net/virtio-user: ignore result if status is unsupported

GET/SET STATUS is an optional feature, so it may not be negotiated. In
that case, the VIRTIO_GET_STATUS call will not update the status (given
as a pointer argument). Failing to identify this case would lead to
undefined behavior as the device status will be updated with the value
of a stack-allocated variable.

To fix this, return ENOTSUP if the feature is not supported and, in that
case, don't update device status.

Fixes: 44102e6298e7 ("net/virtio: check protocol feature in user backend")
Cc stable@dpdk.org

Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/drivers/net/virtio/virtio_user/vhost_user.c b/drivers/net/virtio/virtio_user/vhost_user.c
index 450d77e..b93e65c 100644 (file)
--- a/drivers/net/virtio/virtio_user/vhost_user.c
+++ b/drivers/net/virtio/virtio_user/vhost_user.c
@@ -281,7 +281,7 @@ vhost_user_sock(struct virtio_user_dev *dev,
                if (!(dev->status & VIRTIO_CONFIG_STATUS_FEATURES_OK) ||
                    (!(dev->protocol_features &
                                (1ULL << VHOST_USER_PROTOCOL_F_STATUS))))
-                       return 0;
+                       return -ENOTSUP;
                /* Fallthrough */
        case VHOST_USER_GET_FEATURES:
        case VHOST_USER_GET_PROTOCOL_FEATURES:
@@ -292,7 +292,7 @@ vhost_user_sock(struct virtio_user_dev *dev,
                if (!(dev->status & VIRTIO_CONFIG_STATUS_FEATURES_OK) ||
                    (!(dev->protocol_features &
                                (1ULL << VHOST_USER_PROTOCOL_F_STATUS))))
-                       return 0;
+                       return -ENOTSUP;
 
                if (has_reply_ack)
                        msg.flags |= VHOST_USER_NEED_REPLY_MASK;

diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index 27814ea..5a1e760 100644 (file)
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -818,15 +818,13 @@ virtio_user_send_status_update(struct virtio_user_dev *dev, uint8_t status)
                ret = dev->ops->send_request(dev,
                                VHOST_USER_SET_STATUS, &status);
        else
-               return 0;
+               ret = -ENOTSUP;
 
-       if (ret) {
+       if (ret && ret != -ENOTSUP) {
                PMD_INIT_LOG(ERR, "VHOST_USER_SET_STATUS failed (%d): %s", ret,
                             strerror(errno));
-               return -1;
        }
-
-       return 0;
+       return ret;
 }
 
 int
@@ -849,17 +847,12 @@ virtio_user_update_status(struct virtio_user_dev *dev)
                err = dev->ops->send_request(dev, VHOST_USER_GET_STATUS,
                                &status);
        } else {
-               return 0;
-       }
-
-       if (err) {
-               PMD_INIT_LOG(ERR, "VHOST_USER_GET_STATUS failed (%d): %s", err,
-                            strerror(errno));
-               return -1;
+               err = -ENOTSUP;
        }
 
-       dev->status = status;
-       PMD_INIT_LOG(DEBUG, "Updated Device Status(0x%08x):\n"
+       if (!err) {
+               dev->status = status;
+               PMD_INIT_LOG(DEBUG, "Updated Device Status(0x%08x):\n"
                        "\t-RESET: %u\n"
                        "\t-ACKNOWLEDGE: %u\n"
                        "\t-DRIVER: %u\n"
@@ -875,5 +868,10 @@ virtio_user_update_status(struct virtio_user_dev *dev)
                        !!(dev->status & VIRTIO_CONFIG_STATUS_FEATURES_OK),
                        !!(dev->status & VIRTIO_CONFIG_STATUS_DEV_NEED_RESET),
                        !!(dev->status & VIRTIO_CONFIG_STATUS_FAILED));
-       return 0;
+       } else if (err != -ENOTSUP) {
+               PMD_INIT_LOG(ERR, "VHOST_USER_GET_STATUS failed (%d): %s", err,
+                            strerror(errno));
+       }
+
+       return err;
 }