CVE-2009-1883 kernel: missing capability check in z90crypt

[Eugene Teo <eugeneteo () kernel sg>]

There is a missing capability check in the z90crypt driver in the Linux 
kernel. This missing check could allow a local, unprivileged user to 
bypass intended capability restrictions. Thanks to Solar Designer for 
reporting this issue to us.

Note that this does not affect upstream anymore.

@@ -1887,20 +1887,21 @@ z90crypt_unlocked_ioctl(struct file *fil
     PRINTK("No longer issuing messages about depre"
            "cated ioctl Z90STAT_PCIXCCCOUNT.\n");
   }

   tempstat = get_status_PCIXCCcount();
   if (copy_to_user((int *)arg, &tempstat, sizeof(int)) != 0)
    ret = -EFAULT;
   break;

  case Z90QUIESCE:
   if (current->euid != 0) { <-- should check a capability
    PRINTK("QUIESCE fails: euid %d\n",
           current->euid);
    ret = -EACCES;
   } else {
    PRINTK("QUIESCE device from PID %d\n", PID());
    quiesce_z90crypt = 1;
   }
   break;

Thanks, Eugene