Описание
In the Linux kernel, the following vulnerability has been resolved:
bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL
An LWT_SEG6LOCAL program can invalidate its cached SRH with
bpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_data(). The latter
may reallocate skb->head, leaving the per-CPU SRH pointer dangling.
Post-program SRH validation then writes through that pointer.
Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL programs so the verifier
rejects this unsafe helper combination. Other LWT program types continue
to expose the helper through lwt_out_func_proto().
A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) subsystem. A local attacker with privileges to load BPF programs could exploit this vulnerability to cause a Denial of Service (DoS) or potentially corrupt system memory. The issue occurs when an IPv6 segment routing program modifies routing headers and subsequently triggers packet buffer reallocation, leaving an internal pointer referencing invalid memory. Subsequent validation routines write through this dangling pointer, resulting in memory corruption and a system crash.
Отчет
An LWT_SEG6LOCAL BPF program can invalidate its cached SRH with bpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_data(), which may reallocate skb head and leave the per CPU SRH pointer dangling. Post program SRH validation can then write through the stale pointer, creating a write after free style memory corruption primitive in the host kernel. For the CVSS the PR:L value is used for the paranoid score because a reduced capability container root or service with delegated BPF and network administration capabilities may be able to load and attach the required program without full host root privileges. This is not directly network reachable because remote packets cannot install the unsafe BPF program, although packets can execute it after local configuration. Impact is at least a local denial of service and may include privilege escalation or host kernel compromise if the stale write can be shaped reliably.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Fix deferred | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Fix deferred |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL An LWT_SEG6LOCAL program can invalidate its cached SRH with bpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_data(). The latter may reallocate skb->head, leaving the per-CPU SRH pointer dangling. Post-program SRH validation then writes through that pointer. Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL programs so the verifier rejects this unsafe helper combination. Other LWT program types continue to expose the helper through lwt_out_func_proto().
In the Linux kernel, the following vulnerability has been resolved: bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL An LWT_SEG6LOCAL program can invalidate its cached SRH with bpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_data(). The latter may reallocate skb->head, leaving the per-CPU SRH pointer dangling. Post-program SRH validation then writes through that pointer. Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL programs so the verifier rejects this unsafe helper combination. Other LWT program types continue to expose the helper through lwt_out_func_proto().
In the Linux kernel, the following vulnerability has been resolved: b ...
In the Linux kernel, the following vulnerability has been resolved: bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL An LWT_SEG6LOCAL program can invalidate its cached SRH with bpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_data(). The latter may reallocate skb->head, leaving the per-CPU SRH pointer dangling. Post-program SRH validation then writes through that pointer. Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL programs so the verifier rejects this unsafe helper combination. Other LWT program types continue to expose the helper through lwt_out_func_proto().
EPSS
5.5 Medium
CVSS3