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/export.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/string.h>
15#include <linux/unaligned.h>
16
17#ifdef CONFIG_CRYPTO_LIB_POLY1305_ARCH
18#include "poly1305.h" /* $(SRCARCH)/poly1305.h */
19#else
20#define poly1305_block_init poly1305_block_init_generic
21#define poly1305_blocks poly1305_blocks_generic
22#define poly1305_emit poly1305_emit_generic
23#endif
24
25void poly1305_init(struct poly1305_desc_ctx *desc,
26 const u8 key[POLY1305_KEY_SIZE])
27{
28 desc->s[0] = get_unaligned_le32(p: key + 16);
29 desc->s[1] = get_unaligned_le32(p: key + 20);
30 desc->s[2] = get_unaligned_le32(p: key + 24);
31 desc->s[3] = get_unaligned_le32(p: key + 28);
32 desc->buflen = 0;
33 poly1305_block_init(state: &desc->state, raw_key: key);
34}
35EXPORT_SYMBOL(poly1305_init);
36
37void poly1305_update(struct poly1305_desc_ctx *desc,
38 const u8 *src, unsigned int nbytes)
39{
40 if (desc->buflen + nbytes >= POLY1305_BLOCK_SIZE) {
41 unsigned int bulk_len;
42
43 if (desc->buflen) {
44 unsigned int l = POLY1305_BLOCK_SIZE - desc->buflen;
45
46 memcpy(&desc->buf[desc->buflen], src, l);
47 src += l;
48 nbytes -= l;
49
50 poly1305_blocks(state: &desc->state, inp: desc->buf,
51 POLY1305_BLOCK_SIZE, padbit: 1);
52 desc->buflen = 0;
53 }
54
55 bulk_len = round_down(nbytes, POLY1305_BLOCK_SIZE);
56 nbytes %= POLY1305_BLOCK_SIZE;
57
58 if (bulk_len) {
59 poly1305_blocks(state: &desc->state, inp: src, len: bulk_len, padbit: 1);
60 src += bulk_len;
61 }
62 }
63 if (nbytes) {
64 memcpy(&desc->buf[desc->buflen], src, nbytes);
65 desc->buflen += nbytes;
66 }
67}
68EXPORT_SYMBOL(poly1305_update);
69
70void poly1305_final(struct poly1305_desc_ctx *desc, u8 *dst)
71{
72 if (unlikely(desc->buflen)) {
73 desc->buf[desc->buflen++] = 1;
74 memset(desc->buf + desc->buflen, 0,
75 POLY1305_BLOCK_SIZE - desc->buflen);
76 poly1305_blocks(state: &desc->state, inp: desc->buf, POLY1305_BLOCK_SIZE,
77 padbit: 0);
78 }
79
80 poly1305_emit(ctx: &desc->state.h, mac: dst, nonce: desc->s);
81 *desc = (struct poly1305_desc_ctx){};
82}
83EXPORT_SYMBOL(poly1305_final);
84
85#ifdef poly1305_mod_init_arch
86static int __init poly1305_mod_init(void)
87{
88 poly1305_mod_init_arch();
89 return 0;
90}
91subsys_initcall(poly1305_mod_init);
92
93static void __exit poly1305_mod_exit(void)
94{
95}
96module_exit(poly1305_mod_exit);
97#endif
98
99MODULE_LICENSE("GPL");
100MODULE_DESCRIPTION("Poly1305 authenticator algorithm, RFC7539");
101

source code of linux/lib/crypto/poly1305.c