[SRU][Focal][PATCH 0/1] CVE-2023-2269

[Yuxuan Luo]

[Impact]
A denial of service problem was found, due to a possible recursive
locking scenario, resulting in a deadlock in table_clear in
drivers/md/dm-ioctl.c in the Linux Kernel Device Mapper-Multipathing
sub-component.

[Backport]
Clean cherry pick.

[Test]
Tested against the following script to verify that the verity
functionality is not broken and ioctl is still working as intended:

```bash
IMG_SIZE=50M
VERITY_DEV=''
HASH_DEV=''
TARGET_DIR=/mnt/dmtest
ROOT_HASH=''
PARAM=''

# Prepare two loop devices
truncate -s $IMG_SIZE verity.img hash.img

losetup -f verity.img
VERITY_DEV=$(sudo losetup -j verity.img | awk -F: '{print $1}')
losetup -f hash.img
HASH_DEV=$(sudo losetup -j hash.img | awk -F: '{print $1}')

# Create the verity device
ROOT_HASH=`veritysetup format $VERITY_DEV $HASH_DEV
          | tail -n 1
          | awk '{print $3}'`
veritysetup create vroot $VERITY_DEV $HASH_DEV $ROOT_HASH

# Reload the verity device
PARAM=$(sudo dmsetup table | awk '{ret = $2 " " $3; print ret}')
dmsetup suspend vroot

# Expect this command to fail
dmsetup reload vroot --table "$PARAM linear $VERITY_DEV 0"
```

[Potential Regression]
Expect low regression potential.

Mike Snitzer (1):
  dm ioctl: fix nested locking in table_clear() to remove deadlock
    concern

 drivers/md/dm-ioctl.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

-- 
2.34.1