{"id":"CVE-2024-47740","state":"PUBLISHED","title":"f2fs: Require FMODE_WRITE for atomic write ioctls","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: Require FMODE_WRITE for atomic write ioctls\n\nThe F2FS ioctls for starting and committing atomic writes check for\ninode_owner_or_capable(), but this does not give LSMs like SELinux or\nLandlock an opportunity to deny the write access - if the caller's FSUID\nmatches the inode's UID, inode_owner_or_capable() immediately returns true.\n\nThere are scenarios where LSMs want to deny a process the ability to write\nparticular files, even files that the FSUID of the process owns; but this\ncan currently partially be bypassed using atomic write ioctls in two ways:\n\n - F2FS_IOC_START_ATOMIC_REPLACE + F2FS_IOC_COMMIT_ATOMIC_WRITE can\n   truncate an inode to size 0\n - F2FS_IOC_START_ATOMIC_WRITE + F2FS_IOC_ABORT_ATOMIC_WRITE can revert\n   changes another process concurrently made to a file\n\nFix it by requiring FMODE_WRITE for these operations, just like for\nF2FS_IOC_MOVE_RANGE. Since any legitimate caller should only be using these\nioctls when intending to write into the file, that seems unlikely to break\nanything.","publishedAt":"2024-10-21T12:14:09.171Z","updatedAt":"2026-08-05T11:39:50.713Z","severity":{"score":7.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"700f3a7c7fa5764c9f24bbf7c78e0b6e479fa653","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"4ce87674c3a6b4d3b3d45f85b584ab8618a3cece","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"000bab8753ae29a259feb339b99ee759795a48ac","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"88ff021e1fea2d9b40b2d5efd9013c89f7be04ac","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"32f348ecc149e9ca70a1c424ae8fa9b6919d2713","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"5e0de753bfe87768ebe6744d869caa92f35e5731","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"f3bfac2cabf5333506b263bc0c8497c95302f32d","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"4583290898c13c2c2e5eb8773886d153c2c5121d","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"4f5a100f87f32cb65d4bb1ad282a08c92f6f591e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/f2fs/file.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.18","versionType":"semver"},{"version":"4.19.323","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.285","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.227","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.168","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.113","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.54","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.10.13","status":"unaffected","lessThanOrEqual":"6.10.*","versionType":"semver"},{"version":"6.11.2","status":"unaffected","lessThanOrEqual":"6.11.*","versionType":"semver"},{"version":"6.12","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/f2fs/file.c"]}],"references":["https://git.kernel.org/stable/c/700f3a7c7fa5764c9f24bbf7c78e0b6e479fa653","https://git.kernel.org/stable/c/4ce87674c3a6b4d3b3d45f85b584ab8618a3cece","https://git.kernel.org/stable/c/000bab8753ae29a259feb339b99ee759795a48ac","https://git.kernel.org/stable/c/88ff021e1fea2d9b40b2d5efd9013c89f7be04ac","https://git.kernel.org/stable/c/32f348ecc149e9ca70a1c424ae8fa9b6919d2713","https://git.kernel.org/stable/c/5e0de753bfe87768ebe6744d869caa92f35e5731","https://git.kernel.org/stable/c/f3bfac2cabf5333506b263bc0c8497c95302f32d","https://git.kernel.org/stable/c/4583290898c13c2c2e5eb8773886d153c2c5121d","https://git.kernel.org/stable/c/4f5a100f87f32cb65d4bb1ad282a08c92f6f591e","https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html","https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:07:56.516Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2024/47xxx/CVE-2024-47740.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-47740","state":"PUBLISHED","datePublished":"2024-10-21T12:14:09.171Z","dateUpdated":"2026-08-05T11:39:50.713Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-09-30T16:00:12.959Z"},"containers":{"cna":{"title":"f2fs: Require FMODE_WRITE for atomic write ioctls","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: Require FMODE_WRITE for atomic write ioctls\n\nThe F2FS ioctls for starting and committing atomic writes check for\ninode_owner_or_capable(), but this does not give LSMs like SELinux or\nLandlock an opportunity to deny the write access - if the caller's FSUID\nmatches the inode's UID, inode_owner_or_capable() immediately returns true.\n\nThere are scenarios where LSMs want to deny a process the ability to write\nparticular files, even files that the FSUID of the process owns; but this\ncan currently partially be bypassed using atomic write ioctls in two ways:\n\n - F2FS_IOC_START_ATOMIC_REPLACE + F2FS_IOC_COMMIT_ATOMIC_WRITE can\n   truncate an inode to size 0\n - F2FS_IOC_START_ATOMIC_WRITE + F2FS_IOC_ABORT_ATOMIC_WRITE can revert\n   changes another process concurrently made to a file\n\nFix it by requiring FMODE_WRITE for these operations, just like for\nF2FS_IOC_MOVE_RANGE. Since any legitimate caller should only be using these\nioctls when intending to write into the file, that seems unlikely to break\nanything."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"700f3a7c7fa5764c9f24bbf7c78e0b6e479fa653","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"4ce87674c3a6b4d3b3d45f85b584ab8618a3cece","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"000bab8753ae29a259feb339b99ee759795a48ac","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"88ff021e1fea2d9b40b2d5efd9013c89f7be04ac","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"32f348ecc149e9ca70a1c424ae8fa9b6919d2713","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"5e0de753bfe87768ebe6744d869caa92f35e5731","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"f3bfac2cabf5333506b263bc0c8497c95302f32d","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"4583290898c13c2c2e5eb8773886d153c2c5121d","versionType":"git"},{"version":"88b88a66797159949cec32eaab12b4968f6fae2d","status":"affected","lessThan":"4f5a100f87f32cb65d4bb1ad282a08c92f6f591e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/f2fs/file.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.18","versionType":"semver"},{"version":"4.19.323","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.285","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.227","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.168","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.113","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.54","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.10.13","status":"unaffected","lessThanOrEqual":"6.10.*","versionType":"semver"},{"version":"6.11.2","status":"unaffected","lessThanOrEqual":"6.11.*","versionType":"semver"},{"version":"6.12","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/f2fs/file.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/700f3a7c7fa5764c9f24bbf7c78e0b6e479fa653"},{"url":"https://git.kernel.org/stable/c/4ce87674c3a6b4d3b3d45f85b584ab8618a3cece"},{"url":"https://git.kernel.org/stable/c/000bab8753ae29a259feb339b99ee759795a48ac"},{"url":"https://git.kernel.org/stable/c/88ff021e1fea2d9b40b2d5efd9013c89f7be04ac"},{"url":"https://git.kernel.org/stable/c/32f348ecc149e9ca70a1c424ae8fa9b6919d2713"},{"url":"https://git.kernel.org/stable/c/5e0de753bfe87768ebe6744d869caa92f35e5731"},{"url":"https://git.kernel.org/stable/c/f3bfac2cabf5333506b263bc0c8497c95302f32d"},{"url":"https://git.kernel.org/stable/c/4583290898c13c2c2e5eb8773886d153c2c5121d"},{"url":"https://git.kernel.org/stable/c/4f5a100f87f32cb65d4bb1ad282a08c92f6f591e"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Exploitation requires issuing F2FS_IOC_START_ATOMIC_REPLACE/COMMIT/ABORT ioctls on a local file descriptor for a regular file on a locally-mounted f2fs filesystem. There is no network-reachable path to fs/f2fs/file.c ioctl handlers.\nAC:L - The destructive primitive is two deterministic ioctl calls on an fd the attacker already holds — no race, no memory-layout dependency, no timing sensitivity. Even the rollback variant is attacker-timed: it chooses when to START and when to ABORT, and any concurrent writes landing in that window are discarded, so a wider window simply catches more.\nPR:L - Only local unprivileged code execution plus an O_RDONLY fd on a file whose UID matches the attacker's FSUID is needed; inode_owner_or_capable() short-circuits on the UID match, so no capability, user namespace, or root is required. mnt_want_write_file() checks only that the mount is writable, not the fd.\nUI:N - START_ATOMIC_REPLACE + COMMIT_ATOMIC_WRITE truncates the file to zero entirely under attacker control, with no victim action required. The attacker opens the file itself and needs nothing from any other process.\nS:U - The vulnerable f2fs ioctl handler and the impacted files are both governed by the kernel's security authority; bypassing an in-kernel LSM check is not a crossing into a different authority. No hypervisor, IOMMU, or VM boundary is traversed.\nC:N - The bug is purely a missing write-side access-control check — the attacker already holds read access to the target file, so nothing new is disclosed. No kernel memory is leaked and no read primitive is created.\nI:H - The attacker gains write-equivalent power over files the security policy explicitly protected from modification: complete irreversible truncation to size 0, and silent rollback of another process's already-acknowledged writes. For a Landlock- or SELinux-confined process the protected file set is exactly what falls, and every byte of it can be destroyed — a total loss of integrity for the affected resources.\nA:H - Truncating a target such as a system database, keystore, or configuration file to zero permanently destroys the resource and renders the depending service unavailable. Independently, the attacker can pin the inode in atomic-write state for as long as it chooses, causing all O_DIRECT reads/writes from legitimate processes to fail -EOPNOTSUPP and fallocate/MOVE_RANGE/SET_PIN_FILE/defrag to fail -EINVAL — a sustained, attacker-controlled denial of service."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T11:39:50.713Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"4.19.323"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"5.4.285"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"5.10.227"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"5.15.168"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.1.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.6.54"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.10.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.11.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.12"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2024-47740","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-10-21T12:59:19.414286Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-10-21T13:04:14.597Z"}},{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html"},{"url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2025-11-03T22:21:36.961Z"}}]}}}