linux/block/ioctl.c
Christoph Hellwig 719c15a75e blk-lib: check for kill signal in ioctl BLKDISCARD
Discards can access a significant capacity and take longer than the user
expected.  A user may change their mind about wanting to run that command
and attempt to kill the process and do something else with their device.
But since the task is uninterruptable, they have to wait for it to
finish, which could be many hours.

Open code blkdev_issue_discard in the BLKDISCARD ioctl handler and check
for a fatal signal at each iteration so the user doesn't have to wait
for their regretted operation to complete naturally.

Heavily based on an earlier patch from Keith Busch.

Reported-by: Conrad Meyer <conradmeyer@meta.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240506042027.2289826-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-05-07 07:29:42 -06:00

731 lines
18 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/capability.h>
#include <linux/compat.h>
#include <linux/blkdev.h>
#include <linux/export.h>
#include <linux/gfp.h>
#include <linux/blkpg.h>
#include <linux/hdreg.h>
#include <linux/backing-dev.h>
#include <linux/fs.h>
#include <linux/blktrace_api.h>
#include <linux/pr.h>
#include <linux/uaccess.h>
#include "blk.h"
static int blkpg_do_ioctl(struct block_device *bdev,
struct blkpg_partition __user *upart, int op)
{
struct gendisk *disk = bdev->bd_disk;
struct blkpg_partition p;
sector_t start, length, capacity, end;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (copy_from_user(&p, upart, sizeof(struct blkpg_partition)))
return -EFAULT;
if (bdev_is_partition(bdev))
return -EINVAL;
if (p.pno <= 0)
return -EINVAL;
if (op == BLKPG_DEL_PARTITION)
return bdev_del_partition(disk, p.pno);
if (p.start < 0 || p.length <= 0 || LLONG_MAX - p.length < p.start)
return -EINVAL;
/* Check that the partition is aligned to the block size */
if (!IS_ALIGNED(p.start | p.length, bdev_logical_block_size(bdev)))
return -EINVAL;
start = p.start >> SECTOR_SHIFT;
length = p.length >> SECTOR_SHIFT;
capacity = get_capacity(disk);
if (check_add_overflow(start, length, &end))
return -EINVAL;
if (start >= capacity || end > capacity)
return -EINVAL;
switch (op) {
case BLKPG_ADD_PARTITION:
return bdev_add_partition(disk, p.pno, start, length);
case BLKPG_RESIZE_PARTITION:
return bdev_resize_partition(disk, p.pno, start, length);
default:
return -EINVAL;
}
}
static int blkpg_ioctl(struct block_device *bdev,
struct blkpg_ioctl_arg __user *arg)
{
struct blkpg_partition __user *udata;
int op;
if (get_user(op, &arg->op) || get_user(udata, &arg->data))
return -EFAULT;
return blkpg_do_ioctl(bdev, udata, op);
}
#ifdef CONFIG_COMPAT
struct compat_blkpg_ioctl_arg {
compat_int_t op;
compat_int_t flags;
compat_int_t datalen;
compat_caddr_t data;
};
static int compat_blkpg_ioctl(struct block_device *bdev,
struct compat_blkpg_ioctl_arg __user *arg)
{
compat_caddr_t udata;
int op;
if (get_user(op, &arg->op) || get_user(udata, &arg->data))
return -EFAULT;
return blkpg_do_ioctl(bdev, compat_ptr(udata), op);
}
#endif
static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode,
unsigned long arg)
{
unsigned int bs_mask = bdev_logical_block_size(bdev) - 1;
struct inode *inode = bdev->bd_inode;
uint64_t range[2], start, len;
struct bio *prev = NULL, *bio;
sector_t sector, nr_sects;
struct blk_plug plug;
int err;
if (!(mode & BLK_OPEN_WRITE))
return -EBADF;
if (!bdev_max_discard_sectors(bdev))
return -EOPNOTSUPP;
if (bdev_read_only(bdev))
return -EPERM;
if (copy_from_user(range, (void __user *)arg, sizeof(range)))
return -EFAULT;
start = range[0];
len = range[1];
if (!len)
return -EINVAL;
if ((start | len) & bs_mask)
return -EINVAL;
if (start + len > bdev_nr_bytes(bdev))
return -EINVAL;
filemap_invalidate_lock(inode->i_mapping);
err = truncate_bdev_range(bdev, mode, start, start + len - 1);
if (err)
goto fail;
sector = start >> SECTOR_SHIFT;
nr_sects = len >> SECTOR_SHIFT;
blk_start_plug(&plug);
while (1) {
if (fatal_signal_pending(current)) {
if (prev)
bio_await_chain(prev);
err = -EINTR;
goto out_unplug;
}
bio = blk_alloc_discard_bio(bdev, &sector, &nr_sects,
GFP_KERNEL);
if (!bio)
break;
prev = bio_chain_and_submit(prev, bio);
}
if (prev) {
err = submit_bio_wait(prev);
if (err == -EOPNOTSUPP)
err = 0;
bio_put(prev);
}
out_unplug:
blk_finish_plug(&plug);
fail:
filemap_invalidate_unlock(inode->i_mapping);
return err;
}
static int blk_ioctl_secure_erase(struct block_device *bdev, blk_mode_t mode,
void __user *argp)
{
uint64_t start, len;
uint64_t range[2];
int err;
if (!(mode & BLK_OPEN_WRITE))
return -EBADF;
if (!bdev_max_secure_erase_sectors(bdev))
return -EOPNOTSUPP;
if (copy_from_user(range, argp, sizeof(range)))
return -EFAULT;
start = range[0];
len = range[1];
if ((start & 511) || (len & 511))
return -EINVAL;
if (start + len > bdev_nr_bytes(bdev))
return -EINVAL;
filemap_invalidate_lock(bdev->bd_inode->i_mapping);
err = truncate_bdev_range(bdev, mode, start, start + len - 1);
if (!err)
err = blkdev_issue_secure_erase(bdev, start >> 9, len >> 9,
GFP_KERNEL);
filemap_invalidate_unlock(bdev->bd_inode->i_mapping);
return err;
}
static int blk_ioctl_zeroout(struct block_device *bdev, blk_mode_t mode,
unsigned long arg)
{
uint64_t range[2];
uint64_t start, end, len;
struct inode *inode = bdev->bd_inode;
int err;
if (!(mode & BLK_OPEN_WRITE))
return -EBADF;
if (copy_from_user(range, (void __user *)arg, sizeof(range)))
return -EFAULT;
start = range[0];
len = range[1];
end = start + len - 1;
if (start & 511)
return -EINVAL;
if (len & 511)
return -EINVAL;
if (end >= (uint64_t)bdev_nr_bytes(bdev))
return -EINVAL;
if (end < start)
return -EINVAL;
/* Invalidate the page cache, including dirty pages */
filemap_invalidate_lock(inode->i_mapping);
err = truncate_bdev_range(bdev, mode, start, end);
if (err)
goto fail;
err = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL,
BLKDEV_ZERO_NOUNMAP);
fail:
filemap_invalidate_unlock(inode->i_mapping);
return err;
}
static int put_ushort(unsigned short __user *argp, unsigned short val)
{
return put_user(val, argp);
}
static int put_int(int __user *argp, int val)
{
return put_user(val, argp);
}
static int put_uint(unsigned int __user *argp, unsigned int val)
{
return put_user(val, argp);
}
static int put_long(long __user *argp, long val)
{
return put_user(val, argp);
}
static int put_ulong(unsigned long __user *argp, unsigned long val)
{
return put_user(val, argp);
}
static int put_u64(u64 __user *argp, u64 val)
{
return put_user(val, argp);
}
#ifdef CONFIG_COMPAT
static int compat_put_long(compat_long_t __user *argp, long val)
{
return put_user(val, argp);
}
static int compat_put_ulong(compat_ulong_t __user *argp, compat_ulong_t val)
{
return put_user(val, argp);
}
#endif
#ifdef CONFIG_COMPAT
/*
* This is the equivalent of compat_ptr_ioctl(), to be used by block
* drivers that implement only commands that are completely compatible
* between 32-bit and 64-bit user space
*/
int blkdev_compat_ptr_ioctl(struct block_device *bdev, blk_mode_t mode,
unsigned cmd, unsigned long arg)
{
struct gendisk *disk = bdev->bd_disk;
if (disk->fops->ioctl)
return disk->fops->ioctl(bdev, mode, cmd,
(unsigned long)compat_ptr(arg));
return -ENOIOCTLCMD;
}
EXPORT_SYMBOL(blkdev_compat_ptr_ioctl);
#endif
static bool blkdev_pr_allowed(struct block_device *bdev, blk_mode_t mode)
{
/* no sense to make reservations for partitions */
if (bdev_is_partition(bdev))
return false;
if (capable(CAP_SYS_ADMIN))
return true;
/*
* Only allow unprivileged reservations if the file descriptor is open
* for writing.
*/
return mode & BLK_OPEN_WRITE;
}
static int blkdev_pr_register(struct block_device *bdev, blk_mode_t mode,
struct pr_registration __user *arg)
{
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
struct pr_registration reg;
if (!blkdev_pr_allowed(bdev, mode))
return -EPERM;
if (!ops || !ops->pr_register)
return -EOPNOTSUPP;
if (copy_from_user(&reg, arg, sizeof(reg)))
return -EFAULT;
if (reg.flags & ~PR_FL_IGNORE_KEY)
return -EOPNOTSUPP;
return ops->pr_register(bdev, reg.old_key, reg.new_key, reg.flags);
}
static int blkdev_pr_reserve(struct block_device *bdev, blk_mode_t mode,
struct pr_reservation __user *arg)
{
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
struct pr_reservation rsv;
if (!blkdev_pr_allowed(bdev, mode))
return -EPERM;
if (!ops || !ops->pr_reserve)
return -EOPNOTSUPP;
if (copy_from_user(&rsv, arg, sizeof(rsv)))
return -EFAULT;
if (rsv.flags & ~PR_FL_IGNORE_KEY)
return -EOPNOTSUPP;
return ops->pr_reserve(bdev, rsv.key, rsv.type, rsv.flags);
}
static int blkdev_pr_release(struct block_device *bdev, blk_mode_t mode,
struct pr_reservation __user *arg)
{
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
struct pr_reservation rsv;
if (!blkdev_pr_allowed(bdev, mode))
return -EPERM;
if (!ops || !ops->pr_release)
return -EOPNOTSUPP;
if (copy_from_user(&rsv, arg, sizeof(rsv)))
return -EFAULT;
if (rsv.flags)
return -EOPNOTSUPP;
return ops->pr_release(bdev, rsv.key, rsv.type);
}
static int blkdev_pr_preempt(struct block_device *bdev, blk_mode_t mode,
struct pr_preempt __user *arg, bool abort)
{
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
struct pr_preempt p;
if (!blkdev_pr_allowed(bdev, mode))
return -EPERM;
if (!ops || !ops->pr_preempt)
return -EOPNOTSUPP;
if (copy_from_user(&p, arg, sizeof(p)))
return -EFAULT;
if (p.flags)
return -EOPNOTSUPP;
return ops->pr_preempt(bdev, p.old_key, p.new_key, p.type, abort);
}
static int blkdev_pr_clear(struct block_device *bdev, blk_mode_t mode,
struct pr_clear __user *arg)
{
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
struct pr_clear c;
if (!blkdev_pr_allowed(bdev, mode))
return -EPERM;
if (!ops || !ops->pr_clear)
return -EOPNOTSUPP;
if (copy_from_user(&c, arg, sizeof(c)))
return -EFAULT;
if (c.flags)
return -EOPNOTSUPP;
return ops->pr_clear(bdev, c.key);
}
static int blkdev_flushbuf(struct block_device *bdev, unsigned cmd,
unsigned long arg)
{
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
mutex_lock(&bdev->bd_holder_lock);
if (bdev->bd_holder_ops && bdev->bd_holder_ops->sync)
bdev->bd_holder_ops->sync(bdev);
else {
mutex_unlock(&bdev->bd_holder_lock);
sync_blockdev(bdev);
}
invalidate_bdev(bdev);
return 0;
}
static int blkdev_roset(struct block_device *bdev, unsigned cmd,
unsigned long arg)
{
int ret, n;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (get_user(n, (int __user *)arg))
return -EFAULT;
if (bdev->bd_disk->fops->set_read_only) {
ret = bdev->bd_disk->fops->set_read_only(bdev, n);
if (ret)
return ret;
}
bdev->bd_read_only = n;
return 0;
}
static int blkdev_getgeo(struct block_device *bdev,
struct hd_geometry __user *argp)
{
struct gendisk *disk = bdev->bd_disk;
struct hd_geometry geo;
int ret;
if (!argp)
return -EINVAL;
if (!disk->fops->getgeo)
return -ENOTTY;
/*
* We need to set the startsect first, the driver may
* want to override it.
*/
memset(&geo, 0, sizeof(geo));
geo.start = get_start_sect(bdev);
ret = disk->fops->getgeo(bdev, &geo);
if (ret)
return ret;
if (copy_to_user(argp, &geo, sizeof(geo)))
return -EFAULT;
return 0;
}
#ifdef CONFIG_COMPAT
struct compat_hd_geometry {
unsigned char heads;
unsigned char sectors;
unsigned short cylinders;
u32 start;
};
static int compat_hdio_getgeo(struct block_device *bdev,
struct compat_hd_geometry __user *ugeo)
{
struct gendisk *disk = bdev->bd_disk;
struct hd_geometry geo;
int ret;
if (!ugeo)
return -EINVAL;
if (!disk->fops->getgeo)
return -ENOTTY;
memset(&geo, 0, sizeof(geo));
/*
* We need to set the startsect first, the driver may
* want to override it.
*/
geo.start = get_start_sect(bdev);
ret = disk->fops->getgeo(bdev, &geo);
if (ret)
return ret;
ret = copy_to_user(ugeo, &geo, 4);
ret |= put_user(geo.start, &ugeo->start);
if (ret)
ret = -EFAULT;
return ret;
}
#endif
/* set the logical block size */
static int blkdev_bszset(struct block_device *bdev, blk_mode_t mode,
int __user *argp)
{
int ret, n;
struct file *file;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (!argp)
return -EINVAL;
if (get_user(n, argp))
return -EFAULT;
if (mode & BLK_OPEN_EXCL)
return set_blocksize(bdev, n);
file = bdev_file_open_by_dev(bdev->bd_dev, mode, &bdev, NULL);
if (IS_ERR(file))
return -EBUSY;
ret = set_blocksize(bdev, n);
fput(file);
return ret;
}
/*
* Common commands that are handled the same way on native and compat
* user space. Note the separate arg/argp parameters that are needed
* to deal with the compat_ptr() conversion.
*/
static int blkdev_common_ioctl(struct block_device *bdev, blk_mode_t mode,
unsigned int cmd, unsigned long arg,
void __user *argp)
{
unsigned int max_sectors;
switch (cmd) {
case BLKFLSBUF:
return blkdev_flushbuf(bdev, cmd, arg);
case BLKROSET:
return blkdev_roset(bdev, cmd, arg);
case BLKDISCARD:
return blk_ioctl_discard(bdev, mode, arg);
case BLKSECDISCARD:
return blk_ioctl_secure_erase(bdev, mode, argp);
case BLKZEROOUT:
return blk_ioctl_zeroout(bdev, mode, arg);
case BLKGETDISKSEQ:
return put_u64(argp, bdev->bd_disk->diskseq);
case BLKREPORTZONE:
return blkdev_report_zones_ioctl(bdev, cmd, arg);
case BLKRESETZONE:
case BLKOPENZONE:
case BLKCLOSEZONE:
case BLKFINISHZONE:
return blkdev_zone_mgmt_ioctl(bdev, mode, cmd, arg);
case BLKGETZONESZ:
return put_uint(argp, bdev_zone_sectors(bdev));
case BLKGETNRZONES:
return put_uint(argp, bdev_nr_zones(bdev));
case BLKROGET:
return put_int(argp, bdev_read_only(bdev) != 0);
case BLKSSZGET: /* get block device logical block size */
return put_int(argp, bdev_logical_block_size(bdev));
case BLKPBSZGET: /* get block device physical block size */
return put_uint(argp, bdev_physical_block_size(bdev));
case BLKIOMIN:
return put_uint(argp, bdev_io_min(bdev));
case BLKIOOPT:
return put_uint(argp, bdev_io_opt(bdev));
case BLKALIGNOFF:
return put_int(argp, bdev_alignment_offset(bdev));
case BLKDISCARDZEROES:
return put_uint(argp, 0);
case BLKSECTGET:
max_sectors = min_t(unsigned int, USHRT_MAX,
queue_max_sectors(bdev_get_queue(bdev)));
return put_ushort(argp, max_sectors);
case BLKROTATIONAL:
return put_ushort(argp, !bdev_nonrot(bdev));
case BLKRASET:
case BLKFRASET:
if(!capable(CAP_SYS_ADMIN))
return -EACCES;
bdev->bd_disk->bdi->ra_pages = (arg * 512) / PAGE_SIZE;
return 0;
case BLKRRPART:
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (bdev_is_partition(bdev))
return -EINVAL;
return disk_scan_partitions(bdev->bd_disk, mode);
case BLKTRACESTART:
case BLKTRACESTOP:
case BLKTRACETEARDOWN:
return blk_trace_ioctl(bdev, cmd, argp);
case IOC_PR_REGISTER:
return blkdev_pr_register(bdev, mode, argp);
case IOC_PR_RESERVE:
return blkdev_pr_reserve(bdev, mode, argp);
case IOC_PR_RELEASE:
return blkdev_pr_release(bdev, mode, argp);
case IOC_PR_PREEMPT:
return blkdev_pr_preempt(bdev, mode, argp, false);
case IOC_PR_PREEMPT_ABORT:
return blkdev_pr_preempt(bdev, mode, argp, true);
case IOC_PR_CLEAR:
return blkdev_pr_clear(bdev, mode, argp);
default:
return -ENOIOCTLCMD;
}
}
/*
* Always keep this in sync with compat_blkdev_ioctl()
* to handle all incompatible commands in both functions.
*
* New commands must be compatible and go into blkdev_common_ioctl
*/
long blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
{
struct block_device *bdev = I_BDEV(file->f_mapping->host);
void __user *argp = (void __user *)arg;
blk_mode_t mode = file_to_blk_mode(file);
int ret;
switch (cmd) {
/* These need separate implementations for the data structure */
case HDIO_GETGEO:
return blkdev_getgeo(bdev, argp);
case BLKPG:
return blkpg_ioctl(bdev, argp);
/* Compat mode returns 32-bit data instead of 'long' */
case BLKRAGET:
case BLKFRAGET:
if (!argp)
return -EINVAL;
return put_long(argp,
(bdev->bd_disk->bdi->ra_pages * PAGE_SIZE) / 512);
case BLKGETSIZE:
if (bdev_nr_sectors(bdev) > ~0UL)
return -EFBIG;
return put_ulong(argp, bdev_nr_sectors(bdev));
/* The data is compatible, but the command number is different */
case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
return put_int(argp, block_size(bdev));
case BLKBSZSET:
return blkdev_bszset(bdev, mode, argp);
case BLKGETSIZE64:
return put_u64(argp, bdev_nr_bytes(bdev));
/* Incompatible alignment on i386 */
case BLKTRACESETUP:
return blk_trace_ioctl(bdev, cmd, argp);
default:
break;
}
ret = blkdev_common_ioctl(bdev, mode, cmd, arg, argp);
if (ret != -ENOIOCTLCMD)
return ret;
if (!bdev->bd_disk->fops->ioctl)
return -ENOTTY;
return bdev->bd_disk->fops->ioctl(bdev, mode, cmd, arg);
}
#ifdef CONFIG_COMPAT
#define BLKBSZGET_32 _IOR(0x12, 112, int)
#define BLKBSZSET_32 _IOW(0x12, 113, int)
#define BLKGETSIZE64_32 _IOR(0x12, 114, int)
/* Most of the generic ioctls are handled in the normal fallback path.
This assumes the blkdev's low level compat_ioctl always returns
ENOIOCTLCMD for unknown ioctls. */
long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
{
int ret;
void __user *argp = compat_ptr(arg);
struct block_device *bdev = I_BDEV(file->f_mapping->host);
struct gendisk *disk = bdev->bd_disk;
blk_mode_t mode = file_to_blk_mode(file);
switch (cmd) {
/* These need separate implementations for the data structure */
case HDIO_GETGEO:
return compat_hdio_getgeo(bdev, argp);
case BLKPG:
return compat_blkpg_ioctl(bdev, argp);
/* Compat mode returns 32-bit data instead of 'long' */
case BLKRAGET:
case BLKFRAGET:
if (!argp)
return -EINVAL;
return compat_put_long(argp,
(bdev->bd_disk->bdi->ra_pages * PAGE_SIZE) / 512);
case BLKGETSIZE:
if (bdev_nr_sectors(bdev) > ~(compat_ulong_t)0)
return -EFBIG;
return compat_put_ulong(argp, bdev_nr_sectors(bdev));
/* The data is compatible, but the command number is different */
case BLKBSZGET_32: /* get the logical block size (cf. BLKSSZGET) */
return put_int(argp, bdev_logical_block_size(bdev));
case BLKBSZSET_32:
return blkdev_bszset(bdev, mode, argp);
case BLKGETSIZE64_32:
return put_u64(argp, bdev_nr_bytes(bdev));
/* Incompatible alignment on i386 */
case BLKTRACESETUP32:
return blk_trace_ioctl(bdev, cmd, argp);
default:
break;
}
ret = blkdev_common_ioctl(bdev, mode, cmd, arg, argp);
if (ret == -ENOIOCTLCMD && disk->fops->compat_ioctl)
ret = disk->fops->compat_ioctl(bdev, mode, cmd, arg);
return ret;
}
#endif