diff options
Diffstat (limited to 'block/cmd-filter.c')
| -rw-r--r-- | block/cmd-filter.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/block/cmd-filter.c b/block/cmd-filter.c new file mode 100644 index 0000000..504b275 --- /dev/null +++ b/block/cmd-filter.c @@ -0,0 +1,232 @@ +/* + * 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/capability.h> +#include <linux/bitops.h> + +#include <scsi/scsi.h> +#include <linux/cdrom.h> + +int blk_verify_command(struct blk_cmd_filter *filter, + unsigned char *cmd, fmode_t has_write_perm) +{ + /* 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) && has_write_perm) + return 0; + + return -EPERM; +} +EXPORT_SYMBOL(blk_verify_command); + +#if 0 +/* and now, the sysfs stuff */ +static ssize_t rcf_cmds_show(struct blk_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)) { + npage += sprintf(npage, "0x%02x", i); + 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_cmd_filter *filter, char *page) +{ + return rcf_cmds_show(filter, page, READ); +} + +static ssize_t rcf_writecmds_show(struct blk_cmd_filter *filter, + char *page) +{ + return rcf_cmds_show(filter, page, WRITE); +} + +static ssize_t rcf_cmds_store(struct blk_cmd_filter *filter, + const char *page, size_t count, int rw) +{ + unsigned long okbits[BLK_SCSI_CMD_PER_LONG], *target_okbits; + int cmd, set; + char *p, *status; + + if (rw == READ) { + memcpy(&okbits, filter->read_ok, sizeof(okbits)); + target_okbits = filter->read_ok; + } else { + memcpy(&okbits, filter->write_ok, sizeof(okbits)); + target_okbits = filter->write_ok; + } + + while ((p = strsep((char **)&page, " ")) != NULL) { + set = 1; + + if (p[0] == '+') { + p++; + } else if (p[0] == '-') { + set = 0; + p++; + } + + cmd = simple_strtol(p, &status, 16); + + /* either of these cases means invalid input, so do nothing. */ + if ((status == p) || cmd >= BLK_SCSI_MAX_CMDS) + return -EINVAL; + + if (set) + __set_bit(cmd, okbits); + else + __clear_bit(cmd, okbits); + } + + memcpy(target_okbits, okbits, sizeof(okbits)); + return count; +} + +static ssize_t rcf_readcmds_store(struct blk_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_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_cmd_filter *, char *); + ssize_t (*store)(struct blk_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_cmd_filter *filter; + + filter = container_of(kobj, struct blk_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_cmd_filter *filter; + + if (!capable(CAP_SYS_RAWIO)) + return -EPERM; + + if (!entry->store) + return -EINVAL; + + filter = container_of(kobj, struct blk_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, +}; + +int blk_register_filter(struct gendisk *disk) +{ + int ret; + struct blk_cmd_filter *filter = &disk->queue->cmd_filter; + + ret = kobject_init_and_add(&filter->kobj, &rcf_ktype, + &disk_to_dev(disk)->kobj, + "%s", "cmd_filter"); + if (ret < 0) + return ret; + + return 0; +} +EXPORT_SYMBOL(blk_register_filter); + +void blk_unregister_filter(struct gendisk *disk) +{ + struct blk_cmd_filter *filter = &disk->queue->cmd_filter; + + kobject_put(&filter->kobj); +} +EXPORT_SYMBOL(blk_unregister_filter); +#endif |
