1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Accelerated GHASH implementation with Intel PCLMULQDQ-NI
4  * instructions. This file contains glue code.
5  *
6  * Copyright (c) 2009 Intel Corp.
7  *   Author: Huang Ying <ying.huang@intel.com>
8  */
9 
10 #include <linux/err.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/crypto.h>
15 #include <crypto/algapi.h>
16 #include <crypto/cryptd.h>
17 #include <crypto/gf128mul.h>
18 #include <crypto/internal/hash.h>
19 #include <crypto/internal/simd.h>
20 #include <asm/cpu_device_id.h>
21 #include <asm/simd.h>
22 
23 #define GHASH_BLOCK_SIZE	16
24 #define GHASH_DIGEST_SIZE	16
25 
26 void clmul_ghash_mul(char *dst, const u128 *shash);
27 
28 void clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
29 			const u128 *shash);
30 
31 struct ghash_async_ctx {
32 	struct cryptd_ahash *cryptd_tfm;
33 };
34 
35 struct ghash_ctx {
36 	u128 shash;
37 };
38 
39 struct ghash_desc_ctx {
40 	u8 buffer[GHASH_BLOCK_SIZE];
41 	u32 bytes;
42 };
43 
44 static int ghash_init(struct shash_desc *desc)
45 {
46 	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
47 
48 	memset(dctx, 0, sizeof(*dctx));
49 
50 	return 0;
51 }
52 
53 static int ghash_setkey(struct crypto_shash *tfm,
54 			const u8 *key, unsigned int keylen)
55 {
56 	struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
57 	be128 *x = (be128 *)key;
58 	u64 a, b;
59 
60 	if (keylen != GHASH_BLOCK_SIZE)
61 		return -EINVAL;
62 
63 	/* perform multiplication by 'x' in GF(2^128) */
64 	a = be64_to_cpu(x->a);
65 	b = be64_to_cpu(x->b);
66 
67 	ctx->shash.a = (b << 1) | (a >> 63);
68 	ctx->shash.b = (a << 1) | (b >> 63);
69 
70 	if (a >> 63)
71 		ctx->shash.b ^= ((u64)0xc2) << 56;
72 
73 	return 0;
74 }
75 
76 static int ghash_update(struct shash_desc *desc,
77 			 const u8 *src, unsigned int srclen)
78 {
79 	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
80 	struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
81 	u8 *dst = dctx->buffer;
82 
83 	kernel_fpu_begin();
84 	if (dctx->bytes) {
85 		int n = min(srclen, dctx->bytes);
86 		u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
87 
88 		dctx->bytes -= n;
89 		srclen -= n;
90 
91 		while (n--)
92 			*pos++ ^= *src++;
93 
94 		if (!dctx->bytes)
95 			clmul_ghash_mul(dst, &ctx->shash);
96 	}
97 
98 	clmul_ghash_update(dst, src, srclen, &ctx->shash);
99 	kernel_fpu_end();
100 
101 	if (srclen & 0xf) {
102 		src += srclen - (srclen & 0xf);
103 		srclen &= 0xf;
104 		dctx->bytes = GHASH_BLOCK_SIZE - srclen;
105 		while (srclen--)
106 			*dst++ ^= *src++;
107 	}
108 
109 	return 0;
110 }
111 
112 static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
113 {
114 	u8 *dst = dctx->buffer;
115 
116 	if (dctx->bytes) {
117 		u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
118 
119 		while (dctx->bytes--)
120 			*tmp++ ^= 0;
121 
122 		kernel_fpu_begin();
123 		clmul_ghash_mul(dst, &ctx->shash);
124 		kernel_fpu_end();
125 	}
126 
127 	dctx->bytes = 0;
128 }
129 
130 static int ghash_final(struct shash_desc *desc, u8 *dst)
131 {
132 	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
133 	struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
134 	u8 *buf = dctx->buffer;
135 
136 	ghash_flush(ctx, dctx);
137 	memcpy(dst, buf, GHASH_BLOCK_SIZE);
138 
139 	return 0;
140 }
141 
142 static struct shash_alg ghash_alg = {
143 	.digestsize	= GHASH_DIGEST_SIZE,
144 	.init		= ghash_init,
145 	.update		= ghash_update,
146 	.final		= ghash_final,
147 	.setkey		= ghash_setkey,
148 	.descsize	= sizeof(struct ghash_desc_ctx),
149 	.base		= {
150 		.cra_name		= "__ghash",
151 		.cra_driver_name	= "__ghash-pclmulqdqni",
152 		.cra_priority		= 0,
153 		.cra_flags		= CRYPTO_ALG_INTERNAL,
154 		.cra_blocksize		= GHASH_BLOCK_SIZE,
155 		.cra_ctxsize		= sizeof(struct ghash_ctx),
156 		.cra_module		= THIS_MODULE,
157 	},
158 };
159 
160 static int ghash_async_init(struct ahash_request *req)
161 {
162 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
163 	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
164 	struct ahash_request *cryptd_req = ahash_request_ctx(req);
165 	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
166 	struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
167 	struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
168 
169 	desc->tfm = child;
170 	return crypto_shash_init(desc);
171 }
172 
173 static int ghash_async_update(struct ahash_request *req)
174 {
175 	struct ahash_request *cryptd_req = ahash_request_ctx(req);
176 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
177 	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
178 	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
179 
180 	if (!crypto_simd_usable() ||
181 	    (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
182 		memcpy(cryptd_req, req, sizeof(*req));
183 		ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
184 		return crypto_ahash_update(cryptd_req);
185 	} else {
186 		struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
187 		return shash_ahash_update(req, desc);
188 	}
189 }
190 
191 static int ghash_async_final(struct ahash_request *req)
192 {
193 	struct ahash_request *cryptd_req = ahash_request_ctx(req);
194 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
195 	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
196 	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
197 
198 	if (!crypto_simd_usable() ||
199 	    (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
200 		memcpy(cryptd_req, req, sizeof(*req));
201 		ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
202 		return crypto_ahash_final(cryptd_req);
203 	} else {
204 		struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
205 		return crypto_shash_final(desc, req->result);
206 	}
207 }
208 
209 static int ghash_async_import(struct ahash_request *req, const void *in)
210 {
211 	struct ahash_request *cryptd_req = ahash_request_ctx(req);
212 	struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
213 	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
214 
215 	ghash_async_init(req);
216 	memcpy(dctx, in, sizeof(*dctx));
217 	return 0;
218 
219 }
220 
221 static int ghash_async_export(struct ahash_request *req, void *out)
222 {
223 	struct ahash_request *cryptd_req = ahash_request_ctx(req);
224 	struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
225 	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
226 
227 	memcpy(out, dctx, sizeof(*dctx));
228 	return 0;
229 
230 }
231 
232 static int ghash_async_digest(struct ahash_request *req)
233 {
234 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
235 	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
236 	struct ahash_request *cryptd_req = ahash_request_ctx(req);
237 	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
238 
239 	if (!crypto_simd_usable() ||
240 	    (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
241 		memcpy(cryptd_req, req, sizeof(*req));
242 		ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
243 		return crypto_ahash_digest(cryptd_req);
244 	} else {
245 		struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
246 		struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
247 
248 		desc->tfm = child;
249 		return shash_ahash_digest(req, desc);
250 	}
251 }
252 
253 static int ghash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
254 			      unsigned int keylen)
255 {
256 	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
257 	struct crypto_ahash *child = &ctx->cryptd_tfm->base;
258 
259 	crypto_ahash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
260 	crypto_ahash_set_flags(child, crypto_ahash_get_flags(tfm)
261 			       & CRYPTO_TFM_REQ_MASK);
262 	return crypto_ahash_setkey(child, key, keylen);
263 }
264 
265 static int ghash_async_init_tfm(struct crypto_tfm *tfm)
266 {
267 	struct cryptd_ahash *cryptd_tfm;
268 	struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
269 
270 	cryptd_tfm = cryptd_alloc_ahash("__ghash-pclmulqdqni",
271 					CRYPTO_ALG_INTERNAL,
272 					CRYPTO_ALG_INTERNAL);
273 	if (IS_ERR(cryptd_tfm))
274 		return PTR_ERR(cryptd_tfm);
275 	ctx->cryptd_tfm = cryptd_tfm;
276 	crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
277 				 sizeof(struct ahash_request) +
278 				 crypto_ahash_reqsize(&cryptd_tfm->base));
279 
280 	return 0;
281 }
282 
283 static void ghash_async_exit_tfm(struct crypto_tfm *tfm)
284 {
285 	struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
286 
287 	cryptd_free_ahash(ctx->cryptd_tfm);
288 }
289 
290 static struct ahash_alg ghash_async_alg = {
291 	.init		= ghash_async_init,
292 	.update		= ghash_async_update,
293 	.final		= ghash_async_final,
294 	.setkey		= ghash_async_setkey,
295 	.digest		= ghash_async_digest,
296 	.export		= ghash_async_export,
297 	.import		= ghash_async_import,
298 	.halg = {
299 		.digestsize	= GHASH_DIGEST_SIZE,
300 		.statesize = sizeof(struct ghash_desc_ctx),
301 		.base = {
302 			.cra_name		= "ghash",
303 			.cra_driver_name	= "ghash-clmulni",
304 			.cra_priority		= 400,
305 			.cra_ctxsize		= sizeof(struct ghash_async_ctx),
306 			.cra_flags		= CRYPTO_ALG_ASYNC,
307 			.cra_blocksize		= GHASH_BLOCK_SIZE,
308 			.cra_module		= THIS_MODULE,
309 			.cra_init		= ghash_async_init_tfm,
310 			.cra_exit		= ghash_async_exit_tfm,
311 		},
312 	},
313 };
314 
315 static const struct x86_cpu_id pcmul_cpu_id[] = {
316 	X86_MATCH_FEATURE(X86_FEATURE_PCLMULQDQ, NULL), /* Pickle-Mickle-Duck */
317 	{}
318 };
319 MODULE_DEVICE_TABLE(x86cpu, pcmul_cpu_id);
320 
321 static int __init ghash_pclmulqdqni_mod_init(void)
322 {
323 	int err;
324 
325 	if (!x86_match_cpu(pcmul_cpu_id))
326 		return -ENODEV;
327 
328 	err = crypto_register_shash(&ghash_alg);
329 	if (err)
330 		goto err_out;
331 	err = crypto_register_ahash(&ghash_async_alg);
332 	if (err)
333 		goto err_shash;
334 
335 	return 0;
336 
337 err_shash:
338 	crypto_unregister_shash(&ghash_alg);
339 err_out:
340 	return err;
341 }
342 
343 static void __exit ghash_pclmulqdqni_mod_exit(void)
344 {
345 	crypto_unregister_ahash(&ghash_async_alg);
346 	crypto_unregister_shash(&ghash_alg);
347 }
348 
349 module_init(ghash_pclmulqdqni_mod_init);
350 module_exit(ghash_pclmulqdqni_mod_exit);
351 
352 MODULE_LICENSE("GPL");
353 MODULE_DESCRIPTION("GHASH hash function, accelerated by PCLMULQDQ-NI");
354 MODULE_ALIAS_CRYPTO("ghash");
355