xref: /linux/drivers/s390/crypto/zcrypt_cex2a.c (revision c537b994505099b7197e7d3125b942ecbcc51eb6) 
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/init.h>
31 #include <linux/err.h>
32 #include <asm/atomic.h>
33 #include <asm/uaccess.h>
34 
35 #include "ap_bus.h"
36 #include "zcrypt_api.h"
37 #include "zcrypt_error.h"
38 #include "zcrypt_cex2a.h"
39 
40 #define CEX2A_MIN_MOD_SIZE	  1	/*    8 bits	*/
41 #define CEX2A_MAX_MOD_SIZE	256	/* 2048 bits	*/
42 
43 #define CEX2A_SPEED_RATING	970
44 
45 #define CEX2A_MAX_MESSAGE_SIZE	0x390	/* sizeof(struct type50_crb2_msg)    */
46 #define CEX2A_MAX_RESPONSE_SIZE 0x110	/* max outputdatalength + type80_hdr */
47 
48 #define CEX2A_CLEANUP_TIME	(15*HZ)
49 
50 static struct ap_device_id zcrypt_cex2a_ids[] = {
51 	{ AP_DEVICE(AP_DEVICE_TYPE_CEX2A) },
52 	{ /* end of list */ },
53 };
54 
55 #ifndef CONFIG_ZCRYPT_MONOLITHIC
56 MODULE_DEVICE_TABLE(ap, zcrypt_cex2a_ids);
57 MODULE_AUTHOR("IBM Corporation");
58 MODULE_DESCRIPTION("CEX2A Cryptographic Coprocessor device driver, "
59 		   "Copyright 2001, 2006 IBM Corporation");
60 MODULE_LICENSE("GPL");
61 #endif
62 
63 static int zcrypt_cex2a_probe(struct ap_device *ap_dev);
64 static void zcrypt_cex2a_remove(struct ap_device *ap_dev);
65 static void zcrypt_cex2a_receive(struct ap_device *, struct ap_message *,
66 				 struct ap_message *);
67 
68 static struct ap_driver zcrypt_cex2a_driver = {
69 	.probe = zcrypt_cex2a_probe,
70 	.remove = zcrypt_cex2a_remove,
71 	.receive = zcrypt_cex2a_receive,
72 	.ids = zcrypt_cex2a_ids,
73 };
74 
75 /**
76  * Convert a ICAMEX message to a type50 MEX message.
77  *
78  * @zdev: crypto device pointer
79  * @zreq: crypto request pointer
80  * @mex: pointer to user input data
81  *
82  * Returns 0 on success or -EFAULT.
83  */
84 static int ICAMEX_msg_to_type50MEX_msg(struct zcrypt_device *zdev,
85 				       struct ap_message *ap_msg,
86 				       struct ica_rsa_modexpo *mex)
87 {
88 	unsigned char *mod, *exp, *inp;
89 	int mod_len;
90 
91 	mod_len = mex->inputdatalength;
92 
93 	if (mod_len <= 128) {
94 		struct type50_meb1_msg *meb1 = ap_msg->message;
95 		memset(meb1, 0, sizeof(*meb1));
96 		ap_msg->length = sizeof(*meb1);
97 		meb1->header.msg_type_code = TYPE50_TYPE_CODE;
98 		meb1->header.msg_len = sizeof(*meb1);
99 		meb1->keyblock_type = TYPE50_MEB1_FMT;
100 		mod = meb1->modulus + sizeof(meb1->modulus) - mod_len;
101 		exp = meb1->exponent + sizeof(meb1->exponent) - mod_len;
102 		inp = meb1->message + sizeof(meb1->message) - mod_len;
103 	} else {
104 		struct type50_meb2_msg *meb2 = ap_msg->message;
105 		memset(meb2, 0, sizeof(*meb2));
106 		ap_msg->length = sizeof(*meb2);
107 		meb2->header.msg_type_code = TYPE50_TYPE_CODE;
108 		meb2->header.msg_len = sizeof(*meb2);
109 		meb2->keyblock_type = TYPE50_MEB2_FMT;
110 		mod = meb2->modulus + sizeof(meb2->modulus) - mod_len;
111 		exp = meb2->exponent + sizeof(meb2->exponent) - mod_len;
112 		inp = meb2->message + sizeof(meb2->message) - mod_len;
113 	}
114 
115 	if (copy_from_user(mod, mex->n_modulus, mod_len) ||
116 	    copy_from_user(exp, mex->b_key, mod_len) ||
117 	    copy_from_user(inp, mex->inputdata, mod_len))
118 		return -EFAULT;
119 	return 0;
120 }
121 
122 /**
123  * Convert a ICACRT message to a type50 CRT message.
124  *
125  * @zdev: crypto device pointer
126  * @zreq: crypto request pointer
127  * @crt: pointer to user input data
128  *
129  * Returns 0 on success or -EFAULT.
130  */
131 static int ICACRT_msg_to_type50CRT_msg(struct zcrypt_device *zdev,
132 				       struct ap_message *ap_msg,
133 				       struct ica_rsa_modexpo_crt *crt)
134 {
135 	int mod_len, short_len, long_len, long_offset;
136 	unsigned char *p, *q, *dp, *dq, *u, *inp;
137 
138 	mod_len = crt->inputdatalength;
139 	short_len = mod_len / 2;
140 	long_len = mod_len / 2 + 8;
141 
142 	/*
143 	 * CEX2A cannot handle p, dp, or U > 128 bytes.
144 	 * If we have one of these, we need to do extra checking.
145 	 */
146 	if (long_len > 128) {
147 		/*
148 		 * zcrypt_rsa_crt already checked for the leading
149 		 * zeroes of np_prime, bp_key and u_mult_inc.
150 		 */
151 		long_offset = long_len - 128;
152 		long_len = 128;
153 	} else
154 		long_offset = 0;
155 
156 	/*
157 	 * Instead of doing extra work for p, dp, U > 64 bytes, we'll just use
158 	 * the larger message structure.
159 	 */
160 	if (long_len <= 64) {
161 		struct type50_crb1_msg *crb1 = ap_msg->message;
162 		memset(crb1, 0, sizeof(*crb1));
163 		ap_msg->length = sizeof(*crb1);
164 		crb1->header.msg_type_code = TYPE50_TYPE_CODE;
165 		crb1->header.msg_len = sizeof(*crb1);
166 		crb1->keyblock_type = TYPE50_CRB1_FMT;
167 		p = crb1->p + sizeof(crb1->p) - long_len;
168 		q = crb1->q + sizeof(crb1->q) - short_len;
169 		dp = crb1->dp + sizeof(crb1->dp) - long_len;
170 		dq = crb1->dq + sizeof(crb1->dq) - short_len;
171 		u = crb1->u + sizeof(crb1->u) - long_len;
172 		inp = crb1->message + sizeof(crb1->message) - mod_len;
173 	} else {
174 		struct type50_crb2_msg *crb2 = ap_msg->message;
175 		memset(crb2, 0, sizeof(*crb2));
176 		ap_msg->length = sizeof(*crb2);
177 		crb2->header.msg_type_code = TYPE50_TYPE_CODE;
178 		crb2->header.msg_len = sizeof(*crb2);
179 		crb2->keyblock_type = TYPE50_CRB2_FMT;
180 		p = crb2->p + sizeof(crb2->p) - long_len;
181 		q = crb2->q + sizeof(crb2->q) - short_len;
182 		dp = crb2->dp + sizeof(crb2->dp) - long_len;
183 		dq = crb2->dq + sizeof(crb2->dq) - short_len;
184 		u = crb2->u + sizeof(crb2->u) - long_len;
185 		inp = crb2->message + sizeof(crb2->message) - mod_len;
186 	}
187 
188 	if (copy_from_user(p, crt->np_prime + long_offset, long_len) ||
189 	    copy_from_user(q, crt->nq_prime, short_len) ||
190 	    copy_from_user(dp, crt->bp_key + long_offset, long_len) ||
191 	    copy_from_user(dq, crt->bq_key, short_len) ||
192 	    copy_from_user(u, crt->u_mult_inv + long_offset, long_len) ||
193 	    copy_from_user(inp, crt->inputdata, mod_len))
194 		return -EFAULT;
195 
196 
197 	return 0;
198 }
199 
200 /**
201  * Copy results from a type 80 reply message back to user space.
202  *
203  * @zdev: crypto device pointer
204  * @reply: reply AP message.
205  * @data: pointer to user output data
206  * @length: size of user output data
207  *
208  * Returns 0 on success or -EFAULT.
209  */
210 static int convert_type80(struct zcrypt_device *zdev,
211 			  struct ap_message *reply,
212 			  char __user *outputdata,
213 			  unsigned int outputdatalength)
214 {
215 	struct type80_hdr *t80h = reply->message;
216 	unsigned char *data;
217 
218 	if (t80h->len < sizeof(*t80h) + outputdatalength) {
219 		/* The result is too short, the CEX2A card may not do that.. */
220 		zdev->online = 0;
221 		return -EAGAIN;	/* repeat the request on a different device. */
222 	}
223 	BUG_ON(t80h->len > CEX2A_MAX_RESPONSE_SIZE);
224 	data = reply->message + t80h->len - outputdatalength;
225 	if (copy_to_user(outputdata, data, outputdatalength))
226 		return -EFAULT;
227 	return 0;
228 }
229 
230 static int convert_response(struct zcrypt_device *zdev,
231 			    struct ap_message *reply,
232 			    char __user *outputdata,
233 			    unsigned int outputdatalength)
234 {
235 	/* Response type byte is the second byte in the response. */
236 	switch (((unsigned char *) reply->message)[1]) {
237 	case TYPE82_RSP_CODE:
238 	case TYPE88_RSP_CODE:
239 		return convert_error(zdev, reply);
240 	case TYPE80_RSP_CODE:
241 		return convert_type80(zdev, reply,
242 				      outputdata, outputdatalength);
243 	default: /* Unknown response type, this should NEVER EVER happen */
244 		PRINTK("Unrecognized Message Header: %08x%08x\n",
245 		       *(unsigned int *) reply->message,
246 		       *(unsigned int *) (reply->message+4));
247 		zdev->online = 0;
248 		return -EAGAIN;	/* repeat the request on a different device. */
249 	}
250 }
251 
252 /**
253  * This function is called from the AP bus code after a crypto request
254  * "msg" has finished with the reply message "reply".
255  * It is called from tasklet context.
256  * @ap_dev: pointer to the AP device
257  * @msg: pointer to the AP message
258  * @reply: pointer to the AP reply message
259  */
260 static void zcrypt_cex2a_receive(struct ap_device *ap_dev,
261 				 struct ap_message *msg,
262 				 struct ap_message *reply)
263 {
264 	static struct error_hdr error_reply = {
265 		.type = TYPE82_RSP_CODE,
266 		.reply_code = REP82_ERROR_MACHINE_FAILURE,
267 	};
268 	struct type80_hdr *t80h = reply->message;
269 	int length;
270 
271 	/* Copy the reply message to the request message buffer. */
272 	if (IS_ERR(reply))
273 		memcpy(msg->message, &error_reply, sizeof(error_reply));
274 	else if (t80h->type == TYPE80_RSP_CODE) {
275 		length = min(CEX2A_MAX_RESPONSE_SIZE, (int) t80h->len);
276 		memcpy(msg->message, reply->message, length);
277 	} else
278 		memcpy(msg->message, reply->message, sizeof error_reply);
279 	complete((struct completion *) msg->private);
280 }
281 
282 static atomic_t zcrypt_step = ATOMIC_INIT(0);
283 
284 /**
285  * The request distributor calls this function if it picked the CEX2A
286  * device to handle a modexpo request.
287  * @zdev: pointer to zcrypt_device structure that identifies the
288  *	  CEX2A device to the request distributor
289  * @mex: pointer to the modexpo request buffer
290  */
291 static long zcrypt_cex2a_modexpo(struct zcrypt_device *zdev,
292 				 struct ica_rsa_modexpo *mex)
293 {
294 	struct ap_message ap_msg;
295 	struct completion work;
296 	int rc;
297 
298 	ap_msg.message = kmalloc(CEX2A_MAX_MESSAGE_SIZE, GFP_KERNEL);
299 	if (!ap_msg.message)
300 		return -ENOMEM;
301 	ap_msg.psmid = (((unsigned long long) current->pid) << 32) +
302 				atomic_inc_return(&zcrypt_step);
303 	ap_msg.private = &work;
304 	rc = ICAMEX_msg_to_type50MEX_msg(zdev, &ap_msg, mex);
305 	if (rc)
306 		goto out_free;
307 	init_completion(&work);
308 	ap_queue_message(zdev->ap_dev, &ap_msg);
309 	rc = wait_for_completion_interruptible_timeout(
310 				&work, CEX2A_CLEANUP_TIME);
311 	if (rc > 0)
312 		rc = convert_response(zdev, &ap_msg, mex->outputdata,
313 				      mex->outputdatalength);
314 	else {
315 		/* Signal pending or message timed out. */
316 		ap_cancel_message(zdev->ap_dev, &ap_msg);
317 		if (rc == 0)
318 			/* Message timed out. */
319 			rc = -ETIME;
320 	}
321 out_free:
322 	kfree(ap_msg.message);
323 	return rc;
324 }
325 
326 /**
327  * The request distributor calls this function if it picked the CEX2A
328  * device to handle a modexpo_crt request.
329  * @zdev: pointer to zcrypt_device structure that identifies the
330  *	  CEX2A device to the request distributor
331  * @crt: pointer to the modexpoc_crt request buffer
332  */
333 static long zcrypt_cex2a_modexpo_crt(struct zcrypt_device *zdev,
334 				     struct ica_rsa_modexpo_crt *crt)
335 {
336 	struct ap_message ap_msg;
337 	struct completion work;
338 	int rc;
339 
340 	ap_msg.message = kmalloc(CEX2A_MAX_MESSAGE_SIZE, GFP_KERNEL);
341 	if (!ap_msg.message)
342 		return -ENOMEM;
343 	ap_msg.psmid = (((unsigned long long) current->pid) << 32) +
344 				atomic_inc_return(&zcrypt_step);
345 	ap_msg.private = &work;
346 	rc = ICACRT_msg_to_type50CRT_msg(zdev, &ap_msg, crt);
347 	if (rc)
348 		goto out_free;
349 	init_completion(&work);
350 	ap_queue_message(zdev->ap_dev, &ap_msg);
351 	rc = wait_for_completion_interruptible_timeout(
352 				&work, CEX2A_CLEANUP_TIME);
353 	if (rc > 0)
354 		rc = convert_response(zdev, &ap_msg, crt->outputdata,
355 				      crt->outputdatalength);
356 	else {
357 		/* Signal pending or message timed out. */
358 		ap_cancel_message(zdev->ap_dev, &ap_msg);
359 		if (rc == 0)
360 			/* Message timed out. */
361 			rc = -ETIME;
362 	}
363 out_free:
364 	kfree(ap_msg.message);
365 	return rc;
366 }
367 
368 /**
369  * The crypto operations for a CEX2A card.
370  */
371 static struct zcrypt_ops zcrypt_cex2a_ops = {
372 	.rsa_modexpo = zcrypt_cex2a_modexpo,
373 	.rsa_modexpo_crt = zcrypt_cex2a_modexpo_crt,
374 };
375 
376 /**
377  * Probe function for CEX2A cards. It always accepts the AP device
378  * since the bus_match already checked the hardware type.
379  * @ap_dev: pointer to the AP device.
380  */
381 static int zcrypt_cex2a_probe(struct ap_device *ap_dev)
382 {
383 	struct zcrypt_device *zdev;
384 	int rc;
385 
386 	zdev = zcrypt_device_alloc(CEX2A_MAX_RESPONSE_SIZE);
387 	if (!zdev)
388 		return -ENOMEM;
389 	zdev->ap_dev = ap_dev;
390 	zdev->ops = &zcrypt_cex2a_ops;
391 	zdev->online = 1;
392 	zdev->user_space_type = ZCRYPT_CEX2A;
393 	zdev->type_string = "CEX2A";
394 	zdev->min_mod_size = CEX2A_MIN_MOD_SIZE;
395 	zdev->max_mod_size = CEX2A_MAX_MOD_SIZE;
396 	zdev->short_crt = 1;
397 	zdev->speed_rating = CEX2A_SPEED_RATING;
398 	ap_dev->reply = &zdev->reply;
399 	ap_dev->private = zdev;
400 	rc = zcrypt_device_register(zdev);
401 	if (rc)
402 		goto out_free;
403 	return 0;
404 
405 out_free:
406 	ap_dev->private = NULL;
407 	zcrypt_device_free(zdev);
408 	return rc;
409 }
410 
411 /**
412  * This is called to remove the extended CEX2A driver information
413  * if an AP device is removed.
414  */
415 static void zcrypt_cex2a_remove(struct ap_device *ap_dev)
416 {
417 	struct zcrypt_device *zdev = ap_dev->private;
418 
419 	zcrypt_device_unregister(zdev);
420 }
421 
422 int __init zcrypt_cex2a_init(void)
423 {
424 	return ap_driver_register(&zcrypt_cex2a_driver, THIS_MODULE, "cex2a");
425 }
426 
427 void __exit zcrypt_cex2a_exit(void)
428 {
429 	ap_driver_unregister(&zcrypt_cex2a_driver);
430 }
431 
432 #ifndef CONFIG_ZCRYPT_MONOLITHIC
433 module_init(zcrypt_cex2a_init);
434 module_exit(zcrypt_cex2a_exit);
435 #endif
436