1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Michael MIC implementation - optimized for TKIP MIC operations
4*4882a593Smuzhiyun * Copyright 2002-2003, Instant802 Networks, Inc.
5*4882a593Smuzhiyun */
6*4882a593Smuzhiyun #include <linux/types.h>
7*4882a593Smuzhiyun #include <linux/bitops.h>
8*4882a593Smuzhiyun #include <linux/ieee80211.h>
9*4882a593Smuzhiyun #include <asm/unaligned.h>
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun #include "michael.h"
12*4882a593Smuzhiyun
michael_block(struct michael_mic_ctx * mctx,u32 val)13*4882a593Smuzhiyun static void michael_block(struct michael_mic_ctx *mctx, u32 val)
14*4882a593Smuzhiyun {
15*4882a593Smuzhiyun mctx->l ^= val;
16*4882a593Smuzhiyun mctx->r ^= rol32(mctx->l, 17);
17*4882a593Smuzhiyun mctx->l += mctx->r;
18*4882a593Smuzhiyun mctx->r ^= ((mctx->l & 0xff00ff00) >> 8) |
19*4882a593Smuzhiyun ((mctx->l & 0x00ff00ff) << 8);
20*4882a593Smuzhiyun mctx->l += mctx->r;
21*4882a593Smuzhiyun mctx->r ^= rol32(mctx->l, 3);
22*4882a593Smuzhiyun mctx->l += mctx->r;
23*4882a593Smuzhiyun mctx->r ^= ror32(mctx->l, 2);
24*4882a593Smuzhiyun mctx->l += mctx->r;
25*4882a593Smuzhiyun }
26*4882a593Smuzhiyun
michael_mic_hdr(struct michael_mic_ctx * mctx,const u8 * key,struct ieee80211_hdr * hdr)27*4882a593Smuzhiyun static void michael_mic_hdr(struct michael_mic_ctx *mctx, const u8 *key,
28*4882a593Smuzhiyun struct ieee80211_hdr *hdr)
29*4882a593Smuzhiyun {
30*4882a593Smuzhiyun u8 *da, *sa, tid;
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun da = ieee80211_get_DA(hdr);
33*4882a593Smuzhiyun sa = ieee80211_get_SA(hdr);
34*4882a593Smuzhiyun if (ieee80211_is_data_qos(hdr->frame_control))
35*4882a593Smuzhiyun tid = ieee80211_get_tid(hdr);
36*4882a593Smuzhiyun else
37*4882a593Smuzhiyun tid = 0;
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun mctx->l = get_unaligned_le32(key);
40*4882a593Smuzhiyun mctx->r = get_unaligned_le32(key + 4);
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun /*
43*4882a593Smuzhiyun * A pseudo header (DA, SA, Priority, 0, 0, 0) is used in Michael MIC
44*4882a593Smuzhiyun * calculation, but it is _not_ transmitted
45*4882a593Smuzhiyun */
46*4882a593Smuzhiyun michael_block(mctx, get_unaligned_le32(da));
47*4882a593Smuzhiyun michael_block(mctx, get_unaligned_le16(&da[4]) |
48*4882a593Smuzhiyun (get_unaligned_le16(sa) << 16));
49*4882a593Smuzhiyun michael_block(mctx, get_unaligned_le32(&sa[2]));
50*4882a593Smuzhiyun michael_block(mctx, tid);
51*4882a593Smuzhiyun }
52*4882a593Smuzhiyun
michael_mic(const u8 * key,struct ieee80211_hdr * hdr,const u8 * data,size_t data_len,u8 * mic)53*4882a593Smuzhiyun void michael_mic(const u8 *key, struct ieee80211_hdr *hdr,
54*4882a593Smuzhiyun const u8 *data, size_t data_len, u8 *mic)
55*4882a593Smuzhiyun {
56*4882a593Smuzhiyun u32 val;
57*4882a593Smuzhiyun size_t block, blocks, left;
58*4882a593Smuzhiyun struct michael_mic_ctx mctx;
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun michael_mic_hdr(&mctx, key, hdr);
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun /* Real data */
63*4882a593Smuzhiyun blocks = data_len / 4;
64*4882a593Smuzhiyun left = data_len % 4;
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun for (block = 0; block < blocks; block++)
67*4882a593Smuzhiyun michael_block(&mctx, get_unaligned_le32(&data[block * 4]));
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun /* Partial block of 0..3 bytes and padding: 0x5a + 4..7 zeros to make
70*4882a593Smuzhiyun * total length a multiple of 4. */
71*4882a593Smuzhiyun val = 0x5a;
72*4882a593Smuzhiyun while (left > 0) {
73*4882a593Smuzhiyun val <<= 8;
74*4882a593Smuzhiyun left--;
75*4882a593Smuzhiyun val |= data[blocks * 4 + left];
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun michael_block(&mctx, val);
79*4882a593Smuzhiyun michael_block(&mctx, 0);
80*4882a593Smuzhiyun
81*4882a593Smuzhiyun put_unaligned_le32(mctx.l, mic);
82*4882a593Smuzhiyun put_unaligned_le32(mctx.r, mic + 4);
83*4882a593Smuzhiyun }
84