从NetCore报错到MySql安全

之前项目在测试服务器上的一些接口时不时会报出下面的错误：（采用Abp框架）

"SocketException: 你的主机中的软件中止了一个已建立的连接。
STACK TRACE:    at MySqlConnector.Protocol.Serialization.SocketByteHandler.WriteBytesAsync(ArraySegment` data, IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\Protocol\Serialization\SocketByteHandler.cs:line
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySqlConnector.Utilities.ValueTaskExtensions.<ContinueWith>d__0`.MoveNext() in C:\projects\mysqlconnector\src\MySqlConnector\Utilities\ValueTaskExtensions.cs:line
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySqlConnector.Core.ServerSession.TryAsyncContinuation(Task` task) in C:\projects\mysqlconnector\src\MySqlConnector\Core\ServerSession.cs:line
   at System.Threading.Tasks.ContinuationResultTaskFromResultTask`.InnerInvoke()
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySqlConnector.Core.TextCommandExecutor.<ExecuteReaderAsync>d__1.MoveNext() in C:\projects\mysqlconnector\src\MySqlConnector\Core\TextCommandExecutor.cs:line
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySql.Data.MySqlClient.MySqlCommand.<ExecuteNonQueryAsync>d__60.MoveNext() in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlCommand.cs:line
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlCommand.cs:line
   at MySql.Data.MySqlClient.MySqlTransaction.Dispose(Boolean disposing) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlTransaction.cs:line
   at Microsoft.EntityFrameworkCore.Storage.RelationalTransaction.Dispose()
   at Abp.EntityFrameworkCore.Uow.DbContextEfCoreTransactionStrategy.Dispose(IIocResolver iocResolver)
   at Abp.EntityFrameworkCore.Uow.EfCoreUnitOfWork.DisposeUow()
   at Abp.Domain.Uow.UnitOfWorkBase.Dispose()
   at Abp.AspNetCore.Mvc.Uow.AbpUowActionFilter.<OnActionExecutionAsync>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeNextActionFilterAsync>d__10.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ActionExecutedContext context)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeInnerFilterAsync>d__13.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.<InvokeNextExceptionFilterAsync>d__24.MoveNext()
"

MySql.Data.MySqlClient.MySqlException (0x80004005): Failed to read the result set.
---> System.IO.EndOfStreamException: Expected to read  header bytes but only received .
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySqlConnector.Protocol.Serialization.ProtocolUtility.DoReadPayloadAsync(BufferedByteReader bufferedByteReader, IByteHandler byteHandler, Func` getNextSequenceNumber, ArraySegmentHolder` previousPayloads, ProtocolErrorBehavior protocolErrorBehavior, IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\Protocol\Serialization\ProtocolUtility.cs:line
   at MySqlConnector.Protocol.Serialization.StandardPayloadHandler.ReadPayloadAsync(ArraySegmentHolder` cache, ProtocolErrorBehavior protocolErrorBehavior, IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\Protocol\Serialization\StandardPayloadHandler.cs:line
   at MySqlConnector.Core.ServerSession.ReceiveReplyAsync(IOBehavior ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\Core\ServerSession.cs:line
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySqlConnector.Core.ServerSession.TryAsyncContinuation(Task` task) in C:\projects\mysqlconnector\src\MySqlConnector\Core\ServerSession.cs:line
   at System.Threading.Tasks.ContinuationResultTaskFromResultTask`.InnerInvoke()
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot)
--- End of stack trace from previous location where exception was thrown ---

然后我使用swagger+miniprofiler，查看生成的sql语句

查看Mysql错误日志：

Aborted connection 422 to db: '数据库名称' user: 'root' host: 'localhost' (Got a packet bigger than 'max_allowed_packet' bytes)

可能因为传输的数据过大，而Mysql的max_allowed_packet默认为1024b，导致sql执行不成功。

然后将Mysql配置文件中的max_allowed_packet值改为max_allowed_packet = 4M

重启Mysql，问题解决。

然而过了一段时间，同样的报错又出现了，首先看了下max_allowed_packet的值，果然max_allowed_packet又被修改为了1024b，查看命令如下：

show variables like '%max_allowed_packet%';

然后询问同事，他们说并没有动数据库，上网查了下说是有可能是被攻击了。

于是我开启了Mysql的日志，命令如下：

set global general_log=on;

在日志里看到了被修改信息，然后看了下ip~~~

还发现了几个新增用户TvT，把它删掉：

查看Mysql用户命令如下：

select * from mysql.user

目前解决方法是，加强密码，限制远程连接ip：把上图的% 改为指定ip段xxx.xxx.xxx.%，重启Mysql。