f2fs: fix to do sanity check on node footer for non inode dnode

{
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "cveMetadata": {
    "cveId": "CVE-2025-40025",
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "dateUpdated": "2025-10-28T09:32:31.806Z",
    "dateReserved": "2025-04-16T07:20:57.152Z",
    "datePublished": "2025-10-28T09:32:31.806Z",
    "state": "PUBLISHED"
  },
  "containers": {
    "cna": {
      "providerMetadata": {
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux",
        "dateUpdated": "2025-10-28T09:32:31.806Z"
      },
      "title": "f2fs: fix to do sanity check on node footer for non inode dnode",
      "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\""
        }
      ],
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/f2fs.h",
            "fs/f2fs/gc.c",
            "fs/f2fs/node.c",
            "fs/f2fs/node.h",
            "fs/f2fs/recovery.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "status": "affected",
              "versionType": "git",
              "lessThan": "186098f34b8a5d65eb828f952c8cc56272c60ea0"
            },
            {
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "status": "affected",
              "versionType": "git",
              "lessThan": "c18ecd99e0c707ef8f83cace861cbc3162f4fdf1"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/f2fs.h",
            "fs/f2fs/gc.c",
            "fs/f2fs/node.c",
            "fs/f2fs/node.h",
            "fs/f2fs/recovery.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "6.17.2",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.17.*"
            },
            {
              "version": "6.18-rc1",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ],
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/186098f34b8a5d65eb828f952c8cc56272c60ea0"
        },
        {
          "url": "https://git.kernel.org/stable/c/c18ecd99e0c707ef8f83cace861cbc3162f4fdf1"
        }
      ]
    }
  }
}