Описание
In the Linux kernel, the following vulnerability has been resolved:
nfs: return EISDIR on nfs3_proc_create if d_alias is a dir
If we found an alias through nfs3_do_create/nfs_add_or_obtain
/d_splice_alias which happens to be a dir dentry, we don't return
any error, and simply forget about this alias, but the original
dentry we were adding and passed as parameter remains negative.
This later causes an oops on nfs_atomic_open_v23/finish_open since we
supply a negative dentry to do_dentry_open.
This has been observed running lustre-racer, where dirs and files are
created/removed concurrently with the same name and O_EXCL is not
used to open files (frequent file redirection).
While d_splice_alias typically returns a directory alias or NULL, we
explicitly check d_is_dir() to ensure that we don't attempt to perform
file operations (like finish_open) on a directory inode, which triggers
the observed oops.
A flaw was found in the Network File System (NFS) implementation within the Linux kernel. When directories and files are created and removed concurrently with the same name, a race condition can occur. This can lead to the system attempting to perform file operations on a directory, resulting in a kernel "oops" and causing a Denial of Service (DoS).
Отчет
This Moderate severity flaw in the Linux kernel's NFS implementation can lead to a denial of service. It requires a local attacker to perform specific concurrent file and directory operations on an NFS mount, which can trigger a kernel 'oops'. Remote exploitation without prior local access is not possible.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not 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 | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: nfs: return EISDIR on nfs3_proc_create if d_alias is a dir If we found an alias through nfs3_do_create/nfs_add_or_obtain /d_splice_alias which happens to be a dir dentry, we don't return any error, and simply forget about this alias, but the original dentry we were adding and passed as parameter remains negative. This later causes an oops on nfs_atomic_open_v23/finish_open since we supply a negative dentry to do_dentry_open. This has been observed running lustre-racer, where dirs and files are created/removed concurrently with the same name and O_EXCL is not used to open files (frequent file redirection). While d_splice_alias typically returns a directory alias or NULL, we explicitly check d_is_dir() to ensure that we don't attempt to perform file operations (like finish_open) on a directory inode, which triggers the observed oops.
In the Linux kernel, the following vulnerability has been resolved: nfs: return EISDIR on nfs3_proc_create if d_alias is a dir If we found an alias through nfs3_do_create/nfs_add_or_obtain /d_splice_alias which happens to be a dir dentry, we don't return any error, and simply forget about this alias, but the original dentry we were adding and passed as parameter remains negative. This later causes an oops on nfs_atomic_open_v23/finish_open since we supply a negative dentry to do_dentry_open. This has been observed running lustre-racer, where dirs and files are created/removed concurrently with the same name and O_EXCL is not used to open files (frequent file redirection). While d_splice_alias typically returns a directory alias or NULL, we explicitly check d_is_dir() to ensure that we don't attempt to perform file operations (like finish_open) on a directory inode, which triggers the observed oops.
In the Linux kernel, the following vulnerability has been resolved: n ...
In the Linux kernel, the following vulnerability has been resolved: nfs: return EISDIR on nfs3_proc_create if d_alias is a dir If we found an alias through nfs3_do_create/nfs_add_or_obtain /d_splice_alias which happens to be a dir dentry, we don't return any error, and simply forget about this alias, but the original dentry we were adding and passed as parameter remains negative. This later causes an oops on nfs_atomic_open_v23/finish_open since we supply a negative dentry to do_dentry_open. This has been observed running lustre-racer, where dirs and files are created/removed concurrently with the same name and O_EXCL is not used to open files (frequent file redirection). While d_splice_alias typically returns a directory alias or NULL, we explicitly check d_is_dir() to ensure that we don't attempt to perform file operations (like finish_open) on a directory inode, which triggers the observed oops.
EPSS
5.5 Medium
CVSS3