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1c08a104 JD |
1 | // SPDX-License-Identifier: GPL-2.0 OR MIT |
2 | /* | |
3 | * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. | |
4 | * | |
5 | * This is based in part on Andrew Moon's poly1305-donna, which is in the | |
6 | * public domain. | |
7 | */ | |
8 | ||
9 | #include <linux/kernel.h> | |
10 | #include <asm/unaligned.h> | |
11 | #include <crypto/internal/poly1305.h> | |
12 | ||
13 | void poly1305_core_setkey(struct poly1305_core_key *key, const u8 raw_key[16]) | |
14 | { | |
15 | /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */ | |
16 | key->key.r[0] = (get_unaligned_le32(&raw_key[0])) & 0x3ffffff; | |
17 | key->key.r[1] = (get_unaligned_le32(&raw_key[3]) >> 2) & 0x3ffff03; | |
18 | key->key.r[2] = (get_unaligned_le32(&raw_key[6]) >> 4) & 0x3ffc0ff; | |
19 | key->key.r[3] = (get_unaligned_le32(&raw_key[9]) >> 6) & 0x3f03fff; | |
20 | key->key.r[4] = (get_unaligned_le32(&raw_key[12]) >> 8) & 0x00fffff; | |
21 | ||
22 | /* s = 5*r */ | |
23 | key->precomputed_s.r[0] = key->key.r[1] * 5; | |
24 | key->precomputed_s.r[1] = key->key.r[2] * 5; | |
25 | key->precomputed_s.r[2] = key->key.r[3] * 5; | |
26 | key->precomputed_s.r[3] = key->key.r[4] * 5; | |
27 | } | |
28 | EXPORT_SYMBOL(poly1305_core_setkey); | |
29 | ||
30 | void poly1305_core_blocks(struct poly1305_state *state, | |
31 | const struct poly1305_core_key *key, const void *src, | |
32 | unsigned int nblocks, u32 hibit) | |
33 | { | |
34 | const u8 *input = src; | |
35 | u32 r0, r1, r2, r3, r4; | |
36 | u32 s1, s2, s3, s4; | |
37 | u32 h0, h1, h2, h3, h4; | |
38 | u64 d0, d1, d2, d3, d4; | |
39 | u32 c; | |
40 | ||
41 | if (!nblocks) | |
42 | return; | |
43 | ||
44 | hibit <<= 24; | |
45 | ||
46 | r0 = key->key.r[0]; | |
47 | r1 = key->key.r[1]; | |
48 | r2 = key->key.r[2]; | |
49 | r3 = key->key.r[3]; | |
50 | r4 = key->key.r[4]; | |
51 | ||
52 | s1 = key->precomputed_s.r[0]; | |
53 | s2 = key->precomputed_s.r[1]; | |
54 | s3 = key->precomputed_s.r[2]; | |
55 | s4 = key->precomputed_s.r[3]; | |
56 | ||
57 | h0 = state->h[0]; | |
58 | h1 = state->h[1]; | |
59 | h2 = state->h[2]; | |
60 | h3 = state->h[3]; | |
61 | h4 = state->h[4]; | |
62 | ||
63 | do { | |
64 | /* h += m[i] */ | |
65 | h0 += (get_unaligned_le32(&input[0])) & 0x3ffffff; | |
66 | h1 += (get_unaligned_le32(&input[3]) >> 2) & 0x3ffffff; | |
67 | h2 += (get_unaligned_le32(&input[6]) >> 4) & 0x3ffffff; | |
68 | h3 += (get_unaligned_le32(&input[9]) >> 6) & 0x3ffffff; | |
69 | h4 += (get_unaligned_le32(&input[12]) >> 8) | hibit; | |
70 | ||
71 | /* h *= r */ | |
72 | d0 = ((u64)h0 * r0) + ((u64)h1 * s4) + | |
73 | ((u64)h2 * s3) + ((u64)h3 * s2) + | |
74 | ((u64)h4 * s1); | |
75 | d1 = ((u64)h0 * r1) + ((u64)h1 * r0) + | |
76 | ((u64)h2 * s4) + ((u64)h3 * s3) + | |
77 | ((u64)h4 * s2); | |
78 | d2 = ((u64)h0 * r2) + ((u64)h1 * r1) + | |
79 | ((u64)h2 * r0) + ((u64)h3 * s4) + | |
80 | ((u64)h4 * s3); | |
81 | d3 = ((u64)h0 * r3) + ((u64)h1 * r2) + | |
82 | ((u64)h2 * r1) + ((u64)h3 * r0) + | |
83 | ((u64)h4 * s4); | |
84 | d4 = ((u64)h0 * r4) + ((u64)h1 * r3) + | |
85 | ((u64)h2 * r2) + ((u64)h3 * r1) + | |
86 | ((u64)h4 * r0); | |
87 | ||
88 | /* (partial) h %= p */ | |
89 | c = (u32)(d0 >> 26); | |
90 | h0 = (u32)d0 & 0x3ffffff; | |
91 | d1 += c; | |
92 | c = (u32)(d1 >> 26); | |
93 | h1 = (u32)d1 & 0x3ffffff; | |
94 | d2 += c; | |
95 | c = (u32)(d2 >> 26); | |
96 | h2 = (u32)d2 & 0x3ffffff; | |
97 | d3 += c; | |
98 | c = (u32)(d3 >> 26); | |
99 | h3 = (u32)d3 & 0x3ffffff; | |
100 | d4 += c; | |
101 | c = (u32)(d4 >> 26); | |
102 | h4 = (u32)d4 & 0x3ffffff; | |
103 | h0 += c * 5; | |
104 | c = (h0 >> 26); | |
105 | h0 = h0 & 0x3ffffff; | |
106 | h1 += c; | |
107 | ||
108 | input += POLY1305_BLOCK_SIZE; | |
109 | } while (--nblocks); | |
110 | ||
111 | state->h[0] = h0; | |
112 | state->h[1] = h1; | |
113 | state->h[2] = h2; | |
114 | state->h[3] = h3; | |
115 | state->h[4] = h4; | |
116 | } | |
117 | EXPORT_SYMBOL(poly1305_core_blocks); | |
118 | ||
119 | void poly1305_core_emit(const struct poly1305_state *state, const u32 nonce[4], | |
120 | void *dst) | |
121 | { | |
122 | u8 *mac = dst; | |
123 | u32 h0, h1, h2, h3, h4, c; | |
124 | u32 g0, g1, g2, g3, g4; | |
125 | u64 f; | |
126 | u32 mask; | |
127 | ||
128 | /* fully carry h */ | |
129 | h0 = state->h[0]; | |
130 | h1 = state->h[1]; | |
131 | h2 = state->h[2]; | |
132 | h3 = state->h[3]; | |
133 | h4 = state->h[4]; | |
134 | ||
135 | c = h1 >> 26; | |
136 | h1 = h1 & 0x3ffffff; | |
137 | h2 += c; | |
138 | c = h2 >> 26; | |
139 | h2 = h2 & 0x3ffffff; | |
140 | h3 += c; | |
141 | c = h3 >> 26; | |
142 | h3 = h3 & 0x3ffffff; | |
143 | h4 += c; | |
144 | c = h4 >> 26; | |
145 | h4 = h4 & 0x3ffffff; | |
146 | h0 += c * 5; | |
147 | c = h0 >> 26; | |
148 | h0 = h0 & 0x3ffffff; | |
149 | h1 += c; | |
150 | ||
151 | /* compute h + -p */ | |
152 | g0 = h0 + 5; | |
153 | c = g0 >> 26; | |
154 | g0 &= 0x3ffffff; | |
155 | g1 = h1 + c; | |
156 | c = g1 >> 26; | |
157 | g1 &= 0x3ffffff; | |
158 | g2 = h2 + c; | |
159 | c = g2 >> 26; | |
160 | g2 &= 0x3ffffff; | |
161 | g3 = h3 + c; | |
162 | c = g3 >> 26; | |
163 | g3 &= 0x3ffffff; | |
164 | g4 = h4 + c - (1UL << 26); | |
165 | ||
166 | /* select h if h < p, or h + -p if h >= p */ | |
167 | mask = (g4 >> ((sizeof(u32) * 8) - 1)) - 1; | |
168 | g0 &= mask; | |
169 | g1 &= mask; | |
170 | g2 &= mask; | |
171 | g3 &= mask; | |
172 | g4 &= mask; | |
173 | mask = ~mask; | |
174 | ||
175 | h0 = (h0 & mask) | g0; | |
176 | h1 = (h1 & mask) | g1; | |
177 | h2 = (h2 & mask) | g2; | |
178 | h3 = (h3 & mask) | g3; | |
179 | h4 = (h4 & mask) | g4; | |
180 | ||
181 | /* h = h % (2^128) */ | |
182 | h0 = ((h0) | (h1 << 26)) & 0xffffffff; | |
183 | h1 = ((h1 >> 6) | (h2 << 20)) & 0xffffffff; | |
184 | h2 = ((h2 >> 12) | (h3 << 14)) & 0xffffffff; | |
185 | h3 = ((h3 >> 18) | (h4 << 8)) & 0xffffffff; | |
186 | ||
187 | if (likely(nonce)) { | |
188 | /* mac = (h + nonce) % (2^128) */ | |
189 | f = (u64)h0 + nonce[0]; | |
190 | h0 = (u32)f; | |
191 | f = (u64)h1 + nonce[1] + (f >> 32); | |
192 | h1 = (u32)f; | |
193 | f = (u64)h2 + nonce[2] + (f >> 32); | |
194 | h2 = (u32)f; | |
195 | f = (u64)h3 + nonce[3] + (f >> 32); | |
196 | h3 = (u32)f; | |
197 | } | |
198 | ||
199 | put_unaligned_le32(h0, &mac[0]); | |
200 | put_unaligned_le32(h1, &mac[4]); | |
201 | put_unaligned_le32(h2, &mac[8]); | |
202 | put_unaligned_le32(h3, &mac[12]); | |
203 | } | |
204 | EXPORT_SYMBOL(poly1305_core_emit); |