Описание
In the Linux kernel, the following vulnerability has been resolved:
net/sched: Handle TC_ACT_REDIRECT from qdisc filter chains
When a TC filter attached to a qdisc filter chain returns
TC_ACT_REDIRECT (ex: via an eBPF program calling bpf_redirect() or an
act_bpf action), the redirect was silently lost i.e no qdisc classify
function handled TC_ACT_REDIRECT, so the packet fell through the
switch and was enqueued normally instead of being redirected.
This has been broken since bpf_redirect() was introduced for TC in
commit 27b29f63058d ("bpf: add bpf_redirect() helper"). We got lucky
for a long time because bpf_net_context was a per-CPU variable that
was always available.
commit 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct
on PREEMPT_RT.") turned bpf_net_context into a task_struct member that
is only set up by explicit callers. Without a caller setting it up,
bpf_redirect() itself crashes with a NULL pointer dereference in
bpf_net_ctx_get_ri(). However, even with bpf_net_context available,
TC_ACT_REDIRECT from qdisc filter chains cannot be honored without
adding skb_do_redirect() calls to every qdisc classify function, which
would require changes across net/sched/. Isolate it to ebpf core where
it belongs.
Instead, add a tcf_classify_qdisc() inline helper in pkt_cls.h, as a
wrapper around tcf_classify() for use by qdisc classify functions and
tcf_qevent_handle(). When the classify verdict is TC_ACT_REDIRECT,
the wrapper converts it to TC_ACT_SHOT, dropping the packet rather
than letting it continue silently. Dropping is preferred over
letting the packet through because the user immediately sees packet
loss. Silently passing the packet through would hide the problem and
leave the user wondering why their redirect is not working.
The clsact fast path, tc_run() continues to call tcf_classify() directly
and is unaffected: TC_ACT_REDIRECT is returned as-is and handled by
sch_handle_egress/ingress() calling skb_do_redirect() as before.
A flaw was found in the Linux kernel's networking scheduler (net/sched). When a Traffic Control (TC) filter, configured with an eBPF program or act_bpf action, attempts to redirect a packet, the redirection is silently ignored. This causes the packet to be processed normally instead of being redirected, potentially leading to unexpected network behavior or a bypass of intended traffic management policies.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| 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 Enterprise Linux for NVIDIA 26 | kernel | Out of support scope | ||
| Red Hat OpenShift Container Platform 4 | rhcos | 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: net/sched: Handle TC_ACT_REDIRECT from qdisc filter chains When a TC filter attached to a qdisc filter chain returns TC_ACT_REDIRECT (ex: via an eBPF program calling bpf_redirect() or an act_bpf action), the redirect was silently lost i.e no qdisc classify function handled TC_ACT_REDIRECT, so the packet fell through the switch and was enqueued normally instead of being redirected. This has been broken since bpf_redirect() was introduced for TC in commit 27b29f63058d ("bpf: add bpf_redirect() helper"). We got lucky for a long time because bpf_net_context was a per-CPU variable that was always available. commit 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") turned bpf_net_context into a task_struct member that is only set up by explicit callers. Without a caller setting it up, bpf_redirect() itself crashes with a NULL pointer dereference in bpf_net_ctx_get_ri(). However, even with bpf...
In the Linux kernel, the following vulnerability has been resolved: net/sched: Handle TC_ACT_REDIRECT from qdisc filter chains When a TC filter attached to a qdisc filter chain returns TC_ACT_REDIRECT (ex: via an eBPF program calling bpf_redirect() or an act_bpf action), the redirect was silently lost i.e no qdisc classify function handled TC_ACT_REDIRECT, so the packet fell through the switch and was enqueued normally instead of being redirected. This has been broken since bpf_redirect() was introduced for TC in commit 27b29f63058d ("bpf: add bpf_redirect() helper"). We got lucky for a long time because bpf_net_context was a per-CPU variable that was always available. commit 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") turned bpf_net_context into a task_struct member that is only set up by explicit callers. Without a caller setting it up, bpf_redirect() itself crashes with a NULL pointer dereference in bpf_net_ctx_get_ri(). However, even with bp
In the Linux kernel, the following vulnerability has been resolved: n ...
In the Linux kernel, the following vulnerability has been resolved: net/sched: Handle TC_ACT_REDIRECT from qdisc filter chains When a TC filter attached to a qdisc filter chain returns TC_ACT_REDIRECT (ex: via an eBPF program calling bpf_redirect() or an act_bpf action), the redirect was silently lost i.e no qdisc classify function handled TC_ACT_REDIRECT, so the packet fell through the switch and was enqueued normally instead of being redirected. This has been broken since bpf_redirect() was introduced for TC in commit 27b29f63058d ("bpf: add bpf_redirect() helper"). We got lucky for a long time because bpf_net_context was a per-CPU variable that was always available. commit 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") turned bpf_net_context into a task_struct member that is only set up by explicit callers. Without a caller setting it up, bpf_redirect() itself crashes with a NULL pointer dereference in bpf_net_ctx_get_ri(). However, even with...
EPSS
5.5 Medium
CVSS3