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().

Link: https://lore.kernel.org/20260519110404.1803902-1-michael.bommarito@gmail.com
Link: https://lore.kernel.org/20260519110404.1803902-2-michael.bommarito@gmail.com
Fixes: b657c95c1108 ("ocfs2: Wrap inode block reads in a dedicated function.")
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Link: https://sashiko.dev/#/patchset/20260517111015.3187935-1-michael.bommarito%40gmail.com
Assisted-by: Claude:claude-opus-4-7
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Heming Zhao <heming.zhao@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0 files changed, 0 insertions, 0 deletions