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
50static 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
56MODULE_DEVICE_TABLE(ap, zcrypt_cex2a_ids);
57MODULE_AUTHOR("IBM Corporation");
58MODULE_DESCRIPTION("CEX2A Cryptographic Coprocessor device driver, "
59		   "Copyright 2001, 2006 IBM Corporation");
60MODULE_LICENSE("GPL");
61#endif
62
63static int zcrypt_cex2a_probe(struct ap_device *ap_dev);
64static void zcrypt_cex2a_remove(struct ap_device *ap_dev);
65static void zcrypt_cex2a_receive(struct ap_device *, struct ap_message *,
66				 struct ap_message *);
67
68static 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 */
84static 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 */
131static 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 */
210static 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
230static 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 */
260static 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
282static 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 */
291static 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	}
321out_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 */
333static 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	}
363out_free:
364	kfree(ap_msg.message);
365	return rc;
366}
367
368/**
369 * The crypto operations for a CEX2A card.
370 */
371static 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 */
381static 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
405out_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 */
415static 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
422int __init zcrypt_cex2a_init(void)
423{
424	return ap_driver_register(&zcrypt_cex2a_driver, THIS_MODULE, "cex2a");
425}
426
427void __exit zcrypt_cex2a_exit(void)
428{
429	ap_driver_unregister(&zcrypt_cex2a_driver);
430}
431
432#ifndef CONFIG_ZCRYPT_MONOLITHIC
433module_init(zcrypt_cex2a_init);
434module_exit(zcrypt_cex2a_exit);
435#endif
436