projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
| f0706e82 JB |
2 | /* |
| 3 | * Michael MIC implementation - optimized for TKIP MIC operations | |
| 4 | * Copyright 2002-2003, Instant802 Networks, Inc. | |
| f0706e82 | 5 | */ |
| f0706e82 | 6 | #include <linux/types.h> |
| 1bd3dff5 | 7 | #include <linux/bitops.h> |
| 8e8862b7 | 8 | #include <linux/ieee80211.h> |
| 1bd3dff5 | 9 | #include <asm/unaligned.h> |
| f0706e82 JB |
10 | |
| 11 | #include "michael.h" | |
| 12 | ||
| 1b19ca39 HH |
13 | static void michael_block(struct michael_mic_ctx *mctx, u32 val) |
| 14 | { | |
| 15 | mctx->l ^= val; | |
| 16 | mctx->r ^= rol32(mctx->l, 17); | |
| 17 | mctx->l += mctx->r; | |
| 18 | mctx->r ^= ((mctx->l & 0xff00ff00) >> 8) | | |
| 19 | ((mctx->l & 0x00ff00ff) << 8); | |
| 20 | mctx->l += mctx->r; | |
| 21 | mctx->r ^= rol32(mctx->l, 3); | |
| 22 | mctx->l += mctx->r; | |
| 23 | mctx->r ^= ror32(mctx->l, 2); | |
| 24 | mctx->l += mctx->r; | |
| 25 | } | |
| 26 | ||
| 8e8862b7 HH |
27 | static void michael_mic_hdr(struct michael_mic_ctx *mctx, const u8 *key, |
| 28 | struct ieee80211_hdr *hdr) | |
| 1b19ca39 | 29 | { |
| 8e8862b7 HH |
30 | u8 *da, *sa, tid; |
| 31 | ||
| 32 | da = ieee80211_get_DA(hdr); | |
| 33 | sa = ieee80211_get_SA(hdr); | |
| 34 | if (ieee80211_is_data_qos(hdr->frame_control)) | |
| a1f2ba04 | 35 | tid = ieee80211_get_tid(hdr); |
| 8e8862b7 HH |
36 | else |
| 37 | tid = 0; | |
| 38 | ||
| 1b19ca39 HH |
39 | mctx->l = get_unaligned_le32(key); |
| 40 | mctx->r = get_unaligned_le32(key + 4); | |
| 41 | ||
| 42 | /* | |
| 43 | * A pseudo header (DA, SA, Priority, 0, 0, 0) is used in Michael MIC | |
| 44 | * calculation, but it is _not_ transmitted | |
| 45 | */ | |
| 46 | michael_block(mctx, get_unaligned_le32(da)); | |
| 47 | michael_block(mctx, get_unaligned_le16(&da[4]) | | |
| 48 | (get_unaligned_le16(sa) << 16)); | |
| 49 | michael_block(mctx, get_unaligned_le32(&sa[2])); | |
| 8e8862b7 | 50 | michael_block(mctx, tid); |
| 1b19ca39 | 51 | } |
| f0706e82 | 52 | |
| 8e8862b7 | 53 | void michael_mic(const u8 *key, struct ieee80211_hdr *hdr, |
| a7b6f0c5 | 54 | const u8 *data, size_t data_len, u8 *mic) |
| f0706e82 | 55 | { |
| 1b19ca39 | 56 | u32 val; |
| f0706e82 | 57 | size_t block, blocks, left; |
| 1b19ca39 | 58 | struct michael_mic_ctx mctx; |
| f0706e82 | 59 | |
| 8e8862b7 | 60 | michael_mic_hdr(&mctx, key, hdr); |
| f0706e82 JB |
61 | |
| 62 | /* Real data */ | |
| 63 | blocks = data_len / 4; | |
| 64 | left = data_len % 4; | |
| 65 | ||
| 1b19ca39 HH |
66 | for (block = 0; block < blocks; block++) |
| 67 | michael_block(&mctx, get_unaligned_le32(&data[block * 4])); | |
| f0706e82 JB |
68 | |
| 69 | /* Partial block of 0..3 bytes and padding: 0x5a + 4..7 zeros to make | |
| 70 | * total length a multiple of 4. */ | |
| 71 | val = 0x5a; | |
| 72 | while (left > 0) { | |
| 73 | val <<= 8; | |
| 74 | left--; | |
| 75 | val |= data[blocks * 4 + left]; | |
| 76 | } | |
| f0706e82 | 77 | |
| 1b19ca39 HH |
78 | michael_block(&mctx, val); |
| 79 | michael_block(&mctx, 0); | |
| 80 | ||
| 81 | put_unaligned_le32(mctx.l, mic); | |
| 82 | put_unaligned_le32(mctx.r, mic + 4); | |
| f0706e82 | 83 | } |