Remove BASE64 reference testing as it's only libb64 now.
Improve the test to ignore \r and \n when comparing BASE-encoded
strings to not fail on system (unpatched) libb64.
Some crypto libraries (like CyaSSL, MatrixSSL and CommonCrypto) either
don't have or expose this functionality at all, expose only part of it,
or (like OpenSSL) have heavyweight API for it. Also, for the task as
easy as BASE64 encoding and decoding it's much better to use small and
simple specialized library.
Additionally,
* always close file descriptor on error in cached_file_open (FD leak),
* only store file descriptor to tr_cached_file on success,
* call ftruncate after xfsctl-based preallocation so that correct size
is reported by the system.
On a way to factoring out OpenSSL support to a standalone file to ease
addition of other crypto libraries support in the future, move helpers
providing DH key exchange to crypto-utils.{c,h}. OpenSSL-related
functionality (DH context management) is moved to crypto-utils-openssl.c.
Since we know in advance that DH secret key management code will be the
same for most of backends, implement common functionality in separate
crypto-utils-fallback.c.
Add new tr_dh_ctx_t and tr_dh_secret_t types and functions to be
implemented by crypto backends:
* tr_dh_new - allocate DH context,
* tr_dh_free - free the context,
* tr_dh_make_key - generate private/public keypair,
* tr_dh_agree - perform DH key exchange and generate secret key,
* tr_dh_secret_derive - calculate secret key hash,
* tr_dh_secret_free - free the secret key,
* tr_dh_align_key - align some DH key in the buffer allocated for it.
Make DH secret key not accessible in plain form outside the crypto
backend. This allows for implementations where the key is managed by
the underlying library and is not even exposed to our backend.
On a way to factoring out OpenSSL support to a standalone file to ease
addition of other crypto libraries support in the future, move helpers
providing SHA1 calculation to crypto-utils.{c,h}. OpenSSL-related
functionality (SHA1 context management) is moved to crypto-utils-openssl.c.
Add new tr_sha1_ctx_t type and functions to be implemented by crypto
backends:
* tr_sha1_init - allocate SHA1 context and and initialize it,
* tr_sha1_update - hash some [more] data,
* tr_sha1_final - finish hash calculation and free the context.
Add new files to CMakeLists.txt (leftover from previous commit) to fix
CMake-based configuration.