Описание
In the Linux kernel, the following vulnerability has been resolved:
pidfd: hold exec_update_lock around namespace ioctl
The PIDFD_GET_*_NAMESPACE ioctls in pidfd_ioctl() perform a filesystem
credentials ptrace access check before handing out a namespace file
descriptor. The accompanying comment states that the code "mirrors nsfs
behavior", but, unlike the corresponding procfs paths, it does so without
holding the target task's exec_update_lock.
proc_ns_get_link() and proc_ns_readlink() both take exec_update_lock for
reading around the ptrace check and the namespace lookup, so that the
credentials used for the access decision match those of the task when its
namespace is read. Without it, a caller can pass the check against the
target's old credentials and then read the namespace after the target has
execve()'d a setuid binary and committed new credentials -- accessing
namespace information it should have been denied.
Hold exec_update_lock for reading around the ptrace check and the
namespace lookup so that pidfd truly mirrors nsfs behavior, as the comment
already claims. open_namespace() itself runs outside the lock: once a
namespace reference is obtained it carries its own refcount and is opened
with the caller's own credentials, so a concurrent execve() on the target
can no longer affect the outcome.
A flaw was found in the Linux kernel. A local attacker could exploit a race condition in the pidfd subsystem, specifically within the PIDFD_GET_*_NAMESPACE ioctls. This vulnerability occurs because the system does not properly hold a lock (exec_update_lock) during credential checks. This allows an attacker to bypass security restrictions and access sensitive namespace information after a target process has changed its privileges, leading to unauthorized information disclosure.
Отчет
A TOCTOU race in pidfd namespace ioctls can allow the caller to pass a filesystem credential ptrace check against the targets old credentials and then obtain a namespace file descriptor after the target completes execve with new setuid credentials. This can bypass the intended access decision for PIDFD_GET_*_NAMESPACE and expose namespace information or a namespace handle that should have been denied. For the CVSS the PR:L is used because a local user or local process context is required to use pidfd ioctls and race the target execve path. AC:H is used because reliable triggering depends on a timing window between the ptrace access check and the namespace lookup. The issue is not network reachable and does not indicate memory corruption. Impact is mainly an access control bypass with confidentiality impact and possible limited integrity policy impact through unauthorized namespace fd acquisition.
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 |
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Дополнительная информация
Статус:
EPSS
5.3 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: pidfd: hold exec_update_lock around namespace ioctl The PIDFD_GET_*_NAMESPACE ioctls in pidfd_ioctl() perform a filesystem credentials ptrace access check before handing out a namespace file descriptor. The accompanying comment states that the code "mirrors nsfs behavior", but, unlike the corresponding procfs paths, it does so without holding the target task's exec_update_lock. proc_ns_get_link() and proc_ns_readlink() both take exec_update_lock for reading around the ptrace check and the namespace lookup, so that the credentials used for the access decision match those of the task when its namespace is read. Without it, a caller can pass the check against the target's old credentials and then read the namespace after the target has execve()'d a setuid binary and committed new credentials -- accessing namespace information it should have been denied. Hold exec_update_lock for reading around the ptrace check and th...
In the Linux kernel, the following vulnerability has been resolved: pidfd: hold exec_update_lock around namespace ioctl The PIDFD_GET_*_NAMESPACE ioctls in pidfd_ioctl() perform a filesystem credentials ptrace access check before handing out a namespace file descriptor. The accompanying comment states that the code "mirrors nsfs behavior", but, unlike the corresponding procfs paths, it does so without holding the target task's exec_update_lock. proc_ns_get_link() and proc_ns_readlink() both take exec_update_lock for reading around the ptrace check and the namespace lookup, so that the credentials used for the access decision match those of the task when its namespace is read. Without it, a caller can pass the check against the target's old credentials and then read the namespace after the target has execve()'d a setuid binary and committed new credentials -- accessing namespace information it should have been denied. Hold exec_update_lock for reading around the ptrace check and t
In the Linux kernel, the following vulnerability has been resolved: p ...
In the Linux kernel, the following vulnerability has been resolved: pidfd: hold exec_update_lock around namespace ioctl The PIDFD_GET_*_NAMESPACE ioctls in pidfd_ioctl() perform a filesystem credentials ptrace access check before handing out a namespace file descriptor. The accompanying comment states that the code "mirrors nsfs behavior", but, unlike the corresponding procfs paths, it does so without holding the target task's exec_update_lock. proc_ns_get_link() and proc_ns_readlink() both take exec_update_lock for reading around the ptrace check and the namespace lookup, so that the credentials used for the access decision match those of the task when its namespace is read. Without it, a caller can pass the check against the target's old credentials and then read the namespace after the target has execve()'d a setuid binary and committed new credentials -- accessing namespace information it should have been denied. Hold exec_update_lock for reading around the ptrace check an...
ELSA-2026-500394: Unbreakable Enterprise kernel security update (IMPORTANT)
EPSS
5.3 Medium
CVSS3