1 /*
2  *  linux/drivers/s390/crypto/zcrypt_cex2a.c
3  *
4  *  zcrypt 2.1.0
5  *
6  *  Copyright (C)  2001, 2006 IBM Corporation
7  *  Author(s): Robert Burroughs
8  *	       Eric Rossman (edrossma@us.ibm.com)
9  *
10  *  Hotplug & misc device support: Jochen Roehrig (roehrig@de.ibm.com)
11  *  Major cleanup & driver split: Martin Schwidefsky <schwidefsky@de.ibm.com>
12  *				  Ralph Wuerthner <rwuerthn@de.ibm.com>
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License as published by
16  * the Free Software Foundation; either version 2, or (at your option)
17  * any later version.
18  *
19  * This program is distributed in the hope that it will be useful,
20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22  * GNU General Public License for more details.
23  *
24  * You should have received a copy of the GNU General Public License
25  * along with this program; if not, write to the Free Software
26  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
27  */
28 
29 #include <linux/module.h>
30 #include <linux/slab.h>
31 #include <linux/init.h>
32 #include <linux/err.h>
33 #include <asm/atomic.h>
34 #include <asm/uaccess.h>
35 
36 #include "ap_bus.h"
37 #include "zcrypt_api.h"
38 #include "zcrypt_error.h"
39 #include "zcrypt_cex2a.h"
40 
41 #define CEX2A_MIN_MOD_SIZE	  1	/*    8 bits	*/
42 #define CEX2A_MAX_MOD_SIZE	256	/* 2048 bits	*/
43 #define CEX3A_MIN_MOD_SIZE	CEX2A_MIN_MOD_SIZE
44 #define CEX3A_MAX_MOD_SIZE	512	/* 4096 bits	*/
45 
46 #define CEX2A_SPEED_RATING	970
47 #define CEX3A_SPEED_RATING	900 /* Fixme: Needs finetuning */
48 
49 #define CEX2A_MAX_MESSAGE_SIZE	0x390	/* sizeof(struct type50_crb2_msg)    */
50 #define CEX2A_MAX_RESPONSE_SIZE 0x110	/* max outputdatalength + type80_hdr */
51 
52 #define CEX3A_MAX_RESPONSE_SIZE	0x210	/* 512 bit modulus
53 					 * (max outputdatalength) +
54 					 * type80_hdr*/
55 #define CEX3A_MAX_MESSAGE_SIZE	sizeof(struct type50_crb3_msg)
56 
57 #define CEX2A_CLEANUP_TIME	(15*HZ)
58 #define CEX3A_CLEANUP_TIME	CEX2A_CLEANUP_TIME
59 
60 static struct ap_device_id zcrypt_cex2a_ids[] = {
61 	{ AP_DEVICE(AP_DEVICE_TYPE_CEX2A) },
62 	{ AP_DEVICE(AP_DEVICE_TYPE_CEX3A) },
63 	{ /* end of list */ },
64 };
65 
66 #ifndef CONFIG_ZCRYPT_MONOLITHIC
67 MODULE_DEVICE_TABLE(ap, zcrypt_cex2a_ids);
68 MODULE_AUTHOR("IBM Corporation");
69 MODULE_DESCRIPTION("CEX2A Cryptographic Coprocessor device driver, "
70 		   "Copyright 2001, 2006 IBM Corporation");
71 MODULE_LICENSE("GPL");
72 #endif
73 
74 static int zcrypt_cex2a_probe(struct ap_device *ap_dev);
75 static void zcrypt_cex2a_remove(struct ap_device *ap_dev);
76 static void zcrypt_cex2a_receive(struct ap_device *, struct ap_message *,
77 				 struct ap_message *);
78 
79 static struct ap_driver zcrypt_cex2a_driver = {
80 	.probe = zcrypt_cex2a_probe,
81 	.remove = zcrypt_cex2a_remove,
82 	.receive = zcrypt_cex2a_receive,
83 	.ids = zcrypt_cex2a_ids,
84 	.request_timeout = CEX2A_CLEANUP_TIME,
85 };
86 
87 /**
88  * Convert a ICAMEX message to a type50 MEX message.
89  *
90  * @zdev: crypto device pointer
91  * @zreq: crypto request pointer
92  * @mex: pointer to user input data
93  *
94  * Returns 0 on success or -EFAULT.
95  */
96 static int ICAMEX_msg_to_type50MEX_msg(struct zcrypt_device *zdev,
97 				       struct ap_message *ap_msg,
98 				       struct ica_rsa_modexpo *mex)
99 {
100 	unsigned char *mod, *exp, *inp;
101 	int mod_len;
102 
103 	mod_len = mex->inputdatalength;
104 
105 	if (mod_len <= 128) {
106 		struct type50_meb1_msg *meb1 = ap_msg->message;
107 		memset(meb1, 0, sizeof(*meb1));
108 		ap_msg->length = sizeof(*meb1);
109 		meb1->header.msg_type_code = TYPE50_TYPE_CODE;
110 		meb1->header.msg_len = sizeof(*meb1);
111 		meb1->keyblock_type = TYPE50_MEB1_FMT;
112 		mod = meb1->modulus + sizeof(meb1->modulus) - mod_len;
113 		exp = meb1->exponent + sizeof(meb1->exponent) - mod_len;
114 		inp = meb1->message + sizeof(meb1->message) - mod_len;
115 	} else if (mod_len <= 256) {
116 		struct type50_meb2_msg *meb2 = ap_msg->message;
117 		memset(meb2, 0, sizeof(*meb2));
118 		ap_msg->length = sizeof(*meb2);
119 		meb2->header.msg_type_code = TYPE50_TYPE_CODE;
120 		meb2->header.msg_len = sizeof(*meb2);
121 		meb2->keyblock_type = TYPE50_MEB2_FMT;
122 		mod = meb2->modulus + sizeof(meb2->modulus) - mod_len;
123 		exp = meb2->exponent + sizeof(meb2->exponent) - mod_len;
124 		inp = meb2->message + sizeof(meb2->message) - mod_len;
125 	} else {
126 		/* mod_len > 256 = 4096 bit RSA Key */
127 		struct type50_meb3_msg *meb3 = ap_msg->message;
128 		memset(meb3, 0, sizeof(*meb3));
129 		ap_msg->length = sizeof(*meb3);
130 		meb3->header.msg_type_code = TYPE50_TYPE_CODE;
131 		meb3->header.msg_len = sizeof(*meb3);
132 		meb3->keyblock_type = TYPE50_MEB3_FMT;
133 		mod = meb3->modulus + sizeof(meb3->modulus) - mod_len;
134 		exp = meb3->exponent + sizeof(meb3->exponent) - mod_len;
135 		inp = meb3->message + sizeof(meb3->message) - mod_len;
136 	}
137 
138 	if (copy_from_user(mod, mex->n_modulus, mod_len) ||
139 	    copy_from_user(exp, mex->b_key, mod_len) ||
140 	    copy_from_user(inp, mex->inputdata, mod_len))
141 		return -EFAULT;
142 	return 0;
143 }
144 
145 /**
146  * Convert a ICACRT message to a type50 CRT message.
147  *
148  * @zdev: crypto device pointer
149  * @zreq: crypto request pointer
150  * @crt: pointer to user input data
151  *
152  * Returns 0 on success or -EFAULT.
153  */
154 static int ICACRT_msg_to_type50CRT_msg(struct zcrypt_device *zdev,
155 				       struct ap_message *ap_msg,
156 				       struct ica_rsa_modexpo_crt *crt)
157 {
158 	int mod_len, short_len, long_len, long_offset, limit;
159 	unsigned char *p, *q, *dp, *dq, *u, *inp;
160 
161 	mod_len = crt->inputdatalength;
162 	short_len = mod_len / 2;
163 	long_len = mod_len / 2 + 8;
164 
165 	/*
166 	 * CEX2A cannot handle p, dp, or U > 128 bytes.
167 	 * If we have one of these, we need to do extra checking.
168 	 * For CEX3A the limit is 256 bytes.
169 	 */
170 	if (zdev->max_mod_size == CEX3A_MAX_MOD_SIZE)
171 		limit = 256;
172 	else
173 		limit = 128;
174 
175 	if (long_len > limit) {
176 		/*
177 		 * zcrypt_rsa_crt already checked for the leading
178 		 * zeroes of np_prime, bp_key and u_mult_inc.
179 		 */
180 		long_offset = long_len - limit;
181 		long_len = limit;
182 	} else
183 		long_offset = 0;
184 
185 	/*
186 	 * Instead of doing extra work for p, dp, U > 64 bytes, we'll just use
187 	 * the larger message structure.
188 	 */
189 	if (long_len <= 64) {
190 		struct type50_crb1_msg *crb1 = ap_msg->message;
191 		memset(crb1, 0, sizeof(*crb1));
192 		ap_msg->length = sizeof(*crb1);
193 		crb1->header.msg_type_code = TYPE50_TYPE_CODE;
194 		crb1->header.msg_len = sizeof(*crb1);
195 		crb1->keyblock_type = TYPE50_CRB1_FMT;
196 		p = crb1->p + sizeof(crb1->p) - long_len;
197 		q = crb1->q + sizeof(crb1->q) - short_len;
198 		dp = crb1->dp + sizeof(crb1->dp) - long_len;
199 		dq = crb1->dq + sizeof(crb1->dq) - short_len;
200 		u = crb1->u + sizeof(crb1->u) - long_len;
201 		inp = crb1->message + sizeof(crb1->message) - mod_len;
202 	} else if (long_len <= 128) {
203 		struct type50_crb2_msg *crb2 = ap_msg->message;
204 		memset(crb2, 0, sizeof(*crb2));
205 		ap_msg->length = sizeof(*crb2);
206 		crb2->header.msg_type_code = TYPE50_TYPE_CODE;
207 		crb2->header.msg_len = sizeof(*crb2);
208 		crb2->keyblock_type = TYPE50_CRB2_FMT;
209 		p = crb2->p + sizeof(crb2->p) - long_len;
210 		q = crb2->q + sizeof(crb2->q) - short_len;
211 		dp = crb2->dp + sizeof(crb2->dp) - long_len;
212 		dq = crb2->dq + sizeof(crb2->dq) - short_len;
213 		u = crb2->u + sizeof(crb2->u) - long_len;
214 		inp = crb2->message + sizeof(crb2->message) - mod_len;
215 	} else {
216 		/* long_len >= 256 */
217 		struct type50_crb3_msg *crb3 = ap_msg->message;
218 		memset(crb3, 0, sizeof(*crb3));
219 		ap_msg->length = sizeof(*crb3);
220 		crb3->header.msg_type_code = TYPE50_TYPE_CODE;
221 		crb3->header.msg_len = sizeof(*crb3);
222 		crb3->keyblock_type = TYPE50_CRB3_FMT;
223 		p = crb3->p + sizeof(crb3->p) - long_len;
224 		q = crb3->q + sizeof(crb3->q) - short_len;
225 		dp = crb3->dp + sizeof(crb3->dp) - long_len;
226 		dq = crb3->dq + sizeof(crb3->dq) - short_len;
227 		u = crb3->u + sizeof(crb3->u) - long_len;
228 		inp = crb3->message + sizeof(crb3->message) - mod_len;
229 	}
230 
231 	if (copy_from_user(p, crt->np_prime + long_offset, long_len) ||
232 	    copy_from_user(q, crt->nq_prime, short_len) ||
233 	    copy_from_user(dp, crt->bp_key + long_offset, long_len) ||
234 	    copy_from_user(dq, crt->bq_key, short_len) ||
235 	    copy_from_user(u, crt->u_mult_inv + long_offset, long_len) ||
236 	    copy_from_user(inp, crt->inputdata, mod_len))
237 		return -EFAULT;
238 
239 	return 0;
240 }
241 
242 /**
243  * Copy results from a type 80 reply message back to user space.
244  *
245  * @zdev: crypto device pointer
246  * @reply: reply AP message.
247  * @data: pointer to user output data
248  * @length: size of user output data
249  *
250  * Returns 0 on success or -EFAULT.
251  */
252 static int convert_type80(struct zcrypt_device *zdev,
253 			  struct ap_message *reply,
254 			  char __user *outputdata,
255 			  unsigned int outputdatalength)
256 {
257 	struct type80_hdr *t80h = reply->message;
258 	unsigned char *data;
259 
260 	if (t80h->len < sizeof(*t80h) + outputdatalength) {
261 		/* The result is too short, the CEX2A card may not do that.. */
262 		zdev->online = 0;
263 		return -EAGAIN;	/* repeat the request on a different device. */
264 	}
265 	if (zdev->user_space_type == ZCRYPT_CEX2A)
266 		BUG_ON(t80h->len > CEX2A_MAX_RESPONSE_SIZE);
267 	else
268 		BUG_ON(t80h->len > CEX3A_MAX_RESPONSE_SIZE);
269 	data = reply->message + t80h->len - outputdatalength;
270 	if (copy_to_user(outputdata, data, outputdatalength))
271 		return -EFAULT;
272 	return 0;
273 }
274 
275 static int convert_response(struct zcrypt_device *zdev,
276 			    struct ap_message *reply,
277 			    char __user *outputdata,
278 			    unsigned int outputdatalength)
279 {
280 	/* Response type byte is the second byte in the response. */
281 	switch (((unsigned char *) reply->message)[1]) {
282 	case TYPE82_RSP_CODE:
283 	case TYPE88_RSP_CODE:
284 		return convert_error(zdev, reply);
285 	case TYPE80_RSP_CODE:
286 		return convert_type80(zdev, reply,
287 				      outputdata, outputdatalength);
288 	default: /* Unknown response type, this should NEVER EVER happen */
289 		zdev->online = 0;
290 		return -EAGAIN;	/* repeat the request on a different device. */
291 	}
292 }
293 
294 /**
295  * This function is called from the AP bus code after a crypto request
296  * "msg" has finished with the reply message "reply".
297  * It is called from tasklet context.
298  * @ap_dev: pointer to the AP device
299  * @msg: pointer to the AP message
300  * @reply: pointer to the AP reply message
301  */
302 static void zcrypt_cex2a_receive(struct ap_device *ap_dev,
303 				 struct ap_message *msg,
304 				 struct ap_message *reply)
305 {
306 	static struct error_hdr error_reply = {
307 		.type = TYPE82_RSP_CODE,
308 		.reply_code = REP82_ERROR_MACHINE_FAILURE,
309 	};
310 	struct type80_hdr *t80h;
311 	int length;
312 
313 	/* Copy the reply message to the request message buffer. */
314 	if (IS_ERR(reply)) {
315 		memcpy(msg->message, &error_reply, sizeof(error_reply));
316 		goto out;
317 	}
318 	t80h = reply->message;
319 	if (t80h->type == TYPE80_RSP_CODE) {
320 		if (ap_dev->device_type == AP_DEVICE_TYPE_CEX2A)
321 			length = min(CEX2A_MAX_RESPONSE_SIZE, (int) t80h->len);
322 		else
323 			length = min(CEX3A_MAX_RESPONSE_SIZE, (int) t80h->len);
324 		memcpy(msg->message, reply->message, length);
325 	} else
326 		memcpy(msg->message, reply->message, sizeof error_reply);
327 out:
328 	complete((struct completion *) msg->private);
329 }
330 
331 static atomic_t zcrypt_step = ATOMIC_INIT(0);
332 
333 /**
334  * The request distributor calls this function if it picked the CEX2A
335  * device to handle a modexpo request.
336  * @zdev: pointer to zcrypt_device structure that identifies the
337  *	  CEX2A device to the request distributor
338  * @mex: pointer to the modexpo request buffer
339  */
340 static long zcrypt_cex2a_modexpo(struct zcrypt_device *zdev,
341 				 struct ica_rsa_modexpo *mex)
342 {
343 	struct ap_message ap_msg;
344 	struct completion work;
345 	int rc;
346 
347 	ap_init_message(&ap_msg);
348 	if (zdev->user_space_type == ZCRYPT_CEX2A)
349 		ap_msg.message = kmalloc(CEX2A_MAX_MESSAGE_SIZE, GFP_KERNEL);
350 	else
351 		ap_msg.message = kmalloc(CEX3A_MAX_MESSAGE_SIZE, GFP_KERNEL);
352 	if (!ap_msg.message)
353 		return -ENOMEM;
354 	ap_msg.psmid = (((unsigned long long) current->pid) << 32) +
355 				atomic_inc_return(&zcrypt_step);
356 	ap_msg.private = &work;
357 	rc = ICAMEX_msg_to_type50MEX_msg(zdev, &ap_msg, mex);
358 	if (rc)
359 		goto out_free;
360 	init_completion(&work);
361 	ap_queue_message(zdev->ap_dev, &ap_msg);
362 	rc = wait_for_completion_interruptible(&work);
363 	if (rc == 0)
364 		rc = convert_response(zdev, &ap_msg, mex->outputdata,
365 				      mex->outputdatalength);
366 	else
367 		/* Signal pending. */
368 		ap_cancel_message(zdev->ap_dev, &ap_msg);
369 out_free:
370 	kfree(ap_msg.message);
371 	return rc;
372 }
373 
374 /**
375  * The request distributor calls this function if it picked the CEX2A
376  * device to handle a modexpo_crt request.
377  * @zdev: pointer to zcrypt_device structure that identifies the
378  *	  CEX2A device to the request distributor
379  * @crt: pointer to the modexpoc_crt request buffer
380  */
381 static long zcrypt_cex2a_modexpo_crt(struct zcrypt_device *zdev,
382 				     struct ica_rsa_modexpo_crt *crt)
383 {
384 	struct ap_message ap_msg;
385 	struct completion work;
386 	int rc;
387 
388 	ap_init_message(&ap_msg);
389 	if (zdev->user_space_type == ZCRYPT_CEX2A)
390 		ap_msg.message = kmalloc(CEX2A_MAX_MESSAGE_SIZE, GFP_KERNEL);
391 	else
392 		ap_msg.message = kmalloc(CEX3A_MAX_MESSAGE_SIZE, GFP_KERNEL);
393 	if (!ap_msg.message)
394 		return -ENOMEM;
395 	ap_msg.psmid = (((unsigned long long) current->pid) << 32) +
396 				atomic_inc_return(&zcrypt_step);
397 	ap_msg.private = &work;
398 	rc = ICACRT_msg_to_type50CRT_msg(zdev, &ap_msg, crt);
399 	if (rc)
400 		goto out_free;
401 	init_completion(&work);
402 	ap_queue_message(zdev->ap_dev, &ap_msg);
403 	rc = wait_for_completion_interruptible(&work);
404 	if (rc == 0)
405 		rc = convert_response(zdev, &ap_msg, crt->outputdata,
406 				      crt->outputdatalength);
407 	else
408 		/* Signal pending. */
409 		ap_cancel_message(zdev->ap_dev, &ap_msg);
410 out_free:
411 	kfree(ap_msg.message);
412 	return rc;
413 }
414 
415 /**
416  * The crypto operations for a CEX2A card.
417  */
418 static struct zcrypt_ops zcrypt_cex2a_ops = {
419 	.rsa_modexpo = zcrypt_cex2a_modexpo,
420 	.rsa_modexpo_crt = zcrypt_cex2a_modexpo_crt,
421 };
422 
423 /**
424  * Probe function for CEX2A cards. It always accepts the AP device
425  * since the bus_match already checked the hardware type.
426  * @ap_dev: pointer to the AP device.
427  */
428 static int zcrypt_cex2a_probe(struct ap_device *ap_dev)
429 {
430 	struct zcrypt_device *zdev = NULL;
431 	int rc = 0;
432 
433 	switch (ap_dev->device_type) {
434 	case AP_DEVICE_TYPE_CEX2A:
435 		zdev = zcrypt_device_alloc(CEX2A_MAX_RESPONSE_SIZE);
436 		if (!zdev)
437 			return -ENOMEM;
438 		zdev->user_space_type = ZCRYPT_CEX2A;
439 		zdev->type_string = "CEX2A";
440 		zdev->min_mod_size = CEX2A_MIN_MOD_SIZE;
441 		zdev->max_mod_size = CEX2A_MAX_MOD_SIZE;
442 		zdev->short_crt = 1;
443 		zdev->speed_rating = CEX2A_SPEED_RATING;
444 		zdev->max_exp_bit_length = CEX2A_MAX_MOD_SIZE;
445 		break;
446 	case AP_DEVICE_TYPE_CEX3A:
447 		zdev = zcrypt_device_alloc(CEX3A_MAX_RESPONSE_SIZE);
448 		if (!zdev)
449 			return -ENOMEM;
450 		zdev->user_space_type = ZCRYPT_CEX3A;
451 		zdev->type_string = "CEX3A";
452 		zdev->min_mod_size = CEX2A_MIN_MOD_SIZE;
453 		zdev->max_mod_size = CEX2A_MAX_MOD_SIZE;
454 		zdev->max_exp_bit_length = CEX2A_MAX_MOD_SIZE;
455 		if (ap_4096_commands_available(ap_dev->qid)) {
456 			zdev->max_mod_size = CEX3A_MAX_MOD_SIZE;
457 			zdev->max_exp_bit_length = CEX3A_MAX_MOD_SIZE;
458 		}
459 		zdev->short_crt = 1;
460 		zdev->speed_rating = CEX3A_SPEED_RATING;
461 		break;
462 	}
463 	if (zdev != NULL) {
464 		zdev->ap_dev = ap_dev;
465 		zdev->ops = &zcrypt_cex2a_ops;
466 		zdev->online = 1;
467 		ap_dev->reply = &zdev->reply;
468 		ap_dev->private = zdev;
469 		rc = zcrypt_device_register(zdev);
470 	}
471 	if (rc) {
472 		ap_dev->private = NULL;
473 		zcrypt_device_free(zdev);
474 	}
475 	return rc;
476 }
477 
478 /**
479  * This is called to remove the extended CEX2A driver information
480  * if an AP device is removed.
481  */
482 static void zcrypt_cex2a_remove(struct ap_device *ap_dev)
483 {
484 	struct zcrypt_device *zdev = ap_dev->private;
485 
486 	zcrypt_device_unregister(zdev);
487 }
488 
489 int __init zcrypt_cex2a_init(void)
490 {
491 	return ap_driver_register(&zcrypt_cex2a_driver, THIS_MODULE, "cex2a");
492 }
493 
494 void __exit zcrypt_cex2a_exit(void)
495 {
496 	ap_driver_unregister(&zcrypt_cex2a_driver);
497 }
498 
499 #ifndef CONFIG_ZCRYPT_MONOLITHIC
500 module_init(zcrypt_cex2a_init);
501 module_exit(zcrypt_cex2a_exit);
502 #endif
503