Bugs
Add missing NULL guards to SM2 key-agreement and key-pair JNI entry points
Native memory may leak and miss NULL guards in SM2/ECDSA/ECDH/SM4 JNI layer
Native context may leak in SM3/SM3HMac clone() and SM4OneShotCrypt
Native JNI build should default to a Release build and hide non-exported symbols
Native context-creating functions should return 0 instead of OPENSSL_FAILURE for handles
Native sm3hmac_create_ctx should return NULL instead of OPENSSL_FAILURE on error
Native context-creating functions should return 0 instead of OPENSSL_FAILURE for handles
Native sm3hmac_create_ctx should return NULL instead of OPENSSL_FAILURE on error
Native EC key pair generation and SM2 key agreement should not corrupt or leak memory
Native SM2 key agreement should avoid floating-point and clarify return value naming
Native sm2ToUncompPubKey should reuse the cached SM2 group
Native SM4/ECDSA context creation should validate iv length and check digest init
Native SM2/SM4 operations should not leak resources or overflow on invalid input
Native crypto should harden init and free operations
Native SM4/SM2/EC operations should not leak memory on key handling
Native signature verify should not treat internal error as success