• Phillip Potter's avatar
    fs: common implementation of file type · d44170a7
    Phillip Potter authored
    Many file systems use a copy&paste implementation of dirent to on-disk
    file type conversions. Furthermore the current ext2 implementation that
    gets copy&pasted has a lurking out-of-bounds access bug to the
    ext2_type_by_mode array. The array is defined with size S_IFMT >>
    S_SHIFT, so 15. This means that a corrupted inode with mode == S_IFMT
    will result in access beyond the end of the array as the array is always
    accessed with:
    
    ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
    
    Create a common implementation to be used by file systems with some
    useful conversion helpers to reduce open coded file type conversions in
    file system code. Since the type ids are part of on-disk format of each
    filesystem, conversion of each filesystem will take care to build-assert
    that on-disk format type ids defined by the generic header match the
    filesystem defined ones.
    Signed-off-by: 's avatarAmir Goldstein <amir73il@gmail.com>
    Signed-off-by: 's avatarPhillip Potter <phil@philpotter.co.uk>
    Signed-off-by: 's avatarJan Kara <jack@suse.cz>
    d44170a7
fs_types.c 2.53 KB