On Thu, 2019-12-12 at 10:57 +0100, Arnd Bergmann wrote:
> On Thu, Dec 12, 2019 at 1:14 AM Ben Hutchings
> <ben.hutchings@xxxxxxxxxxxxxxx> wrote:
> > On Wed, 2019-12-11 at 22:20 +0100, Arnd Bergmann wrote:
> > [...]
> > > +static int snd_timer_user_tread(void __user *argp, struct snd_timer_user *tu,
> > > + unsigned int cmd, bool compat)
> > > +{
> > > + int __user *p = argp;
> > > + int xarg, old_tread;
> > > +
> > > + if (tu->timeri) /* too late */
> > > + return -EBUSY;
> > > + if (get_user(xarg, p))
> > > + return -EFAULT;
> > > +
> > > + old_tread = tu->tread;
> > > +
> > > + if (!xarg)
> > > + tu->tread = TREAD_FORMAT_NONE;
> > > + else if (cmd == SNDRV_TIMER_IOCTL_TREAD64 ||
> > > + (IS_ENABLED(CONFIG_64BITS) && !compat))
> >
> > This needs to check for CONFIG_64BIT not CONFIG_64BITS.
>
> Fixed now, good catch!
>
> > > @@ -2145,14 +2202,34 @@ static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
> > > + case TREAD_FORMAT_NONE:
> > > if (copy_to_user(buffer, &tu->queue[qhead],
> > > sizeof(struct snd_timer_read)))
> > > err = -EFAULT;
> > > + break;
> > > + default:
> > > + err = -ENOTSUPP;
> > [...]
> >
> > This is not a valid error code for returning to user-space, but this
> > case should be impossible so I don't think it matters.
>
> Agreed. Maybe it should also WARN_ON(1), as there getting here
> would indicate a bug in the kernel.
Yes, WARN_ON() or WARN_ON_ONCE() would make sense.
Ben.
--
Ben Hutchings, Software Developer Codethink Ltd
https://www.codethink.co.uk/ Dale House, 35 Dale Street
Manchester, M1 2HF, United Kingdom
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