From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 11 Oct 2018 06:43:56 -0700 From: Christoph Hellwig To: "Darrick J. Wong" Cc: david@fromorbit.com, sandeen@redhat.com, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, Amir Goldstein , linux-unionfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, ocfs2-devel@oss.oracle.com Subject: Re: [PATCH 04/25] vfs: strengthen checking of file range inputs to generic_remap_checks Message-ID: <20181011134356.GD23424@infradead.org> References: <153923113649.5546.9840926895953408273.stgit@magnolia> <153923116686.5546.8711942394464060950.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <153923116686.5546.8711942394464060950.stgit@magnolia> Sender: owner-linux-mm@kvack.org List-ID: On Wed, Oct 10, 2018 at 09:12:46PM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong > > File range remapping, if allowed to run past the destination file's EOF, > is an optimization on a regular file write. Regular file writes that > extend the file length are subject to various constraints which are not > checked by range cloning. > > This is a correctness problem because we're never allowed to touch > ranges that the page cache can't support (s_maxbytes); we're not > supposed to deal with large offsets (MAX_NON_LFS) if O_LARGEFILE isn't > set; and we must obey resource limits (RLIMIT_FSIZE). > > Therefore, add these checks to the new generic_remap_checks function so > that we curtail unexpected behavior. > > Signed-off-by: Darrick J. Wong > Reviewed-by: Amir Goldstein Looks good, Reviewed-by: Christoph Hellwig