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
poly1305_init(struct poly1305_desc_ctx * desc,const u8 key[POLY1305_KEY_SIZE])25 void poly1305_init(struct poly1305_desc_ctx *desc,
26 const u8 key[POLY1305_KEY_SIZE])
27 {
28 desc->s[0] = get_unaligned_le32(key + 16);
29 desc->s[1] = get_unaligned_le32(key + 20);
30 desc->s[2] = get_unaligned_le32(key + 24);
31 desc->s[3] = get_unaligned_le32(key + 28);
32 desc->buflen = 0;
33 poly1305_block_init(&desc->state, key);
34 }
35 EXPORT_SYMBOL(poly1305_init);
36
poly1305_update(struct poly1305_desc_ctx * desc,const u8 * src,unsigned int nbytes)37 void 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(&desc->state, desc->buf,
51 POLY1305_BLOCK_SIZE, 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(&desc->state, src, bulk_len, 1);
60 src += bulk_len;
61 }
62 }
63 if (nbytes) {
64 memcpy(&desc->buf[desc->buflen], src, nbytes);
65 desc->buflen += nbytes;
66 }
67 }
68 EXPORT_SYMBOL(poly1305_update);
69
poly1305_final(struct poly1305_desc_ctx * desc,u8 * dst)70 void 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(&desc->state, desc->buf, POLY1305_BLOCK_SIZE,
77 0);
78 }
79
80 poly1305_emit(&desc->state.h, dst, desc->s);
81 *desc = (struct poly1305_desc_ctx){};
82 }
83 EXPORT_SYMBOL(poly1305_final);
84
85 #ifdef poly1305_mod_init_arch
poly1305_mod_init(void)86 static int __init poly1305_mod_init(void)
87 {
88 poly1305_mod_init_arch();
89 return 0;
90 }
91 subsys_initcall(poly1305_mod_init);
92
poly1305_mod_exit(void)93 static void __exit poly1305_mod_exit(void)
94 {
95 }
96 module_exit(poly1305_mod_exit);
97 #endif
98
99 MODULE_LICENSE("GPL");
100 MODULE_DESCRIPTION("Poly1305 authenticator algorithm, RFC7539");
101