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bh=ziK62NPFE+h1hWBxVnfPWzQnp4NkUiewSsIzh0Y7llY=; b=dwIJjcHLlXxlZgnD9Jz4JPkHtUBUj91OPcuDxjYGlX4a9TEq6jAych49+wUmJWGEMHTqHU HA2LByaSUft67cPinPyue0cvzAHLxVBEIU652x9tFTlomiJNYh5m37fJCHTe00HGnWa2C9 oSyJgpKX8ZjE4Wh3UOzxsXd32O3nt4U= X-MC-Unique: RxHKDfm7NBmm8XEoBsrGeA-1 From: Jason Wang To: mst@redhat.com, jasowang@redhat.com, qemu-devel@nongnu.org Subject: [PATCH V2] virtio-net: check the existence of peer before accessing vDPA config Date: Mon, 27 Jul 2020 20:51:50 +0800 Message-Id: <20200727125150.4687-1-jasowang@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=205.139.110.61; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/27 01:46:13 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: cohuck@redhat.com, Cindy Lu Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" We try to check whether a peer is VDPA in order to get config from there - with no peer, this leads to a NULL pointer dereference. Add a check before trying to access the peer type. No peer means not VDPA. Fixes: 108a64818e69b ("vhost-vdpa: introduce vhost-vdpa backend") Cc: Cindy Lu Tested-by: Cornelia Huck Reviewed-by: Cornelia Huck Signed-off-by: Jason Wang Reviewed-by: Michael S. Tsirkin --- Changes from V1: - Tweak the log - Add the comment in the code --- hw/net/virtio-net.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-) diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 4895af1cbe..a1fe9e9285 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -125,6 +125,7 @@ static void virtio_net_get_config(VirtIODevice *vdev, u= int8_t *config) { VirtIONet *n =3D VIRTIO_NET(vdev); struct virtio_net_config netcfg; + NetClientState *nc =3D qemu_get_queue(n->nic); =20 int ret =3D 0; memset(&netcfg, 0 , sizeof(struct virtio_net_config)); @@ -142,13 +143,16 @@ static void virtio_net_get_config(VirtIODevice *vdev,= uint8_t *config) VIRTIO_NET_RSS_SUPPORTED_HASHES); memcpy(config, &netcfg, n->config_size); =20 - NetClientState *nc =3D qemu_get_queue(n->nic); - if (nc->peer->info->type =3D=3D NET_CLIENT_DRIVER_VHOST_VDPA) { + /* + * Is this VDPA? No peer means not VDPA: there's no way to + * disconnect/reconnect a VDPA peer. + */ + if (nc->peer && nc->peer->info->type =3D=3D NET_CLIENT_DRIVER_VHOST_VD= PA) { ret =3D vhost_net_get_config(get_vhost_net(nc->peer), (uint8_t *)&= netcfg, - n->config_size); - if (ret !=3D -1) { - memcpy(config, &netcfg, n->config_size); - } + n->config_size); + if (ret !=3D -1) { + memcpy(config, &netcfg, n->config_size); + } } } =20 @@ -156,6 +160,7 @@ static void virtio_net_set_config(VirtIODevice *vdev, c= onst uint8_t *config) { VirtIONet *n =3D VIRTIO_NET(vdev); struct virtio_net_config netcfg =3D {}; + NetClientState *nc =3D qemu_get_queue(n->nic); =20 memcpy(&netcfg, config, n->config_size); =20 @@ -166,11 +171,14 @@ static void virtio_net_set_config(VirtIODevice *vdev,= const uint8_t *config) qemu_format_nic_info_str(qemu_get_queue(n->nic), n->mac); } =20 - NetClientState *nc =3D qemu_get_queue(n->nic); - if (nc->peer->info->type =3D=3D NET_CLIENT_DRIVER_VHOST_VDPA) { - vhost_net_set_config(get_vhost_net(nc->peer), (uint8_t *)&netcfg, - 0, n->config_size, - VHOST_SET_CONFIG_TYPE_MASTER); + /* + * Is this VDPA? No peer means not VDPA: there's no way to + * disconnect/reconnect a VDPA peer. + */ + if (nc->peer && nc->peer->info->type =3D=3D NET_CLIENT_DRIVER_VHOST_VD= PA) { + vhost_net_set_config(get_vhost_net(nc->peer), + (uint8_t *)&netcfg, 0, n->config_size, + VHOST_SET_CONFIG_TYPE_MASTER); } } =20 --=20 2.20.1