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:

voidSSL_close_all(SSL*ssl,SSL_CTX*ctx,intclient_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); }