{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40025", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.152Z", "datePublished": "2025-10-28T09:32:31.806Z", "dateUpdated": "2026-08-05T12:07:07.729Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:07:07.729Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to do sanity check on node footer for non inode dnode\n\nAs syzbot reported below:\n\n------------[ cut here ]------------\nkernel BUG at fs/f2fs/file.c:1243!\nOops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\nCPU: 0 UID: 0 PID: 5354 Comm: syz.0.0 Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(full)\nRIP: 0010:f2fs_truncate_hole+0x69e/0x6c0 fs/f2fs/file.c:1243\nCall Trace:\n \n f2fs_punch_hole+0x2db/0x330 fs/f2fs/file.c:1306\n f2fs_fallocate+0x546/0x990 fs/f2fs/file.c:2018\n vfs_fallocate+0x666/0x7e0 fs/open.c:342\n ksys_fallocate fs/open.c:366 [inline]\n __do_sys_fallocate fs/open.c:371 [inline]\n __se_sys_fallocate fs/open.c:369 [inline]\n __x64_sys_fallocate+0xc0/0x110 fs/open.c:369\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7f1e65f8ebe9\n\nw/ a fuzzed image, f2fs may encounter panic due to it detects inconsistent\ntruncation range in direct node in f2fs_truncate_hole().\n\nThe root cause is: a non-inode dnode may has the same footer.ino and\nfooter.nid, so the dnode will be parsed as an inode, then ADDRS_PER_PAGE()\nmay return wrong blkaddr count which may be 923 typically, by chance,\ndn.ofs_in_node is equal to 923, then count can be calculated to 0 in below\nstatement, later it will trigger panic w/ f2fs_bug_on(, count == 0 || ...).\n\n\tcount = min(end_offset - dn.ofs_in_node, pg_end - pg_start);\n\nThis patch introduces a new node_type NODE_TYPE_NON_INODE, then allowing\npassing the new_type to sanity_check_node_footer in f2fs_get_node_folio()\nto detect corruption that a non-inode dnode has the same footer.ino and\nfooter.nid.\n\nScripts to reproduce:\nmkfs.f2fs -f /dev/vdb\nmount /dev/vdb /mnt/f2fs\ntouch /mnt/f2fs/foo\ntouch /mnt/f2fs/bar\ndd if=/dev/zero of=/mnt/f2fs/foo bs=1M count=8\numount /mnt/f2fs\ninject.f2fs --node --mb i_nid --nid 4 --idx 0 --val 5 /dev/vdb\nmount /dev/vdb /mnt/f2fs\nxfs_io /mnt/f2fs/foo -c \"fpunch 6984k 4k\"" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerability is reached through local syscalls (fallocate/read/write/truncate) on a file residing in a mounted, attacker-crafted f2fs image; no network or remote protocol handling is involved.\nAC:L - The attacker fully controls the on-disk node footer (footer.ino == footer.nid) and the punch-hole offset/length, so the misparse and the resulting out-of-bounds access are deterministic — the commit ships a byte-exact reproducer via inject.f2fs plus a single xfs_io fpunch.\nPR:L - Once the crafted image is mounted (removable media/automount, shared workstation, or Android SD card), triggering requires only an unprivileged local user issuing a normal fallocate or read on a file in that filesystem — no capability check exists on the path from vfs_fallocate to f2fs_get_dnode_of_data.\nUI:N - After the malicious image is present, the attacker performs every step themselves; no victim action is needed to reach f2fs_truncate_hole or the read/write paths that hit the same misparse.\nS:U - The corruption is confined to kernel memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - f2fs_data_blkaddr() indexes i_addr (base byte 360) with a direct-node offset up to 1017, reading past the end of the 4 KiB node folio; the leaked adjacent kernel memory becomes dn->data_blkaddr, which f2fs then treats as a physical block address and may read into the page cache, exposing arbitrary disk and heap contents.\nI:H - __set_data_blkaddr() writes through the same out-of-bounds pointer, and with CONFIG_F2FS_CHECK_FS disabled the f2fs_bug_on degrades to WARN_ON so the underflowed, attacker-chosen count is passed to f2fs_truncate_data_blocks_range, yielding an attacker-controlled-length out-of-bounds write past the node folio plus invalidation of arbitrary filesystem blocks.\nA:H - With CONFIG_F2FS_CHECK_FS enabled this is a hard BUG_ON at fs/f2fs/file.c:1243 causing immediate kernel panic (as syzbot reported), and without it the out-of-bounds writes corrupt adjacent kernel memory and filesystem metadata, crashing the system." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/f2fs/f2fs.h", "fs/f2fs/gc.c", "fs/f2fs/node.c", "fs/f2fs/node.h", "fs/f2fs/recovery.c" ], "versions": [ { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "186098f34b8a5d65eb828f952c8cc56272c60ea0", "status": "affected", "versionType": "git" }, { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "c18ecd99e0c707ef8f83cace861cbc3162f4fdf1", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/f2fs/f2fs.h", "fs/f2fs/gc.c", "fs/f2fs/node.c", "fs/f2fs/node.h", "fs/f2fs/recovery.c" ], "versions": [ { "version": "3.8", "status": "affected" }, { "version": "0", "lessThan": "3.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.2", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.17.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/186098f34b8a5d65eb828f952c8cc56272c60ea0" }, { "url": "https://git.kernel.org/stable/c/c18ecd99e0c707ef8f83cace861cbc3162f4fdf1" } ], "title": "f2fs: fix to do sanity check on node footer for non inode dnode", "x_generator": { "engine": "bippy-1.2.0" } } } }