| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Driver for KeyStream wireless LAN |
| * |
| * Copyright (C) 2005-2008 KeyStream Corp. |
| * Copyright (C) 2009 Renesas Technology Corp. |
| */ |
| |
| #include <asm/unaligned.h> |
| #include <linux/bitops.h> |
| #include <linux/string.h> |
| #include "michael_mic.h" |
| |
| |
| // Reset the state to the empty message. |
| static inline void michael_clear(struct michael_mic *mic) |
| { |
| mic->l = mic->k0; |
| mic->r = mic->k1; |
| mic->m_bytes = 0; |
| } |
| |
| static void michael_init(struct michael_mic *mic, u8 *key) |
| { |
| // Set the key |
| mic->k0 = get_unaligned_le32(key); |
| mic->k1 = get_unaligned_le32(key + 4); |
| |
| //clear(); |
| michael_clear(mic); |
| } |
| |
| static inline void michael_block(struct michael_mic *mic) |
| { |
| mic->r ^= rol32(mic->l, 17); |
| mic->l += mic->r; |
| mic->r ^= ((mic->l & 0xff00ff00) >> 8) | |
| ((mic->l & 0x00ff00ff) << 8); |
| mic->l += mic->r; |
| mic->r ^= rol32(mic->l, 3); |
| mic->l += mic->r; |
| mic->r ^= ror32(mic->l, 2); |
| mic->l += mic->r; |
| } |
| |
| static void michael_append(struct michael_mic *mic, u8 *src, int bytes) |
| { |
| int addlen; |
| |
| if (mic->m_bytes) { |
| addlen = 4 - mic->m_bytes; |
| if (addlen > bytes) |
| addlen = bytes; |
| memcpy(&mic->m[mic->m_bytes], src, addlen); |
| mic->m_bytes += addlen; |
| src += addlen; |
| bytes -= addlen; |
| |
| if (mic->m_bytes < 4) |
| return; |
| |
| mic->l ^= get_unaligned_le32(mic->m); |
| michael_block(mic); |
| mic->m_bytes = 0; |
| } |
| |
| while (bytes >= 4) { |
| mic->l ^= get_unaligned_le32(src); |
| michael_block(mic); |
| src += 4; |
| bytes -= 4; |
| } |
| |
| if (bytes > 0) { |
| mic->m_bytes = bytes; |
| memcpy(mic->m, src, bytes); |
| } |
| } |
| |
| static void michael_get_mic(struct michael_mic *mic, u8 *dst) |
| { |
| u8 *data = mic->m; |
| |
| switch (mic->m_bytes) { |
| case 0: |
| mic->l ^= 0x5a; |
| break; |
| case 1: |
| mic->l ^= data[0] | 0x5a00; |
| break; |
| case 2: |
| mic->l ^= data[0] | (data[1] << 8) | 0x5a0000; |
| break; |
| case 3: |
| mic->l ^= data[0] | (data[1] << 8) | (data[2] << 16) | |
| 0x5a000000; |
| break; |
| } |
| michael_block(mic); |
| michael_block(mic); |
| // The appendByte function has already computed the result. |
| put_unaligned_le32(mic->l, dst); |
| put_unaligned_le32(mic->r, dst + 4); |
| |
| // Reset to the empty message. |
| michael_clear(mic); |
| } |
| |
| void michael_mic_function(struct michael_mic *mic, u8 *key, |
| u8 *data, unsigned int len, u8 priority, u8 *result) |
| { |
| u8 pad_data[4] = { priority, 0, 0, 0 }; |
| // Compute the MIC value |
| /* |
| * IEEE802.11i page 47 |
| * Figure 43g TKIP MIC processing format |
| * +--+--+--------+--+----+--+--+--+--+--+--+--+--+ |
| * |6 |6 |1 |3 |M |1 |1 |1 |1 |1 |1 |1 |1 | Octet |
| * +--+--+--------+--+----+--+--+--+--+--+--+--+--+ |
| * |DA|SA|Priority|0 |Data|M0|M1|M2|M3|M4|M5|M6|M7| |
| * +--+--+--------+--+----+--+--+--+--+--+--+--+--+ |
| */ |
| michael_init(mic, key); |
| michael_append(mic, data, 12); /* |DA|SA| */ |
| michael_append(mic, pad_data, 4); /* |Priority|0|0|0| */ |
| michael_append(mic, data + 12, len - 12); /* |Data| */ |
| michael_get_mic(mic, result); |
| } |