Many blkdev ioctls require CAP_SYS_ADMIN, preventing them from
being used on block devices owned by unpriveleged user
namespaces. Change this to requiring only CAP_SYS_ADMIN within
the namespace which owns the device. Most devices are owned by
init_user_ns, and in that case this check is equivalent.
Signed-off-by: Seth Forshee <seth.fors...@canonical.com>
---
block/compat_ioctl.c | 3 ++-
block/ioctl.c | 16 ++++++++--------
2 files changed, 10 insertions(+), 9 deletions(-)
diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c
index fbd5a67cb773..b16745d14ac2 100644
--- a/block/compat_ioctl.c
+++ b/block/compat_ioctl.c
@@ -10,6 +10,7 @@
#include <linux/syscalls.h>
#include <linux/types.h>
#include <linux/uaccess.h>
+#include <linux/user_namespace.h>
static int compat_put_ushort(unsigned long arg, unsigned short val)
{
@@ -725,7 +726,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd,
unsigned long arg)
!blk_queue_nonrot(bdev_get_queue(bdev)));
case BLKRASET: /* compatible, but no compat_ptr (!) */
case BLKFRASET:
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(disk_to_dev(disk)->ns, CAP_SYS_ADMIN))
return -EACCES;
bdi = blk_get_backing_dev_info(bdev);
if (bdi == NULL)
diff --git a/block/ioctl.c b/block/ioctl.c
index 7d5c3b20af45..45bb28d59b56 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -7,12 +7,13 @@
#include <linux/backing-dev.h>
#include <linux/fs.h>
#include <linux/blktrace_api.h>
+#include <linux/user_namespace.h>
#include <asm/uaccess.h>
static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg
__user *arg)
{
struct block_device *bdevp;
- struct gendisk *disk;
+ struct gendisk *disk = bdev->bd_disk;
struct hd_struct *part, *lpart;
struct blkpg_ioctl_arg a;
struct blkpg_partition p;
@@ -20,13 +21,12 @@ static int blkpg_ioctl(struct block_device *bdev, struct
blkpg_ioctl_arg __user
long long start, length;
int partno;
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(disk_to_dev(disk)->ns, CAP_SYS_ADMIN))
return -EACCES;
if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
return -EFAULT;
if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
return -EFAULT;
- disk = bdev->bd_disk;
if (bdev != bdev->bd_contains)
return -EINVAL;
partno = p.pno;
@@ -157,7 +157,7 @@ static int blkdev_reread_part(struct block_device *bdev)
if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
return -EINVAL;
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(disk_to_dev(disk)->ns, CAP_SYS_ADMIN))
return -EACCES;
if (!mutex_trylock(&bdev->bd_mutex))
return -EBUSY;
@@ -281,7 +281,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode,
unsigned cmd,
switch(cmd) {
case BLKFLSBUF:
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(disk_to_dev(disk)->ns, CAP_SYS_ADMIN))
return -EACCES;
ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
@@ -296,7 +296,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode,
unsigned cmd,
ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
if (!is_unrecognized_ioctl(ret))
return ret;
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(disk_to_dev(disk)->ns, CAP_SYS_ADMIN))
return -EACCES;
if (get_user(n, (int __user *)(arg)))
return -EFAULT;
@@ -380,7 +380,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode,
unsigned cmd,
return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
case BLKRASET:
case BLKFRASET:
- if(!capable(CAP_SYS_ADMIN))
+ if(!ns_capable(disk_to_dev(disk)->ns, CAP_SYS_ADMIN))
return -EACCES;
bdi = blk_get_backing_dev_info(bdev);
if (bdi == NULL)
@@ -389,7 +389,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode,
unsigned cmd,
return 0;
case BLKBSZSET:
/* set the logical block size */
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(disk_to_dev(disk)->ns, CAP_SYS_ADMIN))
return -EACCES;
if (!arg)
return -EINVAL;
--
1.9.1
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