what is vulnerable in this password checking C code?

int main(int param_1,char *param_2) 
{
  __uid_t _Var1;
  uint uVar2;
  uint uVar3;
  uint uVar4;
  __pid_t __pid;
  __pid_t __pid_00;
  
  if (param_1 != 2) {
    FUN_00100f72(*(undefined8 *)param_2);
  }
  _Var1 = geteuid();
  if (_Var1 != 0) {
    fwrite("this program must run as root\n",1,0x1e,stderr);
                    /* WARNING: Subroutine does not return */
    exit(1);
  }
  uVar2 = atoi(*(char **)(param_2 + 8));
  if (((int)uVar2 < 1) || (0x10 < (int)uVar2)) {
    fwrite("error: number of workers must be between 1 and 16\n",1,0x32,stderr);
                    /* WARNING: Subroutine does not return */
    exit(1);
  }
  uVar3 = FUN_00100fab("/pwv-hashes");
  uVar4 = FUN_00100fab("/pwv-results");
  signal(0xf,FUN_00100f25);
  signal(2,FUN_00100f25);
  __pid = fork();
  if (__pid == 0) {
    FUN_00101824((ulong)uVar3);
                    /* WARNING: Subroutine does not return */
    exit(0);
  }
  __pid_00 = fork();
  if (__pid_00 == 0) {
    FUN_0010172a((ulong)uVar2,(ulong)uVar3,(ulong)uVar4,(ulong)uVar3);
                    /* WARNING: Subroutine does not return */
    exit(0);
  }
  waitpid(__pid,(int *)0x0,0);
  waitpid(__pid_00,(int *)0x0,0);
  FUN_00100f0a("/pwv-hashes");
  FUN_00100f0a("/pwv-results");
  fwrite("Exiting.\n",1,9,stderr);
  return 0;
}

this is password checking app for linux shadow file is there any vulnerability? ghidra also shows char *param_2 instead of char *param_2[] is there any difference? application makes some very simple checks (whether a user has a password which is the same as his/her username, whether the password is the username plus '1234' or '!@#$' patterns and finally, whether the password is a 4-digit number).

Down you will see some functions what they have inside them

    ulong FUN_00100fab(char *param_1)
{
  uint uVar1;
  long in_FS_OFFSET;
  undefined local_58 [8];
  undefined8 local_50;
  undefined8 local_48;
  long local_10;
  
  local_10 = *(long *)(in_FS_OFFSET + 0x28);
  local_50 = 4;
  local_48 = 0x421;
  uVar1 = mq_open(param_1,0xc2,0x1b6,local_58);
  if (uVar1 == 0xffffffff) {
    fwrite("error: could not create message queue!\n",1,0x27,stderr);
                    /* WARNING: Subroutine does not return */
    exit(1);
  }
  if (local_10 != *(long *)(in_FS_OFFSET + 0x28)) {
                    /* WARNING: Subroutine does not return */
    __stack_chk_fail();
  }
  return (ulong)uVar1;
}

 void FUN_00101824(mqd_t param_1)
{
  char *pcVar1;
  char *local_18;
  
  local_18 = (char *)FUN_00101044();
  while (local_18 != (char *)0x0) {
    mq_send(param_1,local_18,0x421,0);
    pcVar1 = *(char **)(local_18 + 0x428);
    free(local_18);
    local_18 = pcVar1;
  }
  return;
}




void FUN_00100f25(void)
{
  fwrite("caught signal, exiting!\n",1,0x18,stderr);
  FUN_00100f0a("/pwv-hashes");
  FUN_00100f0a("/pwv-results");
                    /* WARNING: Subroutine does not return */
  exit(1);
}

void FUN_00100f0a(char *param_1)

{
  mq_unlink(param_1);
  return;
}

void FUN_00100f72(undefined8 param_1)

{
  fprintf(stderr,
          "usage: %s <num_workers>\nexample: \n%s 2 # starts two worker processes to analyzepasswords\n"
          ,param_1,param_1);
                    /* WARNING: Subroutine does not return */
  exit(1);
}

void FUN_00101824(mqd_t param_1)

{
  char *pcVar1;
  char *local_18;
  
  local_18 = (char *)FUN_00101044();
  while (local_18 != (char *)0x0) {
    mq_send(param_1,local_18,0x421,0);
    pcVar1 = *(char **)(local_18 + 0x428);
    free(local_18);
    local_18 = pcVar1;
  }
  return;
}

char * FUN_00101044(void)

{
  int iVar1;
  int *piVar2;
  char *__dest;
  char **ppcVar3;
  char *local_28;
  char *local_20;
  
  local_28 = (char *)0x0;
  local_20 = (char *)0x0;
  iVar1 = lckpwdf();
  if (iVar1 != 0) {
    piVar2 = __errno_location();
    if (*piVar2 == 0xd) {
      fwrite("error: could not obtain shadow file lock. Are you root?\n",1,0x38,stderr);
    }
    else {
      fwrite("error: could not obtain shadow file lock for 15s. Exiting...\n",1,0x3d,stderr);
    }
                    /* WARNING: Subroutine does not return */
    exit(1);
  }
  setspent();
  __dest = local_28;
  do {
    do {
      local_28 = __dest;
      ppcVar3 = (char **)getspent();
      if (ppcVar3 == (char **)0x0) {
LAB_001011f6:
        endspent();
        ulckpwdf();
        return local_20;
      }
      iVar1 = strcmp(ppcVar3[1],"*");
      __dest = local_28;
    } while (((iVar1 == 0) || (iVar1 = strcmp(ppcVar3[1],"!"), iVar1 == 0)) || (*ppcVar3[1] == '\0')
            );
    __dest = (char *)malloc(0x430);
    if (__dest == (char *)0x0) {
      fwrite(
             "error: could not allocate memory for hash entry, shadow file will not be processed infull!\n"
             ,1,0x5c,stderr);
      goto LAB_001011f6;
    }
    strncpy(__dest,*ppcVar3,0x21);
    __dest[0x20] = '\0';
    strncpy(__dest + 0x21,ppcVar3[1],0x400);
    __dest[0x420] = '\0';
    *(undefined8 *)(__dest + 0x428) = 0;
    if (local_20 == (char *)0x0) {
      local_20 = __dest;
    }
    if (local_28 != (char *)0x0) {
      *(char **)(local_28 + 0x428) = __dest;
    }
  } while( true );
}

new functions

void FUN_0010172a(uint param_1,uint param_2,uint param_3)

{
  __pid_t __pid;
  __pid_t __pid_00;
  long in_FS_OFFSET;
  char local_438 [1064];
  long local_10;
  
  local_10 = *(long *)(in_FS_OFFSET + 0x28);
  __pid = fork();
  if (__pid == 0) {
    FUN_00101206((ulong)param_3);
                    /* WARNING: Subroutine does not return */
    exit(0);
  }
  __pid_00 = fork();
  if (__pid_00 == 0) {
    FUN_0010169f((ulong)param_1,(ulong)param_2,(ulong)param_3,(ulong)param_2);
                    /* WARNING: Subroutine does not return */
    exit(0);
  }
  waitpid(__pid_00,(int *)0x0,0);
  local_438[0] = '\0';
  mq_send(param_3,local_438,0x421,0);
  waitpid(__pid,(int *)0x0,0);
  if (local_10 != *(long *)(in_FS_OFFSET + 0x28)) {
                    /* WARNING: Subroutine does not return */
    __stack_chk_fail();
  }
  return;
}

void FUN_00101206(mqd_t param_1)

{
  ssize_t sVar1;
  long in_FS_OFFSET;
  char local_438 [33];
  undefined local_417 [1031];
  long local_10;
  
  local_10 = *(long *)(in_FS_OFFSET + 0x28);
  while( true ) {
    sVar1 = mq_receive(param_1,local_438,0x421,(uint *)0x0);
    if ((int)sVar1 == -1) {
      fwrite("error: could not dequeue message!\n",1,0x22,stderr);
                    /* WARNING: Subroutine does not return */
      exit(1);
    }
    if (local_438[0] == '\0') break;
    fprintf(stdout,"weak credentials {%s:%s} found\n",local_438,local_417);
  }
  if (local_10 != *(long *)(in_FS_OFFSET + 0x28)) {
                    /* WARNING: Subroutine does not return */
    __stack_chk_fail();
  }
  return;
}

ulong FUN_0010169f(int param_1,uint param_2,uint param_3)

{
  __pid_t _Var1;
  ulong uVar2;
  undefined4 extraout_var;
  uint local_c;
  
  fwrite("Trying username patterns and 4-digit patterns, please stand by.\n",1,0x40,stderr);
  local_c = 0;
  while( true ) {
    uVar2 = (ulong)local_c;
    if (param_1 <= (int)local_c) {
      while (0 < (int)local_c) {
        _Var1 = waitpid(-1,(int *)0x0,0);
        uVar2 = CONCAT44(extraout_var,_Var1);
        local_c = local_c - 1;
      }
      return uVar2;
    }
    _Var1 = fork();
    if (_Var1 == 0) break;
    local_c = local_c + 1;
  }
  FUN_00101563((ulong)param_2,(ulong)param_3,(ulong)param_3);
                    /* WARNING: Subroutine does not return */
  exit(0);
}
void FUN_00101563(mqd_t param_1,mqd_t param_2)

{
  int iVar1;
  time_t tVar2;
  ssize_t sVar3;
  int *piVar4;
  long in_FS_OFFSET;
  timespec local_878;
  char local_868 [1072];
  char local_438 [1064];
  long local_10;
  
  local_10 = *(long *)(in_FS_OFFSET + 0x28);
LAB_00101589:
  tVar2 = time((time_t *)0x0);
  local_878.tv_sec = tVar2 + 1;
  local_878.tv_nsec = 0;
  sVar3 = mq_timedreceive(param_1,local_868,0x421,(uint *)0x0,&local_878);
  if ((int)sVar3 == -1) {
    piVar4 = __errno_location();
    if (*piVar4 != 0x6e) {
      perror("worker: ");
      fwrite("error: could not dequeue message!\n",1,0x22,stderr);
                    /* WARNING: Subroutine does not return */
      exit(1);
    }
    if (local_10 != *(long *)(in_FS_OFFSET + 0x28)) {
                    /* WARNING: Subroutine does not return */
      __stack_chk_fail();
    }
    return;
  }
  iVar1 = FUN_00101388(local_868,local_438,local_438);
  if (iVar1 == 0) goto code_r0x00101643;
  goto LAB_00101664;
code_r0x00101643:
  iVar1 = FUN_001014b8(local_868,local_438,local_438);
  if (iVar1 != 0) {
LAB_00101664:
    mq_send(param_2,local_438,0x421,0);
  }
  goto LAB_00101589;
}