From 0d322413d6cff0bd2ccafc03ab9314dc55417e9d Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Wed, 20 May 2015 11:10:03 +0100 Subject: [PATCH] sfc: protect filter table against use-after-free If MCDI timeouts are encountered during efx_ef10_filter_table_remove(), an FLR will be queued, but efx->filter_state will still be kfree()d. The queued FLR will then call efx_ef10_filter_table_restore(), which will try to use efx->filter_state. This previously caused a panic. This patch adds an rwsem to protect the existence of efx->filter_state, separately from the spinlock protecting its contents. Users which can race against efx_ef10_filter_table_remove() should down_read this rwsem. Signed-off-by: Shradha Shah Signed-off-by: David S. Miller --- drivers/net/ethernet/sfc/ef10.c | 19 +++++++++++++ drivers/net/ethernet/sfc/efx.c | 39 ++++++++++++++++++++------- drivers/net/ethernet/sfc/efx.h | 2 ++ drivers/net/ethernet/sfc/ethtool.c | 2 +- drivers/net/ethernet/sfc/net_driver.h | 5 +++- 5 files changed, 55 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c index 78d3236a3d67..9e2e8e14313b 100644 --- a/drivers/net/ethernet/sfc/ef10.c +++ b/drivers/net/ethernet/sfc/ef10.c @@ -3314,6 +3314,9 @@ fail: return rc; } +/* Caller must hold efx->filter_sem for read if race against + * efx_ef10_filter_table_remove() is possible + */ static void efx_ef10_filter_table_restore(struct efx_nic *efx) { struct efx_ef10_filter_table *table = efx->filter_state; @@ -3323,9 +3326,14 @@ static void efx_ef10_filter_table_restore(struct efx_nic *efx) bool failed = false; int rc; + WARN_ON(!rwsem_is_locked(&efx->filter_sem)); + if (!nic_data->must_restore_filters) return; + if (!table) + return; + spin_lock_bh(&efx->filter_lock); for (filter_idx = 0; filter_idx < HUNT_FILTER_TBL_ROWS; filter_idx++) { @@ -3361,6 +3369,7 @@ static void efx_ef10_filter_table_restore(struct efx_nic *efx) nic_data->must_restore_filters = false; } +/* Caller must hold efx->filter_sem for write */ static void efx_ef10_filter_table_remove(struct efx_nic *efx) { struct efx_ef10_filter_table *table = efx->filter_state; @@ -3369,6 +3378,10 @@ static void efx_ef10_filter_table_remove(struct efx_nic *efx) unsigned int filter_idx; int rc; + efx->filter_state = NULL; + if (!table) + return; + for (filter_idx = 0; filter_idx < HUNT_FILTER_TBL_ROWS; filter_idx++) { spec = efx_ef10_filter_entry_spec(table, filter_idx); if (!spec) @@ -3394,6 +3407,9 @@ static void efx_ef10_filter_table_remove(struct efx_nic *efx) kfree(table); } +/* Caller must hold efx->filter_sem for read if race against + * efx_ef10_filter_table_remove() is possible + */ static void efx_ef10_filter_sync_rx_mode(struct efx_nic *efx) { struct efx_ef10_filter_table *table = efx->filter_state; @@ -3408,6 +3424,9 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic *efx) if (!efx_dev_registered(efx)) return; + if (!table) + return; + /* Mark old filters that may need to be removed */ spin_lock_bh(&efx->filter_lock); n = table->dev_uc_count < 0 ? 1 : table->dev_uc_count; diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c index 864c33789b8f..50816cdbcc95 100644 --- a/drivers/net/ethernet/sfc/efx.c +++ b/drivers/net/ethernet/sfc/efx.c @@ -949,6 +949,16 @@ void efx_link_set_wanted_fc(struct efx_nic *efx, u8 wanted_fc) static void efx_fini_port(struct efx_nic *efx); +/* We assume that efx->type->reconfigure_mac will always try to sync RX + * filters and therefore needs to read-lock the filter table against freeing + */ +void efx_mac_reconfigure(struct efx_nic *efx) +{ + down_read(&efx->filter_sem); + efx->type->reconfigure_mac(efx); + up_read(&efx->filter_sem); +} + /* Push loopback/power/transmit disable settings to the PHY, and reconfigure * the MAC appropriately. All other PHY configuration changes are pushed * through phy_op->set_settings(), and pushed asynchronously to the MAC @@ -1002,7 +1012,7 @@ static void efx_mac_work(struct work_struct *data) mutex_lock(&efx->mac_lock); if (efx->port_enabled) - efx->type->reconfigure_mac(efx); + efx_mac_reconfigure(efx); mutex_unlock(&efx->mac_lock); } @@ -1042,7 +1052,7 @@ static int efx_init_port(struct efx_nic *efx) /* Reconfigure the MAC before creating dma queues (required for * Falcon/A1 where RX_INGR_EN/TX_DRAIN_EN isn't supported) */ - efx->type->reconfigure_mac(efx); + efx_mac_reconfigure(efx); /* Ensure the PHY advertises the correct flow control settings */ rc = efx->phy_op->reconfigure(efx); @@ -1068,7 +1078,7 @@ static void efx_start_port(struct efx_nic *efx) efx->port_enabled = true; /* Ensure MAC ingress/egress is enabled */ - efx->type->reconfigure_mac(efx); + efx_mac_reconfigure(efx); mutex_unlock(&efx->mac_lock); } @@ -1672,10 +1682,11 @@ static int efx_probe_filters(struct efx_nic *efx) int rc; spin_lock_init(&efx->filter_lock); - + init_rwsem(&efx->filter_sem); + down_write(&efx->filter_sem); rc = efx->type->filter_table_probe(efx); if (rc) - return rc; + goto out_unlock; #ifdef CONFIG_RFS_ACCEL if (efx->type->offload_features & NETIF_F_NTUPLE) { @@ -1684,12 +1695,14 @@ static int efx_probe_filters(struct efx_nic *efx) GFP_KERNEL); if (!efx->rps_flow_id) { efx->type->filter_table_remove(efx); - return -ENOMEM; + rc = -ENOMEM; + goto out_unlock; } } #endif - - return 0; +out_unlock: + up_write(&efx->filter_sem); + return rc; } static void efx_remove_filters(struct efx_nic *efx) @@ -1697,12 +1710,16 @@ static void efx_remove_filters(struct efx_nic *efx) #ifdef CONFIG_RFS_ACCEL kfree(efx->rps_flow_id); #endif + down_write(&efx->filter_sem); efx->type->filter_table_remove(efx); + up_write(&efx->filter_sem); } static void efx_restore_filters(struct efx_nic *efx) { + down_read(&efx->filter_sem); efx->type->filter_table_restore(efx); + up_read(&efx->filter_sem); } /************************************************************************** @@ -2183,7 +2200,7 @@ static int efx_change_mtu(struct net_device *net_dev, int new_mtu) mutex_lock(&efx->mac_lock); net_dev->mtu = new_mtu; - efx->type->reconfigure_mac(efx); + efx_mac_reconfigure(efx); mutex_unlock(&efx->mac_lock); efx_start_all(efx); @@ -2219,7 +2236,7 @@ static int efx_set_mac_address(struct net_device *net_dev, void *data) /* Reconfigure the MAC */ mutex_lock(&efx->mac_lock); - efx->type->reconfigure_mac(efx); + efx_mac_reconfigure(efx); mutex_unlock(&efx->mac_lock); return 0; @@ -2464,7 +2481,9 @@ int efx_reset_up(struct efx_nic *efx, enum reset_type method, bool ok) " VFs may not function\n", rc); #endif + down_read(&efx->filter_sem); efx_restore_filters(efx); + up_read(&efx->filter_sem); if (efx->type->sriov_reset) efx->type->sriov_reset(efx); diff --git a/drivers/net/ethernet/sfc/efx.h b/drivers/net/ethernet/sfc/efx.h index 9097906ecfb4..46aee41a7c27 100644 --- a/drivers/net/ethernet/sfc/efx.h +++ b/drivers/net/ethernet/sfc/efx.h @@ -74,6 +74,8 @@ void efx_schedule_slow_fill(struct efx_rx_queue *rx_queue); /* Filters */ +void efx_mac_reconfigure(struct efx_nic *efx); + /** * efx_filter_insert_filter - add or replace a filter * @efx: NIC in which to insert the filter diff --git a/drivers/net/ethernet/sfc/ethtool.c b/drivers/net/ethernet/sfc/ethtool.c index 03829b48547a..034797661f96 100644 --- a/drivers/net/ethernet/sfc/ethtool.c +++ b/drivers/net/ethernet/sfc/ethtool.c @@ -734,7 +734,7 @@ static int efx_ethtool_set_pauseparam(struct net_device *net_dev, /* Reconfigure the MAC. The PHY *may* generate a link state change event * if the user just changed the advertised capabilities, but there's no * harm doing this twice */ - efx->type->reconfigure_mac(efx); + efx_mac_reconfigure(efx); out: mutex_unlock(&efx->mac_lock); diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h index 55a5f4863e60..f6c4832770ba 100644 --- a/drivers/net/ethernet/sfc/net_driver.h +++ b/drivers/net/ethernet/sfc/net_driver.h @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -896,7 +897,8 @@ struct vfdi_status; * @loopback_mode: Loopback status * @loopback_modes: Supported loopback mode bitmask * @loopback_selftest: Offline self-test private state - * @filter_lock: Filter table lock + * @filter_sem: Filter table rw_semaphore, for freeing the table + * @filter_lock: Filter table lock, for mere content changes * @filter_state: Architecture-dependent filter table state * @rps_flow_id: Flow IDs of filters allocated for accelerated RFS, * indexed by filter ID @@ -1038,6 +1040,7 @@ struct efx_nic { void *loopback_selftest; + struct rw_semaphore filter_sem; spinlock_t filter_lock; void *filter_state; #ifdef CONFIG_RFS_ACCEL -- 2.20.1