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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 | /* * Cryptographic API * * Michael MIC (IEEE 802.11i/TKIP) keyed digest * * Copyright (c) 2004 Jouni Malinen <j@w1.fi> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <crypto/internal/hash.h> #include <asm/byteorder.h> #include <linux/init.h> #include <linux/module.h> #include <linux/string.h> #include <linux/types.h> struct michael_mic_ctx { u32 l, r; }; struct michael_mic_desc_ctx { u8 pending[4]; size_t pending_len; u32 l, r; }; static inline u32 xswap(u32 val) { return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8); } #define michael_block(l, r) \ do { \ r ^= rol32(l, 17); \ l += r; \ r ^= xswap(l); \ l += r; \ r ^= rol32(l, 3); \ l += r; \ r ^= ror32(l, 2); \ l += r; \ } while (0) static int michael_init(struct shash_desc *desc) { struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc); struct michael_mic_ctx *ctx = crypto_shash_ctx(desc->tfm); mctx->pending_len = 0; mctx->l = ctx->l; mctx->r = ctx->r; return 0; } static int michael_update(struct shash_desc *desc, const u8 *data, unsigned int len) { struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc); const __le32 *src; if (mctx->pending_len) { int flen = 4 - mctx->pending_len; if (flen > len) flen = len; memcpy(&mctx->pending[mctx->pending_len], data, flen); mctx->pending_len += flen; data += flen; len -= flen; if (mctx->pending_len < 4) return 0; src = (const __le32 *)mctx->pending; mctx->l ^= le32_to_cpup(src); michael_block(mctx->l, mctx->r); mctx->pending_len = 0; } src = (const __le32 *)data; while (len >= 4) { mctx->l ^= le32_to_cpup(src++); michael_block(mctx->l, mctx->r); len -= 4; } if (len > 0) { mctx->pending_len = len; memcpy(mctx->pending, src, len); } return 0; } static int michael_final(struct shash_desc *desc, u8 *out) { struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc); u8 *data = mctx->pending; __le32 *dst = (__le32 *)out; /* Last block and padding (0x5a, 4..7 x 0) */ switch (mctx->pending_len) { case 0: mctx->l ^= 0x5a; break; case 1: mctx->l ^= data[0] | 0x5a00; break; case 2: mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000; break; case 3: mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) | 0x5a000000; break; } michael_block(mctx->l, mctx->r); /* l ^= 0; */ michael_block(mctx->l, mctx->r); dst[0] = cpu_to_le32(mctx->l); dst[1] = cpu_to_le32(mctx->r); return 0; } static int michael_setkey(struct crypto_shash *tfm, const u8 *key, unsigned int keylen) { struct michael_mic_ctx *mctx = crypto_shash_ctx(tfm); const __le32 *data = (const __le32 *)key; if (keylen != 8) { crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); return -EINVAL; } mctx->l = le32_to_cpu(data[0]); mctx->r = le32_to_cpu(data[1]); return 0; } static struct shash_alg alg = { .digestsize = 8, .setkey = michael_setkey, .init = michael_init, .update = michael_update, .final = michael_final, .descsize = sizeof(struct michael_mic_desc_ctx), .base = { .cra_name = "michael_mic", .cra_blocksize = 8, .cra_alignmask = 3, .cra_ctxsize = sizeof(struct michael_mic_ctx), .cra_module = THIS_MODULE, } }; static int __init michael_mic_init(void) { return crypto_register_shash(&alg); } static void __exit michael_mic_exit(void) { crypto_unregister_shash(&alg); } module_init(michael_mic_init); module_exit(michael_mic_exit); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("Michael MIC"); MODULE_AUTHOR("Jouni Malinen <j@w1.fi>"); MODULE_ALIAS_CRYPTO("michael_mic"); |