Описание
In the Linux kernel, the following vulnerability has been resolved:
net: fix __dst_negative_advice() race
__dst_negative_advice() does not enforce proper RCU rules when
sk->dst_cache must be cleared, leading to possible UAF.
RCU rules are that we must first clear sk->sk_dst_cache,
then call dst_release(old_dst).
Note that sk_dst_reset(sk) is implementing this protocol correctly,
while __dst_negative_advice() uses the wrong order.
Given that ip6_negative_advice() has special logic
against RTF_CACHE, this means each of the three ->negative_advice()
existing methods must perform the sk_dst_reset() themselves.
Note the check against NULL dst is centralized in
__dst_negative_advice(), there is no need to duplicate
it in various callbacks.
Many thanks to Clement Lecigne for tracking this issue.
This old bug became visible after the blamed commit, using UDP sockets.
A use-after-free flaw was found in the Linux kernel's network route management. This flaw allows an attacker to alter the behavior of certain network connections.
Отчет
Environments which use third-party KABI modules may experience kernel crashes after applying errata for CVE-2024-36971. Contact your module vendor about an update. Until these third party modules can be fixed, you can prevent crashes by disabling them. This problem stems from modules which use the negative_advice() function.
Меры по смягчению последствий
Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Out of support scope | ||
| Red Hat Enterprise Linux 7.7 Advanced Update Support | kernel | Fixed | RHSA-2024:5261 | 13.08.2024 |
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | kernel | Fixed | RHSA-2024:5259 | 13.08.2024 |
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2024:5102 | 08.08.2024 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2024:5101 | 08.08.2024 |
| Red Hat Enterprise Linux 8 | kpatch-patch | Fixed | RHSA-2024:5522 | 20.08.2024 |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | kernel | Fixed | RHSA-2024:5388 | 14.08.2024 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | kernel | Fixed | RHSA-2024:5266 | 13.08.2024 |
| Red Hat Enterprise Linux 8.4 Telecommunications Update Service | kernel-rt | Fixed | RHSA-2024:5282 | 13.08.2024 |
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Дополнительная информация
Статус:
EPSS
7.8 High
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: net: fix __dst_negative_advice() race __dst_negative_advice() does not enforce proper RCU rules when sk->dst_cache must be cleared, leading to possible UAF. RCU rules are that we must first clear sk->sk_dst_cache, then call dst_release(old_dst). Note that sk_dst_reset(sk) is implementing this protocol correctly, while __dst_negative_advice() uses the wrong order. Given that ip6_negative_advice() has special logic against RTF_CACHE, this means each of the three ->negative_advice() existing methods must perform the sk_dst_reset() themselves. Note the check against NULL dst is centralized in __dst_negative_advice(), there is no need to duplicate it in various callbacks. Many thanks to Clement Lecigne for tracking this issue. This old bug became visible after the blamed commit, using UDP sockets.
In the Linux kernel, the following vulnerability has been resolved: net: fix __dst_negative_advice() race __dst_negative_advice() does not enforce proper RCU rules when sk->dst_cache must be cleared, leading to possible UAF. RCU rules are that we must first clear sk->sk_dst_cache, then call dst_release(old_dst). Note that sk_dst_reset(sk) is implementing this protocol correctly, while __dst_negative_advice() uses the wrong order. Given that ip6_negative_advice() has special logic against RTF_CACHE, this means each of the three ->negative_advice() existing methods must perform the sk_dst_reset() themselves. Note the check against NULL dst is centralized in __dst_negative_advice(), there is no need to duplicate it in various callbacks. Many thanks to Clement Lecigne for tracking this issue. This old bug became visible after the blamed commit, using UDP sockets.
In the Linux kernel, the following vulnerability has been resolved: n ...
Security update for the Linux Kernel (Live Patch 22 for SLE 15 SP4)
EPSS
7.8 High
CVSS3