[PATCH 1/3] ext4: require key for truncate(2) of encrypted file

[Theodore Ts'o]

On Tue, Jun 13, 2017 at 04:47:53PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers at google.com>
> 
> Currently, filesystems allow truncate(2) on an encrypted file without
> the encryption key.  However, it's impossible to correctly handle the
> case where the size being truncated to is not a multiple of the
> filesystem block size, because that would require decrypting the final
> block, zeroing the part beyond i_size, then encrypting the block.
> 
> As other modifications to encrypted file contents are prohibited without
> the key, just prohibit truncate(2) as well, making it fail with ENOKEY.
> 
> Signed-off-by: Eric Biggers <ebiggers at google.com>

Thanks, applied.

					- Ted