解决和修复静态分析工具SPLINT指出的漏洞

Question

我正在处理我的项目并尝试运行夹板以查看一些隐藏的漏洞并提高我的代码质量，我运行夹板在我的项目的一个 .c 文件上我遇到了这 4 个警告

Splint 3.1.2 --- 20 Feb 2018

quit_again_final.c: (in function quit)
quit_again_final.c:10:5: Return value (type int) ignored: scanf("%s", ans)
  Result returned by function call is not used. If this is intended, can cast
  result to (void) to eliminate message. (Use -retvalint to inhibit warning)
quit_again_final.c:11:9: Incompatible types for == (char, char):
                            tolower(ans[0]) == 'y'
  A character constant is used as an int. Use +charintliteral to allow
  character constants to be used as ints.  (This is safe since the actual type
  of a char constant is int.)
quit_again_final.c: (in function again)
quit_again_final.c:26:5: Return value (type int) ignored: scanf("%s", ans1)
quit_again_final.c:27:9: Incompatible types for == (char, char):
                            tolower(ans1[0]) == 'y'

Finished checking --- 4 code warnings

我不太确定我应该采取哪些步骤来消除漏洞 .c文件如下

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<ctype.h>
#include"server.h"
void quit()
{
    char ans[5];
    printf("ARE YOU SURE YOU WANT TO QUIT THE WIZARD? Y OR N\n");
    scanf("%s", ans);
    if (tolower(ans[0]) == 'y')
    {
        final_print();
        printf("\n\n");
        printf("---THANK YOU FOR USING OUR PORTAL--\n");
    }
    else
    {
        main2();
    }
}
void again()
{
    char ans1[5];
    printf("SEARCH AGAIN USING ID AND PASSWORD? Y OR N\n");
    scanf("%s", ans1);
    if (tolower(ans1[0]) == 'y')
    {
        main2();//FOR RE-LOGIN PROCESS
    }
    else
    {
        quit();
    }
    printf("\n\n\n\n\n\n");
}
void final_print()
{
    printf("----------------FINAL STATEMENT OF LEAVE OF EACH EMPLOYEE------------------------\n\n");
    int i;
    for (i = 0; i < 5; i++)
    {
        printf("NAME : %s\n",emp[i].name);
        printf("USER ID : %s\n",emp[i].id);
        printf("CASUAL LEAVE LEFT : %d\n",emp[i].casual);
        printf("MEDICAL LEAVE LEFT : %d\n",emp[i].medical);
        printf("EARNED LEAVE LEFT : %d\n\n",emp[i].earned);
    }
    printf("---------THANK YOU FOR USING LEAVE MANEGMENT PORTAL-----\n");
}

有人可以指导我解决这些错误，因为我是处理这些错误的新手

错误重复出现，只需解决其中的 2 个错误即可解决整个文件

Answer 1

要消除 scanf 的警告，请尝试工具建议的操作：

    (void)scanf("%s", ans);

要消除 tolower(ans[0]) == 'y' 的警告，试试这个：

    if (tolower(ans[0]) == (int)'y')

但后者不应该是警告，因为在 C 中，char 文字（例如 'y'）的类型是 int，因此 IMO 警告无论如何都是虚假的。

解决和修复静态分析工具SPLINT指出的漏洞

Solving and fixing vulnerability pointed by the static analysis tool SPLINT

c

security

static-analysis

splint

secure-coding