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-rw-r--r--block/cmd-filter.c325
1 files changed, 325 insertions, 0 deletions
diff --git a/block/cmd-filter.c b/block/cmd-filter.c
new file mode 100644
index 00000000000..35e327ceaa9
--- /dev/null
+++ b/block/cmd-filter.c
@@ -0,0 +1,325 @@
+/*
+ * Copyright 2004 Peter M. Jones <pjones@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public Licens
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
+ *
+ */
+
+#include <linux/list.h>
+#include <linux/genhd.h>
+#include <linux/spinlock.h>
+#include <linux/parser.h>
+#include <linux/capability.h>
+#include <linux/bitops.h>
+
+#include <scsi/scsi.h>
+#include <linux/cdrom.h>
+
+int blk_cmd_filter_verify_command(struct blk_scsi_cmd_filter *filter,
+ unsigned char *cmd, mode_t *f_mode)
+{
+ /* root can do any command. */
+ if (capable(CAP_SYS_RAWIO))
+ return 0;
+
+ /* if there's no filter set, assume we're filtering everything out */
+ if (!filter)
+ return -EPERM;
+
+ /* Anybody who can open the device can do a read-safe command */
+ if (test_bit(cmd[0], filter->read_ok))
+ return 0;
+
+ /* Write-safe commands require a writable open */
+ if (test_bit(cmd[0], filter->write_ok) && (*f_mode & FMODE_WRITE))
+ return 0;
+
+ return -EPERM;
+}
+EXPORT_SYMBOL(blk_cmd_filter_verify_command);
+
+int blk_verify_command(struct file *file, unsigned char *cmd)
+{
+ struct gendisk *disk;
+ struct inode *inode;
+
+ if (!file)
+ return -EINVAL;
+
+ inode = file->f_dentry->d_inode;
+ if (!inode)
+ return -EINVAL;
+
+ disk = inode->i_bdev->bd_disk;
+
+ return blk_cmd_filter_verify_command(&disk->cmd_filter,
+ cmd, &file->f_mode);
+}
+EXPORT_SYMBOL(blk_verify_command);
+
+/* and now, the sysfs stuff */
+static ssize_t rcf_cmds_show(struct blk_scsi_cmd_filter *filter, char *page,
+ int rw)
+{
+ char *npage = page;
+ unsigned long *okbits;
+ int i;
+
+ if (rw == READ)
+ okbits = filter->read_ok;
+ else
+ okbits = filter->write_ok;
+
+ for (i = 0; i < BLK_SCSI_MAX_CMDS; i++) {
+ if (test_bit(i, okbits)) {
+ sprintf(npage, "%02x", i);
+ npage += 2;
+ if (i < BLK_SCSI_MAX_CMDS - 1)
+ sprintf(npage++, " ");
+ }
+ }
+
+ if (npage != page)
+ npage += sprintf(npage, "\n");
+
+ return npage - page;
+}
+
+static ssize_t rcf_readcmds_show(struct blk_scsi_cmd_filter *filter, char *page)
+{
+ return rcf_cmds_show(filter, page, READ);
+}
+
+static ssize_t rcf_writecmds_show(struct blk_scsi_cmd_filter *filter,
+ char *page)
+{
+ return rcf_cmds_show(filter, page, WRITE);
+}
+
+static ssize_t rcf_cmds_store(struct blk_scsi_cmd_filter *filter,
+ const char *page, size_t count, int rw)
+{
+ ssize_t ret = 0;
+ unsigned long okbits[BLK_SCSI_CMD_PER_LONG], *target_okbits;
+ int cmd, status, len;
+ substring_t ss;
+
+ memset(&okbits, 0, sizeof(okbits));
+
+ for (len = strlen(page); len > 0; len -= 3) {
+ if (len < 2)
+ break;
+ ss.from = (char *) page + ret;
+ ss.to = (char *) page + ret + 2;
+ ret += 3;
+ status = match_hex(&ss, &cmd);
+ /* either of these cases means invalid input, so do nothing. */
+ if (status || cmd >= BLK_SCSI_MAX_CMDS)
+ return -EINVAL;
+
+ __set_bit(cmd, okbits);
+ }
+
+ if (rw == READ)
+ target_okbits = filter->read_ok;
+ else
+ target_okbits = filter->write_ok;
+
+ memmove(target_okbits, okbits, sizeof(okbits));
+ return count;
+}
+
+static ssize_t rcf_readcmds_store(struct blk_scsi_cmd_filter *filter,
+ const char *page, size_t count)
+{
+ return rcf_cmds_store(filter, page, count, READ);
+}
+
+static ssize_t rcf_writecmds_store(struct blk_scsi_cmd_filter *filter,
+ const char *page, size_t count)
+{
+ return rcf_cmds_store(filter, page, count, WRITE);
+}
+
+struct rcf_sysfs_entry {
+ struct attribute attr;
+ ssize_t (*show)(struct blk_scsi_cmd_filter *, char *);
+ ssize_t (*store)(struct blk_scsi_cmd_filter *, const char *, size_t);
+};
+
+static struct rcf_sysfs_entry rcf_readcmds_entry = {
+ .attr = { .name = "read_table", .mode = S_IRUGO | S_IWUSR },
+ .show = rcf_readcmds_show,
+ .store = rcf_readcmds_store,
+};
+
+static struct rcf_sysfs_entry rcf_writecmds_entry = {
+ .attr = {.name = "write_table", .mode = S_IRUGO | S_IWUSR },
+ .show = rcf_writecmds_show,
+ .store = rcf_writecmds_store,
+};
+
+static struct attribute *default_attrs[] = {
+ &rcf_readcmds_entry.attr,
+ &rcf_writecmds_entry.attr,
+ NULL,
+};
+
+#define to_rcf(atr) container_of((atr), struct rcf_sysfs_entry, attr)
+
+static ssize_t
+rcf_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
+{
+ struct rcf_sysfs_entry *entry = to_rcf(attr);
+ struct blk_scsi_cmd_filter *filter;
+
+ filter = container_of(kobj, struct blk_scsi_cmd_filter, kobj);
+ if (entry->show)
+ return entry->show(filter, page);
+
+ return 0;
+}
+
+static ssize_t
+rcf_attr_store(struct kobject *kobj, struct attribute *attr,
+ const char *page, size_t length)
+{
+ struct rcf_sysfs_entry *entry = to_rcf(attr);
+ struct blk_scsi_cmd_filter *filter;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ if (!entry->store)
+ return -EINVAL;
+
+ filter = container_of(kobj, struct blk_scsi_cmd_filter, kobj);
+ return entry->store(filter, page, length);
+}
+
+static struct sysfs_ops rcf_sysfs_ops = {
+ .show = rcf_attr_show,
+ .store = rcf_attr_store,
+};
+
+static struct kobj_type rcf_ktype = {
+ .sysfs_ops = &rcf_sysfs_ops,
+ .default_attrs = default_attrs,
+};
+
+static void rcf_set_defaults(struct blk_scsi_cmd_filter *filter)
+{
+ /* Basic read-only commands */
+ __set_bit(TEST_UNIT_READY, filter->read_ok);
+ __set_bit(REQUEST_SENSE, filter->read_ok);
+ __set_bit(READ_6, filter->read_ok);
+ __set_bit(READ_10, filter->read_ok);
+ __set_bit(READ_12, filter->read_ok);
+ __set_bit(READ_16, filter->read_ok);
+ __set_bit(READ_BUFFER, filter->read_ok);
+ __set_bit(READ_DEFECT_DATA, filter->read_ok);
+ __set_bit(READ_LONG, filter->read_ok);
+ __set_bit(INQUIRY, filter->read_ok);
+ __set_bit(MODE_SENSE, filter->read_ok);
+ __set_bit(MODE_SENSE_10, filter->read_ok);
+ __set_bit(LOG_SENSE, filter->read_ok);
+ __set_bit(START_STOP, filter->read_ok);
+ __set_bit(GPCMD_VERIFY_10, filter->read_ok);
+ __set_bit(VERIFY_16, filter->read_ok);
+ __set_bit(GPCMD_READ_BUFFER_CAPACITY, filter->read_ok);
+
+ /* Audio CD commands */
+ __set_bit(GPCMD_PLAY_CD, filter->read_ok);
+ __set_bit(GPCMD_PLAY_AUDIO_10, filter->read_ok);
+ __set_bit(GPCMD_PLAY_AUDIO_MSF, filter->read_ok);
+ __set_bit(GPCMD_PLAY_AUDIO_TI, filter->read_ok);
+ __set_bit(GPCMD_PAUSE_RESUME, filter->read_ok);
+
+ /* CD/DVD data reading */
+ __set_bit(GPCMD_READ_CD, filter->read_ok);
+ __set_bit(GPCMD_READ_CD_MSF, filter->read_ok);
+ __set_bit(GPCMD_READ_DISC_INFO, filter->read_ok);
+ __set_bit(GPCMD_READ_CDVD_CAPACITY, filter->read_ok);
+ __set_bit(GPCMD_READ_DVD_STRUCTURE, filter->read_ok);
+ __set_bit(GPCMD_READ_HEADER, filter->read_ok);
+ __set_bit(GPCMD_READ_TRACK_RZONE_INFO, filter->read_ok);
+ __set_bit(GPCMD_READ_SUBCHANNEL, filter->read_ok);
+ __set_bit(GPCMD_READ_TOC_PMA_ATIP, filter->read_ok);
+ __set_bit(GPCMD_REPORT_KEY, filter->read_ok);
+ __set_bit(GPCMD_SCAN, filter->read_ok);
+ __set_bit(GPCMD_GET_CONFIGURATION, filter->read_ok);
+ __set_bit(GPCMD_READ_FORMAT_CAPACITIES, filter->read_ok);
+ __set_bit(GPCMD_GET_EVENT_STATUS_NOTIFICATION, filter->read_ok);
+ __set_bit(GPCMD_GET_PERFORMANCE, filter->read_ok);
+ __set_bit(GPCMD_SEEK, filter->read_ok);
+ __set_bit(GPCMD_STOP_PLAY_SCAN, filter->read_ok);
+
+ /* Basic writing commands */
+ __set_bit(WRITE_6, filter->write_ok);
+ __set_bit(WRITE_10, filter->write_ok);
+ __set_bit(WRITE_VERIFY, filter->write_ok);
+ __set_bit(WRITE_12, filter->write_ok);
+ __set_bit(WRITE_VERIFY_12, filter->write_ok);
+ __set_bit(WRITE_16, filter->write_ok);
+ __set_bit(WRITE_LONG, filter->write_ok);
+ __set_bit(WRITE_LONG_2, filter->write_ok);
+ __set_bit(ERASE, filter->write_ok);
+ __set_bit(GPCMD_MODE_SELECT_10, filter->write_ok);
+ __set_bit(MODE_SELECT, filter->write_ok);
+ __set_bit(LOG_SELECT, filter->write_ok);
+ __set_bit(GPCMD_BLANK, filter->write_ok);
+ __set_bit(GPCMD_CLOSE_TRACK, filter->write_ok);
+ __set_bit(GPCMD_FLUSH_CACHE, filter->write_ok);
+ __set_bit(GPCMD_FORMAT_UNIT, filter->write_ok);
+ __set_bit(GPCMD_REPAIR_RZONE_TRACK, filter->write_ok);
+ __set_bit(GPCMD_RESERVE_RZONE_TRACK, filter->write_ok);
+ __set_bit(GPCMD_SEND_DVD_STRUCTURE, filter->write_ok);
+ __set_bit(GPCMD_SEND_EVENT, filter->write_ok);
+ __set_bit(GPCMD_SEND_KEY, filter->write_ok);
+ __set_bit(GPCMD_SEND_OPC, filter->write_ok);
+ __set_bit(GPCMD_SEND_CUE_SHEET, filter->write_ok);
+ __set_bit(GPCMD_SET_SPEED, filter->write_ok);
+ __set_bit(GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL, filter->write_ok);
+ __set_bit(GPCMD_LOAD_UNLOAD, filter->write_ok);
+ __set_bit(GPCMD_SET_STREAMING, filter->write_ok);
+}
+
+int blk_register_filter(struct gendisk *disk)
+{
+ int ret;
+ struct blk_scsi_cmd_filter *filter = &disk->cmd_filter;
+ struct kobject *parent = kobject_get(disk->holder_dir->parent);
+
+ if (!parent)
+ return -ENODEV;
+
+ ret = kobject_init_and_add(&filter->kobj, &rcf_ktype, parent,
+ "%s", "cmd_filter");
+
+ if (ret < 0)
+ return ret;
+
+ rcf_set_defaults(filter);
+ return 0;
+}
+
+void blk_unregister_filter(struct gendisk *disk)
+{
+ struct blk_scsi_cmd_filter *filter = &disk->cmd_filter;
+
+ kobject_put(&filter->kobj);
+ kobject_put(disk->holder_dir->parent);
+}
+