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
/*
 *  linux/drivers/s390/crypto/zcrypt_cex2a.c
 *
 *  zcrypt 2.1.0
 *
 *  Copyright (C)  2001, 2006 IBM Corporation
 *  Author(s): Robert Burroughs
 *	       Eric Rossman (edrossma@us.ibm.com)
 *
 *  Hotplug & misc device support: Jochen Roehrig (roehrig@de.ibm.com)
 *  Major cleanup & driver split: Martin Schwidefsky <schwidefsky@de.ibm.com>
 *				  Ralph Wuerthner <rwuerthn@de.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <asm/atomic.h>
#include <asm/uaccess.h>

#include "ap_bus.h"
#include "zcrypt_api.h"
#include "zcrypt_error.h"
#include "zcrypt_cex2a.h"

#define CEX2A_MIN_MOD_SIZE	  1	/*    8 bits	*/
#define CEX2A_MAX_MOD_SIZE	256	/* 2048 bits	*/

#define CEX2A_SPEED_RATING	970

#define CEX2A_MAX_MESSAGE_SIZE	0x390	/* sizeof(struct type50_crb2_msg)    */
#define CEX2A_MAX_RESPONSE_SIZE 0x110	/* max outputdatalength + type80_hdr */

#define CEX2A_CLEANUP_TIME	(15*HZ)

static struct ap_device_id zcrypt_cex2a_ids[] = {
	{ AP_DEVICE(AP_DEVICE_TYPE_CEX2A) },
	{ AP_DEVICE(AP_DEVICE_TYPE_CEX2A2) },
	{ /* end of list */ },
};

#ifndef CONFIG_ZCRYPT_MONOLITHIC
MODULE_DEVICE_TABLE(ap, zcrypt_cex2a_ids);
MODULE_AUTHOR("IBM Corporation");
MODULE_DESCRIPTION("CEX2A Cryptographic Coprocessor device driver, "
		   "Copyright 2001, 2006 IBM Corporation");
MODULE_LICENSE("GPL");
#endif

static int zcrypt_cex2a_probe(struct ap_device *ap_dev);
static void zcrypt_cex2a_remove(struct ap_device *ap_dev);
static void zcrypt_cex2a_receive(struct ap_device *, struct ap_message *,
				 struct ap_message *);

static struct ap_driver zcrypt_cex2a_driver = {
	.probe = zcrypt_cex2a_probe,
	.remove = zcrypt_cex2a_remove,
	.receive = zcrypt_cex2a_receive,
	.ids = zcrypt_cex2a_ids,
	.request_timeout = CEX2A_CLEANUP_TIME,
};

/**
 * Convert a ICAMEX message to a type50 MEX message.
 *
 * @zdev: crypto device pointer
 * @zreq: crypto request pointer
 * @mex: pointer to user input data
 *
 * Returns 0 on success or -EFAULT.
 */
static int ICAMEX_msg_to_type50MEX_msg(struct zcrypt_device *zdev,
				       struct ap_message *ap_msg,
				       struct ica_rsa_modexpo *mex)
{
	unsigned char *mod, *exp, *inp;
	int mod_len;

	mod_len = mex->inputdatalength;

	if (mod_len <= 128) {
		struct type50_meb1_msg *meb1 = ap_msg->message;
		memset(meb1, 0, sizeof(*meb1));
		ap_msg->length = sizeof(*meb1);
		meb1->header.msg_type_code = TYPE50_TYPE_CODE;
		meb1->header.msg_len = sizeof(*meb1);
		meb1->keyblock_type = TYPE50_MEB1_FMT;
		mod = meb1->modulus + sizeof(meb1->modulus) - mod_len;
		exp = meb1->exponent + sizeof(meb1->exponent) - mod_len;
		inp = meb1->message + sizeof(meb1->message) - mod_len;
	} else {
		struct type50_meb2_msg *meb2 = ap_msg->message;
		memset(meb2, 0, sizeof(*meb2));
		ap_msg->length = sizeof(*meb2);
		meb2->header.msg_type_code = TYPE50_TYPE_CODE;
		meb2->header.msg_len = sizeof(*meb2);
		meb2->keyblock_type = TYPE50_MEB2_FMT;
		mod = meb2->modulus + sizeof(meb2->modulus) - mod_len;
		exp = meb2->exponent + sizeof(meb2->exponent) - mod_len;
		inp = meb2->message + sizeof(meb2->message) - mod_len;
	}

	if (copy_from_user(mod, mex->n_modulus, mod_len) ||
	    copy_from_user(exp, mex->b_key, mod_len) ||
	    copy_from_user(inp, mex->inputdata, mod_len))
		return -EFAULT;
	return 0;
}

/**
 * Convert a ICACRT message to a type50 CRT message.
 *
 * @zdev: crypto device pointer
 * @zreq: crypto request pointer
 * @crt: pointer to user input data
 *
 * Returns 0 on success or -EFAULT.
 */
static int ICACRT_msg_to_type50CRT_msg(struct zcrypt_device *zdev,
				       struct ap_message *ap_msg,
				       struct ica_rsa_modexpo_crt *crt)
{
	int mod_len, short_len, long_len, long_offset;
	unsigned char *p, *q, *dp, *dq, *u, *inp;

	mod_len = crt->inputdatalength;
	short_len = mod_len / 2;
	long_len = mod_len / 2 + 8;

	/*
	 * CEX2A cannot handle p, dp, or U > 128 bytes.
	 * If we have one of these, we need to do extra checking.
	 */
	if (long_len > 128) {
		/*
		 * zcrypt_rsa_crt already checked for the leading
		 * zeroes of np_prime, bp_key and u_mult_inc.
		 */
		long_offset = long_len - 128;
		long_len = 128;
	} else
		long_offset = 0;

	/*
	 * Instead of doing extra work for p, dp, U > 64 bytes, we'll just use
	 * the larger message structure.
	 */
	if (long_len <= 64) {
		struct type50_crb1_msg *crb1 = ap_msg->message;
		memset(crb1, 0, sizeof(*crb1));
		ap_msg->length = sizeof(*crb1);
		crb1->header.msg_type_code = TYPE50_TYPE_CODE;
		crb1->header.msg_len = sizeof(*crb1);
		crb1->keyblock_type = TYPE50_CRB1_FMT;
		p = crb1->p + sizeof(crb1->p) - long_len;
		q = crb1->q + sizeof(crb1->q) - short_len;
		dp = crb1->dp + sizeof(crb1->dp) - long_len;
		dq = crb1->dq + sizeof(crb1->dq) - short_len;
		u = crb1->u + sizeof(crb1->u) - long_len;
		inp = crb1->message + sizeof(crb1->message) - mod_len;
	} else {
		struct type50_crb2_msg *crb2 = ap_msg->message;
		memset(crb2, 0, sizeof(*crb2));
		ap_msg->length = sizeof(*crb2);
		crb2->header.msg_type_code = TYPE50_TYPE_CODE;
		crb2->header.msg_len = sizeof(*crb2);
		crb2->keyblock_type = TYPE50_CRB2_FMT;
		p = crb2->p + sizeof(crb2->p) - long_len;
		q = crb2->q + sizeof(crb2->q) - short_len;
		dp = crb2->dp + sizeof(crb2->dp) - long_len;
		dq = crb2->dq + sizeof(crb2->dq) - short_len;
		u = crb2->u + sizeof(crb2->u) - long_len;
		inp = crb2->message + sizeof(crb2->message) - mod_len;
	}

	if (copy_from_user(p, crt->np_prime + long_offset, long_len) ||
	    copy_from_user(q, crt->nq_prime, short_len) ||
	    copy_from_user(dp, crt->bp_key + long_offset, long_len) ||
	    copy_from_user(dq, crt->bq_key, short_len) ||
	    copy_from_user(u, crt->u_mult_inv + long_offset, long_len) ||
	    copy_from_user(inp, crt->inputdata, mod_len))
		return -EFAULT;


	return 0;
}

/**
 * Copy results from a type 80 reply message back to user space.
 *
 * @zdev: crypto device pointer
 * @reply: reply AP message.
 * @data: pointer to user output data
 * @length: size of user output data
 *
 * Returns 0 on success or -EFAULT.
 */
static int convert_type80(struct zcrypt_device *zdev,
			  struct ap_message *reply,
			  char __user *outputdata,
			  unsigned int outputdatalength)
{
	struct type80_hdr *t80h = reply->message;
	unsigned char *data;

	if (t80h->len < sizeof(*t80h) + outputdatalength) {
		/* The result is too short, the CEX2A card may not do that.. */
		zdev->online = 0;
		return -EAGAIN;	/* repeat the request on a different device. */
	}
	BUG_ON(t80h->len > CEX2A_MAX_RESPONSE_SIZE);
	data = reply->message + t80h->len - outputdatalength;
	if (copy_to_user(outputdata, data, outputdatalength))
		return -EFAULT;
	return 0;
}

static int convert_response(struct zcrypt_device *zdev,
			    struct ap_message *reply,
			    char __user *outputdata,
			    unsigned int outputdatalength)
{
	/* Response type byte is the second byte in the response. */
	switch (((unsigned char *) reply->message)[1]) {
	case TYPE82_RSP_CODE:
	case TYPE88_RSP_CODE:
		return convert_error(zdev, reply);
	case TYPE80_RSP_CODE:
		return convert_type80(zdev, reply,
				      outputdata, outputdatalength);
	default: /* Unknown response type, this should NEVER EVER happen */
		zdev->online = 0;
		return -EAGAIN;	/* repeat the request on a different device. */
	}
}

/**
 * This function is called from the AP bus code after a crypto request
 * "msg" has finished with the reply message "reply".
 * It is called from tasklet context.
 * @ap_dev: pointer to the AP device
 * @msg: pointer to the AP message
 * @reply: pointer to the AP reply message
 */
static void zcrypt_cex2a_receive(struct ap_device *ap_dev,
				 struct ap_message *msg,
				 struct ap_message *reply)
{
	static struct error_hdr error_reply = {
		.type = TYPE82_RSP_CODE,
		.reply_code = REP82_ERROR_MACHINE_FAILURE,
	};
	struct type80_hdr *t80h;
	int length;

	/* Copy the reply message to the request message buffer. */
	if (IS_ERR(reply)) {
		memcpy(msg->message, &error_reply, sizeof(error_reply));
		goto out;
	}
	t80h = reply->message;
	if (t80h->type == TYPE80_RSP_CODE) {
		length = min(CEX2A_MAX_RESPONSE_SIZE, (int) t80h->len);
		memcpy(msg->message, reply->message, length);
	} else
		memcpy(msg->message, reply->message, sizeof error_reply);
out:
	complete((struct completion *) msg->private);
}

static atomic_t zcrypt_step = ATOMIC_INIT(0);

/**
 * The request distributor calls this function if it picked the CEX2A
 * device to handle a modexpo request.
 * @zdev: pointer to zcrypt_device structure that identifies the
 *	  CEX2A device to the request distributor
 * @mex: pointer to the modexpo request buffer
 */
static long zcrypt_cex2a_modexpo(struct zcrypt_device *zdev,
				 struct ica_rsa_modexpo *mex)
{
	struct ap_message ap_msg;
	struct completion work;
	int rc;

	ap_msg.message = kmalloc(CEX2A_MAX_MESSAGE_SIZE, GFP_KERNEL);
	if (!ap_msg.message)
		return -ENOMEM;
	ap_msg.psmid = (((unsigned long long) current->pid) << 32) +
				atomic_inc_return(&zcrypt_step);
	ap_msg.private = &work;
	rc = ICAMEX_msg_to_type50MEX_msg(zdev, &ap_msg, mex);
	if (rc)
		goto out_free;
	init_completion(&work);
	ap_queue_message(zdev->ap_dev, &ap_msg);
	rc = wait_for_completion_interruptible(&work);
	if (rc == 0)
		rc = convert_response(zdev, &ap_msg, mex->outputdata,
				      mex->outputdatalength);
	else
		/* Signal pending. */
		ap_cancel_message(zdev->ap_dev, &ap_msg);
out_free:
	kfree(ap_msg.message);
	return rc;
}

/**
 * The request distributor calls this function if it picked the CEX2A
 * device to handle a modexpo_crt request.
 * @zdev: pointer to zcrypt_device structure that identifies the
 *	  CEX2A device to the request distributor
 * @crt: pointer to the modexpoc_crt request buffer
 */
static long zcrypt_cex2a_modexpo_crt(struct zcrypt_device *zdev,
				     struct ica_rsa_modexpo_crt *crt)
{
	struct ap_message ap_msg;
	struct completion work;
	int rc;

	ap_msg.message = kmalloc(CEX2A_MAX_MESSAGE_SIZE, GFP_KERNEL);
	if (!ap_msg.message)
		return -ENOMEM;
	ap_msg.psmid = (((unsigned long long) current->pid) << 32) +
				atomic_inc_return(&zcrypt_step);
	ap_msg.private = &work;
	rc = ICACRT_msg_to_type50CRT_msg(zdev, &ap_msg, crt);
	if (rc)
		goto out_free;
	init_completion(&work);
	ap_queue_message(zdev->ap_dev, &ap_msg);
	rc = wait_for_completion_interruptible(&work);
	if (rc == 0)
		rc = convert_response(zdev, &ap_msg, crt->outputdata,
				      crt->outputdatalength);
	else
		/* Signal pending. */
		ap_cancel_message(zdev->ap_dev, &ap_msg);
out_free:
	kfree(ap_msg.message);
	return rc;
}

/**
 * The crypto operations for a CEX2A card.
 */
static struct zcrypt_ops zcrypt_cex2a_ops = {
	.rsa_modexpo = zcrypt_cex2a_modexpo,
	.rsa_modexpo_crt = zcrypt_cex2a_modexpo_crt,
};

/**
 * Probe function for CEX2A cards. It always accepts the AP device
 * since the bus_match already checked the hardware type.
 * @ap_dev: pointer to the AP device.
 */
static int zcrypt_cex2a_probe(struct ap_device *ap_dev)
{
	struct zcrypt_device *zdev;
	int rc;

	zdev = zcrypt_device_alloc(CEX2A_MAX_RESPONSE_SIZE);
	if (!zdev)
		return -ENOMEM;
	zdev->ap_dev = ap_dev;
	zdev->ops = &zcrypt_cex2a_ops;
	zdev->online = 1;
	zdev->user_space_type = ZCRYPT_CEX2A;
	zdev->type_string = "CEX2A";
	zdev->min_mod_size = CEX2A_MIN_MOD_SIZE;
	zdev->max_mod_size = CEX2A_MAX_MOD_SIZE;
	zdev->short_crt = 1;
	zdev->speed_rating = CEX2A_SPEED_RATING;
	ap_dev->reply = &zdev->reply;
	ap_dev->private = zdev;
	rc = zcrypt_device_register(zdev);
	if (rc)
		goto out_free;
	return 0;

out_free:
	ap_dev->private = NULL;
	zcrypt_device_free(zdev);
	return rc;
}

/**
 * This is called to remove the extended CEX2A driver information
 * if an AP device is removed.
 */
static void zcrypt_cex2a_remove(struct ap_device *ap_dev)
{
	struct zcrypt_device *zdev = ap_dev->private;

	zcrypt_device_unregister(zdev);
}

int __init zcrypt_cex2a_init(void)
{
	return ap_driver_register(&zcrypt_cex2a_driver, THIS_MODULE, "cex2a");
}

void __exit zcrypt_cex2a_exit(void)
{
	ap_driver_unregister(&zcrypt_cex2a_driver);
}

#ifndef CONFIG_ZCRYPT_MONOLITHIC
module_init(zcrypt_cex2a_init);
module_exit(zcrypt_cex2a_exit);
#endif