ocfs2: handle invalid dinode in ocfs2_group_extend

{
  "id": "8a22272fe3f0ba14ae2fdafb9920636973c99b3553f02b85d945a63e65805caf",
  "url": "https://osv.dev/vulnerability/CVE-2026-31596",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ocfs2: handle invalid dinode in ocfs2_group_extend",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ocfs2: handle invalid dinode in ocfs2_group_extend [BUG] kernel BUG at fs/ocfs2/resize.c:308! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI RIP: 0010:ocfs2_group_extend+0x10aa/0x1ae0 fs/ocfs2/resize.c:308 Code: 8b8520ff ffff83f8 860f8580 030000e8 5cc3c1fe Call Trace: ... ocfs2_ioctl+0x175/0x6e0 fs/ocfs2/ioctl.c:869 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x197/0x1e0 fs/ioctl.c:583 x64_sys_call+0x1144/0x26a0 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x93/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e ... [CAUSE] ocfs2_group_extend() assumes that the global bitmap inode block returned from ocfs2_inode_lock() has already been validated and BUG_ONs when the signature is not a dinode. That assumption is too strong for crafted filesystems because the JBD2-managed buffer path can bypass structural validation and return an invalid dinode to the resize ioctl. [FIX] Validate the dinode explicitly in ocfs2_group_extend(). If the global bitmap buffer does not contain a valid dinode, report filesystem corruption with ocfs2_error() and fail the resize operation instead of crashing the kernel.",
    "evidence": "osv:CVE-2026-31596",
    "products": [
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    "severity": "unknown",
    "structured": {
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      "aliases": [
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      "modified": "2026-10-28T02:30:25.182775238Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/10fb72c47aac446f12a4ccd962c7daa60cc890a1",
        "https://git.kernel.org/stable/c/41c6e9bc3a09539deab43957a3211d902a4818f0",
        "https://git.kernel.org/stable/c/4a1c0ddc6e7bcf2e9db0eeaab9340dcfe97f448f",
        "https://git.kernel.org/stable/c/6575f9fbf084502b7118a628425bf7866666498d",
        "https://git.kernel.org/stable/c/7eafcf507fbd68f3276c00f6c02ef155ad69f79b",
        "https://git.kernel.org/stable/c/911b557dd7817460881fd51a03069b539c674d0e",
        "https://git.kernel.org/stable/c/b328d8e7c437d0f026ba2c13788af6eae77700f1",
        "https://git.kernel.org/stable/c/e384a850a3370d89a7a446cdeccd964bfba2a302",
        "https://git.kernel.org/stable/c/fabfa6b81bd386154d7e59f8cd8f760f9e68b48c",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31596.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-31596",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
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    "security_relevant": true,
    "severity_evidence": null
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  "source_id": "core-osv",
  "document_id": 491804,
  "published_at": "2026-04-24T14:42:22.003+00:00"
}