CVE-2024-47740 Affecting kernel-uek-core package, versions <0:5.15.0-303.171.5.2.el9uek


Severity

Recommended
high

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.04% (15th percentile)

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  • Snyk IDSNYK-ORACLE9-KERNELUEKCORE-8528451
  • published19 Dec 2024
  • disclosed21 Oct 2024

Introduced: 21 Oct 2024

CVE-2024-47740  (opens in a new tab)

How to fix?

Upgrade Oracle:9 kernel-uek-core to version 0:5.15.0-303.171.5.2.el9uek or higher.
This issue was patched in ELSA-2024-12887.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-uek-core package and not the kernel-uek-core package as distributed by Oracle. See How to fix? for Oracle:9 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

f2fs: Require FMODE_WRITE for atomic write ioctls

The F2FS ioctls for starting and committing atomic writes check for inode_owner_or_capable(), but this does not give LSMs like SELinux or Landlock an opportunity to deny the write access - if the caller's FSUID matches the inode's UID, inode_owner_or_capable() immediately returns true.

There are scenarios where LSMs want to deny a process the ability to write particular files, even files that the FSUID of the process owns; but this can currently partially be bypassed using atomic write ioctls in two ways:

  • F2FS_IOC_START_ATOMIC_REPLACE + F2FS_IOC_COMMIT_ATOMIC_WRITE can truncate an inode to size 0
  • F2FS_IOC_START_ATOMIC_WRITE + F2FS_IOC_ABORT_ATOMIC_WRITE can revert changes another process concurrently made to a file

Fix it by requiring FMODE_WRITE for these operations, just like for F2FS_IOC_MOVE_RANGE. Since any legitimate caller should only be using these ioctls when intending to write into the file, that seems unlikely to break anything.

CVSS Scores

version 3.1