Описание
In the Linux kernel, the following vulnerability has been resolved:
zram: fix NULL pointer in comp_algorithm_show()
LTP reported a NULL pointer dereference as followed:
CPU: 7 UID: 0 PID: 5995 Comm: cat Kdump: loaded Not tainted 6.12.0-rc6+ #3
Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __pi_strcmp+0x24/0x140
lr : zcomp_available_show+0x60/0x100 [zram]
sp : ffff800088b93b90
x29: ffff800088b93b90 x28: 0000000000000001 x27: 0000000000400cc0
x26: 0000000000000ffe x25: ffff80007b3e2388 x24: 0000000000000000
x23: ffff80007b3e2390 x22: ffff0004041a9000 x21: ffff80007b3e2900
x20: 0000000000000000 x19: 0000000000000000 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: ffff80007b3e2900 x9 : ffff80007b3cb280
x8 : 0101010101010101 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000040 x4 : 0000000000000000 x3 : 00656c722d6f7a6c
x2 : 0000000000000000 x1 : ffff80007b3e2900 x0 : 0000000000000000
Call trace:
__pi_strcmp+0x24/0x140
comp_algorithm_show+0x40/0x70 [zram]
dev_attr_show+0x28/0x80
sysfs_kf_seq_show+0x90/0x140
kernfs_seq_show+0x34/0x48
seq_read_iter+0x1d4/0x4e8
kernfs_fop_read_iter+0x40/0x58
new_sync_read+0x9c/0x168
vfs_read+0x1a8/0x1f8
ksys_read+0x74/0x108
__arm64_sys_read+0x24/0x38
invoke_syscall+0x50/0x120
el0_svc_common.constprop.0+0xc8/0xf0
do_el0_svc+0x24/0x38
el0_svc+0x38/0x138
el0t_64_sync_handler+0xc0/0xc8
el0t_64_sync+0x188/0x190
The zram->comp_algs[ZRAM_PRIMARY_COMP] can be NULL in zram_add() if
comp_algorithm_set() has not been called. User can access the zram device
by sysfs after device_add_disk(), so there is a time window to trigger the
NULL pointer dereference. Move it ahead device_add_disk() to make sure
when user can access the zram device, it is ready. comp_algorithm_set()
is protected by zram->init_lock in other places and no such problem.
A flaw was found in the Linux kernel's zram driver. This vulnerability can lead to a Denial of Service (DoS) by causing a system crash. During device initialization, a timing window allows a local user to access the device attributes through the sysfs interface before compression algorithms are properly initialized, triggering a NULL pointer dereference.
Меры по смягчению последствий
To mitigate this vulnerability, prevent the kernel from loading the zram module on systems where compressed in-memory block devices are not required.
- Add a modprobe configuration file to prevent loading the module:
echo "install zram /bin/true" > /etc/modprobe.d/zram.conf
- If the module is already loaded and not actively backing any devices, unload it:
modprobe -r zram
Caveats: Blacklisting this module disables zram compressed swap functionality. If zram devices are actively configured, unloading the module will fail or disrupt swap operations, and a system restart may be required to apply the change.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Out of support scope | ||
| Red Hat Enterprise Linux 8 | kernel | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 10 | kernel | Fixed | RHSA-2025:20095 | 11.11.2025 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2025:6966 | 13.05.2025 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2025:6966 | 13.05.2025 |
Показывать по
Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: zram: fix NULL pointer in comp_algorithm_show() LTP reported a NULL pointer dereference as followed: CPU: 7 UID: 0 PID: 5995 Comm: cat Kdump: loaded Not tainted 6.12.0-rc6+ #3 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __pi_strcmp+0x24/0x140 lr : zcomp_available_show+0x60/0x100 [zram] sp : ffff800088b93b90 x29: ffff800088b93b90 x28: 0000000000000001 x27: 0000000000400cc0 x26: 0000000000000ffe x25: ffff80007b3e2388 x24: 0000000000000000 x23: ffff80007b3e2390 x22: ffff0004041a9000 x21: ffff80007b3e2900 x20: 0000000000000000 x19: 0000000000000000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: ffff80007b3e2900 x9 : ffff80007b3cb280 x8 : 0101010101010101 x7 : 0000000000000000 x6 : 0000000000000000 x5 :...
In the Linux kernel, the following vulnerability has been resolved: zram: fix NULL pointer in comp_algorithm_show() LTP reported a NULL pointer dereference as followed: CPU: 7 UID: 0 PID: 5995 Comm: cat Kdump: loaded Not tainted 6.12.0-rc6+ #3 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __pi_strcmp+0x24/0x140 lr : zcomp_available_show+0x60/0x100 [zram] sp : ffff800088b93b90 x29: ffff800088b93b90 x28: 0000000000000001 x27: 0000000000400cc0 x26: 0000000000000ffe x25: ffff80007b3e2388 x24: 0000000000000000 x23: ffff80007b3e2390 x22: ffff0004041a9000 x21: ffff80007b3e2900 x20: 0000000000000000 x19: 0000000000000000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: ffff80007b3e2900 x9 : ffff80007b3cb280 x8 : 0101010101010101 x7 : 0000000000000000 x6 : 0000000
In the Linux kernel, the following vulnerability has been resolved: z ...
In the Linux kernel, the following vulnerability has been resolved: zram: fix NULL pointer in comp_algorithm_show() LTP reported a NULL pointer dereference as followed: CPU: 7 UID: 0 PID: 5995 Comm: cat Kdump: loaded Not tainted 6.12.0-rc6+ #3 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __pi_strcmp+0x24/0x140 lr : zcomp_available_show+0x60/0x100 [zram] sp : ffff800088b93b90 x29: ffff800088b93b90 x28: 0000000000000001 x27: 0000000000400cc0 x26: 0000000000000ffe x25: ffff80007b3e2388 x24: 0000000000000000 x23: ffff80007b3e2390 x22: ffff0004041a9000 x21: ffff80007b3e2900 x20: 0000000000000000 x19: 0000000000000000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: ffff80007b3e2900 x9 : ffff80007b3cb280 x8 : 0101010101010101 x7 : 0000000000000000 x6 : 0000...
EPSS
5.5 Medium
CVSS3