GNU Linux-libre 5.19-rc6-gnu
[releases.git] / lib / crypto / poly1305.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Poly1305 authenticator algorithm, RFC7539
4  *
5  * Copyright (C) 2015 Martin Willi
6  *
7  * Based on public domain code by Andrew Moon and Daniel J. Bernstein.
8  */
9
10 #include <crypto/internal/poly1305.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <asm/unaligned.h>
14
15 void poly1305_init_generic(struct poly1305_desc_ctx *desc,
16                            const u8 key[POLY1305_KEY_SIZE])
17 {
18         poly1305_core_setkey(&desc->core_r, key);
19         desc->s[0] = get_unaligned_le32(key + 16);
20         desc->s[1] = get_unaligned_le32(key + 20);
21         desc->s[2] = get_unaligned_le32(key + 24);
22         desc->s[3] = get_unaligned_le32(key + 28);
23         poly1305_core_init(&desc->h);
24         desc->buflen = 0;
25         desc->sset = true;
26         desc->rset = 2;
27 }
28 EXPORT_SYMBOL_GPL(poly1305_init_generic);
29
30 void poly1305_update_generic(struct poly1305_desc_ctx *desc, const u8 *src,
31                              unsigned int nbytes)
32 {
33         unsigned int bytes;
34
35         if (unlikely(desc->buflen)) {
36                 bytes = min(nbytes, POLY1305_BLOCK_SIZE - desc->buflen);
37                 memcpy(desc->buf + desc->buflen, src, bytes);
38                 src += bytes;
39                 nbytes -= bytes;
40                 desc->buflen += bytes;
41
42                 if (desc->buflen == POLY1305_BLOCK_SIZE) {
43                         poly1305_core_blocks(&desc->h, &desc->core_r, desc->buf,
44                                              1, 1);
45                         desc->buflen = 0;
46                 }
47         }
48
49         if (likely(nbytes >= POLY1305_BLOCK_SIZE)) {
50                 poly1305_core_blocks(&desc->h, &desc->core_r, src,
51                                      nbytes / POLY1305_BLOCK_SIZE, 1);
52                 src += nbytes - (nbytes % POLY1305_BLOCK_SIZE);
53                 nbytes %= POLY1305_BLOCK_SIZE;
54         }
55
56         if (unlikely(nbytes)) {
57                 desc->buflen = nbytes;
58                 memcpy(desc->buf, src, nbytes);
59         }
60 }
61 EXPORT_SYMBOL_GPL(poly1305_update_generic);
62
63 void poly1305_final_generic(struct poly1305_desc_ctx *desc, u8 *dst)
64 {
65         if (unlikely(desc->buflen)) {
66                 desc->buf[desc->buflen++] = 1;
67                 memset(desc->buf + desc->buflen, 0,
68                        POLY1305_BLOCK_SIZE - desc->buflen);
69                 poly1305_core_blocks(&desc->h, &desc->core_r, desc->buf, 1, 0);
70         }
71
72         poly1305_core_emit(&desc->h, desc->s, dst);
73         *desc = (struct poly1305_desc_ctx){};
74 }
75 EXPORT_SYMBOL_GPL(poly1305_final_generic);
76
77 MODULE_LICENSE("GPL");
78 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");