i < 4; ++i)
+		x[i] = get_unaligned_be32(&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)
+		put_unaligned_be32(x[3 - i], &out[i]);
+}
+
+/* encrypt a block of text */
+
+static void sm4_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	const struct crypto_sm4_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	sm4_do_crypt(ctx->rkey_enc, (u32 *)out, (u32 *)in);
+}
+
+/* decrypt a block of text */
+
+static void sm4_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	const struct crypto_sm4_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	sm4_do_crypt(ctx->rkey_dec, (u32 *)out, (u32 *)in);
+}
+
+static struct crypto_alg sm4_alg = {
+	.cra_name		=	"sm4",
+	.cra_driver_name	=	"sm4-generic",
+	.cra_priority		=	100,
+	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
+	.cra_blocksize		=	SM4_BLOCK_SIZE,
+	.cra_ctxsize		=	sizeof(struct crypto_sm4_ctx),
+	.cra_module		=	THIS_MODULE,
+	.cra_u			=	{
+		.cipher = {
+			.cia_min_keysize	=	SM4_KEY_SIZE,
+			.cia_max_keysize	=	SM4_KEY_SIZE,
+			.cia_setkey		=	crypto_sm4_set_key,
+			.cia_encrypt		=	sm4_encrypt,
+			.cia_decrypt		=	sm4_decrypt
+		}
+	}
+};
+
+static int __init sm4_init(void)
+{
+	return crypto_register_alg(&sm4_alg);
+}
+
+static void __exit sm4_fini(void)
+{
+	crypto_unregister_alg(&sm4_alg);
+}
+
+module_init(sm4_init);
+module_exit(sm4_fini);
+
+MODULE_DESCRIPTION("SM4 Cipher Algorithm");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_CRYPTO("sm4");
+MODULE_ALIAS_CRYPTO("sm4-generic");
diff --git a/include/crypto/sm4.h b/include/crypto/sm4.h
new file mode 100644
index 0000000..b64e64d
--- /dev/null
+++ b/include/crypto/sm4.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Common values for the SM4 algorithm
+ * Copyright (C) 2018 ARM Limited or its affiliates.
+ */
+
+#ifndef _CRYPTO_SM4_H
+#define _CRYPTO_SM4_H
+
+#include <linux/types.h>
+#include <linux/crypto.h>
+
+#define SM4_KEY_SIZE	16
+#define SM4_BLOCK_SIZE	16
+#define SM4_RKEY_WORDS	32
+
+struct crypto_sm4_ctx {
+	u32 rkey_enc[SM4_RKEY_WORDS];
+	u32 rkey_dec[SM4_RKEY_WORDS];
+};
+
+int crypto_sm4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
+		       unsigned int key_len);
+int crypto_sm4_expand_key(struct crypto_sm4_ctx *ctx, const u8 *in_key,
+			  unsigned int key_len);
+
+#endif
-- 
2.7.4