Описание
In the Linux kernel, the following vulnerability has been resolved:
bpf: Use array_map_meta_equal for percpu array inner map replacement
percpu_array_map_ops.map_meta_equal points to the generic
bpf_map_meta_equal(), which does not compare max_entries. When a
percpu array serves as an inner map, replacing it with one that has
fewer max_entries bypasses the check. Since percpu_array_map_gen_lookup()
inlines the original template's index_mask as a JIT immediate, a lookup
on the replacement map can access pptrs[] out of bounds.
Point percpu_array_map_ops.map_meta_equal to array_map_meta_equal(),
which already enforces the max_entries equality check.
Add a selftest to verify that replacing a percpu array inner map with
a differently-sized one is rejected.
A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) subsystem. When replacing an inner per-CPU array map within a map-in-map structure, the kernel fails to verify that the replacement map matches the size of the original template map. A local attacker can exploit this flaw by substituting an inner map with one that has fewer entries, causing subsequent lookups to perform out-of-bounds memory access. This issue can lead to kernel memory corruption, resulting in a system crash (Denial of Service) or potential privilege escalation.
Отчет
A BPF map compatibility check can allow a PERCPU_ARRAY inner map to be replaced with a smaller map because max_entries is not compared. The JIT compiled lookup continues to use the index_mask from the original template and can therefore access the replacement map pptrs array out of bounds. The immediate primitive is an out of bounds pointer load. Subsequent BPF access through the resulting per CPU value pointer creates a plausible path to an invalid kernel memory read or write, a kernel crash, information exposure, or local privilege escalation. For the CVSS the PR:L in the paranoid score reflects systems where unprivileged BPF is enabled or limited BPF capabilities are delegated to a local user or service account. The typical hardened configuration requires stronger BPF capabilities and is represented by PR:H in the base score. The issue is not network reachable and requires local BPF operations. Impact may include confidentiality, integrity, and availability compromise and should be reviewed manually.
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 | 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 | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Not affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Fix deferred |
Показывать по
Дополнительная информация
Статус:
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: bpf: Use array_map_meta_equal for percpu array inner map replacement percpu_array_map_ops.map_meta_equal points to the generic bpf_map_meta_equal(), which does not compare max_entries. When a percpu array serves as an inner map, replacing it with one that has fewer max_entries bypasses the check. Since percpu_array_map_gen_lookup() inlines the original template's index_mask as a JIT immediate, a lookup on the replacement map can access pptrs[] out of bounds. Point percpu_array_map_ops.map_meta_equal to array_map_meta_equal(), which already enforces the max_entries equality check. Add a selftest to verify that replacing a percpu array inner map with a differently-sized one is rejected.
In the Linux kernel, the following vulnerability has been resolved: bpf: Use array_map_meta_equal for percpu array inner map replacement percpu_array_map_ops.map_meta_equal points to the generic bpf_map_meta_equal(), which does not compare max_entries. When a percpu array serves as an inner map, replacing it with one that has fewer max_entries bypasses the check. Since percpu_array_map_gen_lookup() inlines the original template's index_mask as a JIT immediate, a lookup on the replacement map can access pptrs[] out of bounds. Point percpu_array_map_ops.map_meta_equal to array_map_meta_equal(), which already enforces the max_entries equality check. Add a selftest to verify that replacing a percpu array inner map with a differently-sized one is rejected.
In the Linux kernel, the following vulnerability has been resolved: b ...
In the Linux kernel, the following vulnerability has been resolved: bpf: Use array_map_meta_equal for percpu array inner map replacement percpu_array_map_ops.map_meta_equal points to the generic bpf_map_meta_equal(), which does not compare max_entries. When a percpu array serves as an inner map, replacing it with one that has fewer max_entries bypasses the check. Since percpu_array_map_gen_lookup() inlines the original template's index_mask as a JIT immediate, a lookup on the replacement map can access pptrs[] out of bounds. Point percpu_array_map_ops.map_meta_equal to array_map_meta_equal(), which already enforces the max_entries equality check. Add a selftest to verify that replacing a percpu array inner map with a differently-sized one is rejected.
5.5 Medium
CVSS3