aboutsummaryrefslogtreecommitdiffstats
path: root/crypto/siphash/siphash.c
blob: be74a38d934df78aadd235bd15c91129d0b4b568 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
/*
 * Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/* Based on https://131002.net/siphash C reference implementation */
/*
   SipHash reference C implementation

   Copyright (c) 2012-2016 Jean-Philippe Aumasson
   Copyright (c) 2012-2014 Daniel J. Bernstein

   To the extent possible under law, the author(s) have dedicated all copyright
   and related and neighboring rights to this software to the public domain
   worldwide. This software is distributed without any warranty.

   You should have received a copy of the CC0 Public Domain Dedication along
   with this software. If not, see
   <http://creativecommons.org/publicdomain/zero/1.0/>.
 */

#include <stdlib.h>
#include <string.h>
#include <openssl/crypto.h>

#include "internal/siphash.h"
#include "siphash_local.h"

/* default: SipHash-2-4 */
#define SIPHASH_C_ROUNDS 2
#define SIPHASH_D_ROUNDS 4

#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))

#define U32TO8_LE(p, v)                                                        \
    (p)[0] = (uint8_t)((v));                                                   \
    (p)[1] = (uint8_t)((v) >> 8);                                              \
    (p)[2] = (uint8_t)((v) >> 16);                                             \
    (p)[3] = (uint8_t)((v) >> 24);

#define U64TO8_LE(p, v)                                                        \
    U32TO8_LE((p), (uint32_t)((v)));                                           \
    U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));

#define U8TO64_LE(p)                                                           \
    (((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) |                        \
     ((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) |                 \
     ((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) |                 \
     ((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56))

#define SIPROUND                                                               \
    do {                                                                       \
        v0 += v1;                                                              \
        v1 = ROTL(v1, 13);                                                     \
        v1 ^= v0;                                                              \
        v0 = ROTL(v0, 32);                                                     \
        v2 += v3;                                                              \
        v3 = ROTL(v3, 16);                                                     \
        v3 ^= v2;                                                              \
        v0 += v3;                                                              \
        v3 = ROTL(v3, 21);                                                     \
        v3 ^= v0;                                                              \
        v2 += v1;                                                              \
        v1 = ROTL(v1, 17);                                                     \
        v1 ^= v2;                                                              \
        v2 = ROTL(v2, 32);                                                     \
    } while (0)

size_t SipHash_ctx_size(void)
{
    return sizeof(SIPHASH);
}

size_t SipHash_hash_size(SIPHASH *ctx)
{
    return ctx->hash_size;
}

static size_t siphash_adjust_hash_size(size_t hash_size)
{
    if (hash_size == 0)
        hash_size = SIPHASH_MAX_DIGEST_SIZE;
    return hash_size;
}

int SipHash_set_hash_size(SIPHASH *ctx, size_t hash_size)
{
    hash_size = siphash_adjust_hash_size(hash_size);
    if (hash_size != SIPHASH_MIN_DIGEST_SIZE
        && hash_size != SIPHASH_MAX_DIGEST_SIZE)
        return 0;

    /*
     * It's possible that the key was set first.  If the hash size changes,
     * we need to adjust v1 (see SipHash_Init().
     */

    /* Start by adjusting the stored size, to make things easier */
    ctx->hash_size = siphash_adjust_hash_size(ctx->hash_size);

    /* Now, adjust ctx->v1 if the old and the new size differ */
    if ((size_t)ctx->hash_size != hash_size) {
        ctx->v1 ^= 0xee;
        ctx->hash_size = hash_size;
    }
    return 1;
}

/* hash_size = crounds = drounds = 0 means SipHash24 with 16-byte output */
int SipHash_Init(SIPHASH *ctx, const unsigned char *k, int crounds, int drounds)
{
    uint64_t k0 = U8TO64_LE(k);
    uint64_t k1 = U8TO64_LE(k + 8);

    /* If the hash size wasn't set, i.e. is zero */
    ctx->hash_size = siphash_adjust_hash_size(ctx->hash_size);

    if (drounds == 0)
        drounds = SIPHASH_D_ROUNDS;
    if (crounds == 0)
        crounds = SIPHASH_C_ROUNDS;

    ctx->crounds = crounds;
    ctx->drounds = drounds;

    ctx->len = 0;
    ctx->total_inlen = 0;

    ctx->v0 = 0x736f6d6570736575ULL ^ k0;
    ctx->v1 = 0x646f72616e646f6dULL ^ k1;
    ctx->v2 = 0x6c7967656e657261ULL ^ k0;
    ctx->v3 = 0x7465646279746573ULL ^ k1;

    if (ctx->hash_size == SIPHASH_MAX_DIGEST_SIZE)
        ctx->v1 ^= 0xee;

    return 1;
}

void SipHash_Update(SIPHASH *ctx, const unsigned char *in, size_t inlen)
{
    uint64_t m;
    const uint8_t *end;
    int left;
    int i;
    uint64_t v0 = ctx->v0;
    uint64_t v1 = ctx->v1;
    uint64_t v2 = ctx->v2;
    uint64_t v3 = ctx->v3;

    ctx->total_inlen += inlen;

    if (ctx->len) {
        /* deal with leavings */
        size_t available = SIPHASH_BLOCK_SIZE - ctx->len;

        /* not enough to fill leavings */
        if (inlen < available) {
            memcpy(&ctx->leavings[ctx->len], in, inlen);
            ctx->len += inlen;
            return;
        }

        /* copy data into leavings and reduce input */
        memcpy(&ctx->leavings[ctx->len], in, available);
        inlen -= available;
        in += available;

        /* process leavings */
        m = U8TO64_LE(ctx->leavings);
        v3 ^= m;
        for (i = 0; i < ctx->crounds; ++i)
            SIPROUND;
        v0 ^= m;
    }
    left = inlen & (SIPHASH_BLOCK_SIZE-1); /* gets put into leavings */
    end = in + inlen - left;

    for (; in != end; in += 8) {
        m = U8TO64_LE(in);
        v3 ^= m;
        for (i = 0; i < ctx->crounds; ++i)
            SIPROUND;
        v0 ^= m;
    }

    /* save leavings and other ctx */
    if (left)
        memcpy(ctx->leavings, end, left);
    ctx->len = left;

    ctx->v0 = v0;
    ctx->v1 = v1;
    ctx->v2 = v2;
    ctx->v3 = v3;
}

int SipHash_Final(SIPHASH *ctx, unsigned char *out, size_t outlen)
{
    /* finalize hash */
    int i;
    uint64_t b = ctx->total_inlen << 56;
    uint64_t v0 = ctx->v0;
    uint64_t v1 = ctx->v1;
    uint64_t v2 = ctx->v2;
    uint64_t v3 = ctx->v3;

    if (outlen != (size_t)ctx->hash_size)
        return 0;

    switch (ctx->len) {
    case 7:
        b |= ((uint64_t)ctx->leavings[6]) << 48;
        /* fall thru */
    case 6:
        b |= ((uint64_t)ctx->leavings[5]) << 40;
        /* fall thru */
    case 5:
        b |= ((uint64_t)ctx->leavings[4]) << 32;
        /* fall thru */
    case 4:
        b |= ((uint64_t)ctx->leavings[3]) << 24;
        /* fall thru */
    case 3:
        b |= ((uint64_t)ctx->leavings[2]) << 16;
        /* fall thru */
    case 2:
        b |= ((uint64_t)ctx->leavings[1]) <<  8;
        /* fall thru */
    case 1:
        b |= ((uint64_t)ctx->leavings[0]);
    case 0:
        break;
    }

    v3 ^= b;
    for (i = 0; i < ctx->crounds; ++i)
        SIPROUND;
    v0 ^= b;
    if (ctx->hash_size == SIPHASH_MAX_DIGEST_SIZE)
        v2 ^= 0xee;
    else
        v2 ^= 0xff;
    for (i = 0; i < ctx->drounds; ++i)
        SIPROUND;
    b = v0 ^ v1 ^ v2  ^ v3;
    U64TO8_LE(out, b);
    if (ctx->hash_size == SIPHASH_MIN_DIGEST_SIZE)
        return 1;
    v1 ^= 0xdd;
    for (i = 0; i < ctx->drounds; ++i)
        SIPROUND;
    b = v0 ^ v1 ^ v2  ^ v3;
    U64TO8_LE(out + 8, b);
    return 1;
}