[android-common:mirror-chromeos-5.10-arcvm 0/4] fs/fuse/file.c:2777:19: warning: result of comparison of constant 4294967291 with expression of type '__u16' (aka 'unsigned short') is always false

[kernel test robot <lkp@intel.com>]

Hi Chirantan,

FYI, the error/warning still remains.

tree:   https://android.googlesource.com/kernel/common mirror-chromeos-5.10-arcvm
head:   6f82755ed602e815541b2c6617a3f30f53500cdc
commit: 7f33c2b5012b1ada851aafcf8620e1723b8db574 [0/4] CHROMIUM: Support fsverity in fuse
config: i386-buildonly-randconfig-1004-20261006 (https://download.01.org/0day-ci/archive/20261006/202610061536.Xi3mAvpP-lkp@intel.com/config)
compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project 80cd965b6323b208519f8ab1d5ee86e4ea9862f4)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261006/202610061536.Xi3mAvpP-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202610061536.Xi3mAvpP-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> fs/fuse/file.c:2777:19: warning: result of comparison of constant 4294967291 with expression of type '__u16' (aka 'unsigned short') is always false [-Wtautological-constant-out-of-range-compare]
    2777 |                 if (digest_size > SIZE_MAX - sizeof(struct fsverity_digest))
         |                     ~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   1 warning generated.


vim +2777 fs/fuse/file.c

  2745	
  2746	static int fuse_get_ioctl_len(unsigned int cmd, unsigned long arg, size_t *len)
  2747	{
  2748		switch (cmd) {
  2749		case FS_IOC_GETFLAGS:
  2750		case FS_IOC_SETFLAGS:
  2751			*len = sizeof(int);
  2752			break;
  2753		case FS_IOC_GET_ENCRYPTION_POLICY_EX: {
  2754			__u64 policy_size;
  2755			struct fscrypt_get_policy_ex_arg __user *uarg =
  2756				(struct fscrypt_get_policy_ex_arg __user *)arg;
  2757	
  2758			if (copy_from_user(&policy_size, &uarg->policy_size,
  2759					   sizeof(policy_size)))
  2760				return -EFAULT;
  2761	
  2762			if (policy_size > SIZE_MAX - sizeof(policy_size))
  2763				return -EINVAL;
  2764	
  2765			*len = sizeof(policy_size) + policy_size;
  2766			break;
  2767		}
  2768		case FS_IOC_MEASURE_VERITY: {
  2769			__u16 digest_size;
  2770			struct fsverity_digest __user *uarg =
  2771				(struct fsverity_digest __user *)arg;
  2772	
  2773			if (copy_from_user(&digest_size, &uarg->digest_size,
  2774					   sizeof(digest_size)))
  2775				return -EFAULT;
  2776	
> 2777			if (digest_size > SIZE_MAX - sizeof(struct fsverity_digest))
  2778				return -EINVAL;
  2779	
  2780			*len = sizeof(struct fsverity_digest) + digest_size;
  2781			break;
  2782		}
  2783		default:
  2784			*len = _IOC_SIZE(cmd);
  2785			break;
  2786		}
  2787	
  2788		return 0;
  2789	}
  2790	

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0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki