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
- 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
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().