CVE-2026-53041ocfs2: fix listxattr handling when the buffer is full

Official description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix listxattr handling when the buffer is full [BUG] If an OCFS2 inode has both inline and block-based xattrs, listxattr() can return a size larger than the caller's buffer when the inline names consume that buffer exactly. kernel BUG at mm/usercopy.c:102! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI RIP: 0010:usercopy_abort+0xb7/0xd0 mm/usercopy.c:102 Call Trace: __check_heap_object+0xe3/0x120 mm/slub.c:8243 check_heap_object mm/usercopy.c:196 [inline] __check_object_size mm/usercopy.c:250 [inline] __check_object_size+0x5c5/0x780 mm/usercopy.c:215 check_object_size include/linux/ucopysize.h:22 [inline] check_copy_size include/linux/ucopysize.h:59 [inline] copy_to_user include/linux/uaccess.h:219 [inline] listxattr+0xb0/0x170 fs/xattr.c:926 filename_listxattr fs/xattr.c:958 [inline] path_listxattrat+0x137/0x320 fs/xattr.c:988 __do_sys_listxattr fs/xattr.c:1001 [inline] __se_sys_listxattr fs/xattr.c:998 [inline] __x64_sys_listxattr+0x7f/0xd0 fs/xattr.c:998 ... [CAUSE] Commit 936b8834366e ("ocfs2: Refactor xattr list and remove ocfs2_xattr_handler().") replaced the old per-handler list accounting with ocfs2_xattr_list_entry(), but it kept using size == 0 to detect probe mode. That assumption stops being true once ocfs2_listxattr() finishes the inline-xattr pass. If the inline names fill the caller buffer exactly, the block-xattr pass runs with a non-NULL buffer and a remaining size of zero. ocfs2_xattr_list_entry() then skips the bounds check, keeps counting block names, and returns a positive size larger than the supplied buffer. [FIX] Detect probe mode by testing whether the destination buffer pointer is NULL instead of whether the remaining size is zero. That restores the pre-refactor behavior and matches the OCFS2 getxattr helpers. Once the remaining buffer reaches zero while more names are left, the block-xattr pass now returns -ERANGE instead of reporting a size larger than the allocated list buffer.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/a35a1c2b170b5b578b1b3fecb95694796552af9a
• https://git.kernel.org/stable/c/2323084c17370304f49c84b354fe7b3edbb264fe
• https://git.kernel.org/stable/c/6f702b00b8124c5d3525f19172934544826a114d
• https://git.kernel.org/stable/c/d919b905939eda93393e3572900ff70dbad2b47f
• https://git.kernel.org/stable/c/46e66fefb83811958127bc9ad736983ec629d82b
• https://git.kernel.org/stable/c/2685df8577a38d83b367c8cf52eda9dc286959ff
• https://git.kernel.org/stable/c/50033ec1350fe68abdc63b950ced7ae57364b77a
• https://git.kernel.org/stable/c/d12f558e6200b3f47dbef9331ed6d115d2410e59