The API for pwhash_str returns a cstring in the output buffer. These
are null terminated. However, we return the full buffer as a binary
back to Erlang. This means that we have a buffer with 0'es in the end.
The tests take this buffer and passes it back in as is. Hence all the
tests pass. However, it is conceivable that if we write said buffer to
disk somewhere, we are not going to write those 0's out.
When we then load the ASCII-armored Argon2 string into memory again,
it is not 0-terminated as a cstring should be, and this produces
errors all over the place.
The fix is twofold:
* Return the full buffer to Erlang, but use binary:split/2 to create a
subbinary with the relevant part.
* Add a 0 in the end of ASCII Argon2 string before passing it to
libsodium
Since we are looking at pwhashing, and Argon2, we expect the
computational problem to be memory bound. Thus, spending a bit more
work in memory is not going to have any considerable impact on the
speed of this system.
A lot of people who pushed functions they missed have not pushed any
kind of test cases for them. To make sure we have test coverage, I've
marked the functions we have under test and the functions we are still
missing tests for.
This involves:
- Removing calls to conjunction function
- Modifying fault* functions to _always_ return "Good" generator
- Commenting-out the eqc_parallelize parse_transform
These variables are being initialized via calls to `enif_get_uint`,
so it's safer to declare them as unsigned int's rather than size_t's.
Their being used in calls to `enif_alloc_binary`, which takes a size_t
as its size.
However, the resulting ErlNifBinary keeps its size as an unsigned int,
so asking for a size that's an unsigned int should be safe.
This would be problematic in the case where sizeof(size_t) <
sizeof(unsigned), which would mean we're getting fewer bytes allocated
than expected.
Perhaps an explicit check for, for example, `hashSize > MAX_SIZE` would
be good here?
