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 | u64 t0, t1; |
17 | |
18 | /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */ |
19 | t0 = get_unaligned_le64(p: &raw_key[0]); |
20 | t1 = get_unaligned_le64(p: &raw_key[8]); |
21 | |
22 | key->key.r64[0] = t0 & 0xffc0fffffffULL; |
23 | key->key.r64[1] = ((t0 >> 44) | (t1 << 20)) & 0xfffffc0ffffULL; |
24 | key->key.r64[2] = ((t1 >> 24)) & 0x00ffffffc0fULL; |
25 | |
26 | /* s = 20*r */ |
27 | key->precomputed_s.r64[0] = key->key.r64[1] * 20; |
28 | key->precomputed_s.r64[1] = key->key.r64[2] * 20; |
29 | } |
30 | EXPORT_SYMBOL(poly1305_core_setkey); |
31 | |
32 | void poly1305_core_blocks(struct poly1305_state *state, |
33 | const struct poly1305_core_key *key, const void *src, |
34 | unsigned int nblocks, u32 hibit) |
35 | { |
36 | const u8 *input = src; |
37 | u64 hibit64; |
38 | u64 r0, r1, r2; |
39 | u64 s1, s2; |
40 | u64 h0, h1, h2; |
41 | u64 c; |
42 | u128 d0, d1, d2, d; |
43 | |
44 | if (!nblocks) |
45 | return; |
46 | |
47 | hibit64 = ((u64)hibit) << 40; |
48 | |
49 | r0 = key->key.r64[0]; |
50 | r1 = key->key.r64[1]; |
51 | r2 = key->key.r64[2]; |
52 | |
53 | h0 = state->h64[0]; |
54 | h1 = state->h64[1]; |
55 | h2 = state->h64[2]; |
56 | |
57 | s1 = key->precomputed_s.r64[0]; |
58 | s2 = key->precomputed_s.r64[1]; |
59 | |
60 | do { |
61 | u64 t0, t1; |
62 | |
63 | /* h += m[i] */ |
64 | t0 = get_unaligned_le64(p: &input[0]); |
65 | t1 = get_unaligned_le64(p: &input[8]); |
66 | |
67 | h0 += t0 & 0xfffffffffffULL; |
68 | h1 += ((t0 >> 44) | (t1 << 20)) & 0xfffffffffffULL; |
69 | h2 += (((t1 >> 24)) & 0x3ffffffffffULL) | hibit64; |
70 | |
71 | /* h *= r */ |
72 | d0 = (u128)h0 * r0; |
73 | d = (u128)h1 * s2; |
74 | d0 += d; |
75 | d = (u128)h2 * s1; |
76 | d0 += d; |
77 | d1 = (u128)h0 * r1; |
78 | d = (u128)h1 * r0; |
79 | d1 += d; |
80 | d = (u128)h2 * s2; |
81 | d1 += d; |
82 | d2 = (u128)h0 * r2; |
83 | d = (u128)h1 * r1; |
84 | d2 += d; |
85 | d = (u128)h2 * r0; |
86 | d2 += d; |
87 | |
88 | /* (partial) h %= p */ |
89 | c = (u64)(d0 >> 44); |
90 | h0 = (u64)d0 & 0xfffffffffffULL; |
91 | d1 += c; |
92 | c = (u64)(d1 >> 44); |
93 | h1 = (u64)d1 & 0xfffffffffffULL; |
94 | d2 += c; |
95 | c = (u64)(d2 >> 42); |
96 | h2 = (u64)d2 & 0x3ffffffffffULL; |
97 | h0 += c * 5; |
98 | c = h0 >> 44; |
99 | h0 = h0 & 0xfffffffffffULL; |
100 | h1 += c; |
101 | |
102 | input += POLY1305_BLOCK_SIZE; |
103 | } while (--nblocks); |
104 | |
105 | state->h64[0] = h0; |
106 | state->h64[1] = h1; |
107 | state->h64[2] = h2; |
108 | } |
109 | EXPORT_SYMBOL(poly1305_core_blocks); |
110 | |
111 | void poly1305_core_emit(const struct poly1305_state *state, const u32 nonce[4], |
112 | void *dst) |
113 | { |
114 | u8 *mac = dst; |
115 | u64 h0, h1, h2, c; |
116 | u64 g0, g1, g2; |
117 | u64 t0, t1; |
118 | |
119 | /* fully carry h */ |
120 | h0 = state->h64[0]; |
121 | h1 = state->h64[1]; |
122 | h2 = state->h64[2]; |
123 | |
124 | c = h1 >> 44; |
125 | h1 &= 0xfffffffffffULL; |
126 | h2 += c; |
127 | c = h2 >> 42; |
128 | h2 &= 0x3ffffffffffULL; |
129 | h0 += c * 5; |
130 | c = h0 >> 44; |
131 | h0 &= 0xfffffffffffULL; |
132 | h1 += c; |
133 | c = h1 >> 44; |
134 | h1 &= 0xfffffffffffULL; |
135 | h2 += c; |
136 | c = h2 >> 42; |
137 | h2 &= 0x3ffffffffffULL; |
138 | h0 += c * 5; |
139 | c = h0 >> 44; |
140 | h0 &= 0xfffffffffffULL; |
141 | h1 += c; |
142 | |
143 | /* compute h + -p */ |
144 | g0 = h0 + 5; |
145 | c = g0 >> 44; |
146 | g0 &= 0xfffffffffffULL; |
147 | g1 = h1 + c; |
148 | c = g1 >> 44; |
149 | g1 &= 0xfffffffffffULL; |
150 | g2 = h2 + c - (1ULL << 42); |
151 | |
152 | /* select h if h < p, or h + -p if h >= p */ |
153 | c = (g2 >> ((sizeof(u64) * 8) - 1)) - 1; |
154 | g0 &= c; |
155 | g1 &= c; |
156 | g2 &= c; |
157 | c = ~c; |
158 | h0 = (h0 & c) | g0; |
159 | h1 = (h1 & c) | g1; |
160 | h2 = (h2 & c) | g2; |
161 | |
162 | if (likely(nonce)) { |
163 | /* h = (h + nonce) */ |
164 | t0 = ((u64)nonce[1] << 32) | nonce[0]; |
165 | t1 = ((u64)nonce[3] << 32) | nonce[2]; |
166 | |
167 | h0 += t0 & 0xfffffffffffULL; |
168 | c = h0 >> 44; |
169 | h0 &= 0xfffffffffffULL; |
170 | h1 += (((t0 >> 44) | (t1 << 20)) & 0xfffffffffffULL) + c; |
171 | c = h1 >> 44; |
172 | h1 &= 0xfffffffffffULL; |
173 | h2 += (((t1 >> 24)) & 0x3ffffffffffULL) + c; |
174 | h2 &= 0x3ffffffffffULL; |
175 | } |
176 | |
177 | /* mac = h % (2^128) */ |
178 | h0 = h0 | (h1 << 44); |
179 | h1 = (h1 >> 20) | (h2 << 24); |
180 | |
181 | put_unaligned_le64(val: h0, p: &mac[0]); |
182 | put_unaligned_le64(val: h1, p: &mac[8]); |
183 | } |
184 | EXPORT_SYMBOL(poly1305_core_emit); |
185 | |