Re: [PATCH 4.19 33/75] f2fs: fix to avoid accessing xattr across the boundary

[Pavel Machek]

Hi!

> When we traverse xattr entries via __find_xattr(),
> if the raw filesystem content is faked or any hardware failure occurs,
> out-of-bound error can be detected by KASAN.
> Fix the issue by introducing boundary check.

Ok, so this prevents fs corruption from causing problems,

> @@ -340,7 +347,11 @@ static int lookup_all_xattrs(struct inode *inode, struct page *ipage,
>  	else
>  		cur_addr = txattr_addr;
>  
> -	*xe = __find_xattr(cur_addr, index, len, name);
> +	*xe = __find_xattr(cur_addr, last_txattr_addr, index, len, name);
> +	if (!*xe) {
> +		err = -EFAULT;
> +		goto out;
> +	}

Is -EFAULT suitable here? We do not have userspace passing pointers to us, we
have fs corruption. -EUNCLEAN?

Should it do some kind of printk to let the user know fs is corrupted, and mark
it as needing fsck?

Thanks,
									Pavel