f2fs: Require FMODE_WRITE for atomic write ioctls (Linux Linux)

CVE-2024-47740
HIGH 7.1

At a glance

Source
NVD
EPSS
EPSS 0.23 % · percentile 14 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

Description

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.

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 7.1CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:HLinux
CVSS 3.1HIGH 7.1CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)
CVSS 3.1MEDIUM 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HNVD · nvd@nist.gov (Primary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected 88b88a66797159949cec32eaab12b4968f6fae2d < 700f3a7c7fa5764c9f24bbf7c78e0b6e479fa653 ; affected 88b88a66797159949cec32eaab12b4968f6fae2d < 4ce87674c3a6b4d3b3d45f85b584ab8618a3cece ; affected 88b88a66797159949cec32eaab12b4968f6fae2d < 000bab8753ae29a259feb339b99ee759795a48ac ; affected 88b88a66797159949cec32eaab12b4968f6fae2d < 88ff021e1fea2d9b40b2d5efd9013c89f7be04ac ; affected 88b88a66797159949cec32eaab12b4968f6fae2d < 32f348ecc149e9ca70a1c424ae8fa9b6919d2713 ; affected 88b88a66797159949cec32eaab12b4968f6fae2d < 5e0de753bfe87768ebe6744d869caa92f35e5731
Linux · Linuxaffected 3.18 ; unaffected 0 < 3.18 ; unaffected 4.19.323 ≤ 4.19.* ; unaffected 5.4.285 ≤ 5.4.* ; unaffected 5.10.227 ≤ 5.10.* ; unaffected 5.15.168 ≤ 5.15.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD