1 // SPDX-License-Identifier: GPL-2.0-only
5 * Michael MIC (IEEE 802.11i/TKIP) keyed digest
7 * Copyright (c) 2004 Jouni Malinen <j@w1.fi>
9 #include <crypto/internal/hash.h>
10 #include <asm/byteorder.h>
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/string.h>
14 #include <linux/types.h>
17 struct michael_mic_ctx {
21 struct michael_mic_desc_ctx {
28 static inline u32 xswap(u32 val)
30 return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
34 #define michael_block(l, r) \
47 static int michael_init(struct shash_desc *desc)
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;
59 static int michael_update(struct shash_desc *desc, const u8 *data,
62 struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
65 if (mctx->pending_len) {
66 int flen = 4 - mctx->pending_len;
69 memcpy(&mctx->pending[mctx->pending_len], data, flen);
70 mctx->pending_len += flen;
74 if (mctx->pending_len < 4)
77 src = (const __le32 *)mctx->pending;
78 mctx->l ^= le32_to_cpup(src);
79 michael_block(mctx->l, mctx->r);
80 mctx->pending_len = 0;
83 src = (const __le32 *)data;
86 mctx->l ^= le32_to_cpup(src++);
87 michael_block(mctx->l, mctx->r);
92 mctx->pending_len = len;
93 memcpy(mctx->pending, src, len);
100 static int michael_final(struct shash_desc *desc, u8 *out)
102 struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
103 u8 *data = mctx->pending;
104 __le32 *dst = (__le32 *)out;
106 /* Last block and padding (0x5a, 4..7 x 0) */
107 switch (mctx->pending_len) {
112 mctx->l ^= data[0] | 0x5a00;
115 mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000;
118 mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) |
122 michael_block(mctx->l, mctx->r);
124 michael_block(mctx->l, mctx->r);
126 dst[0] = cpu_to_le32(mctx->l);
127 dst[1] = cpu_to_le32(mctx->r);
133 static int michael_setkey(struct crypto_shash *tfm, const u8 *key,
136 struct michael_mic_ctx *mctx = crypto_shash_ctx(tfm);
138 const __le32 *data = (const __le32 *)key;
143 mctx->l = le32_to_cpu(data[0]);
144 mctx->r = le32_to_cpu(data[1]);
148 static struct shash_alg alg = {
150 .setkey = michael_setkey,
151 .init = michael_init,
152 .update = michael_update,
153 .final = michael_final,
154 .descsize = sizeof(struct michael_mic_desc_ctx),
156 .cra_name = "michael_mic",
157 .cra_driver_name = "michael_mic-generic",
160 .cra_ctxsize = sizeof(struct michael_mic_ctx),
161 .cra_module = THIS_MODULE,
165 static int __init michael_mic_init(void)
167 return crypto_register_shash(&alg);
171 static void __exit michael_mic_exit(void)
173 crypto_unregister_shash(&alg);
177 subsys_initcall(michael_mic_init);
178 module_exit(michael_mic_exit);
180 MODULE_LICENSE("GPL v2");
181 MODULE_DESCRIPTION("Michael MIC");
182 MODULE_AUTHOR("Jouni Malinen <j@w1.fi>");
183 MODULE_ALIAS_CRYPTO("michael_mic");