1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Driver for KeyStream wireless LAN
4 *
5 * Copyright (C) 2005-2008 KeyStream Corp.
6 * Copyright (C) 2009 Renesas Technology Corp.
7 */
8
9 #include <asm/unaligned.h>
10 #include <linux/bitops.h>
11 #include <linux/string.h>
12 #include "michael_mic.h"
13
14
15 // Reset the state to the empty message.
michael_clear(struct michael_mic * mic)16 static inline void michael_clear(struct michael_mic *mic)
17 {
18 mic->l = mic->k0;
19 mic->r = mic->k1;
20 mic->m_bytes = 0;
21 }
22
michael_init(struct michael_mic * mic,u8 * key)23 static void michael_init(struct michael_mic *mic, u8 *key)
24 {
25 // Set the key
26 mic->k0 = get_unaligned_le32(key);
27 mic->k1 = get_unaligned_le32(key + 4);
28
29 //clear();
30 michael_clear(mic);
31 }
32
michael_block(struct michael_mic * mic)33 static inline void michael_block(struct michael_mic *mic)
34 {
35 mic->r ^= rol32(mic->l, 17);
36 mic->l += mic->r;
37 mic->r ^= ((mic->l & 0xff00ff00) >> 8) |
38 ((mic->l & 0x00ff00ff) << 8);
39 mic->l += mic->r;
40 mic->r ^= rol32(mic->l, 3);
41 mic->l += mic->r;
42 mic->r ^= ror32(mic->l, 2);
43 mic->l += mic->r;
44 }
45
michael_append(struct michael_mic * mic,u8 * src,int bytes)46 static void michael_append(struct michael_mic *mic, u8 *src, int bytes)
47 {
48 int addlen;
49
50 if (mic->m_bytes) {
51 addlen = 4 - mic->m_bytes;
52 if (addlen > bytes)
53 addlen = bytes;
54 memcpy(&mic->m[mic->m_bytes], src, addlen);
55 mic->m_bytes += addlen;
56 src += addlen;
57 bytes -= addlen;
58
59 if (mic->m_bytes < 4)
60 return;
61
62 mic->l ^= get_unaligned_le32(mic->m);
63 michael_block(mic);
64 mic->m_bytes = 0;
65 }
66
67 while (bytes >= 4) {
68 mic->l ^= get_unaligned_le32(src);
69 michael_block(mic);
70 src += 4;
71 bytes -= 4;
72 }
73
74 if (bytes > 0) {
75 mic->m_bytes = bytes;
76 memcpy(mic->m, src, bytes);
77 }
78 }
79
michael_get_mic(struct michael_mic * mic,u8 * dst)80 static void michael_get_mic(struct michael_mic *mic, u8 *dst)
81 {
82 u8 *data = mic->m;
83
84 switch (mic->m_bytes) {
85 case 0:
86 mic->l ^= 0x5a;
87 break;
88 case 1:
89 mic->l ^= data[0] | 0x5a00;
90 break;
91 case 2:
92 mic->l ^= data[0] | (data[1] << 8) | 0x5a0000;
93 break;
94 case 3:
95 mic->l ^= data[0] | (data[1] << 8) | (data[2] << 16) |
96 0x5a000000;
97 break;
98 }
99 michael_block(mic);
100 michael_block(mic);
101 // The appendByte function has already computed the result.
102 put_unaligned_le32(mic->l, dst);
103 put_unaligned_le32(mic->r, dst + 4);
104
105 // Reset to the empty message.
106 michael_clear(mic);
107 }
108
michael_mic_function(struct michael_mic * mic,u8 * key,u8 * data,unsigned int len,u8 priority,u8 * result)109 void michael_mic_function(struct michael_mic *mic, u8 *key,
110 u8 *data, unsigned int len, u8 priority, u8 *result)
111 {
112 u8 pad_data[4] = { priority, 0, 0, 0 };
113 // Compute the MIC value
114 /*
115 * IEEE802.11i page 47
116 * Figure 43g TKIP MIC processing format
117 * +--+--+--------+--+----+--+--+--+--+--+--+--+--+
118 * |6 |6 |1 |3 |M |1 |1 |1 |1 |1 |1 |1 |1 | Octet
119 * +--+--+--------+--+----+--+--+--+--+--+--+--+--+
120 * |DA|SA|Priority|0 |Data|M0|M1|M2|M3|M4|M5|M6|M7|
121 * +--+--+--------+--+----+--+--+--+--+--+--+--+--+
122 */
123 michael_init(mic, key);
124 michael_append(mic, data, 12); /* |DA|SA| */
125 michael_append(mic, pad_data, 4); /* |Priority|0|0|0| */
126 michael_append(mic, data + 12, len - 12); /* |Data| */
127 michael_get_mic(mic, result);
128 }
129
