This one is a little thorny. All the various block cipher modes
functions and callbacks take a void *key. This allows them to be used
with multiple kinds of block ciphers.
However, the implementations of those callbacks are the normal typed
functions, like AES_encrypt. Those take AES_KEY *key. While, at the ABI
level, this is perfectly fine, C considers this undefined behavior.
If we wish to preserve this genericness, we could either instantiate
multiple versions of these mode functions or create wrappers of
AES_encrypt, etc., that take void *key.
The former means more code and is tedious without C++ templates (maybe
someday...). The latter would not be difficult for a compiler to
optimize out. C mistakenly allowed comparing function pointers for
equality, which means a compiler cannot replace pointers to wrapper
functions with the real thing. (That said, the performance-sensitive
bits already act in chunks, e.g. ctr128_f, so the function call overhead
shouldn't matter.)
But our only 128-bit block cipher is AES anyway, so I just switched
things to use AES_KEY throughout. AES is doing fine, and hopefully we
would have the sense not to pair a hypothetical future block cipher with
so many modes!
Change-Id: Ied3e843f0e3042a439f09e655b29847ade9d4c7d
Reviewed-on: https://boringssl-review.googlesource.com/32107
Reviewed-by: Adam Langley <agl@google.com>
The changes to delocate.go are needed because modes/ does things like
return the address of a module function. Both of these need to be
changed from referencing the GOT to using local symbols.
Rather than testing whether |ghash| is |gcm_ghash_avx|, we can just keep
that information in a flag.
The test for |aesni_ctr32_encrypt_blocks| is more problematic, but I
believe that it's superfluous and can be dropped: if you passed in a
stream function that was semantically different from
|aesni_ctr32_encrypt_blocks| you would already have a bug because
|CRYPTO_gcm128_[en|de]crypt_ctr32| will handle a block at the end
themselves, and assume a big-endian, 32-bit counter anyway.
Change-Id: I68a84ebdab6c6006e11e9467e3362d7585461385
Reviewed-on: https://boringssl-review.googlesource.com/15064
Reviewed-by: Adam Langley <agl@google.com>
