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, |
14 | const u8 raw_key[POLY1305_BLOCK_SIZE]) |
15 | { |
16 | /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */ |
17 | key->key.r[0] = (get_unaligned_le32(p: &raw_key[0])) & 0x3ffffff; |
18 | key->key.r[1] = (get_unaligned_le32(p: &raw_key[3]) >> 2) & 0x3ffff03; |
19 | key->key.r[2] = (get_unaligned_le32(p: &raw_key[6]) >> 4) & 0x3ffc0ff; |
20 | key->key.r[3] = (get_unaligned_le32(p: &raw_key[9]) >> 6) & 0x3f03fff; |
21 | key->key.r[4] = (get_unaligned_le32(p: &raw_key[12]) >> 8) & 0x00fffff; |
22 | |
23 | /* s = 5*r */ |
24 | key->precomputed_s.r[0] = key->key.r[1] * 5; |
25 | key->precomputed_s.r[1] = key->key.r[2] * 5; |
26 | key->precomputed_s.r[2] = key->key.r[3] * 5; |
27 | key->precomputed_s.r[3] = key->key.r[4] * 5; |
28 | } |
29 | EXPORT_SYMBOL(poly1305_core_setkey); |
30 | |
31 | void poly1305_core_blocks(struct poly1305_state *state, |
32 | const struct poly1305_core_key *key, const void *src, |
33 | unsigned int nblocks, u32 hibit) |
34 | { |
35 | const u8 *input = src; |
36 | u32 r0, r1, r2, r3, r4; |
37 | u32 s1, s2, s3, s4; |
38 | u32 h0, h1, h2, h3, h4; |
39 | u64 d0, d1, d2, d3, d4; |
40 | u32 c; |
41 | |
42 | if (!nblocks) |
43 | return; |
44 | |
45 | hibit <<= 24; |
46 | |
47 | r0 = key->key.r[0]; |
48 | r1 = key->key.r[1]; |
49 | r2 = key->key.r[2]; |
50 | r3 = key->key.r[3]; |
51 | r4 = key->key.r[4]; |
52 | |
53 | s1 = key->precomputed_s.r[0]; |
54 | s2 = key->precomputed_s.r[1]; |
55 | s3 = key->precomputed_s.r[2]; |
56 | s4 = key->precomputed_s.r[3]; |
57 | |
58 | h0 = state->h[0]; |
59 | h1 = state->h[1]; |
60 | h2 = state->h[2]; |
61 | h3 = state->h[3]; |
62 | h4 = state->h[4]; |
63 | |
64 | do { |
65 | /* h += m[i] */ |
66 | h0 += (get_unaligned_le32(p: &input[0])) & 0x3ffffff; |
67 | h1 += (get_unaligned_le32(p: &input[3]) >> 2) & 0x3ffffff; |
68 | h2 += (get_unaligned_le32(p: &input[6]) >> 4) & 0x3ffffff; |
69 | h3 += (get_unaligned_le32(p: &input[9]) >> 6) & 0x3ffffff; |
70 | h4 += (get_unaligned_le32(p: &input[12]) >> 8) | hibit; |
71 | |
72 | /* h *= r */ |
73 | d0 = ((u64)h0 * r0) + ((u64)h1 * s4) + |
74 | ((u64)h2 * s3) + ((u64)h3 * s2) + |
75 | ((u64)h4 * s1); |
76 | d1 = ((u64)h0 * r1) + ((u64)h1 * r0) + |
77 | ((u64)h2 * s4) + ((u64)h3 * s3) + |
78 | ((u64)h4 * s2); |
79 | d2 = ((u64)h0 * r2) + ((u64)h1 * r1) + |
80 | ((u64)h2 * r0) + ((u64)h3 * s4) + |
81 | ((u64)h4 * s3); |
82 | d3 = ((u64)h0 * r3) + ((u64)h1 * r2) + |
83 | ((u64)h2 * r1) + ((u64)h3 * r0) + |
84 | ((u64)h4 * s4); |
85 | d4 = ((u64)h0 * r4) + ((u64)h1 * r3) + |
86 | ((u64)h2 * r2) + ((u64)h3 * r1) + |
87 | ((u64)h4 * r0); |
88 | |
89 | /* (partial) h %= p */ |
90 | c = (u32)(d0 >> 26); |
91 | h0 = (u32)d0 & 0x3ffffff; |
92 | d1 += c; |
93 | c = (u32)(d1 >> 26); |
94 | h1 = (u32)d1 & 0x3ffffff; |
95 | d2 += c; |
96 | c = (u32)(d2 >> 26); |
97 | h2 = (u32)d2 & 0x3ffffff; |
98 | d3 += c; |
99 | c = (u32)(d3 >> 26); |
100 | h3 = (u32)d3 & 0x3ffffff; |
101 | d4 += c; |
102 | c = (u32)(d4 >> 26); |
103 | h4 = (u32)d4 & 0x3ffffff; |
104 | h0 += c * 5; |
105 | c = (h0 >> 26); |
106 | h0 = h0 & 0x3ffffff; |
107 | h1 += c; |
108 | |
109 | input += POLY1305_BLOCK_SIZE; |
110 | } while (--nblocks); |
111 | |
112 | state->h[0] = h0; |
113 | state->h[1] = h1; |
114 | state->h[2] = h2; |
115 | state->h[3] = h3; |
116 | state->h[4] = h4; |
117 | } |
118 | EXPORT_SYMBOL(poly1305_core_blocks); |
119 | |
120 | void poly1305_core_emit(const struct poly1305_state *state, const u32 nonce[4], |
121 | void *dst) |
122 | { |
123 | u8 *mac = dst; |
124 | u32 h0, h1, h2, h3, h4, c; |
125 | u32 g0, g1, g2, g3, g4; |
126 | u64 f; |
127 | u32 mask; |
128 | |
129 | /* fully carry h */ |
130 | h0 = state->h[0]; |
131 | h1 = state->h[1]; |
132 | h2 = state->h[2]; |
133 | h3 = state->h[3]; |
134 | h4 = state->h[4]; |
135 | |
136 | c = h1 >> 26; |
137 | h1 = h1 & 0x3ffffff; |
138 | h2 += c; |
139 | c = h2 >> 26; |
140 | h2 = h2 & 0x3ffffff; |
141 | h3 += c; |
142 | c = h3 >> 26; |
143 | h3 = h3 & 0x3ffffff; |
144 | h4 += c; |
145 | c = h4 >> 26; |
146 | h4 = h4 & 0x3ffffff; |
147 | h0 += c * 5; |
148 | c = h0 >> 26; |
149 | h0 = h0 & 0x3ffffff; |
150 | h1 += c; |
151 | |
152 | /* compute h + -p */ |
153 | g0 = h0 + 5; |
154 | c = g0 >> 26; |
155 | g0 &= 0x3ffffff; |
156 | g1 = h1 + c; |
157 | c = g1 >> 26; |
158 | g1 &= 0x3ffffff; |
159 | g2 = h2 + c; |
160 | c = g2 >> 26; |
161 | g2 &= 0x3ffffff; |
162 | g3 = h3 + c; |
163 | c = g3 >> 26; |
164 | g3 &= 0x3ffffff; |
165 | g4 = h4 + c - (1UL << 26); |
166 | |
167 | /* select h if h < p, or h + -p if h >= p */ |
168 | mask = (g4 >> ((sizeof(u32) * 8) - 1)) - 1; |
169 | g0 &= mask; |
170 | g1 &= mask; |
171 | g2 &= mask; |
172 | g3 &= mask; |
173 | g4 &= mask; |
174 | mask = ~mask; |
175 | |
176 | h0 = (h0 & mask) | g0; |
177 | h1 = (h1 & mask) | g1; |
178 | h2 = (h2 & mask) | g2; |
179 | h3 = (h3 & mask) | g3; |
180 | h4 = (h4 & mask) | g4; |
181 | |
182 | /* h = h % (2^128) */ |
183 | h0 = ((h0) | (h1 << 26)) & 0xffffffff; |
184 | h1 = ((h1 >> 6) | (h2 << 20)) & 0xffffffff; |
185 | h2 = ((h2 >> 12) | (h3 << 14)) & 0xffffffff; |
186 | h3 = ((h3 >> 18) | (h4 << 8)) & 0xffffffff; |
187 | |
188 | if (likely(nonce)) { |
189 | /* mac = (h + nonce) % (2^128) */ |
190 | f = (u64)h0 + nonce[0]; |
191 | h0 = (u32)f; |
192 | f = (u64)h1 + nonce[1] + (f >> 32); |
193 | h1 = (u32)f; |
194 | f = (u64)h2 + nonce[2] + (f >> 32); |
195 | h2 = (u32)f; |
196 | f = (u64)h3 + nonce[3] + (f >> 32); |
197 | h3 = (u32)f; |
198 | } |
199 | |
200 | put_unaligned_le32(val: h0, p: &mac[0]); |
201 | put_unaligned_le32(val: h1, p: &mac[4]); |
202 | put_unaligned_le32(val: h2, p: &mac[8]); |
203 | put_unaligned_le32(val: h3, p: &mac[12]); |
204 | } |
205 | EXPORT_SYMBOL(poly1305_core_emit); |
206 | |