In the Linux kernel, the following vulnerability has been resolved:

ocfs2: reject dinodes with non-canonical i_mode type

Patch series "ocfs2: harden inode validators against forged metadata", v2.

This series adds three structural checks to OCFS2 dinode validation so
malformed on-disk fields are rejected before ocfs2_populate_inode() copies
them into the in-core inode.

The checks cover:

  - i_mode values whose type bits do not name a canonical POSIX file
    type;
  - non-device dinodes whose id1.dev1.i_rdev field is non-zero; and
  - non-inline dinodes that claim non-zero i_size while i_clusters is
    zero, covering directories unconditionally and regular files on
    non-sparse volumes.

The normal read path reports these through ocfs2_error(), matching the
existing suballoc-slot, inline-data, chain-list, and refcount checks.  The
online filecheck path uses the same structural predicates but keeps its
own reporting contract, returning OCFS2_FILECHECK_ERR_INVALIDINO instead
of calling ocfs2_error().


This patch (of 3):

ocfs2_validate_inode_block() currently accepts any non-zero i_mode value. 
ocfs2_populate_inode() then copies that mode verbatim into inode->i_mode
and dispatches on i_mode & S_IFMT to the file/dir/symlink/special_file
iops; an unrecognised type falls through to ocfs2_special_file_iops and
init_special_inode().

Reject dinodes whose type bits do not name one of the seven canonical
POSIX file types.  Use fs_umode_to_ftype(), the same generic file-type
conversion helper OCFS2 already uses for directory entries, so the
accepted inode type set matches the kernel file-type vocabulary instead of
open-coding a local switch.

Apply the same structural check to the online filecheck read path. 
filecheck keeps its own error namespace, so it reports malformed i_mode
through the filecheck logger and OCFS2_FILECHECK_ERR_INVALIDINO instead of
calling ocfs2_error(), but it must not allow a malformed dinode to proceed
into ocfs2_populate_inode().