Описание
The Linux kernel before 5.1-rc5 allows page->_refcount reference count overflow, with resultant use-after-free issues, if about 140 GiB of RAM exists. This is related to fs/fuse/dev.c, fs/pipe.c, fs/splice.c, include/linux/mm.h, include/linux/pipe_fs_i.h, kernel/trace/trace.c, mm/gup.c, and mm/hugetlb.c. It can occur with FUSE requests.
A flaw was found in the Linux kernel's implementation of the FUSE filesystem, where it allows a page reference counter overflow. If a page reference counter overflows into a negative value, it can be placed back into the "free" list for reuse by other applications. This flaw allows a local attacker who can manipulate memory page reference counters to cause memory corruption and possible privilege escalation by triggering a use-after-free condition.
The current attack requires the system to have approximately 140 GB of RAM for this attack to be performed. It may be possible that the attack can occur with fewer memory requirements.
Меры по смягчению последствий
Preventing loading of the 'fuse' kernel module will prevent attackers from using this exploit against the system; howeve the functionality of being able to access the filesystems that would be allowed by fuse would no longer be allowed . See “How do I blacklist a kernel module to prevent it from loading automatically?" ( https://access.redhat.com/solutions/41278) for instructions on how to disable the 'fuse' kernel module from autoloading. This mitigation may not be suitable if access to the functionality provided by fuse is required.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 5 | kernel | Not affected | ||
| Red Hat Enterprise Linux 6 | kernel | Fixed | RHSA-2020:4182 | 07.10.2020 |
| Red Hat Enterprise Linux 7 | kernel-rt | Fixed | RHSA-2020:0839 | 17.03.2020 |
| Red Hat Enterprise Linux 7 | kernel-alt | Fixed | RHSA-2020:0174 | 21.01.2020 |
| Red Hat Enterprise Linux 7 | kernel | Fixed | RHSA-2020:0834 | 17.03.2020 |
| Red Hat Enterprise Linux 7.4 Advanced Update Support | kernel | Fixed | RHSA-2020:3230 | 29.07.2020 |
| Red Hat Enterprise Linux 7.4 Telco Extended Update Support | kernel | Fixed | RHSA-2020:3230 | 29.07.2020 |
| Red Hat Enterprise Linux 7.4 Update Services for SAP Solutions | kernel | Fixed | RHSA-2020:3230 | 29.07.2020 |
| Red Hat Enterprise Linux 7.6 Extended Update Support | kernel | Fixed | RHSA-2020:2851 | 07.07.2020 |
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2019:2741 | 12.09.2019 |
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Дополнительная информация
Статус:
7.8 High
CVSS3
Связанные уязвимости
The Linux kernel before 5.1-rc5 allows page->_refcount reference count overflow, with resultant use-after-free issues, if about 140 GiB of RAM exists. This is related to fs/fuse/dev.c, fs/pipe.c, fs/splice.c, include/linux/mm.h, include/linux/pipe_fs_i.h, kernel/trace/trace.c, mm/gup.c, and mm/hugetlb.c. It can occur with FUSE requests.
The Linux kernel before 5.1-rc5 allows page->_refcount reference count overflow, with resultant use-after-free issues, if about 140 GiB of RAM exists. This is related to fs/fuse/dev.c, fs/pipe.c, fs/splice.c, include/linux/mm.h, include/linux/pipe_fs_i.h, kernel/trace/trace.c, mm/gup.c, and mm/hugetlb.c. It can occur with FUSE requests.
The Linux kernel before 5.1-rc5 allows page->_refcount reference count ...
Security update for the Linux Kernel (Live Patch 26 for SLE 12 SP3)
The Linux kernel before 5.1-rc5 allows page->_refcount reference count overflow, with resultant use-after-free issues, if about 140 GiB of RAM exists. This is related to fs/fuse/dev.c, fs/pipe.c, fs/splice.c, include/linux/mm.h, include/linux/pipe_fs_i.h, kernel/trace/trace.c, mm/gup.c, and mm/hugetlb.c. It can occur with FUSE requests.
7.8 High
CVSS3