linux/lib/crypto/sm4.c
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   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/*
   3 * SM4, as specified in
   4 * https://tools.ietf.org/id/draft-ribose-cfrg-sm4-10.html
   5 *
   6 * Copyright (C) 2018 ARM Limited or its affiliates.
   7 * Copyright (c) 2021 Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
   8 */
   9
  10#include <linux/module.h>
  11#include <asm/unaligned.h>
  12#include <crypto/sm4.h>
  13
  14static const u32 fk[4] = {
  15        0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
  16};
  17
  18static const u32 __cacheline_aligned ck[32] = {
  19        0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
  20        0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
  21        0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
  22        0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
  23        0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
  24        0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
  25        0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
  26        0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
  27};
  28
  29static const u8 __cacheline_aligned sbox[256] = {
  30        0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7,
  31        0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
  32        0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3,
  33        0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
  34        0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a,
  35        0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62,
  36        0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95,
  37        0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
  38        0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba,
  39        0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
  40        0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b,
  41        0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35,
  42        0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2,
  43        0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
  44        0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52,
  45        0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
  46        0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5,
  47        0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1,
  48        0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55,
  49        0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
  50        0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60,
  51        0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
  52        0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f,
  53        0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51,
  54        0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f,
  55        0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
  56        0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd,
  57        0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
  58        0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e,
  59        0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84,
  60        0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20,
  61        0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48
  62};
  63
  64static inline u32 sm4_t_non_lin_sub(u32 x)
  65{
  66        u32 out;
  67
  68        out  = (u32)sbox[x & 0xff];
  69        out |= (u32)sbox[(x >> 8) & 0xff] << 8;
  70        out |= (u32)sbox[(x >> 16) & 0xff] << 16;
  71        out |= (u32)sbox[(x >> 24) & 0xff] << 24;
  72
  73        return out;
  74}
  75
  76static inline u32 sm4_key_lin_sub(u32 x)
  77{
  78        return x ^ rol32(x, 13) ^ rol32(x, 23);
  79}
  80
  81static inline u32 sm4_enc_lin_sub(u32 x)
  82{
  83        return x ^ rol32(x, 2) ^ rol32(x, 10) ^ rol32(x, 18) ^ rol32(x, 24);
  84}
  85
  86static inline u32 sm4_key_sub(u32 x)
  87{
  88        return sm4_key_lin_sub(sm4_t_non_lin_sub(x));
  89}
  90
  91static inline u32 sm4_enc_sub(u32 x)
  92{
  93        return sm4_enc_lin_sub(sm4_t_non_lin_sub(x));
  94}
  95
  96static inline u32 sm4_round(u32 x0, u32 x1, u32 x2, u32 x3, u32 rk)
  97{
  98        return x0 ^ sm4_enc_sub(x1 ^ x2 ^ x3 ^ rk);
  99}
 100
 101
 102/**
 103 * sm4_expandkey - Expands the SM4 key as described in GB/T 32907-2016
 104 * @ctx:        The location where the computed key will be stored.
 105 * @in_key:     The supplied key.
 106 * @key_len:    The length of the supplied key.
 107 *
 108 * Returns 0 on success. The function fails only if an invalid key size (or
 109 * pointer) is supplied.
 110 */
 111int sm4_expandkey(struct sm4_ctx *ctx, const u8 *in_key,
 112                          unsigned int key_len)
 113{
 114        u32 rk[4];
 115        const u32 *key = (u32 *)in_key;
 116        int i;
 117
 118        if (key_len != SM4_KEY_SIZE)
 119                return -EINVAL;
 120
 121        rk[0] = get_unaligned_be32(&key[0]) ^ fk[0];
 122        rk[1] = get_unaligned_be32(&key[1]) ^ fk[1];
 123        rk[2] = get_unaligned_be32(&key[2]) ^ fk[2];
 124        rk[3] = get_unaligned_be32(&key[3]) ^ fk[3];
 125
 126        for (i = 0; i < 32; i += 4) {
 127                rk[0] ^= sm4_key_sub(rk[1] ^ rk[2] ^ rk[3] ^ ck[i + 0]);
 128                rk[1] ^= sm4_key_sub(rk[2] ^ rk[3] ^ rk[0] ^ ck[i + 1]);
 129                rk[2] ^= sm4_key_sub(rk[3] ^ rk[0] ^ rk[1] ^ ck[i + 2]);
 130                rk[3] ^= sm4_key_sub(rk[0] ^ rk[1] ^ rk[2] ^ ck[i + 3]);
 131
 132                ctx->rkey_enc[i + 0] = rk[0];
 133                ctx->rkey_enc[i + 1] = rk[1];
 134                ctx->rkey_enc[i + 2] = rk[2];
 135                ctx->rkey_enc[i + 3] = rk[3];
 136                ctx->rkey_dec[31 - 0 - i] = rk[0];
 137                ctx->rkey_dec[31 - 1 - i] = rk[1];
 138                ctx->rkey_dec[31 - 2 - i] = rk[2];
 139                ctx->rkey_dec[31 - 3 - i] = rk[3];
 140        }
 141
 142        return 0;
 143}
 144EXPORT_SYMBOL_GPL(sm4_expandkey);
 145
 146/**
 147 * sm4_crypt_block - Encrypt or decrypt a single SM4 block
 148 * @rk:         The rkey_enc for encrypt or rkey_dec for decrypt
 149 * @out:        Buffer to store output data
 150 * @in:         Buffer containing the input data
 151 */
 152void sm4_crypt_block(const u32 *rk, u8 *out, const u8 *in)
 153{
 154        u32 x[4], i;
 155
 156        x[0] = get_unaligned_be32(in + 0 * 4);
 157        x[1] = get_unaligned_be32(in + 1 * 4);
 158        x[2] = get_unaligned_be32(in + 2 * 4);
 159        x[3] = get_unaligned_be32(in + 3 * 4);
 160
 161        for (i = 0; i < 32; i += 4) {
 162                x[0] = sm4_round(x[0], x[1], x[2], x[3], rk[i + 0]);
 163                x[1] = sm4_round(x[1], x[2], x[3], x[0], rk[i + 1]);
 164                x[2] = sm4_round(x[2], x[3], x[0], x[1], rk[i + 2]);
 165                x[3] = sm4_round(x[3], x[0], x[1], x[2], rk[i + 3]);
 166        }
 167
 168        put_unaligned_be32(x[3 - 0], out + 0 * 4);
 169        put_unaligned_be32(x[3 - 1], out + 1 * 4);
 170        put_unaligned_be32(x[3 - 2], out + 2 * 4);
 171        put_unaligned_be32(x[3 - 3], out + 3 * 4);
 172}
 173EXPORT_SYMBOL_GPL(sm4_crypt_block);
 174
 175MODULE_DESCRIPTION("Generic SM4 library");
 176MODULE_LICENSE("GPL v2");
 177