CVE-2023-53791

published 2025-12-09

CVE-2023-53791: In the Linux kernel, the following vulnerability has been resolved: md: fix warning for holder mismatch from export_rdev() Commit a1d767191096 ("md: use…

Priority P4 20 low 3.7

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

md: fix warning for holder mismatch from export_rdev()

Commit a1d767191096 ("md: use mddev->external to select holder in
export_rdev()") fix the problem that 'claim_rdev' is used for
blkdev_get_by_dev() while 'rdev' is used for blkdev_put().

However, if mddev->external is changed from 0 to 1, then 'rdev' is used
for blkdev_get_by_dev() while 'claim_rdev' is used for blkdev_put(). And
this problem can be reporduced reliably by following:

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_by_sysfs &
pid="$pid $!"

sleep $runtime
exit 0

Test cmd:

./test --save-logs --logdir=/tmp/ --keep-going --dev=loop --tests=23rdev-lifetime

Test result:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 960 at block/bdev.c:618 blkdev_put+0x27c/0x330
Modules linked in: multipath md_mod loop
CPU: 0 PID: 960 Comm: test Not tainted 6.5.0-rc2-00121-g01e55c376936-dirty #50
RIP: 0010:blkdev_put+0x27c/0x330
Call Trace:

export_rdev.isra.23+0x50/0xa0 [md_mod]
mddev_unlock+0x19d/0x300 [md_mod]
rdev_attr_store+0xec/0x190 [md_mod]
sysfs_kf_write+0x52/0x70
kernfs_fop_write_iter+0x19a/0x2a0
vfs_write+0x3b5/0x770
ksys_write+0x74/0x150
__x64_sys_write+0x22/0x30
do_syscall_64+0x40/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fix the problem by recording if 'rdev' is used as holder.

Affected

7 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 6.5.6-1 (forky)	linux 6.5.6-1 (forky)
linux	linux	—	—
linux	linux	>= a1d7671910965ca9f8f0377e7e3bfd1179fba4d8 < 99fcd427178d0f58f5520f8f01df727f8eaeb2c7	99fcd427178d0f58f5520f8f01df727f8eaeb2c7
linux	linux	>= a1d7671910965ca9f8f0377e7e3bfd1179fba4d8 < 99892147f028d711f9d40fefad4f33632593864c	99892147f028d711f9d40fefad4f33632593864c
linux	linux_kernel	>= 0 < 6.5.6-1	6.5.6-1
linux	linux_kernel	>= 0 < 6.5.6-1	6.5.6-1
linux	linux_kernel	>= 6.5.0 < 6.5.5	6.5.5

Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.

CWE-772