{"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 <TASK>\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"}}}}