Описание
The bio_map_user_iov and bio_unmap_user functions in block/bio.c in the Linux kernel before 4.13.8 do unbalanced refcounting when a SCSI I/O vector has small consecutive buffers belonging to the same page. The bio_add_pc_page function merges them into one, but the page reference is never dropped. This causes a memory leak and possible system lockup (exploitable against the host OS by a guest OS user, if a SCSI disk is passed through to a virtual machine) due to an out-of-memory condition.
It was found that in the Linux kernel through v4.14-rc5, bio_map_user_iov() and bio_unmap_user() in 'block/bio.c' do unbalanced pages refcounting if IO vector has small consecutive buffers belonging to the same page. bio_add_pc_page() merges them into one, but the page reference is never dropped, causing a memory leak and possible system lockup due to out-of-memory condition.
Отчет
This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 5. This is not currently planned to be addressed in future updates of the product due to its life cycle. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/. This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 6, 7 and MRG-2. Future updates for the respective releases may address this issue.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 5 | kernel | Will not fix | ||
| Red Hat Enterprise Linux 6 | kernel | Fixed | RHSA-2018:1854 | 19.06.2018 |
| Red Hat Enterprise Linux 7 | kernel-rt | Fixed | RHSA-2018:0676 | 10.04.2018 |
| Red Hat Enterprise Linux 7 | kernel-alt | Fixed | RHSA-2018:0654 | 10.04.2018 |
| Red Hat Enterprise Linux 7 | kernel | Fixed | RHSA-2018:1062 | 10.04.2018 |
| Red Hat Enterprise Linux 7.4 Extended Update Support | kernel | Fixed | RHSA-2019:1170 | 14.05.2019 |
| Red Hat Enterprise MRG 2 | kernel-rt | Fixed | RHSA-2019:1190 | 14.05.2019 |
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Дополнительная информация
Статус:
6.2 Medium
CVSS3
Связанные уязвимости
The bio_map_user_iov and bio_unmap_user functions in block/bio.c in the Linux kernel before 4.13.8 do unbalanced refcounting when a SCSI I/O vector has small consecutive buffers belonging to the same page. The bio_add_pc_page function merges them into one, but the page reference is never dropped. This causes a memory leak and possible system lockup (exploitable against the host OS by a guest OS user, if a SCSI disk is passed through to a virtual machine) due to an out-of-memory condition.
The bio_map_user_iov and bio_unmap_user functions in block/bio.c in the Linux kernel before 4.13.8 do unbalanced refcounting when a SCSI I/O vector has small consecutive buffers belonging to the same page. The bio_add_pc_page function merges them into one, but the page reference is never dropped. This causes a memory leak and possible system lockup (exploitable against the host OS by a guest OS user, if a SCSI disk is passed through to a virtual machine) due to an out-of-memory condition.
The bio_map_user_iov and bio_unmap_user functions in block/bio.c in th ...
The bio_map_user_iov and bio_unmap_user functions in block/bio.c in the Linux kernel before 4.13.8 do unbalanced refcounting when a SCSI I/O vector has small consecutive buffers belonging to the same page. The bio_add_pc_page function merges them into one, but the page reference is never dropped. This causes a memory leak and possible system lockup (exploitable against the host OS by a guest OS user, if a SCSI disk is passed through to a virtual machine) due to an out-of-memory condition.
ELSA-2017-3657: Unbreakable Enterprise kernel security update (IMPORTANT)
6.2 Medium
CVSS3