{"id":"CVE-2025-40025","summary":"f2fs: fix to do sanity check on node footer for non inode dnode","details":"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 \u003cTASK\u003e\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\"","modified":"2026-04-02T12:48:15.597040Z","published":"2025-10-28T09:32:31.806Z","related":["openSUSE-SU-2025:15702-1","openSUSE-SU-2026:10301-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40025.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/186098f34b8a5d65eb828f952c8cc56272c60ea0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c18ecd99e0c707ef8f83cace861cbc3162f4fdf1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40025.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-40025"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"98e4da8ca301e062d79ae168c67e56f3c3de3ce4"},{"fixed":"186098f34b8a5d65eb828f952c8cc56272c60ea0"},{"fixed":"c18ecd99e0c707ef8f83cace861cbc3162f4fdf1"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40025.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.8.0"},{"fixed":"6.17.2"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40025.json"}}],"schema_version":"1.7.5"}