eas 中由 ssl.c 文件中 SSL_close_all 引发的 bug

SSL_close_all 函数的源码如下:

void SSL_close_all ( SSL * ssl , SSL_CTX * ctx , int client_fd ) { s_log ( eDEBUG1 , "calling shutdown(%i, SHUT_RDWR)" , client_fd ); if ( shutdown ( client_fd , SHUT_RDWR ) < 0 ) { s_log ( eERROR , "shutdown(%i, SHUT_RDWR): %.100s (%i)" , client_fd , strerror ( errno ), errno ); s_log ( eDEBUG1 , "calling exit(%i)" , EXIT_FAILURE ); exit ( EXIT_FAILURE ); } s_log ( eDEBUG1 , "calling close(%i)" , client_fd ); if ( close ( client_fd ) < 0 ) { s_log ( eERROR , "close(%i): %.100s (%i)" , client_fd , strerror ( errno ), errno ); s_log ( eDEBUG1 , "calling exit(%i)" , EXIT_FAILURE ); exit ( EXIT_FAILURE ); } s_log ( eDEBUG2 , "calling SSL_shutdown(%x)" , ssl ); if ( SSL_shutdown ( ssl ) < 0 ) { s_log ( eERROR , "SSL_shutdown: %.100s (%i)" , strerror ( errno ), errno ); s_log ( eDEBUG1 , "calling exit(%i)" , EXIT_FAILURE ); exit ( EXIT_FAILURE ); } s_log ( eDEBUG2 , "calling SSL_free(%x)" , ssl ); SSL_free ( ssl ); s_log ( eDEBUG2 , "calling SSL_CTX_free(%x)" , ctx ); SSL_CTX_free ( ctx ); }

在出现问题的服务器上使用 "strace" 对 easd 进程的系统调用进行跟踪, 发现

shutdown(client_fd, SHUT_RDWR) 使 socket 连接双方不能通过 client_fd 进行发送和接收;

close(client_fd) 关闭 socket 连接 client_fd

SSL_shutdown(ssl) 先往 client_fd 中写入数据, 再关闭 client_fd ( ssl 中应该含有 client_fd )

由上可知, 原有的代码会因为文件描述符引发 bug (关闭后还进行写入操作)

不知道原先很多系统中, 运行程序并没有报 bug, 猜测是因为不同的库对 SSL_shutdown() 的实现不同.

因此, 对于报 bug 的服务器 SSL_close_all 函数的代码应该改为:

voidSSL_close_all(SSL*ssl,SSL_CTX*ctx,intclient_fd) { s_log ( eDEBUG2 , "calling SSL_shutdown(%x)" , ssl ); if ( SSL_shutdown ( ssl ) < 0 ) { s_log ( eERROR , "SSL_shutdown: %.100s (%i)" , strerror ( errno ), errno ); s_log ( eDEBUG1 , "calling exit(%i)" , EXIT_FAILURE ); exit ( EXIT_FAILURE ); } s_log(eDEBUG1,"calling close(%i)",client_fd); if ( close ( client_fd ) < 0 ) { s_log ( eERROR , "close(%i): %.100s (%i)" , client_fd , strerror ( errno ), errno ); s_log ( eDEBUG1 , "calling exit(%i)" , EXIT_FAILURE ); exit ( EXIT_FAILURE ); } s_log ( eDEBUG2 , "calling SSL_free(%x)" , ssl ); SSL_free ( ssl ); s_log ( eDEBUG2 , "calling SSL_CTX_free(%x)" , ctx ); SSL_CTX_free ( ctx ); }