1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Poly1305 authenticator algorithm, RFC7539.
4 *
5 * Copyright 2023- IBM Corp. All rights reserved.
6 */
7
8 #include <crypto/algapi.h>
9 #include <linux/crypto.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/jump_label.h>
13 #include <crypto/internal/hash.h>
14 #include <crypto/internal/poly1305.h>
15 #include <crypto/internal/simd.h>
16 #include <linux/cpufeature.h>
17 #include <asm/unaligned.h>
18 #include <asm/simd.h>
19 #include <asm/switch_to.h>
20
21 asmlinkage void poly1305_p10le_4blocks(void *h, const u8 *m, u32 mlen);
22 asmlinkage void poly1305_64s(void *h, const u8 *m, u32 mlen, int highbit);
23 asmlinkage void poly1305_emit_64(void *h, void *s, u8 *dst);
24
25 static void vsx_begin(void)
26 {
27 preempt_disable();
28 enable_kernel_vsx();
29 }
30
31 static void vsx_end(void)
32 {
33 disable_kernel_vsx();
34 preempt_enable();
35 }
36
37 static int crypto_poly1305_p10_init(struct shash_desc *desc)
38 {
39 struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
40
41 poly1305_core_init(&dctx->h);
42 dctx->buflen = 0;
43 dctx->rset = 0;
44 dctx->sset = false;
45
46 return 0;
47 }
48
49 static unsigned int crypto_poly1305_setdctxkey(struct poly1305_desc_ctx *dctx,
50 const u8 *inp, unsigned int len)
51 {
52 unsigned int acc = 0;
53
54 if (unlikely(!dctx->sset)) {
55 if (!dctx->rset && len >= POLY1305_BLOCK_SIZE) {
56 struct poly1305_core_key *key = &dctx->core_r;
57
58 key->key.r64[0] = get_unaligned_le64(&inp[0]);
59 key->key.r64[1] = get_unaligned_le64(&inp[8]);
60 inp += POLY1305_BLOCK_SIZE;
61 len -= POLY1305_BLOCK_SIZE;
62 acc += POLY1305_BLOCK_SIZE;
63 dctx->rset = 1;
64 }
65 if (len >= POLY1305_BLOCK_SIZE) {
66 dctx->s[0] = get_unaligned_le32(&inp[0]);
67 dctx->s[1] = get_unaligned_le32(&inp[4]);
68 dctx->s[2] = get_unaligned_le32(&inp[8]);
69 dctx->s[3] = get_unaligned_le32(&inp[12]);
70 acc += POLY1305_BLOCK_SIZE;
71 dctx->sset = true;
72 }
73 }
74 return acc;
75 }
76
77 static int crypto_poly1305_p10_update(struct shash_desc *desc,
78 const u8 *src, unsigned int srclen)
79 {
80 struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
81 unsigned int bytes, used;
82
83 if (unlikely(dctx->buflen)) {
84 bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen);
85 memcpy(dctx->buf + dctx->buflen, src, bytes);
86 src += bytes;
87 srclen -= bytes;
88 dctx->buflen += bytes;
89
90 if (dctx->buflen == POLY1305_BLOCK_SIZE) {
91 if (likely(!crypto_poly1305_setdctxkey(dctx, dctx->buf,
92 POLY1305_BLOCK_SIZE))) {
93 vsx_begin();
94 poly1305_64s(&dctx->h, dctx->buf,
95 POLY1305_BLOCK_SIZE, 1);
96 vsx_end();
97 }
98 dctx->buflen = 0;
99 }
100 }
101
102 if (likely(srclen >= POLY1305_BLOCK_SIZE)) {
103 bytes = round_down(srclen, POLY1305_BLOCK_SIZE);
104 used = crypto_poly1305_setdctxkey(dctx, src, bytes);
105 if (likely(used)) {
106 srclen -= used;
107 src += used;
108 }
109 if (crypto_simd_usable() && (srclen >= POLY1305_BLOCK_SIZE*4)) {
110 vsx_begin();
111 poly1305_p10le_4blocks(&dctx->h, src, srclen);
112 vsx_end();
113 src += srclen - (srclen % (POLY1305_BLOCK_SIZE * 4));
114 srclen %= POLY1305_BLOCK_SIZE * 4;
115 }
116 while (srclen >= POLY1305_BLOCK_SIZE) {
117 vsx_begin();
118 poly1305_64s(&dctx->h, src, POLY1305_BLOCK_SIZE, 1);
119 vsx_end();
120 srclen -= POLY1305_BLOCK_SIZE;
121 src += POLY1305_BLOCK_SIZE;
122 }
123 }
124
125 if (unlikely(srclen)) {
126 dctx->buflen = srclen;
127 memcpy(dctx->buf, src, srclen);
128 }
129
130 return 0;
131 }
132
133 static int crypto_poly1305_p10_final(struct shash_desc *desc, u8 *dst)
134 {
135 struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
136
137 if (unlikely(!dctx->sset))
138 return -ENOKEY;
139
140 if ((dctx->buflen)) {
141 dctx->buf[dctx->buflen++] = 1;
142 memset(dctx->buf + dctx->buflen, 0,
143 POLY1305_BLOCK_SIZE - dctx->buflen);
144 vsx_begin();
145 poly1305_64s(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 0);
146 vsx_end();
147 dctx->buflen = 0;
148 }
149
150 poly1305_emit_64(&dctx->h, &dctx->s, dst);
151 return 0;
152 }
153
154 static struct shash_alg poly1305_alg = {
155 .digestsize = POLY1305_DIGEST_SIZE,
156 .init = crypto_poly1305_p10_init,
157 .update = crypto_poly1305_p10_update,
158 .final = crypto_poly1305_p10_final,
159 .descsize = sizeof(struct poly1305_desc_ctx),
160 .base = {
161 .cra_name = "poly1305",
162 .cra_driver_name = "poly1305-p10",
163 .cra_priority = 300,
164 .cra_blocksize = POLY1305_BLOCK_SIZE,
165 .cra_module = THIS_MODULE,
166 },
167 };
168
169 static int __init poly1305_p10_init(void)
170 {
171 return crypto_register_shash(&poly1305_alg);
172 }
173
174 static void __exit poly1305_p10_exit(void)
175 {
176 crypto_unregister_shash(&poly1305_alg);
177 }
178
179 module_cpu_feature_match(PPC_MODULE_FEATURE_P10, poly1305_p10_init);
180 module_exit(poly1305_p10_exit);
181
182 MODULE_LICENSE("GPL");
183 MODULE_AUTHOR("Danny Tsen <dtsen@linux.ibm.com>");
184 MODULE_DESCRIPTION("Optimized Poly1305 for P10");
185 MODULE_ALIAS_CRYPTO("poly1305");
186 MODULE_ALIAS_CRYPTO("poly1305-p10");
187
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