From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Florian Fainelli , Vivien Didelot , "David S. Miller" Subject: [PATCH 4.9 30/59] net: dsa: Ensure validity of dst->ds[0] Date: Fri, 13 Jan 2017 13:01:37 +0100 Message-Id: <20170113113840.505326441@linuxfoundation.org> In-Reply-To: <20170113113839.364876751@linuxfoundation.org> References: <20170113113839.364876751@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Florian Fainelli [ Upstream commit faf3a932fbeb77860226a8323eacb835edc98648 ] It is perfectly possible to have non zero indexed switches being present in a DSA switch tree, in such a case, we will be deferencing a NULL pointer while dsa_cpu_port_ethtool_{setup,restore}. Be more defensive and ensure that dst->ds[0] is valid before doing anything with it. Fixes: 0c73c523cf73 ("net: dsa: Initialize CPU port ethtool ops per tree") Signed-off-by: Florian Fainelli Reviewed-by: Vivien Didelot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/dsa/dsa2.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/net/dsa/dsa2.c +++ b/net/dsa/dsa2.c @@ -394,9 +394,11 @@ static int dsa_dst_apply(struct dsa_swit return err; } - err = dsa_cpu_port_ethtool_setup(dst->ds[0]); - if (err) - return err; + if (dst->ds[0]) { + err = dsa_cpu_port_ethtool_setup(dst->ds[0]); + if (err) + return err; + } /* If we use a tagging format that doesn't have an ethertype * field, make sure that all packets from this point on get @@ -433,7 +435,8 @@ static void dsa_dst_unapply(struct dsa_s dsa_ds_unapply(dst, ds); } - dsa_cpu_port_ethtool_restore(dst->ds[0]); + if (dst->ds[0]) + dsa_cpu_port_ethtool_restore(dst->ds[0]); pr_info("DSA: tree %d unapplied\n", dst->tree); dst->applied = false;