post-review fixes:
* move all ssl implementation related ifdefs/defines to one file
(ssl_compat.h)
* work around OpenSSL-1.1 desire to malloc every EVP context by
run-time checking that context allocated on the stack is big enough
(openssl.c)
* use newer version of the AWS SDK for OpenSSL 1.1
* use get_dh2048() function as generated by openssl 1.1
(viosslfactories.c)
Initial support
tested against OpenSSL 1.0.1, 1.0.2, 1.1.0, Yassl and LibreSSL
not working on Windows with native SChannel support, due to wrong cipher
mapping: Latter one requires push of CONC-241 fixes.
Please note that OpenSSL 0.9.8 and OpenSSL 1.1.0 will not work: Even if
the build succeeds, test cases will fail with various errors, especially
when using different tls libraries or versions for client and server.
Instead of encrypt(src, dst, key, iv) that encrypts all
data in one go, now we have encrypt_init(key,iv),
encrypt_update(src,dst), and encrypt_finish(dst).
This also causes collateral changes in the internal my_crypt.cc
encryption functions and in the encryption service.
There are wrappers to provide the old all-at-once encryption
functionality. But binlog events are often written piecewise,
they'll need the new api.
* Extract it into the "encryption_scheme" service.
* Make these engines to use the service, remove duplicate code.
* Change MY_AES_xxx error codes, to return them safely
from encryption_scheme_encrypt/decrypt without conflicting
with ENCRYPTION_SCHEME_KEY_INVALID error
* no --encryption-algorithm option anymore
* encrypt/decrypt methods in the encryption plugin
* ecnrypt/decrypt methods in the encryption_km service
* file_km plugin has --file-key-management-encryption-algorithm
* debug_km always uses aes_cbc
* example_km changes between aes_cbc and aes_ecb for different key versions
