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[76.119.149.155]) by smtp.gmail.com with ESMTPSA id g21sm10634593qts.18.2020.07.28.04.07.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Jul 2020 04:07:17 -0700 (PDT) Date: Tue, 28 Jul 2020 07:07:15 -0400 From: Peilin Ye To: Daniel Borkmann , Song Liu , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , Magnus Karlsson , Jonathan Lemon Cc: Dan Carpenter , Arnd Bergmann , Greg Kroah-Hartman , "David S. Miller" , Jakub Kicinski , Alexei Starovoitov , Jesper Dangaard Brouer , John Fastabend , Martin KaFai Lau , Yonghong Song , Andrii Nakryiko , KP Singh , linux-kernel-mentees@lists.linuxfoundation.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [Linux-kernel-mentees] [PATCH net v2] xdp: Prevent kernel-infoleak in xsk_getsockopt() Message-ID: <20200728110715.GA407606@PWN> References: <20200728022859.381819-1-yepeilin.cs@gmail.com> <20200728053604.404631-1-yepeilin.cs@gmail.com> <916dbfd3-e601-c4be-41f0-97efc4aaa456@iogearbox.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <916dbfd3-e601-c4be-41f0-97efc4aaa456@iogearbox.net> Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Tue, Jul 28, 2020 at 12:53:59PM +0200, Daniel Borkmann wrote: > On 7/28/20 7:36 AM, Peilin Ye wrote: > > xsk_getsockopt() is copying uninitialized stack memory to userspace when > > `extra_stats` is `false`. Fix it. > > > > Fixes: 8aa5a33578e9 ("xsk: Add new statistics") > > Suggested-by: Dan Carpenter > > Signed-off-by: Peilin Ye > > --- > > Doing `= {};` is sufficient since currently `struct xdp_statistics` is > > defined as follows: > > > > struct xdp_statistics { > > __u64 rx_dropped; > > __u64 rx_invalid_descs; > > __u64 tx_invalid_descs; > > __u64 rx_ring_full; > > __u64 rx_fill_ring_empty_descs; > > __u64 tx_ring_empty_descs; > > }; > > > > When being copied to the userspace, `stats` will not contain any > > uninitialized "holes" between struct fields. > > I've added above explanation to the commit log since it's useful reasoning for later > on 'why' something has been done a certain way. Applied, thanks Peilin! Ah, I see. Thank you for reviewing the patch! Peilin Ye