Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
/*
 * AMD Cryptographic Coprocessor (CCP) SHA crypto API support
 *
 * Copyright (C) 2013 Advanced Micro Devices, Inc.
 *
 * Author: Tom Lendacky <thomas.lendacky@amd.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <crypto/algapi.h>
#include <crypto/hash.h>
#include <crypto/internal/hash.h>
#include <crypto/sha.h>
#include <crypto/scatterwalk.h>

#include "ccp-crypto.h"


static int ccp_sha_complete(struct crypto_async_request *async_req, int ret)
{
	struct ahash_request *req = ahash_request_cast(async_req);
	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
	struct ccp_sha_req_ctx *rctx = ahash_request_ctx(req);
	unsigned int digest_size = crypto_ahash_digestsize(tfm);

	if (ret)
		goto e_free;

	if (rctx->hash_rem) {
		/* Save remaining data to buffer */
		unsigned int offset = rctx->nbytes - rctx->hash_rem;
		scatterwalk_map_and_copy(rctx->buf, rctx->src,
					 offset, rctx->hash_rem, 0);
		rctx->buf_count = rctx->hash_rem;
	} else
		rctx->buf_count = 0;

	/* Update result area if supplied */
	if (req->result)
		memcpy(req->result, rctx->ctx, digest_size);

e_free:
	sg_free_table(&rctx->data_sg);

	return ret;
}

static int ccp_do_sha_update(struct ahash_request *req, unsigned int nbytes,
			     unsigned int final)
{
	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
	struct ccp_ctx *ctx = crypto_ahash_ctx(tfm);
	struct ccp_sha_req_ctx *rctx = ahash_request_ctx(req);
	struct scatterlist *sg;
	unsigned int block_size =
		crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));
	unsigned int sg_count;
	gfp_t gfp;
	u64 len;
	int ret;

	len = (u64)rctx->buf_count + (u64)nbytes;

	if (!final && (len <= block_size)) {
		scatterwalk_map_and_copy(rctx->buf + rctx->buf_count, req->src,
					 0, nbytes, 0);
		rctx->buf_count += nbytes;

		return 0;
	}

	rctx->src = req->src;
	rctx->nbytes = nbytes;

	rctx->final = final;
	rctx->hash_rem = final ? 0 : len & (block_size - 1);
	rctx->hash_cnt = len - rctx->hash_rem;
	if (!final && !rctx->hash_rem) {
		/* CCP can't do zero length final, so keep some data around */
		rctx->hash_cnt -= block_size;
		rctx->hash_rem = block_size;
	}

	/* Initialize the context scatterlist */
	sg_init_one(&rctx->ctx_sg, rctx->ctx, sizeof(rctx->ctx));

	sg = NULL;
	if (rctx->buf_count && nbytes) {
		/* Build the data scatterlist table - allocate enough entries
		 * for both data pieces (buffer and input data)
		 */
		gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
			GFP_KERNEL : GFP_ATOMIC;
		sg_count = sg_nents(req->src) + 1;
		ret = sg_alloc_table(&rctx->data_sg, sg_count, gfp);
		if (ret)
			return ret;

		sg_init_one(&rctx->buf_sg, rctx->buf, rctx->buf_count);
		sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->buf_sg);
		sg = ccp_crypto_sg_table_add(&rctx->data_sg, req->src);
		sg_mark_end(sg);

		sg = rctx->data_sg.sgl;
	} else if (rctx->buf_count) {
		sg_init_one(&rctx->buf_sg, rctx->buf, rctx->buf_count);

		sg = &rctx->buf_sg;
	} else if (nbytes) {
		sg = req->src;
	}

	rctx->msg_bits += (rctx->hash_cnt << 3);	/* Total in bits */

	memset(&rctx->cmd, 0, sizeof(rctx->cmd));
	INIT_LIST_HEAD(&rctx->cmd.entry);
	rctx->cmd.engine = CCP_ENGINE_SHA;
	rctx->cmd.u.sha.type = rctx->type;
	rctx->cmd.u.sha.ctx = &rctx->ctx_sg;
	rctx->cmd.u.sha.ctx_len = sizeof(rctx->ctx);
	rctx->cmd.u.sha.src = sg;
	rctx->cmd.u.sha.src_len = rctx->hash_cnt;
	rctx->cmd.u.sha.opad = ctx->u.sha.key_len ?
		&ctx->u.sha.opad_sg : NULL;
	rctx->cmd.u.sha.opad_len = ctx->u.sha.key_len ?
		ctx->u.sha.opad_count : 0;
	rctx->cmd.u.sha.first = rctx->first;
	rctx->cmd.u.sha.final = rctx->final;
	rctx->cmd.u.sha.msg_bits = rctx->msg_bits;

	rctx->first = 0;

	ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);

	return ret;
}

static int ccp_sha_init(struct ahash_request *req)
{
	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
	struct ccp_ctx *ctx = crypto_ahash_ctx(tfm);
	struct ccp_sha_req_ctx *rctx = ahash_request_ctx(req);
	struct ccp_crypto_ahash_alg *alg =
		ccp_crypto_ahash_alg(crypto_ahash_tfm(tfm));
	unsigned int block_size =
		crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));

	memset(rctx, 0, sizeof(*rctx));

	rctx->type = alg->type;
	rctx->first = 1;

	if (ctx->u.sha.key_len) {
		/* Buffer the HMAC key for first update */
		memcpy(rctx->buf, ctx->u.sha.ipad, block_size);
		rctx->buf_count = block_size;
	}

	return 0;
}

static int ccp_sha_update(struct ahash_request *req)
{
	return ccp_do_sha_update(req, req->nbytes, 0);
}

static int ccp_sha_final(struct ahash_request *req)
{
	return ccp_do_sha_update(req, 0, 1);
}

static int ccp_sha_finup(struct ahash_request *req)
{
	return ccp_do_sha_update(req, req->nbytes, 1);
}

static int ccp_sha_digest(struct ahash_request *req)
{
	int ret;

	ret = ccp_sha_init(req);
	if (ret)
		return ret;

	return ccp_sha_finup(req);
}

static int ccp_sha_setkey(struct crypto_ahash *tfm, const u8 *key,
			  unsigned int key_len)
{
	struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ahash_tfm(tfm));
	struct crypto_shash *shash = ctx->u.sha.hmac_tfm;
	struct {
		struct shash_desc sdesc;
		char ctx[crypto_shash_descsize(shash)];
	} desc;
	unsigned int block_size = crypto_shash_blocksize(shash);
	unsigned int digest_size = crypto_shash_digestsize(shash);
	int i, ret;

	/* Set to zero until complete */
	ctx->u.sha.key_len = 0;

	/* Clear key area to provide zero padding for keys smaller
	 * than the block size
	 */
	memset(ctx->u.sha.key, 0, sizeof(ctx->u.sha.key));

	if (key_len > block_size) {
		/* Must hash the input key */
		desc.sdesc.tfm = shash;
		desc.sdesc.flags = crypto_ahash_get_flags(tfm) &
			CRYPTO_TFM_REQ_MAY_SLEEP;

		ret = crypto_shash_digest(&desc.sdesc, key, key_len,
					  ctx->u.sha.key);
		if (ret) {
			crypto_ahash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
			return -EINVAL;
		}

		key_len = digest_size;
	} else
		memcpy(ctx->u.sha.key, key, key_len);

	for (i = 0; i < block_size; i++) {
		ctx->u.sha.ipad[i] = ctx->u.sha.key[i] ^ 0x36;
		ctx->u.sha.opad[i] = ctx->u.sha.key[i] ^ 0x5c;
	}

	sg_init_one(&ctx->u.sha.opad_sg, ctx->u.sha.opad, block_size);
	ctx->u.sha.opad_count = block_size;

	ctx->u.sha.key_len = key_len;

	return 0;
}

static int ccp_sha_cra_init(struct crypto_tfm *tfm)
{
	struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
	struct crypto_ahash *ahash = __crypto_ahash_cast(tfm);

	ctx->complete = ccp_sha_complete;
	ctx->u.sha.key_len = 0;

	crypto_ahash_set_reqsize(ahash, sizeof(struct ccp_sha_req_ctx));

	return 0;
}

static void ccp_sha_cra_exit(struct crypto_tfm *tfm)
{
}

static int ccp_hmac_sha_cra_init(struct crypto_tfm *tfm)
{
	struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
	struct ccp_crypto_ahash_alg *alg = ccp_crypto_ahash_alg(tfm);
	struct crypto_shash *hmac_tfm;

	hmac_tfm = crypto_alloc_shash(alg->child_alg, 0, 0);
	if (IS_ERR(hmac_tfm)) {
		pr_warn("could not load driver %s need for HMAC support\n",
			alg->child_alg);
		return PTR_ERR(hmac_tfm);
	}

	ctx->u.sha.hmac_tfm = hmac_tfm;

	return ccp_sha_cra_init(tfm);
}

static void ccp_hmac_sha_cra_exit(struct crypto_tfm *tfm)
{
	struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);

	if (ctx->u.sha.hmac_tfm)
		crypto_free_shash(ctx->u.sha.hmac_tfm);

	ccp_sha_cra_exit(tfm);
}

struct ccp_sha_def {
	const char *name;
	const char *drv_name;
	enum ccp_sha_type type;
	u32 digest_size;
	u32 block_size;
};

static struct ccp_sha_def sha_algs[] = {
	{
		.name		= "sha1",
		.drv_name	= "sha1-ccp",
		.type		= CCP_SHA_TYPE_1,
		.digest_size	= SHA1_DIGEST_SIZE,
		.block_size	= SHA1_BLOCK_SIZE,
	},
	{
		.name		= "sha224",
		.drv_name	= "sha224-ccp",
		.type		= CCP_SHA_TYPE_224,
		.digest_size	= SHA224_DIGEST_SIZE,
		.block_size	= SHA224_BLOCK_SIZE,
	},
	{
		.name		= "sha256",
		.drv_name	= "sha256-ccp",
		.type		= CCP_SHA_TYPE_256,
		.digest_size	= SHA256_DIGEST_SIZE,
		.block_size	= SHA256_BLOCK_SIZE,
	},
};

static int ccp_register_hmac_alg(struct list_head *head,
				 const struct ccp_sha_def *def,
				 const struct ccp_crypto_ahash_alg *base_alg)
{
	struct ccp_crypto_ahash_alg *ccp_alg;
	struct ahash_alg *alg;
	struct hash_alg_common *halg;
	struct crypto_alg *base;
	int ret;

	ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
	if (!ccp_alg)
		return -ENOMEM;

	/* Copy the base algorithm and only change what's necessary */
	*ccp_alg = *base_alg;
	INIT_LIST_HEAD(&ccp_alg->entry);

	strncpy(ccp_alg->child_alg, def->name, CRYPTO_MAX_ALG_NAME);

	alg = &ccp_alg->alg;
	alg->setkey = ccp_sha_setkey;

	halg = &alg->halg;

	base = &halg->base;
	snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "hmac(%s)", def->name);
	snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME, "hmac-%s",
		 def->drv_name);
	base->cra_init = ccp_hmac_sha_cra_init;
	base->cra_exit = ccp_hmac_sha_cra_exit;

	ret = crypto_register_ahash(alg);
	if (ret) {
		pr_err("%s ahash algorithm registration error (%d)\n",
			base->cra_name, ret);
		kfree(ccp_alg);
		return ret;
	}

	list_add(&ccp_alg->entry, head);

	return ret;
}

static int ccp_register_sha_alg(struct list_head *head,
				const struct ccp_sha_def *def)
{
	struct ccp_crypto_ahash_alg *ccp_alg;
	struct ahash_alg *alg;
	struct hash_alg_common *halg;
	struct crypto_alg *base;
	int ret;

	ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
	if (!ccp_alg)
		return -ENOMEM;

	INIT_LIST_HEAD(&ccp_alg->entry);

	ccp_alg->type = def->type;

	alg = &ccp_alg->alg;
	alg->init = ccp_sha_init;
	alg->update = ccp_sha_update;
	alg->final = ccp_sha_final;
	alg->finup = ccp_sha_finup;
	alg->digest = ccp_sha_digest;

	halg = &alg->halg;
	halg->digestsize = def->digest_size;

	base = &halg->base;
	snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
	snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
		 def->drv_name);
	base->cra_flags = CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC |
			  CRYPTO_ALG_KERN_DRIVER_ONLY |
			  CRYPTO_ALG_NEED_FALLBACK;
	base->cra_blocksize = def->block_size;
	base->cra_ctxsize = sizeof(struct ccp_ctx);
	base->cra_priority = CCP_CRA_PRIORITY;
	base->cra_type = &crypto_ahash_type;
	base->cra_init = ccp_sha_cra_init;
	base->cra_exit = ccp_sha_cra_exit;
	base->cra_module = THIS_MODULE;

	ret = crypto_register_ahash(alg);
	if (ret) {
		pr_err("%s ahash algorithm registration error (%d)\n",
			base->cra_name, ret);
		kfree(ccp_alg);
		return ret;
	}

	list_add(&ccp_alg->entry, head);

	ret = ccp_register_hmac_alg(head, def, ccp_alg);

	return ret;
}

int ccp_register_sha_algs(struct list_head *head)
{
	int i, ret;

	for (i = 0; i < ARRAY_SIZE(sha_algs); i++) {
		ret = ccp_register_sha_alg(head, &sha_algs[i]);
		if (ret)
			return ret;
	}

	return 0;
}