drivers/scsi/scsi_ioctl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Changes:
   4  * Arnaldo Carvalho de Melo <acme@conectiva.com.br> 08/23/2000
   5  * - get rid of some verify_areas and use __copy*user and __get/put_user
   6  *   for the ones that remain
   7  */
   8 #include <linux/module.h>
   9 #include <linux/blkdev.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/errno.h>
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/mm.h>
  15 #include <linux/string.h>
  16 #include <linux/uaccess.h>
  17
  18 #include <scsi/scsi.h>
  19 #include <scsi/scsi_cmnd.h>
  20 #include <scsi/scsi_device.h>
  21 #include <scsi/scsi_eh.h>
  22 #include <scsi/scsi_host.h>
  23 #include <scsi/scsi_ioctl.h>
  24 #include <scsi/sg.h>
  25 #include <scsi/scsi_dbg.h>
  26
  27 #include "scsi_logging.h"
  28
  29 #define NORMAL_RETRIES                  5
  30 #define IOCTL_NORMAL_TIMEOUT                    (10 * HZ)
  31
  32 #define MAX_BUF PAGE_SIZE
  33
  34 /**
  35  * ioctl_probe  --  return host identification
  36  * @host:       host to identify
  37  * @buffer:     userspace buffer for identification
  38  *
  39  * Return an identifying string at @buffer, if @buffer is non-NULL, filling
  40  * to the length stored at * (int *) @buffer.
  41  */
  42 static int ioctl_probe(struct Scsi_Host *host, void __user *buffer)
  43 {
  44         unsigned int len, slen;
  45         const char *string;
  46
  47         if (buffer) {
  48                 if (get_user(len, (unsigned int __user *) buffer))
  49                         return -EFAULT;
  50
  51                 if (host->hostt->info)
  52                         string = host->hostt->info(host);
  53                 else
  54                         string = host->hostt->name;
  55                 if (string) {
  56                         slen = strlen(string);
  57                         if (len > slen)
  58                                 len = slen + 1;
  59                         if (copy_to_user(buffer, string, len))
  60                                 return -EFAULT;
  61                 }
  62         }
  63         return 1;
  64 }
  65
  66 /*
  67
  68  * The SCSI_IOCTL_SEND_COMMAND ioctl sends a command out to the SCSI host.
  69  * The IOCTL_NORMAL_TIMEOUT and NORMAL_RETRIES  variables are used.
  70  *
  71  * dev is the SCSI device struct ptr, *(int *) arg is the length of the
  72  * input data, if any, not including the command string & counts,
  73  * *((int *)arg + 1) is the output buffer size in bytes.
  74  *
  75  * *(char *) ((int *) arg)[2] the actual command byte.
  76  *
  77  * Note that if more than MAX_BUF bytes are requested to be transferred,
  78  * the ioctl will fail with error EINVAL.
  79  *
  80  * This size *does not* include the initial lengths that were passed.
  81  *
  82  * The SCSI command is read from the memory location immediately after the
  83  * length words, and the input data is right after the command.  The SCSI
  84  * routines know the command size based on the opcode decode.
  85  *
  86  * The output area is then filled in starting from the command byte.
  87  */
  88
  89 static int ioctl_internal_command(struct scsi_device *sdev, char *cmd,
  90                                   int timeout, int retries)
  91 {
  92         int result;
  93         struct scsi_sense_hdr sshdr;
  94
  95         SCSI_LOG_IOCTL(1, sdev_printk(KERN_INFO, sdev,
  96                                       "Trying ioctl with scsi command %d\n", *cmd));
  97
  98         result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0,
  99                                   &sshdr, timeout, retries, NULL);
 100
 101         SCSI_LOG_IOCTL(2, sdev_printk(KERN_INFO, sdev,
 102                                       "Ioctl returned  0x%x\n", result));
 103
 104         if (driver_byte(result) == DRIVER_SENSE &&
 105             scsi_sense_valid(&sshdr)) {
 106                 switch (sshdr.sense_key) {
 107                 case ILLEGAL_REQUEST:
 108                         if (cmd[0] == ALLOW_MEDIUM_REMOVAL)
 109                                 sdev->lockable = 0;
 110                         else
 111                                 sdev_printk(KERN_INFO, sdev,
 112                                             "ioctl_internal_command: "
 113                                             "ILLEGAL REQUEST "
 114                                             "asc=0x%x ascq=0x%x\n",
 115                                             sshdr.asc, sshdr.ascq);
 116                         break;
 117                 case NOT_READY: /* This happens if there is no disc in drive */
 118                         if (sdev->removable)
 119                                 break;
 120                         fallthrough;
 121                 case UNIT_ATTENTION:
 122                         if (sdev->removable) {
 123                                 sdev->changed = 1;
 124                                 result = 0;     /* This is no longer considered an error */
 125                                 break;
 126                         }
 127                         fallthrough;    /* for non-removable media */
 128                 default:
 129                         sdev_printk(KERN_INFO, sdev,
 130                                     "ioctl_internal_command return code = %x\n",
 131                                     result);
 132                         scsi_print_sense_hdr(sdev, NULL, &sshdr);
 133                         break;
 134                 }
 135         }
 136
 137         SCSI_LOG_IOCTL(2, sdev_printk(KERN_INFO, sdev,
 138                                       "IOCTL Releasing command\n"));
 139         return result;
 140 }
 141
 142 int scsi_set_medium_removal(struct scsi_device *sdev, char state)
 143 {
 144         char scsi_cmd[MAX_COMMAND_SIZE];
 145         int ret;
 146
 147         if (!sdev->removable || !sdev->lockable)
 148                return 0;
 149
 150         scsi_cmd[0] = ALLOW_MEDIUM_REMOVAL;
 151         scsi_cmd[1] = 0;
 152         scsi_cmd[2] = 0;
 153         scsi_cmd[3] = 0;
 154         scsi_cmd[4] = state;
 155         scsi_cmd[5] = 0;
 156
 157         ret = ioctl_internal_command(sdev, scsi_cmd,
 158                         IOCTL_NORMAL_TIMEOUT, NORMAL_RETRIES);
 159         if (ret == 0)
 160                 sdev->locked = (state == SCSI_REMOVAL_PREVENT);
 161         return ret;
 162 }
 163 EXPORT_SYMBOL(scsi_set_medium_removal);
 164
 165 /*
 166  * The scsi_ioctl_get_pci() function places into arg the value
 167  * pci_dev::slot_name (8 characters) for the PCI device (if any).
 168  * Returns: 0 on success
 169  *          -ENXIO if there isn't a PCI device pointer
 170  *                 (could be because the SCSI driver hasn't been
 171  *                  updated yet, or because it isn't a SCSI
 172  *                  device)
 173  *          any copy_to_user() error on failure there
 174  */
 175 static int scsi_ioctl_get_pci(struct scsi_device *sdev, void __user *arg)
 176 {
 177         struct device *dev = scsi_get_device(sdev->host);
 178         const char *name;
 179
 180         if (!dev)
 181                 return -ENXIO;
 182
 183         name = dev_name(dev);
 184
 185         /* compatibility with old ioctl which only returned
 186          * 20 characters */
 187         return copy_to_user(arg, name, min(strlen(name), (size_t)20))
 188                 ? -EFAULT: 0;
 189 }
 190
 191
 192 static int scsi_ioctl_common(struct scsi_device *sdev, int cmd, void __user *arg)
 193 {
 194         char scsi_cmd[MAX_COMMAND_SIZE];
 195         struct scsi_sense_hdr sense_hdr;
 196
 197         /* Check for deprecated ioctls ... all the ioctls which don't
 198          * follow the new unique numbering scheme are deprecated */
 199         switch (cmd) {
 200         case SCSI_IOCTL_SEND_COMMAND:
 201         case SCSI_IOCTL_TEST_UNIT_READY:
 202         case SCSI_IOCTL_BENCHMARK_COMMAND:
 203         case SCSI_IOCTL_SYNC:
 204         case SCSI_IOCTL_START_UNIT:
 205         case SCSI_IOCTL_STOP_UNIT:
 206                 printk(KERN_WARNING "program %s is using a deprecated SCSI "
 207                        "ioctl, please convert it to SG_IO\n", current->comm);
 208                 break;
 209         default:
 210                 break;
 211         }
 212
 213         switch (cmd) {
 214         case SCSI_IOCTL_GET_IDLUN: {
 215                 struct scsi_idlun v = {
 216                         .dev_id = (sdev->id & 0xff)
 217                                  + ((sdev->lun & 0xff) << 8)
 218                                  + ((sdev->channel & 0xff) << 16)
 219                                  + ((sdev->host->host_no & 0xff) << 24),
 220                         .host_unique_id = sdev->host->unique_id
 221                 };
 222                 if (copy_to_user(arg, &v, sizeof(struct scsi_idlun)))
 223                         return -EFAULT;
 224                 return 0;
 225         }
 226         case SCSI_IOCTL_GET_BUS_NUMBER:
 227                 return put_user(sdev->host->host_no, (int __user *)arg);
 228         case SCSI_IOCTL_PROBE_HOST:
 229                 return ioctl_probe(sdev->host, arg);
 230         case SCSI_IOCTL_SEND_COMMAND:
 231                 if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
 232                         return -EACCES;
 233                 return sg_scsi_ioctl(sdev->request_queue, NULL, 0, arg);
 234         case SCSI_IOCTL_DOORLOCK:
 235                 return scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
 236         case SCSI_IOCTL_DOORUNLOCK:
 237                 return scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
 238         case SCSI_IOCTL_TEST_UNIT_READY:
 239                 return scsi_test_unit_ready(sdev, IOCTL_NORMAL_TIMEOUT,
 240                                             NORMAL_RETRIES, &sense_hdr);
 241         case SCSI_IOCTL_START_UNIT:
 242                 scsi_cmd[0] = START_STOP;
 243                 scsi_cmd[1] = 0;
 244                 scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
 245                 scsi_cmd[4] = 1;
 246                 return ioctl_internal_command(sdev, scsi_cmd,
 247                                      START_STOP_TIMEOUT, NORMAL_RETRIES);
 248         case SCSI_IOCTL_STOP_UNIT:
 249                 scsi_cmd[0] = START_STOP;
 250                 scsi_cmd[1] = 0;
 251                 scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
 252                 scsi_cmd[4] = 0;
 253                 return ioctl_internal_command(sdev, scsi_cmd,
 254                                      START_STOP_TIMEOUT, NORMAL_RETRIES);
 255         case SCSI_IOCTL_GET_PCI:
 256                 return scsi_ioctl_get_pci(sdev, arg);
 257         case SG_SCSI_RESET:
 258                 return scsi_ioctl_reset(sdev, arg);
 259         }
 260         return -ENOIOCTLCMD;
 261 }
 262
 263 /**
 264  * scsi_ioctl - Dispatch ioctl to scsi device
 265  * @sdev: scsi device receiving ioctl
 266  * @cmd: which ioctl is it
 267  * @arg: data associated with ioctl
 268  *
 269  * Description: The scsi_ioctl() function differs from most ioctls in that it
 270  * does not take a major/minor number as the dev field.  Rather, it takes
 271  * a pointer to a &struct scsi_device.
 272  */
 273 int scsi_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
 274 {
 275         int ret = scsi_ioctl_common(sdev, cmd, arg);
 276
 277         if (ret != -ENOIOCTLCMD)
 278                 return ret;
 279
 280         if (sdev->host->hostt->ioctl)
 281                 return sdev->host->hostt->ioctl(sdev, cmd, arg);
 282
 283         return -EINVAL;
 284 }
 285 EXPORT_SYMBOL(scsi_ioctl);
 286
 287 #ifdef CONFIG_COMPAT
 288 int scsi_compat_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
 289 {
 290         int ret = scsi_ioctl_common(sdev, cmd, arg);
 291
 292         if (ret != -ENOIOCTLCMD)
 293                 return ret;
 294
 295         if (sdev->host->hostt->compat_ioctl)
 296                 return sdev->host->hostt->compat_ioctl(sdev, cmd, arg);
 297
 298         return ret;
 299 }
 300 EXPORT_SYMBOL(scsi_compat_ioctl);
 301 #endif
 302
 303 /*
 304  * We can process a reset even when a device isn't fully operable.
 305  */
 306 int scsi_ioctl_block_when_processing_errors(struct scsi_device *sdev, int cmd,
 307                 bool ndelay)
 308 {
 309         if (cmd == SG_SCSI_RESET && ndelay) {
 310                 if (scsi_host_in_recovery(sdev->host))
 311                         return -EAGAIN;
 312         } else {
 313                 if (!scsi_block_when_processing_errors(sdev))
 314                         return -ENODEV;
 315         }
 316
 317         return 0;
 318 }
 319 EXPORT_SYMBOL_GPL(scsi_ioctl_block_when_processing_errors);