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Commit | Line | Data |
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f0706e82 JB |
1 | /* |
2 | * Michael MIC implementation - optimized for TKIP MIC operations | |
3 | * Copyright 2002-2003, Instant802 Networks, Inc. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | */ | |
f0706e82 | 9 | #include <linux/types.h> |
1bd3dff5 | 10 | #include <linux/bitops.h> |
8e8862b7 | 11 | #include <linux/ieee80211.h> |
1bd3dff5 | 12 | #include <asm/unaligned.h> |
f0706e82 JB |
13 | |
14 | #include "michael.h" | |
15 | ||
1b19ca39 HH |
16 | static void michael_block(struct michael_mic_ctx *mctx, u32 val) |
17 | { | |
18 | mctx->l ^= val; | |
19 | mctx->r ^= rol32(mctx->l, 17); | |
20 | mctx->l += mctx->r; | |
21 | mctx->r ^= ((mctx->l & 0xff00ff00) >> 8) | | |
22 | ((mctx->l & 0x00ff00ff) << 8); | |
23 | mctx->l += mctx->r; | |
24 | mctx->r ^= rol32(mctx->l, 3); | |
25 | mctx->l += mctx->r; | |
26 | mctx->r ^= ror32(mctx->l, 2); | |
27 | mctx->l += mctx->r; | |
28 | } | |
29 | ||
8e8862b7 HH |
30 | static void michael_mic_hdr(struct michael_mic_ctx *mctx, const u8 *key, |
31 | struct ieee80211_hdr *hdr) | |
1b19ca39 | 32 | { |
8e8862b7 HH |
33 | u8 *da, *sa, tid; |
34 | ||
35 | da = ieee80211_get_DA(hdr); | |
36 | sa = ieee80211_get_SA(hdr); | |
37 | if (ieee80211_is_data_qos(hdr->frame_control)) | |
38 | tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; | |
39 | else | |
40 | tid = 0; | |
41 | ||
1b19ca39 HH |
42 | mctx->l = get_unaligned_le32(key); |
43 | mctx->r = get_unaligned_le32(key + 4); | |
44 | ||
45 | /* | |
46 | * A pseudo header (DA, SA, Priority, 0, 0, 0) is used in Michael MIC | |
47 | * calculation, but it is _not_ transmitted | |
48 | */ | |
49 | michael_block(mctx, get_unaligned_le32(da)); | |
50 | michael_block(mctx, get_unaligned_le16(&da[4]) | | |
51 | (get_unaligned_le16(sa) << 16)); | |
52 | michael_block(mctx, get_unaligned_le32(&sa[2])); | |
8e8862b7 | 53 | michael_block(mctx, tid); |
1b19ca39 | 54 | } |
f0706e82 | 55 | |
8e8862b7 | 56 | void michael_mic(const u8 *key, struct ieee80211_hdr *hdr, |
a7b6f0c5 | 57 | const u8 *data, size_t data_len, u8 *mic) |
f0706e82 | 58 | { |
1b19ca39 | 59 | u32 val; |
f0706e82 | 60 | size_t block, blocks, left; |
1b19ca39 | 61 | struct michael_mic_ctx mctx; |
f0706e82 | 62 | |
8e8862b7 | 63 | michael_mic_hdr(&mctx, key, hdr); |
f0706e82 JB |
64 | |
65 | /* Real data */ | |
66 | blocks = data_len / 4; | |
67 | left = data_len % 4; | |
68 | ||
1b19ca39 HH |
69 | for (block = 0; block < blocks; block++) |
70 | michael_block(&mctx, get_unaligned_le32(&data[block * 4])); | |
f0706e82 JB |
71 | |
72 | /* Partial block of 0..3 bytes and padding: 0x5a + 4..7 zeros to make | |
73 | * total length a multiple of 4. */ | |
74 | val = 0x5a; | |
75 | while (left > 0) { | |
76 | val <<= 8; | |
77 | left--; | |
78 | val |= data[blocks * 4 + left]; | |
79 | } | |
f0706e82 | 80 | |
1b19ca39 HH |
81 | michael_block(&mctx, val); |
82 | michael_block(&mctx, 0); | |
83 | ||
84 | put_unaligned_le32(mctx.l, mic); | |
85 | put_unaligned_le32(mctx.r, mic + 4); | |
f0706e82 | 86 | } |