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allow userspace to modify scsi command filter on per device basis
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1 /*
2 * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 *
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public Licens
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
17 *
18 */
19 #include <linux/kernel.h>
20 #include <linux/errno.h>
21 #include <linux/string.h>
22 #include <linux/module.h>
23 #include <linux/blkdev.h>
24 #include <linux/capability.h>
25 #include <linux/completion.h>
26 #include <linux/cdrom.h>
27 #include <linux/slab.h>
28 #include <linux/times.h>
29 #include <asm/uaccess.h>
30
31 #include <scsi/scsi.h>
32 #include <scsi/scsi_ioctl.h>
33 #include <scsi/scsi_cmnd.h>
34
35 /* Command group 3 is reserved and should never be used. */
36 const unsigned char scsi_command_size_tbl[8] =
37 {
38 6, 10, 10, 12,
39 16, 12, 10, 10
40 };
41 EXPORT_SYMBOL(scsi_command_size_tbl);
42
43 #include <scsi/sg.h>
44
45 static int sg_get_version(int __user *p)
46 {
47 static const int sg_version_num = 30527;
48 return put_user(sg_version_num, p);
49 }
50
51 static int scsi_get_idlun(struct request_queue *q, int __user *p)
52 {
53 return put_user(0, p);
54 }
55
56 static int scsi_get_bus(struct request_queue *q, int __user *p)
57 {
58 return put_user(0, p);
59 }
60
61 static int sg_get_timeout(struct request_queue *q)
62 {
63 return q->sg_timeout / (HZ / USER_HZ);
64 }
65
66 static int sg_set_timeout(struct request_queue *q, int __user *p)
67 {
68 int timeout, err = get_user(timeout, p);
69
70 if (!err)
71 q->sg_timeout = timeout * (HZ / USER_HZ);
72
73 return err;
74 }
75
76 static int sg_get_reserved_size(struct request_queue *q, int __user *p)
77 {
78 unsigned val = min(q->sg_reserved_size, q->max_sectors << 9);
79
80 return put_user(val, p);
81 }
82
83 static int sg_set_reserved_size(struct request_queue *q, int __user *p)
84 {
85 int size, err = get_user(size, p);
86
87 if (err)
88 return err;
89
90 if (size < 0)
91 return -EINVAL;
92 if (size > (q->max_sectors << 9))
93 size = q->max_sectors << 9;
94
95 q->sg_reserved_size = size;
96 return 0;
97 }
98
99 /*
100 * will always return that we are ATAPI even for a real SCSI drive, I'm not
101 * so sure this is worth doing anything about (why would you care??)
102 */
103 static int sg_emulated_host(struct request_queue *q, int __user *p)
104 {
105 return put_user(1, p);
106 }
107
108 static int blk_fill_sghdr_rq(struct request_queue *q, struct request *rq,
109 struct sg_io_hdr *hdr, struct file *file)
110 {
111 if (copy_from_user(rq->cmd, hdr->cmdp, hdr->cmd_len))
112 return -EFAULT;
113 if (blk_verify_command(file, rq->cmd))
114 return -EPERM;
115
116 /*
117 * fill in request structure
118 */
119 rq->cmd_len = hdr->cmd_len;
120 rq->cmd_type = REQ_TYPE_BLOCK_PC;
121
122 rq->timeout = msecs_to_jiffies(hdr->timeout);
123 if (!rq->timeout)
124 rq->timeout = q->sg_timeout;
125 if (!rq->timeout)
126 rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
127
128 return 0;
129 }
130
131 /*
132 * unmap a request that was previously mapped to this sg_io_hdr. handles
133 * both sg and non-sg sg_io_hdr.
134 */
135 static int blk_unmap_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr)
136 {
137 blk_rq_unmap_user(rq->bio);
138 blk_put_request(rq);
139 return 0;
140 }
141
142 static int blk_complete_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr,
143 struct bio *bio)
144 {
145 int r, ret = 0;
146
147 /*
148 * fill in all the output members
149 */
150 hdr->status = rq->errors & 0xff;
151 hdr->masked_status = status_byte(rq->errors);
152 hdr->msg_status = msg_byte(rq->errors);
153 hdr->host_status = host_byte(rq->errors);
154 hdr->driver_status = driver_byte(rq->errors);
155 hdr->info = 0;
156 if (hdr->masked_status || hdr->host_status || hdr->driver_status)
157 hdr->info |= SG_INFO_CHECK;
158 hdr->resid = rq->data_len;
159 hdr->sb_len_wr = 0;
160
161 if (rq->sense_len && hdr->sbp) {
162 int len = min((unsigned int) hdr->mx_sb_len, rq->sense_len);
163
164 if (!copy_to_user(hdr->sbp, rq->sense, len))
165 hdr->sb_len_wr = len;
166 else
167 ret = -EFAULT;
168 }
169
170 rq->bio = bio;
171 r = blk_unmap_sghdr_rq(rq, hdr);
172 if (ret)
173 r = ret;
174
175 return r;
176 }
177
178 static int sg_io(struct file *file, struct request_queue *q,
179 struct gendisk *bd_disk, struct sg_io_hdr *hdr)
180 {
181 unsigned long start_time;
182 int writing = 0, ret = 0;
183 struct request *rq;
184 char sense[SCSI_SENSE_BUFFERSIZE];
185 struct bio *bio;
186
187 if (hdr->interface_id != 'S')
188 return -EINVAL;
189 if (hdr->cmd_len > BLK_MAX_CDB)
190 return -EINVAL;
191
192 if (hdr->dxfer_len > (q->max_hw_sectors << 9))
193 return -EIO;
194
195 if (hdr->dxfer_len)
196 switch (hdr->dxfer_direction) {
197 default:
198 return -EINVAL;
199 case SG_DXFER_TO_DEV:
200 writing = 1;
201 break;
202 case SG_DXFER_TO_FROM_DEV:
203 case SG_DXFER_FROM_DEV:
204 break;
205 }
206
207 rq = blk_get_request(q, writing ? WRITE : READ, GFP_KERNEL);
208 if (!rq)
209 return -ENOMEM;
210
211 if (blk_fill_sghdr_rq(q, rq, hdr, file)) {
212 blk_put_request(rq);
213 return -EFAULT;
214 }
215
216 if (hdr->iovec_count) {
217 const int size = sizeof(struct sg_iovec) * hdr->iovec_count;
218 struct sg_iovec *iov;
219
220 iov = kmalloc(size, GFP_KERNEL);
221 if (!iov) {
222 ret = -ENOMEM;
223 goto out;
224 }
225
226 if (copy_from_user(iov, hdr->dxferp, size)) {
227 kfree(iov);
228 ret = -EFAULT;
229 goto out;
230 }
231
232 ret = blk_rq_map_user_iov(q, rq, iov, hdr->iovec_count,
233 hdr->dxfer_len);
234 kfree(iov);
235 } else if (hdr->dxfer_len)
236 ret = blk_rq_map_user(q, rq, hdr->dxferp, hdr->dxfer_len);
237
238 if (ret)
239 goto out;
240
241 bio = rq->bio;
242 memset(sense, 0, sizeof(sense));
243 rq->sense = sense;
244 rq->sense_len = 0;
245 rq->retries = 0;
246
247 start_time = jiffies;
248
249 /* ignore return value. All information is passed back to caller
250 * (if he doesn't check that is his problem).
251 * N.B. a non-zero SCSI status is _not_ necessarily an error.
252 */
253 blk_execute_rq(q, bd_disk, rq, 0);
254
255 hdr->duration = jiffies_to_msecs(jiffies - start_time);
256
257 return blk_complete_sghdr_rq(rq, hdr, bio);
258 out:
259 blk_put_request(rq);
260 return ret;
261 }
262
263 /**
264 * sg_scsi_ioctl -- handle deprecated SCSI_IOCTL_SEND_COMMAND ioctl
265 * @file: file this ioctl operates on (optional)
266 * @q: request queue to send scsi commands down
267 * @disk: gendisk to operate on (option)
268 * @sic: userspace structure describing the command to perform
269 *
270 * Send down the scsi command described by @sic to the device below
271 * the request queue @q. If @file is non-NULL it's used to perform
272 * fine-grained permission checks that allow users to send down
273 * non-destructive SCSI commands. If the caller has a struct gendisk
274 * available it should be passed in as @disk to allow the low level
275 * driver to use the information contained in it. A non-NULL @disk
276 * is only allowed if the caller knows that the low level driver doesn't
277 * need it (e.g. in the scsi subsystem).
278 *
279 * Notes:
280 * - This interface is deprecated - users should use the SG_IO
281 * interface instead, as this is a more flexible approach to
282 * performing SCSI commands on a device.
283 * - The SCSI command length is determined by examining the 1st byte
284 * of the given command. There is no way to override this.
285 * - Data transfers are limited to PAGE_SIZE
286 * - The length (x + y) must be at least OMAX_SB_LEN bytes long to
287 * accommodate the sense buffer when an error occurs.
288 * The sense buffer is truncated to OMAX_SB_LEN (16) bytes so that
289 * old code will not be surprised.
290 * - If a Unix error occurs (e.g. ENOMEM) then the user will receive
291 * a negative return and the Unix error code in 'errno'.
292 * If the SCSI command succeeds then 0 is returned.
293 * Positive numbers returned are the compacted SCSI error codes (4
294 * bytes in one int) where the lowest byte is the SCSI status.
295 */
296 #define OMAX_SB_LEN 16 /* For backward compatibility */
297 int sg_scsi_ioctl(struct file *file, struct request_queue *q,
298 struct gendisk *disk, struct scsi_ioctl_command __user *sic)
299 {
300 struct request *rq;
301 int err;
302 unsigned int in_len, out_len, bytes, opcode, cmdlen;
303 char *buffer = NULL, sense[SCSI_SENSE_BUFFERSIZE];
304
305 if (!sic)
306 return -EINVAL;
307
308 /*
309 * get in an out lengths, verify they don't exceed a page worth of data
310 */
311 if (get_user(in_len, &sic->inlen))
312 return -EFAULT;
313 if (get_user(out_len, &sic->outlen))
314 return -EFAULT;
315 if (in_len > PAGE_SIZE || out_len > PAGE_SIZE)
316 return -EINVAL;
317 if (get_user(opcode, sic->data))
318 return -EFAULT;
319
320 bytes = max(in_len, out_len);
321 if (bytes) {
322 buffer = kzalloc(bytes, q->bounce_gfp | GFP_USER| __GFP_NOWARN);
323 if (!buffer)
324 return -ENOMEM;
325
326 }
327
328 rq = blk_get_request(q, in_len ? WRITE : READ, __GFP_WAIT);
329
330 cmdlen = COMMAND_SIZE(opcode);
331
332 /*
333 * get command and data to send to device, if any
334 */
335 err = -EFAULT;
336 rq->cmd_len = cmdlen;
337 if (copy_from_user(rq->cmd, sic->data, cmdlen))
338 goto error;
339
340 if (in_len && copy_from_user(buffer, sic->data + cmdlen, in_len))
341 goto error;
342
343 err = blk_verify_command(file, rq->cmd);
344 if (err)
345 goto error;
346
347 /* default. possible overriden later */
348 rq->retries = 5;
349
350 switch (opcode) {
351 case SEND_DIAGNOSTIC:
352 case FORMAT_UNIT:
353 rq->timeout = FORMAT_UNIT_TIMEOUT;
354 rq->retries = 1;
355 break;
356 case START_STOP:
357 rq->timeout = START_STOP_TIMEOUT;
358 break;
359 case MOVE_MEDIUM:
360 rq->timeout = MOVE_MEDIUM_TIMEOUT;
361 break;
362 case READ_ELEMENT_STATUS:
363 rq->timeout = READ_ELEMENT_STATUS_TIMEOUT;
364 break;
365 case READ_DEFECT_DATA:
366 rq->timeout = READ_DEFECT_DATA_TIMEOUT;
367 rq->retries = 1;
368 break;
369 default:
370 rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
371 break;
372 }
373
374 if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, __GFP_WAIT)) {
375 err = DRIVER_ERROR << 24;
376 goto out;
377 }
378
379 memset(sense, 0, sizeof(sense));
380 rq->sense = sense;
381 rq->sense_len = 0;
382 rq->cmd_type = REQ_TYPE_BLOCK_PC;
383
384 blk_execute_rq(q, disk, rq, 0);
385
386 out:
387 err = rq->errors & 0xff; /* only 8 bit SCSI status */
388 if (err) {
389 if (rq->sense_len && rq->sense) {
390 bytes = (OMAX_SB_LEN > rq->sense_len) ?
391 rq->sense_len : OMAX_SB_LEN;
392 if (copy_to_user(sic->data, rq->sense, bytes))
393 err = -EFAULT;
394 }
395 } else {
396 if (copy_to_user(sic->data, buffer, out_len))
397 err = -EFAULT;
398 }
399
400 error:
401 kfree(buffer);
402 blk_put_request(rq);
403 return err;
404 }
405 EXPORT_SYMBOL_GPL(sg_scsi_ioctl);
406
407 /* Send basic block requests */
408 static int __blk_send_generic(struct request_queue *q, struct gendisk *bd_disk,
409 int cmd, int data)
410 {
411 struct request *rq;
412 int err;
413
414 rq = blk_get_request(q, WRITE, __GFP_WAIT);
415 rq->cmd_type = REQ_TYPE_BLOCK_PC;
416 rq->data = NULL;
417 rq->data_len = 0;
418 rq->extra_len = 0;
419 rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
420 rq->cmd[0] = cmd;
421 rq->cmd[4] = data;
422 rq->cmd_len = 6;
423 err = blk_execute_rq(q, bd_disk, rq, 0);
424 blk_put_request(rq);
425
426 return err;
427 }
428
429 static inline int blk_send_start_stop(struct request_queue *q,
430 struct gendisk *bd_disk, int data)
431 {
432 return __blk_send_generic(q, bd_disk, GPCMD_START_STOP_UNIT, data);
433 }
434
435 int scsi_cmd_ioctl(struct file *file, struct request_queue *q,
436 struct gendisk *bd_disk, unsigned int cmd, void __user *arg)
437 {
438 int err;
439
440 if (!q || blk_get_queue(q))
441 return -ENXIO;
442
443 switch (cmd) {
444 /*
445 * new sgv3 interface
446 */
447 case SG_GET_VERSION_NUM:
448 err = sg_get_version(arg);
449 break;
450 case SCSI_IOCTL_GET_IDLUN:
451 err = scsi_get_idlun(q, arg);
452 break;
453 case SCSI_IOCTL_GET_BUS_NUMBER:
454 err = scsi_get_bus(q, arg);
455 break;
456 case SG_SET_TIMEOUT:
457 err = sg_set_timeout(q, arg);
458 break;
459 case SG_GET_TIMEOUT:
460 err = sg_get_timeout(q);
461 break;
462 case SG_GET_RESERVED_SIZE:
463 err = sg_get_reserved_size(q, arg);
464 break;
465 case SG_SET_RESERVED_SIZE:
466 err = sg_set_reserved_size(q, arg);
467 break;
468 case SG_EMULATED_HOST:
469 err = sg_emulated_host(q, arg);
470 break;
471 case SG_IO: {
472 struct sg_io_hdr hdr;
473
474 err = -EFAULT;
475 if (copy_from_user(&hdr, arg, sizeof(hdr)))
476 break;
477 err = sg_io(file, q, bd_disk, &hdr);
478 if (err == -EFAULT)
479 break;
480
481 if (copy_to_user(arg, &hdr, sizeof(hdr)))
482 err = -EFAULT;
483 break;
484 }
485 case CDROM_SEND_PACKET: {
486 struct cdrom_generic_command cgc;
487 struct sg_io_hdr hdr;
488
489 err = -EFAULT;
490 if (copy_from_user(&cgc, arg, sizeof(cgc)))
491 break;
492 cgc.timeout = clock_t_to_jiffies(cgc.timeout);
493 memset(&hdr, 0, sizeof(hdr));
494 hdr.interface_id = 'S';
495 hdr.cmd_len = sizeof(cgc.cmd);
496 hdr.dxfer_len = cgc.buflen;
497 err = 0;
498 switch (cgc.data_direction) {
499 case CGC_DATA_UNKNOWN:
500 hdr.dxfer_direction = SG_DXFER_UNKNOWN;
501 break;
502 case CGC_DATA_WRITE:
503 hdr.dxfer_direction = SG_DXFER_TO_DEV;
504 break;
505 case CGC_DATA_READ:
506 hdr.dxfer_direction = SG_DXFER_FROM_DEV;
507 break;
508 case CGC_DATA_NONE:
509 hdr.dxfer_direction = SG_DXFER_NONE;
510 break;
511 default:
512 err = -EINVAL;
513 }
514 if (err)
515 break;
516
517 hdr.dxferp = cgc.buffer;
518 hdr.sbp = cgc.sense;
519 if (hdr.sbp)
520 hdr.mx_sb_len = sizeof(struct request_sense);
521 hdr.timeout = cgc.timeout;
522 hdr.cmdp = ((struct cdrom_generic_command __user*) arg)->cmd;
523 hdr.cmd_len = sizeof(cgc.cmd);
524
525 err = sg_io(file, q, bd_disk, &hdr);
526 if (err == -EFAULT)
527 break;
528
529 if (hdr.status)
530 err = -EIO;
531
532 cgc.stat = err;
533 cgc.buflen = hdr.resid;
534 if (copy_to_user(arg, &cgc, sizeof(cgc)))
535 err = -EFAULT;
536
537 break;
538 }
539
540 /*
541 * old junk scsi send command ioctl
542 */
543 case SCSI_IOCTL_SEND_COMMAND:
544 printk(KERN_WARNING "program %s is using a deprecated SCSI ioctl, please convert it to SG_IO\n", current->comm);
545 err = -EINVAL;
546 if (!arg)
547 break;
548
549 err = sg_scsi_ioctl(file, q, bd_disk, arg);
550 break;
551 case CDROMCLOSETRAY:
552 err = blk_send_start_stop(q, bd_disk, 0x03);
553 break;
554 case CDROMEJECT:
555 err = blk_send_start_stop(q, bd_disk, 0x02);
556 break;
557 default:
558 err = -ENOTTY;
559 }
560
561 blk_put_queue(q);
562 return err;
563 }
564
565 EXPORT_SYMBOL(scsi_cmd_ioctl);