Описание
In the Linux kernel, the following vulnerability has been resolved:
bpf: Check validity of link->type in bpf_link_show_fdinfo()
If a newly-added link type doesn't invoke BPF_LINK_TYPE(), accessing
bpf_link_type_strs[link->type] may result in an out-of-bounds access.
To spot such missed invocations early in the future, checking the
validity of link->type in bpf_link_show_fdinfo() and emitting a warning
when such invocations are missed.
A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) subsystem. A missing validation check on link types in the link file descriptor information handler can result in an out-of-bounds read. A local user could exploit this vulnerability to trigger a kernel crash, resulting in a Denial of Service (DoS), or potentially disclose sensitive kernel memory.
Отчет
The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space. For the Red Hat Enterprise Linux 8 to confirm the current state, inspect the sysctl with the command:
The setting of 1 would mean that unprivileged users can not use eBPF, mitigating the flaw.
Меры по смягчению последствий
Disable unprivileged access to the eBPF subsystem via sysctl:
- Apply the setting immediately:
sysctl -w kernel.unprivileged_bpf_disabled=1
- To persist this setting across system reboots, write the configuration to /etc/sysctl.d/:
echo "kernel.unprivileged_bpf_disabled = 1" > /etc/sysctl.d/50-unprivileged_bpf.conf
sysctl --system
Caveats: This setting prevents processes without CAP_SYS_ADMIN or CAP_BPF capabilities from utilizing eBPF features. Unprivileged eBPF is already disabled by default on supported versions of Red Hat Enterprise Linux. This mitigation does not restrict privileged processes or root users. Applying the sysctl takes effect immediately without requiring a system reboot.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Out of support scope | ||
| Red Hat Enterprise Linux 8 | kernel | Will not fix | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Will not fix | ||
| Red Hat Enterprise Linux 9 | kernel | Will not fix |
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Дополнительная информация
Статус:
6 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: bpf: Check validity of link->type in bpf_link_show_fdinfo() If a newly-added link type doesn't invoke BPF_LINK_TYPE(), accessing bpf_link_type_strs[link->type] may result in an out-of-bounds access. To spot such missed invocations early in the future, checking the validity of link->type in bpf_link_show_fdinfo() and emitting a warning when such invocations are missed.
In the Linux kernel, the following vulnerability has been resolved: bpf: Check validity of link->type in bpf_link_show_fdinfo() If a newly-added link type doesn't invoke BPF_LINK_TYPE(), accessing bpf_link_type_strs[link->type] may result in an out-of-bounds access. To spot such missed invocations early in the future, checking the validity of link->type in bpf_link_show_fdinfo() and emitting a warning when such invocations are missed.
bpf: Check validity of link->type in bpf_link_show_fdinfo()
In the Linux kernel, the following vulnerability has been resolved: b ...
In the Linux kernel, the following vulnerability has been resolved: bpf: Check validity of link->type in bpf_link_show_fdinfo() If a newly-added link type doesn't invoke BPF_LINK_TYPE(), accessing bpf_link_type_strs[link->type] may result in an out-of-bounds access. To spot such missed invocations early in the future, checking the validity of link->type in bpf_link_show_fdinfo() and emitting a warning when such invocations are missed.
6 Medium
CVSS3