Re: security/loadpin/loadpin.c:365 dm_verity_ioctl() warn: maybe return -EFAULT instead of the bytes remaining?
From: Kees Cook
Date: Tue Aug 16 2022 - 15:18:28 EST
On Mon, Aug 15, 2022 at 11:07:12AM +0300, Dan Carpenter wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: aea23e7c464bfdec04b52cf61edb62030e9e0d0a
> commit: 3f805f8cc23ba35679dd01446929292911c2b469 LoadPin: Enable loading from trusted dm-verity devices
> config: s390-randconfig-m031-20220810 (https://download.01.org/0day-ci/archive/20220814/202208141119.RKGSGoZ7-lkp@xxxxxxxxx/config)
> compiler: s390-linux-gcc (GCC) 12.1.0
>
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>
> smatch warnings:
> security/loadpin/loadpin.c:365 dm_verity_ioctl() warn: maybe return -EFAULT instead of the bytes remaining?
>
> vim +365 security/loadpin/loadpin.c
>
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 355 static long dm_verity_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 356 {
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 357 void __user *uarg = (void __user *)arg;
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 358 unsigned int fd;
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 359 int rc;
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 360
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 361 switch (cmd) {
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 362 case LOADPIN_IOC_SET_TRUSTED_VERITY_DIGESTS:
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 363 rc = copy_from_user(&fd, uarg, sizeof(fd));
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 364 if (rc)
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 @365 return rc;
>
> The copy_from_user() function returns the number of bytes remaining to
> be copied. It should be:
>
> if (copy_from_user(&fd, uarg, sizeof(fd)))
> return -EFAULT;
Oops, yes. I'll get this fixed.
-Kees
>
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 366
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 367 return read_trusted_verity_root_digests(fd);
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 368
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 369 default:
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 370 return -EINVAL;
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 371 }
> 3f805f8cc23ba3 Matthias Kaehlcke 2022-06-27 372 }
>
> --
> 0-DAY CI Kernel Test Service
> https://01.org/lkp
>
--
Kees Cook