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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Cryptographic API4 *5 * Michael MIC (IEEE 802.11i/TKIP) keyed digest6 *7 * Copyright (c) 2004 Jouni Malinen <j@w1.fi>8 */9#include <crypto/internal/hash.h>10#include <linux/unaligned.h>11#include <linux/init.h>12#include <linux/module.h>13#include <linux/string.h>14#include <linux/types.h>15 16 17struct michael_mic_ctx {18 u32 l, r;19};20 21struct michael_mic_desc_ctx {22 __le32 pending;23 size_t pending_len;24 25 u32 l, r;26};27 28static inline u32 xswap(u32 val)29{30 return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);31}32 33 34#define michael_block(l, r) \35do { \36 r ^= rol32(l, 17); \37 l += r; \38 r ^= xswap(l); \39 l += r; \40 r ^= rol32(l, 3); \41 l += r; \42 r ^= ror32(l, 2); \43 l += r; \44} while (0)45 46 47static int michael_init(struct shash_desc *desc)48{49 struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);50 struct michael_mic_ctx *ctx = crypto_shash_ctx(desc->tfm);51 mctx->pending_len = 0;52 mctx->l = ctx->l;53 mctx->r = ctx->r;54 55 return 0;56}57 58 59static int michael_update(struct shash_desc *desc, const u8 *data,60 unsigned int len)61{62 struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);63 64 if (mctx->pending_len) {65 int flen = 4 - mctx->pending_len;66 if (flen > len)67 flen = len;68 memcpy((u8 *)&mctx->pending + mctx->pending_len, data, flen);69 mctx->pending_len += flen;70 data += flen;71 len -= flen;72 73 if (mctx->pending_len < 4)74 return 0;75 76 mctx->l ^= le32_to_cpu(mctx->pending);77 michael_block(mctx->l, mctx->r);78 mctx->pending_len = 0;79 }80 81 while (len >= 4) {82 mctx->l ^= get_unaligned_le32(data);83 michael_block(mctx->l, mctx->r);84 data += 4;85 len -= 4;86 }87 88 if (len > 0) {89 mctx->pending_len = len;90 memcpy(&mctx->pending, data, len);91 }92 93 return 0;94}95 96 97static int michael_final(struct shash_desc *desc, u8 *out)98{99 struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);100 u8 *data = (u8 *)&mctx->pending;101 102 /* Last block and padding (0x5a, 4..7 x 0) */103 switch (mctx->pending_len) {104 case 0:105 mctx->l ^= 0x5a;106 break;107 case 1:108 mctx->l ^= data[0] | 0x5a00;109 break;110 case 2:111 mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000;112 break;113 case 3:114 mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) |115 0x5a000000;116 break;117 }118 michael_block(mctx->l, mctx->r);119 /* l ^= 0; */120 michael_block(mctx->l, mctx->r);121 122 put_unaligned_le32(mctx->l, out);123 put_unaligned_le32(mctx->r, out + 4);124 125 return 0;126}127 128 129static int michael_setkey(struct crypto_shash *tfm, const u8 *key,130 unsigned int keylen)131{132 struct michael_mic_ctx *mctx = crypto_shash_ctx(tfm);133 134 if (keylen != 8)135 return -EINVAL;136 137 mctx->l = get_unaligned_le32(key);138 mctx->r = get_unaligned_le32(key + 4);139 return 0;140}141 142static struct shash_alg alg = {143 .digestsize = 8,144 .setkey = michael_setkey,145 .init = michael_init,146 .update = michael_update,147 .final = michael_final,148 .descsize = sizeof(struct michael_mic_desc_ctx),149 .base = {150 .cra_name = "michael_mic",151 .cra_driver_name = "michael_mic-generic",152 .cra_blocksize = 8,153 .cra_ctxsize = sizeof(struct michael_mic_ctx),154 .cra_module = THIS_MODULE,155 }156};157 158static int __init michael_mic_init(void)159{160 return crypto_register_shash(&alg);161}162 163 164static void __exit michael_mic_exit(void)165{166 crypto_unregister_shash(&alg);167}168 169 170subsys_initcall(michael_mic_init);171module_exit(michael_mic_exit);172 173MODULE_LICENSE("GPL v2");174MODULE_DESCRIPTION("Michael MIC");175MODULE_AUTHOR("Jouni Malinen <j@w1.fi>");176MODULE_ALIAS_CRYPTO("michael_mic");177