From 56e6647acb69d3da9a6abe2d227bdcf6e0251146 Mon Sep 17 00:00:00 2001 From: Jiri Pirko Date: Sat, 9 Nov 2019 11:29:46 +0100 Subject: [PATCH] devlink: disallow reload operation during device cleanup [ Upstream commit 5a508a254bed9a2e36a5fb96c9065532a6bf1e9c ] There is a race between driver code that does setup/cleanup of device and devlink reload operation that in some drivers works with the same code. Use after free could we easily obtained by running: while true; do echo "0000:00:10.0" >/sys/bus/pci/drivers/mlxsw_spectrum2/bind devlink dev reload pci/0000:00:10.0 & echo "0000:00:10.0" >/sys/bus/pci/drivers/mlxsw_spectrum2/unbind done Fix this by enabling reload only after setup of device is complete and disabling it at the beginning of the cleanup process. Reported-by: Ido Schimmel Fixes: 2d8dc5bbf4e7 ("devlink: Add support for reload") Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/mellanox/mlx4/main.c | 3 ++ drivers/net/ethernet/mellanox/mlxsw/core.c | 6 +++- drivers/net/netdevsim/dev.c | 2 ++ include/net/devlink.h | 3 ++ net/core/devlink.c | 39 +++++++++++++++++++++- 5 files changed, 51 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c index 309470ec02190..d3654c35d2dda 100644 --- a/drivers/net/ethernet/mellanox/mlx4/main.c +++ b/drivers/net/ethernet/mellanox/mlx4/main.c @@ -3982,6 +3982,7 @@ static int mlx4_init_one(struct pci_dev *pdev, const struct pci_device_id *id) goto err_params_unregister; devlink_params_publish(devlink); + devlink_reload_enable(devlink); pci_save_state(pdev); return 0; @@ -4093,6 +4094,8 @@ static void mlx4_remove_one(struct pci_dev *pdev) struct devlink *devlink = priv_to_devlink(priv); int active_vfs = 0; + devlink_reload_disable(devlink); + if (mlx4_is_slave(dev)) persist->interface_state |= MLX4_INTERFACE_STATE_NOWAIT; diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.c b/drivers/net/ethernet/mellanox/mlxsw/core.c index b94cdbd7bb18b..92ea4a2894298 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/core.c +++ b/drivers/net/ethernet/mellanox/mlxsw/core.c @@ -1128,8 +1128,10 @@ __mlxsw_core_bus_device_register(const struct mlxsw_bus_info *mlxsw_bus_info, if (err) goto err_thermal_init; - if (mlxsw_driver->params_register) + if (mlxsw_driver->params_register) { devlink_params_publish(devlink); + devlink_reload_enable(devlink); + } return 0; @@ -1191,6 +1193,8 @@ void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core, { struct devlink *devlink = priv_to_devlink(mlxsw_core); + if (!reload) + devlink_reload_disable(devlink); if (mlxsw_core->reload_fail) { if (!reload) /* Only the parts that were not de-initialized in the diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c index bcc40a2366248..b2fe271a4f5d5 100644 --- a/drivers/net/netdevsim/dev.c +++ b/drivers/net/netdevsim/dev.c @@ -297,6 +297,7 @@ nsim_dev_create(struct nsim_bus_dev *nsim_bus_dev, unsigned int port_count) if (err) goto err_debugfs_exit; + devlink_reload_enable(devlink); return nsim_dev; err_debugfs_exit: @@ -314,6 +315,7 @@ static void nsim_dev_destroy(struct nsim_dev *nsim_dev) { struct devlink *devlink = priv_to_devlink(nsim_dev); + devlink_reload_disable(devlink); nsim_bpf_dev_exit(nsim_dev); nsim_dev_debugfs_exit(nsim_dev); devlink_unregister(devlink); diff --git a/include/net/devlink.h b/include/net/devlink.h index bc36f942a7d53..ffa506ae50183 100644 --- a/include/net/devlink.h +++ b/include/net/devlink.h @@ -35,6 +35,7 @@ struct devlink { struct device *dev; possible_net_t _net; struct mutex lock; + u8 reload_enabled:1; char priv[0] __aligned(NETDEV_ALIGN); }; @@ -594,6 +595,8 @@ struct ib_device; struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size); int devlink_register(struct devlink *devlink, struct device *dev); void devlink_unregister(struct devlink *devlink); +void devlink_reload_enable(struct devlink *devlink); +void devlink_reload_disable(struct devlink *devlink); void devlink_free(struct devlink *devlink); int devlink_port_register(struct devlink *devlink, struct devlink_port *devlink_port, diff --git a/net/core/devlink.c b/net/core/devlink.c index 4f40aeace9022..707d160cc6ea0 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -2677,7 +2677,7 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info) struct devlink *devlink = info->user_ptr[0]; int err; - if (!devlink->ops->reload) + if (!devlink->ops->reload || !devlink->reload_enabled) return -EOPNOTSUPP; err = devlink_resources_validate(devlink, NULL, info); @@ -5559,12 +5559,49 @@ EXPORT_SYMBOL_GPL(devlink_register); void devlink_unregister(struct devlink *devlink) { mutex_lock(&devlink_mutex); + WARN_ON(devlink_reload_supported(devlink) && + devlink->reload_enabled); devlink_notify(devlink, DEVLINK_CMD_DEL); list_del(&devlink->list); mutex_unlock(&devlink_mutex); } EXPORT_SYMBOL_GPL(devlink_unregister); +/** + * devlink_reload_enable - Enable reload of devlink instance + * + * @devlink: devlink + * + * Should be called at end of device initialization + * process when reload operation is supported. + */ +void devlink_reload_enable(struct devlink *devlink) +{ + mutex_lock(&devlink_mutex); + devlink->reload_enabled = true; + mutex_unlock(&devlink_mutex); +} +EXPORT_SYMBOL_GPL(devlink_reload_enable); + +/** + * devlink_reload_disable - Disable reload of devlink instance + * + * @devlink: devlink + * + * Should be called at the beginning of device cleanup + * process when reload operation is supported. + */ +void devlink_reload_disable(struct devlink *devlink) +{ + mutex_lock(&devlink_mutex); + /* Mutex is taken which ensures that no reload operation is in + * progress while setting up forbidded flag. + */ + devlink->reload_enabled = false; + mutex_unlock(&devlink_mutex); +} +EXPORT_SYMBOL_GPL(devlink_reload_disable); + /** * devlink_free - Free devlink instance resources * -- 2.47.2