From 9b3bc7db759e64c33471025721817467f8c3ecd4 Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Wed, 17 Oct 2018 08:05:45 +0000 Subject: mlxsw: core: Fix use-after-free when flashing firmware during init When the switch driver (e.g., mlxsw_spectrum) determines it needs to flash a new firmware version it resets the ASIC after the flashing process. The bus driver (e.g., mlxsw_pci) then registers itself again with mlxsw_core which means (among other things) that the device registers itself again with the hwmon subsystem again. Since the device was registered with the hwmon subsystem using devm_hwmon_device_register_with_groups(), then the old hwmon device (registered before the flashing) was never unregistered and was referencing stale data, resulting in a use-after free. Fix by removing reliance on device managed APIs in mlxsw_hwmon_init(). Fixes: c86d62cc410c ("mlxsw: spectrum: Reset FW after flash") Signed-off-by: Ido Schimmel Reported-by: Alexander Petrovskiy Tested-by: Alexander Petrovskiy Reviewed-by: Petr Machata Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlxsw/core.c | 2 ++ drivers/net/ethernet/mellanox/mlxsw/core.h | 4 ++++ drivers/net/ethernet/mellanox/mlxsw/core_hwmon.c | 17 +++++++++++------ 3 files changed, 17 insertions(+), 6 deletions(-) (limited to 'drivers/net/ethernet/mellanox/mlxsw') diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.c b/drivers/net/ethernet/mellanox/mlxsw/core.c index 81533d7f395c..937d0ace699a 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/core.c +++ b/drivers/net/ethernet/mellanox/mlxsw/core.c @@ -1055,6 +1055,7 @@ int mlxsw_core_bus_device_register(const struct mlxsw_bus_info *mlxsw_bus_info, err_driver_init: mlxsw_thermal_fini(mlxsw_core->thermal); err_thermal_init: + mlxsw_hwmon_fini(mlxsw_core->hwmon); err_hwmon_init: if (!reload) devlink_unregister(devlink); @@ -1088,6 +1089,7 @@ void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core, if (mlxsw_core->driver->fini) mlxsw_core->driver->fini(mlxsw_core); mlxsw_thermal_fini(mlxsw_core->thermal); + mlxsw_hwmon_fini(mlxsw_core->hwmon); if (!reload) devlink_unregister(devlink); mlxsw_emad_fini(mlxsw_core); diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.h b/drivers/net/ethernet/mellanox/mlxsw/core.h index 655ddd204ab2..c35be477856f 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/core.h +++ b/drivers/net/ethernet/mellanox/mlxsw/core.h @@ -359,6 +359,10 @@ static inline int mlxsw_hwmon_init(struct mlxsw_core *mlxsw_core, return 0; } +static inline void mlxsw_hwmon_fini(struct mlxsw_hwmon *mlxsw_hwmon) +{ +} + #endif struct mlxsw_thermal; diff --git a/drivers/net/ethernet/mellanox/mlxsw/core_hwmon.c b/drivers/net/ethernet/mellanox/mlxsw/core_hwmon.c index f6cf2896d337..e04e8162aa14 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/core_hwmon.c +++ b/drivers/net/ethernet/mellanox/mlxsw/core_hwmon.c @@ -303,8 +303,7 @@ int mlxsw_hwmon_init(struct mlxsw_core *mlxsw_core, struct device *hwmon_dev; int err; - mlxsw_hwmon = devm_kzalloc(mlxsw_bus_info->dev, sizeof(*mlxsw_hwmon), - GFP_KERNEL); + mlxsw_hwmon = kzalloc(sizeof(*mlxsw_hwmon), GFP_KERNEL); if (!mlxsw_hwmon) return -ENOMEM; mlxsw_hwmon->core = mlxsw_core; @@ -321,10 +320,9 @@ int mlxsw_hwmon_init(struct mlxsw_core *mlxsw_core, mlxsw_hwmon->groups[0] = &mlxsw_hwmon->group; mlxsw_hwmon->group.attrs = mlxsw_hwmon->attrs; - hwmon_dev = devm_hwmon_device_register_with_groups(mlxsw_bus_info->dev, - "mlxsw", - mlxsw_hwmon, - mlxsw_hwmon->groups); + hwmon_dev = hwmon_device_register_with_groups(mlxsw_bus_info->dev, + "mlxsw", mlxsw_hwmon, + mlxsw_hwmon->groups); if (IS_ERR(hwmon_dev)) { err = PTR_ERR(hwmon_dev); goto err_hwmon_register; @@ -337,5 +335,12 @@ int mlxsw_hwmon_init(struct mlxsw_core *mlxsw_core, err_hwmon_register: err_fans_init: err_temp_init: + kfree(mlxsw_hwmon); return err; } + +void mlxsw_hwmon_fini(struct mlxsw_hwmon *mlxsw_hwmon) +{ + hwmon_device_unregister(mlxsw_hwmon->hwmon_dev); + kfree(mlxsw_hwmon); +} -- cgit v1.2.3-59-g8ed1b