Описание
In the Linux kernel before 5.2.3, drivers/block/floppy.c allows a denial of service by setup_format_params division-by-zero. Two consecutive ioctls can trigger the bug: the first one should set the drive geometry with .sect and .rate values that make F_SECT_PER_TRACK be zero. Next, the floppy format operation should be called. It can be triggered by an unprivileged local user even when a floppy disk has not been inserted. NOTE: QEMU creates the floppy device by default.
A vulnerability was found in the Linux kernel’s floppy disk driver implementation. A local attacker with access to the floppy disk device file (/dev/fd0 through to /dev/fdN) can create a situation that causes the kernel to divide by zero. This requires two consecutive ioctl calls to be issued. The first ioctl call sets the sector and rate values, and the second ioctl is the call to format the floppy disk to the appropriate values. This flaw can cause the system to divide by zero and panic the host. No media (floppy) is required to be inserted for this attack to work properly.
Меры по смягчению последствий
The kernel module named 'floppy' contains the affected code, this can be blacklisted using the standard blacklisting techniques or disabled in the systems BIOS. See https://access.redhat.com/solutions/41278 for how to blacklist a kernel module. Virtualized guest systems can also remove the system from the guests configuration to ensure that the module does not load.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 5 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 6 | kernel | Will not fix | ||
| Red Hat Enterprise Linux 7 | kernel | Will not fix | ||
| Red Hat Enterprise Linux 7 | kernel-alt | Will not fix | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Will not fix | ||
| Red Hat Enterprise Linux 8 | kernel | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise MRG 2 | kernel-rt | Out of support scope |
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Дополнительная информация
Статус:
EPSS
5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel before 5.2.3, drivers/block/floppy.c allows a denial of service by setup_format_params division-by-zero. Two consecutive ioctls can trigger the bug: the first one should set the drive geometry with .sect and .rate values that make F_SECT_PER_TRACK be zero. Next, the floppy format operation should be called. It can be triggered by an unprivileged local user even when a floppy disk has not been inserted. NOTE: QEMU creates the floppy device by default.
In the Linux kernel before 5.2.3, drivers/block/floppy.c allows a denial of service by setup_format_params division-by-zero. Two consecutive ioctls can trigger the bug: the first one should set the drive geometry with .sect and .rate values that make F_SECT_PER_TRACK be zero. Next, the floppy format operation should be called. It can be triggered by an unprivileged local user even when a floppy disk has not been inserted. NOTE: QEMU creates the floppy device by default.
In the Linux kernel before 5.2.3, drivers/block/floppy.c allows a deni ...
In the Linux kernel before 5.2.3, drivers/block/floppy.c allows a denial of service by setup_format_params division-by-zero. Two consecutive ioctls can trigger the bug: the first one should set the drive geometry with .sect and .rate values that make F_SECT_PER_TRACK be zero. Next, the floppy format operation should be called. It can be triggered by an unprivileged local user even when a floppy disk has not been inserted. NOTE: QEMU creates the floppy device by default.
Уязвимость функции setup_format_params() ядра операционной системы Linux, позволяющая нарушителю вызвать отказ в обслуживании
EPSS
5 Medium
CVSS3