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
15void 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}
28EXPORT_SYMBOL_GPL(poly1305_init_generic);
29
30void 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}
61EXPORT_SYMBOL_GPL(poly1305_update_generic);
62
63void 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}
75EXPORT_SYMBOL_GPL(poly1305_final_generic);
76
77MODULE_LICENSE("GPL");
78MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
79