{"id":"CVE-2025-38218","summary":"f2fs: fix to do sanity check on sit_bitmap_size","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to do sanity check on sit_bitmap_size\n\nw/ below testcase, resize will generate a corrupted image which\ncontains inconsistent metadata, so when mounting such image, it\nwill trigger kernel panic:\n\ntouch img\ntruncate -s $((512*1024*1024*1024)) img\nmkfs.f2fs -f img $((256*1024*1024))\nresize.f2fs -s -i img -t $((1024*1024*1024))\nmount img /mnt/f2fs\n\n------------[ cut here ]------------\nkernel BUG at fs/f2fs/segment.h:863!\nOops: invalid opcode: 0000 [#1] SMP PTI\nCPU: 11 UID: 0 PID: 3922 Comm: mount Not tainted 6.15.0-rc1+ #191 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nRIP: 0010:f2fs_ra_meta_pages+0x47c/0x490\n\nCall Trace:\n f2fs_build_segment_manager+0x11c3/0x2600\n f2fs_fill_super+0xe97/0x2840\n mount_bdev+0xf4/0x140\n legacy_get_tree+0x2b/0x50\n vfs_get_tree+0x29/0xd0\n path_mount+0x487/0xaf0\n __x64_sys_mount+0x116/0x150\n do_syscall_64+0x82/0x190\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\nRIP: 0033:0x7fdbfde1bcfe\n\nThe reaseon is:\n\nsit_i-\u003ebitmap_size is 192, so size of sit bitmap is 192*8=1536, at maximum\nthere are 1536 sit blocks, however MAIN_SEGS is 261893, so that sit_blk_cnt\nis 4762, build_sit_entries() -\u003e current_sit_addr() tries to access\nout-of-boundary in sit_bitmap at offset from [1536, 4762), once sit_bitmap\nand sit_bitmap_mirror is not the same, it will trigger f2fs_bug_on().\n\nLet's add sanity check in f2fs_sanity_check_ckpt() to avoid panic.","modified":"2026-03-20T12:42:44.657153Z","published":"2025-07-04T13:37:35.157Z","related":["MGASA-2025-0218","MGASA-2025-0219"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38218.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/38ef48a8afef8df646b6f6ae7abb872f18b533c1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3e5ac62a56a24f4d88ce8ffd7bc452428b235868"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5db0d252c64e91ba1929c70112352e85dc5751e7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/79ef8a6c4ec53d327580fd7d2b522cf4f1d05b0c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/82f51bff393e4c12cf4de553120ca831cfa4ef19"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ad862f71016ba38039df1c96ed55c0a4314cc183"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ee1b421c469876544e297ec1090574bd76100247"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38218.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-38218"},{"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":"82f51bff393e4c12cf4de553120ca831cfa4ef19"},{"fixed":"38ef48a8afef8df646b6f6ae7abb872f18b533c1"},{"fixed":"ad862f71016ba38039df1c96ed55c0a4314cc183"},{"fixed":"79ef8a6c4ec53d327580fd7d2b522cf4f1d05b0c"},{"fixed":"ee1b421c469876544e297ec1090574bd76100247"},{"fixed":"3e5ac62a56a24f4d88ce8ffd7bc452428b235868"},{"fixed":"5db0d252c64e91ba1929c70112352e85dc5751e7"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-38218.json"}}],"schema_version":"1.7.5"}