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>");
79 MODULE_DESCRIPTION("Poly1305 authenticator algorithm, RFC7539");
80
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