CVE-2023-53665

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

md: don't dereference mddev after export_rdev()

Except for initial reference, mddev->kobject is referenced by

rdev->kobject, and if the last rdev is freed, there is no guarantee that

mddev is still valid. Hence mddev should not be used anymore after

export_rdev().

This problem can be triggered by following test for mdadm at very

low rate:

New file: mdadm/tests/23rdev-lifetime

devname=${dev0##*/}

devt=`cat /sys/block/$devname/dev`

pid=""

runtime=2

clean_up_test() {

pill -9 $pid

echo clear > /sys/block/md0/md/array_state

}

trap 'clean_up_test' EXIT

add_by_sysfs() {

while true; do

echo $devt > /sys/block/md0/md/new_dev

done

}

remove_by_sysfs(){

while true; do

echo remove > /sys/block/md0/md/dev-${devname}/state

done

}

echo md0 > /sys/module/md_mod/parameters/new_array || die "create md0 failed"

add_by_sysfs &

pid="$pid $!"

remove_b

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References