1 /* 1 /*
2 * Poly1305 authenticator algorithm, RFC7539 2 * Poly1305 authenticator algorithm, RFC7539
3 * 3 *
4 * Copyright (C) 2015 Martin Willi 4 * Copyright (C) 2015 Martin Willi
5 * 5 *
6 * Based on public domain code by Andrew Moon 6 * Based on public domain code by Andrew Moon and Daniel J. Bernstein.
7 * 7 *
8 * This program is free software; you can redi 8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Publi 9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either versio 10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version. 11 * (at your option) any later version.
12 */ 12 */
13 13
14 #include <crypto/algapi.h> 14 #include <crypto/algapi.h>
15 #include <crypto/internal/hash.h> 15 #include <crypto/internal/hash.h>
16 #include <crypto/internal/poly1305.h> !! 16 #include <crypto/poly1305.h>
17 #include <linux/crypto.h> 17 #include <linux/crypto.h>
18 #include <linux/kernel.h> 18 #include <linux/kernel.h>
19 #include <linux/module.h> 19 #include <linux/module.h>
20 #include <asm/unaligned.h> 20 #include <asm/unaligned.h>
21 21
22 static int crypto_poly1305_init(struct shash_d !! 22 static inline u64 mlt(u64 a, u64 b)
>> 23 {
>> 24 return a * b;
>> 25 }
>> 26
>> 27 static inline u32 sr(u64 v, u_char n)
>> 28 {
>> 29 return v >> n;
>> 30 }
>> 31
>> 32 static inline u32 and(u32 v, u32 mask)
>> 33 {
>> 34 return v & mask;
>> 35 }
>> 36
>> 37 int crypto_poly1305_init(struct shash_desc *desc)
23 { 38 {
24 struct poly1305_desc_ctx *dctx = shash 39 struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
25 40
26 poly1305_core_init(&dctx->h); 41 poly1305_core_init(&dctx->h);
27 dctx->buflen = 0; 42 dctx->buflen = 0;
28 dctx->rset = 0; !! 43 dctx->rset = false;
29 dctx->sset = false; 44 dctx->sset = false;
30 45
31 return 0; 46 return 0;
32 } 47 }
>> 48 EXPORT_SYMBOL_GPL(crypto_poly1305_init);
>> 49
>> 50 void poly1305_core_setkey(struct poly1305_key *key, const u8 *raw_key)
>> 51 {
>> 52 /* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
>> 53 key->r[0] = (get_unaligned_le32(raw_key + 0) >> 0) & 0x3ffffff;
>> 54 key->r[1] = (get_unaligned_le32(raw_key + 3) >> 2) & 0x3ffff03;
>> 55 key->r[2] = (get_unaligned_le32(raw_key + 6) >> 4) & 0x3ffc0ff;
>> 56 key->r[3] = (get_unaligned_le32(raw_key + 9) >> 6) & 0x3f03fff;
>> 57 key->r[4] = (get_unaligned_le32(raw_key + 12) >> 8) & 0x00fffff;
>> 58 }
>> 59 EXPORT_SYMBOL_GPL(poly1305_core_setkey);
33 60
34 static unsigned int crypto_poly1305_setdesckey !! 61 /*
35 !! 62 * Poly1305 requires a unique key for each tag, which implies that we can't set
>> 63 * it on the tfm that gets accessed by multiple users simultaneously. Instead we
>> 64 * expect the key as the first 32 bytes in the update() call.
>> 65 */
>> 66 unsigned int crypto_poly1305_setdesckey(struct poly1305_desc_ctx *dctx,
>> 67 const u8 *src, unsigned int srclen)
36 { 68 {
37 if (!dctx->sset) { 69 if (!dctx->sset) {
38 if (!dctx->rset && srclen >= P 70 if (!dctx->rset && srclen >= POLY1305_BLOCK_SIZE) {
39 poly1305_core_setkey(& !! 71 poly1305_core_setkey(&dctx->r, src);
40 src += POLY1305_BLOCK_ 72 src += POLY1305_BLOCK_SIZE;
41 srclen -= POLY1305_BLO 73 srclen -= POLY1305_BLOCK_SIZE;
42 dctx->rset = 2; !! 74 dctx->rset = true;
43 } 75 }
44 if (srclen >= POLY1305_BLOCK_S 76 if (srclen >= POLY1305_BLOCK_SIZE) {
45 dctx->s[0] = get_unali 77 dctx->s[0] = get_unaligned_le32(src + 0);
46 dctx->s[1] = get_unali 78 dctx->s[1] = get_unaligned_le32(src + 4);
47 dctx->s[2] = get_unali 79 dctx->s[2] = get_unaligned_le32(src + 8);
48 dctx->s[3] = get_unali 80 dctx->s[3] = get_unaligned_le32(src + 12);
49 src += POLY1305_BLOCK_ 81 src += POLY1305_BLOCK_SIZE;
50 srclen -= POLY1305_BLO 82 srclen -= POLY1305_BLOCK_SIZE;
51 dctx->sset = true; 83 dctx->sset = true;
52 } 84 }
53 } 85 }
54 return srclen; 86 return srclen;
55 } 87 }
>> 88 EXPORT_SYMBOL_GPL(crypto_poly1305_setdesckey);
>> 89
>> 90 static void poly1305_blocks_internal(struct poly1305_state *state,
>> 91 const struct poly1305_key *key,
>> 92 const void *src, unsigned int nblocks,
>> 93 u32 hibit)
>> 94 {
>> 95 u32 r0, r1, r2, r3, r4;
>> 96 u32 s1, s2, s3, s4;
>> 97 u32 h0, h1, h2, h3, h4;
>> 98 u64 d0, d1, d2, d3, d4;
>> 99
>> 100 if (!nblocks)
>> 101 return;
>> 102
>> 103 r0 = key->r[0];
>> 104 r1 = key->r[1];
>> 105 r2 = key->r[2];
>> 106 r3 = key->r[3];
>> 107 r4 = key->r[4];
>> 108
>> 109 s1 = r1 * 5;
>> 110 s2 = r2 * 5;
>> 111 s3 = r3 * 5;
>> 112 s4 = r4 * 5;
>> 113
>> 114 h0 = state->h[0];
>> 115 h1 = state->h[1];
>> 116 h2 = state->h[2];
>> 117 h3 = state->h[3];
>> 118 h4 = state->h[4];
>> 119
>> 120 do {
>> 121 /* h += m[i] */
>> 122 h0 += (get_unaligned_le32(src + 0) >> 0) & 0x3ffffff;
>> 123 h1 += (get_unaligned_le32(src + 3) >> 2) & 0x3ffffff;
>> 124 h2 += (get_unaligned_le32(src + 6) >> 4) & 0x3ffffff;
>> 125 h3 += (get_unaligned_le32(src + 9) >> 6) & 0x3ffffff;
>> 126 h4 += (get_unaligned_le32(src + 12) >> 8) | hibit;
>> 127
>> 128 /* h *= r */
>> 129 d0 = mlt(h0, r0) + mlt(h1, s4) + mlt(h2, s3) +
>> 130 mlt(h3, s2) + mlt(h4, s1);
>> 131 d1 = mlt(h0, r1) + mlt(h1, r0) + mlt(h2, s4) +
>> 132 mlt(h3, s3) + mlt(h4, s2);
>> 133 d2 = mlt(h0, r2) + mlt(h1, r1) + mlt(h2, r0) +
>> 134 mlt(h3, s4) + mlt(h4, s3);
>> 135 d3 = mlt(h0, r3) + mlt(h1, r2) + mlt(h2, r1) +
>> 136 mlt(h3, r0) + mlt(h4, s4);
>> 137 d4 = mlt(h0, r4) + mlt(h1, r3) + mlt(h2, r2) +
>> 138 mlt(h3, r1) + mlt(h4, r0);
>> 139
>> 140 /* (partial) h %= p */
>> 141 d1 += sr(d0, 26); h0 = and(d0, 0x3ffffff);
>> 142 d2 += sr(d1, 26); h1 = and(d1, 0x3ffffff);
>> 143 d3 += sr(d2, 26); h2 = and(d2, 0x3ffffff);
>> 144 d4 += sr(d3, 26); h3 = and(d3, 0x3ffffff);
>> 145 h0 += sr(d4, 26) * 5; h4 = and(d4, 0x3ffffff);
>> 146 h1 += h0 >> 26; h0 = h0 & 0x3ffffff;
>> 147
>> 148 src += POLY1305_BLOCK_SIZE;
>> 149 } while (--nblocks);
>> 150
>> 151 state->h[0] = h0;
>> 152 state->h[1] = h1;
>> 153 state->h[2] = h2;
>> 154 state->h[3] = h3;
>> 155 state->h[4] = h4;
>> 156 }
56 157
57 static void poly1305_blocks(struct poly1305_de !! 158 void poly1305_core_blocks(struct poly1305_state *state,
58 unsigned int srcle !! 159 const struct poly1305_key *key,
>> 160 const void *src, unsigned int nblocks)
>> 161 {
>> 162 poly1305_blocks_internal(state, key, src, nblocks, 1 << 24);
>> 163 }
>> 164 EXPORT_SYMBOL_GPL(poly1305_core_blocks);
>> 165
>> 166 static void poly1305_blocks(struct poly1305_desc_ctx *dctx,
>> 167 const u8 *src, unsigned int srclen, u32 hibit)
59 { 168 {
60 unsigned int datalen; 169 unsigned int datalen;
61 170
62 if (unlikely(!dctx->sset)) { 171 if (unlikely(!dctx->sset)) {
63 datalen = crypto_poly1305_setd 172 datalen = crypto_poly1305_setdesckey(dctx, src, srclen);
64 src += srclen - datalen; 173 src += srclen - datalen;
65 srclen = datalen; 174 srclen = datalen;
66 } 175 }
67 176
68 poly1305_core_blocks(&dctx->h, &dctx-> !! 177 poly1305_blocks_internal(&dctx->h, &dctx->r,
69 srclen / POLY1305 !! 178 src, srclen / POLY1305_BLOCK_SIZE, hibit);
70 } 179 }
71 180
72 static int crypto_poly1305_update(struct shash !! 181 int crypto_poly1305_update(struct shash_desc *desc,
73 const u8 *sr !! 182 const u8 *src, unsigned int srclen)
74 { 183 {
75 struct poly1305_desc_ctx *dctx = shash 184 struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
76 unsigned int bytes; 185 unsigned int bytes;
77 186
78 if (unlikely(dctx->buflen)) { 187 if (unlikely(dctx->buflen)) {
79 bytes = min(srclen, POLY1305_B 188 bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen);
80 memcpy(dctx->buf + dctx->bufle 189 memcpy(dctx->buf + dctx->buflen, src, bytes);
81 src += bytes; 190 src += bytes;
82 srclen -= bytes; 191 srclen -= bytes;
83 dctx->buflen += bytes; 192 dctx->buflen += bytes;
84 193
85 if (dctx->buflen == POLY1305_B 194 if (dctx->buflen == POLY1305_BLOCK_SIZE) {
86 poly1305_blocks(dctx, 195 poly1305_blocks(dctx, dctx->buf,
87 POLY13 !! 196 POLY1305_BLOCK_SIZE, 1 << 24);
88 dctx->buflen = 0; 197 dctx->buflen = 0;
89 } 198 }
90 } 199 }
91 200
92 if (likely(srclen >= POLY1305_BLOCK_SI 201 if (likely(srclen >= POLY1305_BLOCK_SIZE)) {
93 poly1305_blocks(dctx, src, src !! 202 poly1305_blocks(dctx, src, srclen, 1 << 24);
94 src += srclen - (srclen % POLY 203 src += srclen - (srclen % POLY1305_BLOCK_SIZE);
95 srclen %= POLY1305_BLOCK_SIZE; 204 srclen %= POLY1305_BLOCK_SIZE;
96 } 205 }
97 206
98 if (unlikely(srclen)) { 207 if (unlikely(srclen)) {
99 dctx->buflen = srclen; 208 dctx->buflen = srclen;
100 memcpy(dctx->buf, src, srclen) 209 memcpy(dctx->buf, src, srclen);
101 } 210 }
102 211
103 return 0; 212 return 0;
104 } 213 }
>> 214 EXPORT_SYMBOL_GPL(crypto_poly1305_update);
105 215
106 static int crypto_poly1305_final(struct shash_ !! 216 void poly1305_core_emit(const struct poly1305_state *state, void *dst)
>> 217 {
>> 218 u32 h0, h1, h2, h3, h4;
>> 219 u32 g0, g1, g2, g3, g4;
>> 220 u32 mask;
>> 221
>> 222 /* fully carry h */
>> 223 h0 = state->h[0];
>> 224 h1 = state->h[1];
>> 225 h2 = state->h[2];
>> 226 h3 = state->h[3];
>> 227 h4 = state->h[4];
>> 228
>> 229 h2 += (h1 >> 26); h1 = h1 & 0x3ffffff;
>> 230 h3 += (h2 >> 26); h2 = h2 & 0x3ffffff;
>> 231 h4 += (h3 >> 26); h3 = h3 & 0x3ffffff;
>> 232 h0 += (h4 >> 26) * 5; h4 = h4 & 0x3ffffff;
>> 233 h1 += (h0 >> 26); h0 = h0 & 0x3ffffff;
>> 234
>> 235 /* compute h + -p */
>> 236 g0 = h0 + 5;
>> 237 g1 = h1 + (g0 >> 26); g0 &= 0x3ffffff;
>> 238 g2 = h2 + (g1 >> 26); g1 &= 0x3ffffff;
>> 239 g3 = h3 + (g2 >> 26); g2 &= 0x3ffffff;
>> 240 g4 = h4 + (g3 >> 26) - (1 << 26); g3 &= 0x3ffffff;
>> 241
>> 242 /* select h if h < p, or h + -p if h >= p */
>> 243 mask = (g4 >> ((sizeof(u32) * 8) - 1)) - 1;
>> 244 g0 &= mask;
>> 245 g1 &= mask;
>> 246 g2 &= mask;
>> 247 g3 &= mask;
>> 248 g4 &= mask;
>> 249 mask = ~mask;
>> 250 h0 = (h0 & mask) | g0;
>> 251 h1 = (h1 & mask) | g1;
>> 252 h2 = (h2 & mask) | g2;
>> 253 h3 = (h3 & mask) | g3;
>> 254 h4 = (h4 & mask) | g4;
>> 255
>> 256 /* h = h % (2^128) */
>> 257 put_unaligned_le32((h0 >> 0) | (h1 << 26), dst + 0);
>> 258 put_unaligned_le32((h1 >> 6) | (h2 << 20), dst + 4);
>> 259 put_unaligned_le32((h2 >> 12) | (h3 << 14), dst + 8);
>> 260 put_unaligned_le32((h3 >> 18) | (h4 << 8), dst + 12);
>> 261 }
>> 262 EXPORT_SYMBOL_GPL(poly1305_core_emit);
>> 263
>> 264 int crypto_poly1305_final(struct shash_desc *desc, u8 *dst)
107 { 265 {
108 struct poly1305_desc_ctx *dctx = shash 266 struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
>> 267 __le32 digest[4];
>> 268 u64 f = 0;
109 269
110 if (unlikely(!dctx->sset)) 270 if (unlikely(!dctx->sset))
111 return -ENOKEY; 271 return -ENOKEY;
112 272
113 poly1305_final_generic(dctx, dst); !! 273 if (unlikely(dctx->buflen)) {
>> 274 dctx->buf[dctx->buflen++] = 1;
>> 275 memset(dctx->buf + dctx->buflen, 0,
>> 276 POLY1305_BLOCK_SIZE - dctx->buflen);
>> 277 poly1305_blocks(dctx, dctx->buf, POLY1305_BLOCK_SIZE, 0);
>> 278 }
>> 279
>> 280 poly1305_core_emit(&dctx->h, digest);
>> 281
>> 282 /* mac = (h + s) % (2^128) */
>> 283 f = (f >> 32) + le32_to_cpu(digest[0]) + dctx->s[0];
>> 284 put_unaligned_le32(f, dst + 0);
>> 285 f = (f >> 32) + le32_to_cpu(digest[1]) + dctx->s[1];
>> 286 put_unaligned_le32(f, dst + 4);
>> 287 f = (f >> 32) + le32_to_cpu(digest[2]) + dctx->s[2];
>> 288 put_unaligned_le32(f, dst + 8);
>> 289 f = (f >> 32) + le32_to_cpu(digest[3]) + dctx->s[3];
>> 290 put_unaligned_le32(f, dst + 12);
>> 291
114 return 0; 292 return 0;
115 } 293 }
>> 294 EXPORT_SYMBOL_GPL(crypto_poly1305_final);
116 295
117 static struct shash_alg poly1305_alg = { 296 static struct shash_alg poly1305_alg = {
118 .digestsize = POLY1305_DIGEST_SIZE 297 .digestsize = POLY1305_DIGEST_SIZE,
119 .init = crypto_poly1305_init 298 .init = crypto_poly1305_init,
120 .update = crypto_poly1305_upda 299 .update = crypto_poly1305_update,
121 .final = crypto_poly1305_fina 300 .final = crypto_poly1305_final,
122 .descsize = sizeof(struct poly13 301 .descsize = sizeof(struct poly1305_desc_ctx),
123 .base = { 302 .base = {
124 .cra_name = "pol 303 .cra_name = "poly1305",
125 .cra_driver_name = "pol 304 .cra_driver_name = "poly1305-generic",
126 .cra_priority = 100, 305 .cra_priority = 100,
127 .cra_blocksize = POLY 306 .cra_blocksize = POLY1305_BLOCK_SIZE,
128 .cra_module = THIS 307 .cra_module = THIS_MODULE,
129 }, 308 },
130 }; 309 };
131 310
132 static int __init poly1305_mod_init(void) 311 static int __init poly1305_mod_init(void)
133 { 312 {
134 return crypto_register_shash(&poly1305 313 return crypto_register_shash(&poly1305_alg);
135 } 314 }
136 315
137 static void __exit poly1305_mod_exit(void) 316 static void __exit poly1305_mod_exit(void)
138 { 317 {
139 crypto_unregister_shash(&poly1305_alg) 318 crypto_unregister_shash(&poly1305_alg);
140 } 319 }
141 320
142 subsys_initcall(poly1305_mod_init); 321 subsys_initcall(poly1305_mod_init);
143 module_exit(poly1305_mod_exit); 322 module_exit(poly1305_mod_exit);
144 323
145 MODULE_LICENSE("GPL"); 324 MODULE_LICENSE("GPL");
146 MODULE_AUTHOR("Martin Willi <martin@strongswan 325 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
147 MODULE_DESCRIPTION("Poly1305 authenticator"); 326 MODULE_DESCRIPTION("Poly1305 authenticator");
148 MODULE_ALIAS_CRYPTO("poly1305"); 327 MODULE_ALIAS_CRYPTO("poly1305");
149 MODULE_ALIAS_CRYPTO("poly1305-generic"); 328 MODULE_ALIAS_CRYPTO("poly1305-generic");
150 329
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