1 /*
2 * Accelerated GHASH implementation with ARMv8 vmull.p64 instructions.
3 *
4 * Copyright (C) 2015 Linaro Ltd. <ard.biesheuvel@linaro.org>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
9 */
10
11 #include <asm/hwcap.h>
12 #include <asm/neon.h>
13 #include <asm/simd.h>
14 #include <asm/unaligned.h>
15 #include <crypto/cryptd.h>
16 #include <crypto/internal/hash.h>
17 #include <crypto/gf128mul.h>
18 #include <linux/crypto.h>
19 #include <linux/module.h>
20
21 MODULE_DESCRIPTION("GHASH secure hash using ARMv8 Crypto Extensions");
22 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
23 MODULE_LICENSE("GPL v2");
24
25 #define GHASH_BLOCK_SIZE 16
26 #define GHASH_DIGEST_SIZE 16
27
28 struct ghash_key {
29 u64 a;
30 u64 b;
31 };
32
33 struct ghash_desc_ctx {
34 u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
35 u8 buf[GHASH_BLOCK_SIZE];
36 u32 count;
37 };
38
39 struct ghash_async_ctx {
40 struct cryptd_ahash *cryptd_tfm;
41 };
42
43 asmlinkage void pmull_ghash_update(int blocks, u64 dg[], const char *src,
44 struct ghash_key const *k, const char *head);
45
ghash_init(struct shash_desc * desc)46 static int ghash_init(struct shash_desc *desc)
47 {
48 struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
49
50 *ctx = (struct ghash_desc_ctx){};
51 return 0;
52 }
53
ghash_update(struct shash_desc * desc,const u8 * src,unsigned int len)54 static int ghash_update(struct shash_desc *desc, const u8 *src,
55 unsigned int len)
56 {
57 struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
58 unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
59
60 ctx->count += len;
61
62 if ((partial + len) >= GHASH_BLOCK_SIZE) {
63 struct ghash_key *key = crypto_shash_ctx(desc->tfm);
64 int blocks;
65
66 if (partial) {
67 int p = GHASH_BLOCK_SIZE - partial;
68
69 memcpy(ctx->buf + partial, src, p);
70 src += p;
71 len -= p;
72 }
73
74 blocks = len / GHASH_BLOCK_SIZE;
75 len %= GHASH_BLOCK_SIZE;
76
77 kernel_neon_begin();
78 pmull_ghash_update(blocks, ctx->digest, src, key,
79 partial ? ctx->buf : NULL);
80 kernel_neon_end();
81 src += blocks * GHASH_BLOCK_SIZE;
82 partial = 0;
83 }
84 if (len)
85 memcpy(ctx->buf + partial, src, len);
86 return 0;
87 }
88
ghash_final(struct shash_desc * desc,u8 * dst)89 static int ghash_final(struct shash_desc *desc, u8 *dst)
90 {
91 struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
92 unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
93
94 if (partial) {
95 struct ghash_key *key = crypto_shash_ctx(desc->tfm);
96
97 memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);
98 kernel_neon_begin();
99 pmull_ghash_update(1, ctx->digest, ctx->buf, key, NULL);
100 kernel_neon_end();
101 }
102 put_unaligned_be64(ctx->digest[1], dst);
103 put_unaligned_be64(ctx->digest[0], dst + 8);
104
105 *ctx = (struct ghash_desc_ctx){};
106 return 0;
107 }
108
ghash_setkey(struct crypto_shash * tfm,const u8 * inkey,unsigned int keylen)109 static int ghash_setkey(struct crypto_shash *tfm,
110 const u8 *inkey, unsigned int keylen)
111 {
112 struct ghash_key *key = crypto_shash_ctx(tfm);
113 u64 a, b;
114
115 if (keylen != GHASH_BLOCK_SIZE) {
116 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
117 return -EINVAL;
118 }
119
120 /* perform multiplication by 'x' in GF(2^128) */
121 b = get_unaligned_be64(inkey);
122 a = get_unaligned_be64(inkey + 8);
123
124 key->a = (a << 1) | (b >> 63);
125 key->b = (b << 1) | (a >> 63);
126
127 if (b >> 63)
128 key->b ^= 0xc200000000000000UL;
129
130 return 0;
131 }
132
133 static struct shash_alg ghash_alg = {
134 .digestsize = GHASH_DIGEST_SIZE,
135 .init = ghash_init,
136 .update = ghash_update,
137 .final = ghash_final,
138 .setkey = ghash_setkey,
139 .descsize = sizeof(struct ghash_desc_ctx),
140 .base = {
141 .cra_name = "ghash",
142 .cra_driver_name = "__driver-ghash-ce",
143 .cra_priority = 0,
144 .cra_flags = CRYPTO_ALG_TYPE_SHASH | CRYPTO_ALG_INTERNAL,
145 .cra_blocksize = GHASH_BLOCK_SIZE,
146 .cra_ctxsize = sizeof(struct ghash_key),
147 .cra_module = THIS_MODULE,
148 },
149 };
150
ghash_async_init(struct ahash_request * req)151 static int ghash_async_init(struct ahash_request *req)
152 {
153 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
154 struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
155 struct ahash_request *cryptd_req = ahash_request_ctx(req);
156 struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
157
158 if (!may_use_simd()) {
159 memcpy(cryptd_req, req, sizeof(*req));
160 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
161 return crypto_ahash_init(cryptd_req);
162 } else {
163 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
164 struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
165
166 desc->tfm = child;
167 desc->flags = req->base.flags;
168 return crypto_shash_init(desc);
169 }
170 }
171
ghash_async_update(struct ahash_request * req)172 static int ghash_async_update(struct ahash_request *req)
173 {
174 struct ahash_request *cryptd_req = ahash_request_ctx(req);
175
176 if (!may_use_simd()) {
177 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
178 struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
179 struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
180
181 memcpy(cryptd_req, req, sizeof(*req));
182 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
183 return crypto_ahash_update(cryptd_req);
184 } else {
185 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
186 return shash_ahash_update(req, desc);
187 }
188 }
189
ghash_async_final(struct ahash_request * req)190 static int ghash_async_final(struct ahash_request *req)
191 {
192 struct ahash_request *cryptd_req = ahash_request_ctx(req);
193
194 if (!may_use_simd()) {
195 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
196 struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
197 struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
198
199 memcpy(cryptd_req, req, sizeof(*req));
200 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
201 return crypto_ahash_final(cryptd_req);
202 } else {
203 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
204 return crypto_shash_final(desc, req->result);
205 }
206 }
207
ghash_async_digest(struct ahash_request * req)208 static int ghash_async_digest(struct ahash_request *req)
209 {
210 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
211 struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
212 struct ahash_request *cryptd_req = ahash_request_ctx(req);
213 struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
214
215 if (!may_use_simd()) {
216 memcpy(cryptd_req, req, sizeof(*req));
217 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
218 return crypto_ahash_digest(cryptd_req);
219 } else {
220 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
221 struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
222
223 desc->tfm = child;
224 desc->flags = req->base.flags;
225 return shash_ahash_digest(req, desc);
226 }
227 }
228
ghash_async_import(struct ahash_request * req,const void * in)229 static int ghash_async_import(struct ahash_request *req, const void *in)
230 {
231 struct ahash_request *cryptd_req = ahash_request_ctx(req);
232 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
233 struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
234 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
235
236 desc->tfm = cryptd_ahash_child(ctx->cryptd_tfm);
237 desc->flags = req->base.flags;
238
239 return crypto_shash_import(desc, in);
240 }
241
ghash_async_export(struct ahash_request * req,void * out)242 static int ghash_async_export(struct ahash_request *req, void *out)
243 {
244 struct ahash_request *cryptd_req = ahash_request_ctx(req);
245 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
246
247 return crypto_shash_export(desc, out);
248 }
249
ghash_async_setkey(struct crypto_ahash * tfm,const u8 * key,unsigned int keylen)250 static int ghash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
251 unsigned int keylen)
252 {
253 struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
254 struct crypto_ahash *child = &ctx->cryptd_tfm->base;
255 int err;
256
257 crypto_ahash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
258 crypto_ahash_set_flags(child, crypto_ahash_get_flags(tfm)
259 & CRYPTO_TFM_REQ_MASK);
260 err = crypto_ahash_setkey(child, key, keylen);
261 crypto_ahash_set_flags(tfm, crypto_ahash_get_flags(child)
262 & CRYPTO_TFM_RES_MASK);
263
264 return err;
265 }
266
ghash_async_init_tfm(struct crypto_tfm * tfm)267 static int ghash_async_init_tfm(struct crypto_tfm *tfm)
268 {
269 struct cryptd_ahash *cryptd_tfm;
270 struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
271
272 cryptd_tfm = cryptd_alloc_ahash("__driver-ghash-ce",
273 CRYPTO_ALG_INTERNAL,
274 CRYPTO_ALG_INTERNAL);
275 if (IS_ERR(cryptd_tfm))
276 return PTR_ERR(cryptd_tfm);
277 ctx->cryptd_tfm = cryptd_tfm;
278 crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
279 sizeof(struct ahash_request) +
280 crypto_ahash_reqsize(&cryptd_tfm->base));
281
282 return 0;
283 }
284
ghash_async_exit_tfm(struct crypto_tfm * tfm)285 static void ghash_async_exit_tfm(struct crypto_tfm *tfm)
286 {
287 struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
288
289 cryptd_free_ahash(ctx->cryptd_tfm);
290 }
291
292 static struct ahash_alg ghash_async_alg = {
293 .init = ghash_async_init,
294 .update = ghash_async_update,
295 .final = ghash_async_final,
296 .setkey = ghash_async_setkey,
297 .digest = ghash_async_digest,
298 .import = ghash_async_import,
299 .export = ghash_async_export,
300 .halg.digestsize = GHASH_DIGEST_SIZE,
301 .halg.statesize = sizeof(struct ghash_desc_ctx),
302 .halg.base = {
303 .cra_name = "ghash",
304 .cra_driver_name = "ghash-ce",
305 .cra_priority = 300,
306 .cra_flags = CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC,
307 .cra_blocksize = GHASH_BLOCK_SIZE,
308 .cra_type = &crypto_ahash_type,
309 .cra_ctxsize = sizeof(struct ghash_async_ctx),
310 .cra_module = THIS_MODULE,
311 .cra_init = ghash_async_init_tfm,
312 .cra_exit = ghash_async_exit_tfm,
313 },
314 };
315
ghash_ce_mod_init(void)316 static int __init ghash_ce_mod_init(void)
317 {
318 int err;
319
320 if (!(elf_hwcap2 & HWCAP2_PMULL))
321 return -ENODEV;
322
323 err = crypto_register_shash(&ghash_alg);
324 if (err)
325 return err;
326 err = crypto_register_ahash(&ghash_async_alg);
327 if (err)
328 goto err_shash;
329
330 return 0;
331
332 err_shash:
333 crypto_unregister_shash(&ghash_alg);
334 return err;
335 }
336
ghash_ce_mod_exit(void)337 static void __exit ghash_ce_mod_exit(void)
338 {
339 crypto_unregister_ahash(&ghash_async_alg);
340 crypto_unregister_shash(&ghash_alg);
341 }
342
343 module_init(ghash_ce_mod_init);
344 module_exit(ghash_ce_mod_exit);
345