1 /*
2 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25 #include "inner.h"
26
27 /*
28 * This is the 64-bit variant of br_ghash_ctmul32(), with 64-bit operands
29 * and bit reversal of 64-bit words.
30 */
31
32 static inline uint64_t
bmul64(uint64_t x,uint64_t y)33 bmul64(uint64_t x, uint64_t y)
34 {
35 uint64_t x0, x1, x2, x3;
36 uint64_t y0, y1, y2, y3;
37 uint64_t z0, z1, z2, z3;
38
39 x0 = x & (uint64_t)0x1111111111111111;
40 x1 = x & (uint64_t)0x2222222222222222;
41 x2 = x & (uint64_t)0x4444444444444444;
42 x3 = x & (uint64_t)0x8888888888888888;
43 y0 = y & (uint64_t)0x1111111111111111;
44 y1 = y & (uint64_t)0x2222222222222222;
45 y2 = y & (uint64_t)0x4444444444444444;
46 y3 = y & (uint64_t)0x8888888888888888;
47 z0 = (x0 * y0) ^ (x1 * y3) ^ (x2 * y2) ^ (x3 * y1);
48 z1 = (x0 * y1) ^ (x1 * y0) ^ (x2 * y3) ^ (x3 * y2);
49 z2 = (x0 * y2) ^ (x1 * y1) ^ (x2 * y0) ^ (x3 * y3);
50 z3 = (x0 * y3) ^ (x1 * y2) ^ (x2 * y1) ^ (x3 * y0);
51 z0 &= (uint64_t)0x1111111111111111;
52 z1 &= (uint64_t)0x2222222222222222;
53 z2 &= (uint64_t)0x4444444444444444;
54 z3 &= (uint64_t)0x8888888888888888;
55 return z0 | z1 | z2 | z3;
56 }
57
58 static uint64_t
rev64(uint64_t x)59 rev64(uint64_t x)
60 {
61 #define RMS(m, s) do { \
62 x = ((x & (uint64_t)(m)) << (s)) \
63 | ((x >> (s)) & (uint64_t)(m)); \
64 } while (0)
65
66 RMS(0x5555555555555555, 1);
67 RMS(0x3333333333333333, 2);
68 RMS(0x0F0F0F0F0F0F0F0F, 4);
69 RMS(0x00FF00FF00FF00FF, 8);
70 RMS(0x0000FFFF0000FFFF, 16);
71 return (x << 32) | (x >> 32);
72
73 #undef RMS
74 }
75
76 /* see bearssl_ghash.h */
77 void
br_ghash_ctmul64(void * y,const void * h,const void * data,size_t len)78 br_ghash_ctmul64(void *y, const void *h, const void *data, size_t len)
79 {
80 const unsigned char *buf, *hb;
81 unsigned char *yb;
82 uint64_t y0, y1;
83 uint64_t h0, h1, h2, h0r, h1r, h2r;
84
85 buf = data;
86 yb = y;
87 hb = h;
88 y1 = br_dec64be(yb);
89 y0 = br_dec64be(yb + 8);
90 h1 = br_dec64be(hb);
91 h0 = br_dec64be(hb + 8);
92 h0r = rev64(h0);
93 h1r = rev64(h1);
94 h2 = h0 ^ h1;
95 h2r = h0r ^ h1r;
96 while (len > 0) {
97 const unsigned char *src;
98 unsigned char tmp[16];
99 uint64_t y0r, y1r, y2, y2r;
100 uint64_t z0, z1, z2, z0h, z1h, z2h;
101 uint64_t v0, v1, v2, v3;
102
103 if (len >= 16) {
104 src = buf;
105 buf += 16;
106 len -= 16;
107 } else {
108 memcpy(tmp, buf, len);
109 memset(tmp + len, 0, (sizeof tmp) - len);
110 src = tmp;
111 len = 0;
112 }
113 y1 ^= br_dec64be(src);
114 y0 ^= br_dec64be(src + 8);
115
116 y0r = rev64(y0);
117 y1r = rev64(y1);
118 y2 = y0 ^ y1;
119 y2r = y0r ^ y1r;
120
121 z0 = bmul64(y0, h0);
122 z1 = bmul64(y1, h1);
123 z2 = bmul64(y2, h2);
124 z0h = bmul64(y0r, h0r);
125 z1h = bmul64(y1r, h1r);
126 z2h = bmul64(y2r, h2r);
127 z2 ^= z0 ^ z1;
128 z2h ^= z0h ^ z1h;
129 z0h = rev64(z0h) >> 1;
130 z1h = rev64(z1h) >> 1;
131 z2h = rev64(z2h) >> 1;
132
133 v0 = z0;
134 v1 = z0h ^ z2;
135 v2 = z1 ^ z2h;
136 v3 = z1h;
137
138 v3 = (v3 << 1) | (v2 >> 63);
139 v2 = (v2 << 1) | (v1 >> 63);
140 v1 = (v1 << 1) | (v0 >> 63);
141 v0 = (v0 << 1);
142
143 v2 ^= v0 ^ (v0 >> 1) ^ (v0 >> 2) ^ (v0 >> 7);
144 v1 ^= (v0 << 63) ^ (v0 << 62) ^ (v0 << 57);
145 v3 ^= v1 ^ (v1 >> 1) ^ (v1 >> 2) ^ (v1 >> 7);
146 v2 ^= (v1 << 63) ^ (v1 << 62) ^ (v1 << 57);
147
148 y0 = v2;
149 y1 = v3;
150 }
151
152 br_enc64be(yb, y1);
153 br_enc64be(yb + 8, y0);
154 }
155