Bug 2461550 (CVE-2026-31596) - CVE-2026-31596 kernel: ocfs2: handle invalid dinode in ocfs2_group_extend
Summary: CVE-2026-31596 kernel: ocfs2: handle invalid dinode in ocfs2_group_extend
Keywords:
Status: NEW
Alias: CVE-2026-31596
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-24 15:07 UTC by OSIDB Bzimport
Modified: 2026-04-24 19:12 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2026-04-24 15:07:57 UTC
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.


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