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[209.85.221.176]) by smtp.gmail.com with ESMTPSA id x66sm19563289vkx.23.2019.01.08.15.58.51 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 08 Jan 2019 15:58:52 -0800 (PST) Received: by mail-vk1-f176.google.com with SMTP id w72so1288984vkd.5 for ; Tue, 08 Jan 2019 15:58:51 -0800 (PST) X-Received: by 2002:a1f:a8c5:: with SMTP id r188mr1421446vke.44.1546991931435; Tue, 08 Jan 2019 15:58:51 -0800 (PST) MIME-Version: 1.0 References: <20181226075436.11018-1-christophe.jaillet@wanadoo.fr> In-Reply-To: <20181226075436.11018-1-christophe.jaillet@wanadoo.fr> From: Kees Cook Date: Tue, 8 Jan 2019 15:58:40 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 1/2] um: vector: Fix a potential NULL pointer dereference in 'vector_net_open()' To: Christophe JAILLET Cc: Jeff Dike , Richard Weinberger , anton.ivanov@cambridgegreys.com, Mike Rapoport , Andrew Morton , YueHaibing , linux-um@lists.infradead.org, LKML , kernel-janitors@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 28, 2018 at 1:57 AM Christophe JAILLET wrote: > > 'create_queue()' returns NULL in case of memory allocation failure. So we > must check if it succeeds in order to avoid potential NULL pointer > dereference. > > For 'vp->rx_queue', the dereference would occur just one line after the > failed allocation. For 'vp->tx_queue', it would occur later during normal > processing. > > Fixes: 49da7e64f33e ("High Performance UML Vector Network Driver") > Signed-off-by: Christophe JAILLET Reviewed-by: Kees Cook -Kees > --- > arch/um/drivers/vector_kern.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_kern.c > index 046fa9ea0ccc..5b917716289d 100644 > --- a/arch/um/drivers/vector_kern.c > +++ b/arch/um/drivers/vector_kern.c > @@ -1182,6 +1182,8 @@ static int vector_net_open(struct net_device *dev) > vp->rx_header_size, > MAX_IOV_SIZE > ); > + if (!vp->rx_queue) > + goto out_close; > vp->rx_queue->queue_depth = get_depth(vp->parsed); > } else { > vp->header_rxbuffer = kmalloc( > @@ -1198,6 +1200,8 @@ static int vector_net_open(struct net_device *dev) > vp->header_size, > MAX_IOV_SIZE > ); > + if (!vp->tx_queue) > + goto out_close; > } else { > vp->header_txbuffer = kmalloc(vp->header_size, GFP_KERNEL); > if (vp->header_txbuffer == NULL) > -- > 2.19.1 > -- Kees Cook