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Date: Fri, 26 Oct 2018 14:26:31 -0700
From: Matthew Wilcox <willy@infradead.org>
To: Olga Kornievskaia <olga.kornievskaia@gmail.com>
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Subject: Re: [PATCH v4 02/11] VFS: copy_file_range check validity of input
 source offset
Message-ID: <20181026212631.GY25444@bombadil.infradead.org>
References: <20181026201057.36899-1-olga.kornievskaia@gmail.com>
 <20181026201057.36899-4-olga.kornievskaia@gmail.com>
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On Fri, Oct 26, 2018 at 04:10:48PM -0400, Olga Kornievskaia wrote:
> +++ b/fs/read_write.c
> @@ -1594,6 +1594,9 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
>  		}
>  	}
>  
> +	if (pos_in >= i_size_read(inode_in))
> +		return -EINVAL;
> +
>  	if (file_out->f_op->copy_file_range) {
>  		ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out,
>  						      pos_out, len, flags);

Is this the right place to check this?  Surely we should be checking for
this before calling clone_file_range()?