Re: Stricter error handling in mcrypt extension

On Sat, Mar 1, 2014 at 7:12 PM, Nikita Popov <nikita.ppv@gmail.com> wrote: > Hi internals! > > I would like to add a number of additional error checks in > php_mcrypt_do_crypt - which affects the mcrypt_encrypt, mcrypt_decrypt and > mcrypt_{BLOCK_CHAINING_MODE} userland functions. > > The proposed changes are: > * Throw a warning and return bool(false) if the IV size is invalid. The > old behavior was to throw a warning and use a NUL-byte IV. > * Throw a warning and return bool(false) if no IV was specified, but the > block chaining mode requires an IV. The old behavior was to throw a warning > and use a NUL-byte IV. > * Throw a warning and return bool(false) if the key size is invalid. The > old behavior was to **silently** pad the string to the next valid key size > with NUL bytes or, if the key is too long, to throw a warning and truncate > it to the maximum valid key size. > > An implementation of these changes can be found in the PR > https://github.com/php/php-src/pull/610. > > The reason why I'd like to make the mcrypt input handling stricter is to > ensure that incorrectly implemented encryption will fail and fail > violently. With the current lax input checking it is very easy to > completely compromise confidentiality through simple mistakes - like using > a password as the encryption key. > > Thanks, > Nikita > > PS: I'm running this change by the list because stricter error handling is > technically a BC break. Of course this change is targeting PHP 5.6 only. > I think that's a good idea given the number of people I've heard complaints from about confusion around using mcrypt and the default NUL-byte IV. My only concern is, isn't it a bit late in the game to push this to 5.6? Or is that when we're at beta? Overall I think it's a smart change though despite the BC.