semctl bug

[Kris Kennaway]

On Wed, Jul 26, 2006 at 04:04:06PM +0800, ?????? wrote:
> In file kern/sysv_sem.c:
> 554 __semctl(td, uap)
> 555         struct thread *td;
> 556         struct __semctl_args *uap;
> 557 {
> 558         int semid = uap->semid; <<<here  1
> 559         int semnum = uap->semnum;
> 560         int cmd = uap->cmd;
> 561         u_short *array;
> 562         union semun *arg = uap->arg;
> 563         union semun real_arg;
> 564         struct ucred *cred = td->td_ucred;
> 565         int i, rval, error;
> 566         struct semid_ds sbuf;
> 567         struct semid_kernel *semakptr;
> 568         struct mtx *sema_mtxp;
> 569         u_short usval, count;
> 570
> 571         DPRINTF(("call to semctl(%d, %d, %d, 0x%x)\n",
> 572             semid, semnum, cmd, arg));
> 573         if (!jail_sysvipc_allowed && jailed(td->td_ucred))
> 574                 return (ENOSYS);
> 575
> 576         array = NULL;
> 577
> 578         switch(cmd) {
> 579         case SEM_STAT:
> 580                 if (semid < 0 || semid >= seminfo.semmni) <<<here 2
> 581                         return (EINVAL);
> 582                 if ((error = copyin(arg, &real_arg, sizeof(real_arg))) 
> != 0)
> 583                         return (error);
> 584                 semakptr = &sema[semid];<<<here 3
> 
> >From line 558 to line 578, there must be a mechism to convert the
> sem_id to the internal sema array index. In fact, it was missing,
> which make the semctl syscall not work well. The  return valure of
> semget, the semaphore ID, is larger than 65535.  when test on line 580
> return  EINVAL in any case. Following code also using the semid which
> is from user directly as index of sema[] array.

Please submit a PR so this bug report is not lost.

Kris