Messages in this thread | | | From | Arnd Bergmann <> | Date | Tue, 28 Jul 2020 11:00:16 +0200 | Subject | Re: [Linux-kernel-mentees] [PATCH v3] media/v4l2-core: Fix kernel-infoleak in video_put_user() |
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On Tue, Jul 28, 2020 at 12:05 AM Peilin Ye <yepeilin.cs@gmail.com> wrote: > > On Mon, Jul 27, 2020 at 04:16:08PM +0300, Dan Carpenter wrote: > > drivers/char/hpet.c:675 hpet_ioctl() warn: check that 'info' doesn't leak information (struct has a hole after 'hi_timer') > > This one seems like a false positive. > > drivers/char/hpet.c:670: > > mutex_lock(&hpet_mutex); > err = hpet_ioctl_common(file->private_data, cmd, arg, &info); > mutex_unlock(&hpet_mutex); > > if ((cmd == HPET_INFO) && !err && > (copy_to_user((void __user *)arg, &info, sizeof(info)))) > err = -EFAULT; > > `info` is only being copied to userspace when `cmd` is `HPET_INFO`. > However, hpet_ioctl_common() is already doing memset() on `info` in > `case HPET_INFO`: > > drivers/char/hpet.c:612: > > case HPET_INFO: > { > memset(info, 0, sizeof(*info)); > ^^^^^^
Yes, makes sense.
Arnd
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