Null pointer access

[FatsharkGo]

We ported folly to Android and encounted an uncaugth exception while disabling the WIFI, debugger shows that the exception throws in the finall logging block of AsyncSSLSocket::performRead list below:

auto errError = ERR_get_error();
VLOG(6) << "AsyncSSLSocket(fd=" << fd_ << ", "
        << "state=" << state_ << ", "
        << "sslState=" << sslState_ << ", "
        << "events=" << std::hex << eventFlags_ << "): "
        << "bytes: " << bytes << ", "
        << "error: " << error << ", "
        << "errno: " << errno << ", "
        << "func: " << ERR_func_error_string(errError) << ", "
        << "reason: " << ERR_reason_error_string(errError);

The root cause of this exception is that ERR_func_error_string cannot mapping errError to a valid string and returns a nullptr, we add some check of these mappings and passed the test case.

const char* err_func = ERR_func_error_string(errError);
const char* err_reason = ERR_reason_error_string(errError);
VLOG(6) << "AsyncSSLSocket(fd=" << fd_ << ", "
        << "state=" << state_ << ", "
        << "sslState=" << sslState_ << ", "
        << "events=" << std::hex << eventFlags_ << "): "
        << "bytes: " << bytes << ", "
        << "error: " << error << ", "
        << "errno: " << errno << ", "
        << "func: " << (err_func ? err_func : "") << ", "
        << "reason: " << (err_reason ? err_reason : "");

Another two functions involve this defect:

• bool AsyncSSLSocket::willBlock
• AsyncSocket::WriteResult AsyncSSLSocket::interpretSSLError