• Eric Biggers's avatar
    fscrypto: only allow setting encryption policy on directories · 002ced4b
    Eric Biggers authored
    The FS_IOC_SET_ENCRYPTION_POLICY ioctl allowed setting an encryption
    policy on nondirectory files.  This was unintentional, and in the case
    of nonempty regular files did not behave as expected because existing
    data was not actually encrypted by the ioctl.
    
    In the case of ext4, the user could also trigger filesystem errors in
    ->empty_dir(), e.g. due to mismatched "directory" checksums when the
    kernel incorrectly tried to interpret a regular file as a directory.
    
    This bug affected ext4 with kernels v4.8-rc1 or later and f2fs with
    kernels v4.6 and later.  It appears that older kernels only permitted
    directories and that the check was accidentally lost during the
    refactoring to share the file encryption code between ext4 and f2fs.
    
    This patch restores the !S_ISDIR() check that was present in older
    kernels.
    Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
    002ced4b
policy.c 6.5 KB