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176 lines
3.4 KiB
176 lines
3.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Cryptographic API |
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* |
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* Michael MIC (IEEE 802.11i/TKIP) keyed digest |
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* |
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* Copyright (c) 2004 Jouni Malinen <[email protected]> |
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*/ |
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#include <crypto/internal/hash.h> |
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#include <asm/unaligned.h> |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/string.h> |
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#include <linux/types.h> |
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struct michael_mic_ctx { |
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u32 l, r; |
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}; |
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struct michael_mic_desc_ctx { |
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__le32 pending; |
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size_t pending_len; |
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u32 l, r; |
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}; |
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static inline u32 xswap(u32 val) |
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{ |
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return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8); |
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} |
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#define michael_block(l, r) \ |
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do { \ |
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r ^= rol32(l, 17); \ |
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l += r; \ |
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r ^= xswap(l); \ |
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l += r; \ |
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r ^= rol32(l, 3); \ |
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l += r; \ |
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r ^= ror32(l, 2); \ |
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l += r; \ |
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} while (0) |
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static int michael_init(struct shash_desc *desc) |
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{ |
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struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc); |
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struct michael_mic_ctx *ctx = crypto_shash_ctx(desc->tfm); |
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mctx->pending_len = 0; |
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mctx->l = ctx->l; |
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mctx->r = ctx->r; |
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return 0; |
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} |
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static int michael_update(struct shash_desc *desc, const u8 *data, |
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unsigned int len) |
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{ |
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struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc); |
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if (mctx->pending_len) { |
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int flen = 4 - mctx->pending_len; |
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if (flen > len) |
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flen = len; |
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memcpy((u8 *)&mctx->pending + mctx->pending_len, data, flen); |
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mctx->pending_len += flen; |
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data += flen; |
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len -= flen; |
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if (mctx->pending_len < 4) |
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return 0; |
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mctx->l ^= le32_to_cpu(mctx->pending); |
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michael_block(mctx->l, mctx->r); |
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mctx->pending_len = 0; |
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} |
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while (len >= 4) { |
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mctx->l ^= get_unaligned_le32(data); |
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michael_block(mctx->l, mctx->r); |
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data += 4; |
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len -= 4; |
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} |
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if (len > 0) { |
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mctx->pending_len = len; |
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memcpy(&mctx->pending, data, len); |
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} |
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return 0; |
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} |
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static int michael_final(struct shash_desc *desc, u8 *out) |
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{ |
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struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc); |
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u8 *data = (u8 *)&mctx->pending; |
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/* Last block and padding (0x5a, 4..7 x 0) */ |
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switch (mctx->pending_len) { |
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case 0: |
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mctx->l ^= 0x5a; |
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break; |
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case 1: |
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mctx->l ^= data[0] | 0x5a00; |
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break; |
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case 2: |
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mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000; |
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break; |
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case 3: |
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mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) | |
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0x5a000000; |
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break; |
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} |
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michael_block(mctx->l, mctx->r); |
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/* l ^= 0; */ |
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michael_block(mctx->l, mctx->r); |
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put_unaligned_le32(mctx->l, out); |
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put_unaligned_le32(mctx->r, out + 4); |
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return 0; |
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} |
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static int michael_setkey(struct crypto_shash *tfm, const u8 *key, |
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unsigned int keylen) |
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{ |
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struct michael_mic_ctx *mctx = crypto_shash_ctx(tfm); |
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if (keylen != 8) |
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return -EINVAL; |
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mctx->l = get_unaligned_le32(key); |
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mctx->r = get_unaligned_le32(key + 4); |
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return 0; |
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} |
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static struct shash_alg alg = { |
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.digestsize = 8, |
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.setkey = michael_setkey, |
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.init = michael_init, |
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.update = michael_update, |
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.final = michael_final, |
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.descsize = sizeof(struct michael_mic_desc_ctx), |
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.base = { |
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.cra_name = "michael_mic", |
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.cra_driver_name = "michael_mic-generic", |
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.cra_blocksize = 8, |
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.cra_ctxsize = sizeof(struct michael_mic_ctx), |
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.cra_module = THIS_MODULE, |
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} |
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}; |
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static int __init michael_mic_init(void) |
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{ |
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return crypto_register_shash(&alg); |
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} |
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static void __exit michael_mic_exit(void) |
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{ |
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crypto_unregister_shash(&alg); |
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} |
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subsys_initcall(michael_mic_init); |
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module_exit(michael_mic_exit); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_DESCRIPTION("Michael MIC"); |
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MODULE_AUTHOR("Jouni Malinen <[email protected]>"); |
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MODULE_ALIAS_CRYPTO("michael_mic");
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