栈，而退出线程

Question

我有一些问题，我的连接处理线程，该线程似乎工作不错，但我收到此异常，直到它结束：

*** stack smashing detected ***: ./listener2 terminated 
Aborted (core dumped) 

这是我的线程：

void* SocketHandler(void* par) { 
    struct thread_par* parameters=(struct thread_par*) par; 
    int *csock = parameters->client_desc; 
    MYSQL_RES *mysql_res; 

    int buffer_len = 128; 
    char client_message[buffer_len]; 
    int bytecount; 
    memset(client_message, 0, buffer_len); 
    if ((bytecount = read(*csock, client_message, buffer_len) == -1)) { 
     fprintf(stderr, "Error receiving data\n"); 
     close(*csock); 
     return 0; 
    } 
    printf("Received bytes %d\nReceived string \"%s\"\n", bytecount, client_message); 
    char *sensor_alive = strtok(client_message, "&&"); 
    /* 
    * the next operations will be done only for alive sensors 
    */ 
    if (sensor_alive != NULL && strcmp(sensor_alive, "ALIVE") == 0) { 
      puts("sensor Alive OK"); 
      //mysql_quwry returns 
      //Zero for success. Nonzero if an error occurred. 
      if (mysql_query(parameters->mysql_conn, 
        "--query--")) { 
       fprintf(stderr, "%s\n", mysql_error(parameters->mysql_conn)); 
       mysql_free_result(mysql_res); 
       return 0; 
      } 
      mysql_res = mysql_use_result(parameters->mysql_conn); 
     } 

    puts("Query executed"); 
    if (mysql_res->lengths > 0) { 
     //we will do a second query , don't need anymore this 
     mysql_free_result(mysql_res); 

     /* 
     * creation of a string containing the current time with the following format 
     * YYYY-MM-dd hh-mm-ss 
     */ 
     time_t t; 
     struct tm* tm; 
     char Date[11], Time[9]; 

     time(&t); 
     tm = localtime(&t); 

     char time_string[20]; 
     strftime(time_string, sizeof time_string, "%Y-%m-%d %H:%M:%S", tm); 
     puts(time_string); 

     /* 
     * creation of the query 
     * UPDATE sensors SET alive = 1, updated_at='YYYY-MM-dd hh-mm-ss' WHERE id_device='id'; 
     */ 
     char* query_part_1 = "--query--"; 
     char* query_part_2 = "--query--"; 
     char query[sizeof(query_part_1) + sizeof(query_part_2)+ sizeof(time_string)]; 
     strcpy(query, query_part_1); 
     strcpy(query + strlen(query_part_1), time_string); 
     strcpy(query + strlen(query_part_1) + strlen(time_string), 
       query_part_2); 

     //ALIVE UPDATE QUERY 
     if (mysql_query(parameters->mysql_conn, query)) { 
      fprintf(stderr, "%s\n", mysql_error(parameters->mysql_conn)); 
      mysql_free_result(mysql_res); 
      return 0; 
     } 
     //mysql_free_result(mysql_res); 
     puts("Alive value updated"); 

     //jump the part 1 of the message 
     strtok(NULL, "&&"); 
     //jump the part 2 of the message 
     strtok(NULL, "&&"); 
     //jump the part 3 of the message 
     strtok(NULL, "&&"); 
     //jump the part 4 of the message 
     strtok(NULL, "&&"); 

     char* query_begin = "--query--"; 
     char* status_vector = strtok(NULL, "&&"); //part 5 
     strtok(NULL, "&&"); //part 6 don't needed 
     char* local_time = strtok(NULL, "&&"); //part 7 
     char* timer = strtok(NULL, "&&"); //part 8 
     char* created_at = strtok(NULL, "&&"); //part 9 

     int total_len = 150; 

     char query2[total_len]; 
     snprintf(query2, sizeof(query2), "%s('%s','%s','%s','%s','%s');", 
       query_begin, status_vector, local_time, timer, created_at, 
       time_string); 

     puts(query2); 

     if (mysql_query(parameters->mysql_conn, query2)) { 
      fprintf(stderr, "%s\n", mysql_error(parameters->mysql_conn)); 
      return 0; 
     } 
     //mysql_free_result(mysql_res); 
     puts("Value updated"); 

    } 


    /* 
    * ending thread operations 
    */ 
    //close(*csock); 
    //free(csock); 
    puts("exiting thread"); 
    //pthread_exit(0); 
    return 0; 
} 

这是我的输出

Received bytes 0 
Received string "ALIVE&&000000000035&&STATION NUM. 1&&40.1234234&&14.1234234&&0000000&&192.___&&00&&18:9:49&&2&&" 
sensor Alive OK 
Query executed 
2014-10-16 18:08:10 
Alive value updated 
INSERT INTO -------; 
Value updated 
exiting thread 
*** stack smashing detected ***: ./listener2 terminated 
Aborted (core dumped) 

我不是在C那么好，所以我不知道如何解决我的亲blem 你能帮助我吗？

Answer 1

你query变量太小：

char query[sizeof(query_part_1) + sizeof(query_part_2) + sizeof(time_string)]; 

你已经宣布它为大到足以容纳唯一的字符数在query_part_1，query_part_2和time_string。您忘记考虑字符串终止NUL字节，因此第三个strcpy调用将会在query的末尾写入并破坏堆栈。

Answer 2

你有一个缓冲区溢出，这就是为什么你得到“堆栈粉碎检测”消息。检查你的代码。 但我查看了你的代码，并且无法找到任何溢出，诚实地:)

Answer 3

在编译时使用-fno-stack-protector作为选项。这将导致获得不同的错误，主要是分段错误。正如提到的其他答案，这显然是缓冲区溢出。您可以使用strace或gdb运行程序来检测代码中的问题。 e.g strace ./a.out或gdb a.out