Описание
Race condition in drivers/tty/n_hdlc.c in the Linux kernel through 4.10.1 allows local users to gain privileges or cause a denial of service (double free) by setting the HDLC line discipline.
A race condition flaw was found in the N_HLDC Linux kernel driver when accessing n_hdlc.tbuf list that can lead to double free. A local, unprivileged user able to set the HDLC line discipline on the tty device could use this flaw to increase their privileges on the system.
Отчет
This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5. This issue does affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 6, 7 and Red Hat Enterprise MRG 2. As this issue is rated as Important, it has been scheduled to be fixed in future updates for the respective releases.
Меры по смягчению последствий
The n_hdlc kernel module will be automatically loaded when an application attempts to use the HDLC line discipline from userspace. This module can be prevented from being loaded by using the system-wide modprobe rules. The following command, run as root, will prevent accidental or intentional loading of the module. Red Hat Product Security believe this method is a robust method to prevent accidental loading of the module, even by privileged users. # echo "install n_hdlc /bin/true" >> /etc/modprobe.d/disable-n_hdlc.conf The system will need to be restarted if the n_hdlc modules are already loaded. In most circumstances, the n_hdlc kernel modules will be unable to be unloaded if in use and while any current process using this line discipline is required. Exploiting this flaw does not require Microgate or SyncLink hardware to be in use. If further assistance is needed, see this KCS article ( https://access.redhat.com/solutions/41278 ) or contact Red Hat Global Support Services.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 5 | kernel | Not affected | ||
| Red Hat Enterprise Linux 6 | kernel | Fixed | RHSA-2017:0892 | 11.04.2017 |
| Red Hat Enterprise Linux 6.2 Advanced Update Support | kernel | Fixed | RHSA-2017:1126 | 25.04.2017 |
| Red Hat Enterprise Linux 6.4 Advanced Update Support | kernel | Fixed | RHSA-2017:0986 | 18.04.2017 |
| Red Hat Enterprise Linux 6.5 Advanced Update Support | kernel | Fixed | RHSA-2017:1232 | 16.05.2017 |
| Red Hat Enterprise Linux 6.5 Telco Extended Update Support | kernel | Fixed | RHSA-2017:1232 | 16.05.2017 |
| Red Hat Enterprise Linux 6.6 Advanced Update Support | kernel | Fixed | RHSA-2017:1488 | 19.06.2017 |
| Red Hat Enterprise Linux 6.6 Telco Extended Update Support | kernel | Fixed | RHSA-2017:1488 | 19.06.2017 |
| Red Hat Enterprise Linux 6.7 Extended Update Support | kernel | Fixed | RHSA-2017:1233 | 16.05.2017 |
| Red Hat Enterprise Linux 7 | kernel-rt | Fixed | RHSA-2017:0931 | 12.04.2017 |
Показывать по
Дополнительная информация
Статус:
7.8 High
CVSS3
Связанные уязвимости
Race condition in drivers/tty/n_hdlc.c in the Linux kernel through 4.10.1 allows local users to gain privileges or cause a denial of service (double free) by setting the HDLC line discipline.
Race condition in drivers/tty/n_hdlc.c in the Linux kernel through 4.10.1 allows local users to gain privileges or cause a denial of service (double free) by setting the HDLC line discipline.
Race condition in drivers/tty/n_hdlc.c in the Linux kernel through 4.1 ...
7.8 High
CVSS3