Explanation of my code:

It first creates a server and waiting to connect.

Once the client connects to the server he is getting the line, can you solve this? If he put the correct code his getting output -> good job If not -> The software disconnects.

My question is whether there is some sort of security hole in the software that allows you to know (as a client) the password? Is there is any weakness in the code? Is it possible to exploit my code? If so, how?

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <netinet/in.h>
#include <sys/wait.h>

#define ALARM_TIMEOUT_SEC (1200)
#define PASSWORD_LENGTH   (100)
#define BRUTE_FORCE_TIMEOUT (1)

int is_correct(char * given_password_hex)
{
char b2h[256] = {
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1, /* 0-9 */
    -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* A-F */
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /* a-f */
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
};

char password[50] = "hajdgufh{0000000000123456780000000000000000000000}";
char given_password[50];
char value1;
    char value2;
    int i;
    char diff = 0;

    size_t given_password_hex_length = strlen(given_password_hex);
    if (PASSWORD_LENGTH != given_password_hex_length) {
        printf("bad input1: %zu\n", given_password_hex_length);
        return 0;
    }

    bzero(given_password, sizeof(given_password));
    for (i = 0; i < sizeof(given_password); i++) {
        value1 = b2h[given_password_hex[i * 2]];
        value2 = b2h[given_password_hex[i * 2 + 1]];

        if (value1 == -1 || value2 == -1) {
            printf("bad input2\n");
            return 0;
        }

    given_password[i] = (value1 << 4) | value2;
}

for (i = 0; i < 50; i++) {
    diff |= (password[i] ^ given_password[i]);
}

return (diff == 0);
}

void right_trim(char * str)
{
char * t = str + strlen(str) - 1;
char * p;
for (p = t; p >= str; p--) {
    if (!strchr(" \r\n", *p)) {
        break;
    }

    *p = '\0';
}
}

void handle(int s)
{
char inbuf[4096];//we defined inbuf as 4096 size

dup2(s, 0);
dup2(s, 1);

setbuf(stdout, NULL);

alarm(ALARM_TIMEOUT_SEC);

printf("lets see if you able to solve me : ");

if (NULL == fgets(inbuf, sizeof(inbuf), stdin)) {//fgets -> don't have any vulnarble to buffer overflow 
    return;//becoas its restrict the size of the input 
}

right_trim(inbuf);

if (is_correct(inbuf)) {
    printf("Good job!\n");
    }
}

void handle_sigchld(int sig) {
    waitpid((pid_t)(-1), 0, WNOHANG);
}

int main(int argc, char * argv[])//------------------------------------------------------------
{

    printf("we in");
    if (1 == argc) {
        printf("Usage: %s <port>\n", argv[0]);
        printf("section 1");
        exit(-0);
    }

    int port = strtol(argv[1], NULL, 10);
    if (0 == port) {
        printf("section 2");
        perror("Invalid port");
        exit(-1);
    }

struct sigaction sa;
sa.sa_handler = &handle_sigchld;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART | SA_NOCLDSTOP;
if (sigaction(SIGCHLD, &sa, 0) == -1) {
    perror("Unable to register sigaction");
    exit(-2);
}

int s = socket(AF_INET, SOCK_STREAM, 0);
if (-1 == s) {
    perror("Unable to create server socket");
    exit(-3);
}

int optval = 1;
if (0 != setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval))) {
    perror("Unable to setsockopt");
    exit(-4);
}

struct sockaddr_in bind_addr = {
    .sin_family = AF_INET,
    .sin_port = htons(port)
};

if (0 != bind(s, (struct sockaddr *) &bind_addr, sizeof(bind_addr))) {
    perror("Unable to bind socket");
    printf("section 3");
    exit(-5);
}

if (0 != listen(s, 10)) {
    perror("Unable to listen");
    exit(-6);
}

while (1) {
    int s_ = accept(s, NULL, NULL);

    sleep(BRUTE_FORCE_TIMEOUT);

    if (-1 == s_) {
        perror("Unable to accept");
        continue;
    }

    pid_t child_pid = fork();
    if (-1 == child_pid) {
        perror("Unable to fork");
        goto accept_cleanup;
    }

    if (0 == child_pid) {
        close(s);
        handle(s_);
        exit(0);
    }

accept_cleanup:
    close(s_);
}

exit(0);
}