From 0d60d8df6f493bb46bf5db40d39dd60a1bafdd4e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 23 Feb 2024 12:32:08 +0000 Subject: [PATCH] dpll: rely on rcu for netdev_dpll_pin() This fixes a possible UAF in if_nlmsg_size(), which can run without RTNL. Add rcu protection to "struct dpll_pin" Move netdev_dpll_pin() from netdevice.h to dpll.h to decrease name pollution. Note: This looks possible to no longer acquire RTNL in netdev_dpll_pin_assign() later in net-next. v2: do not force rcu_read_lock() in rtnl_dpll_pin_size() (Jiri Pirko) Fixes: 5f1842692880 ("netdev: expose DPLL pin handle for netdevice") Signed-off-by: Eric Dumazet Cc: Arkadiusz Kubalewski Cc: Vadim Fedorenko Reviewed-by: Jiri Pirko Link: https://lore.kernel.org/r/20240223123208.3543319-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- drivers/dpll/dpll_core.c | 2 +- drivers/dpll/dpll_core.h | 2 ++ include/linux/dpll.h | 11 +++++++++++ include/linux/netdevice.h | 11 +---------- net/core/dev.c | 2 +- 5 files changed, 16 insertions(+), 12 deletions(-) diff --git a/drivers/dpll/dpll_core.c b/drivers/dpll/dpll_core.c index 5152bd1b0daf..4c2bb27c99fe 100644 --- a/drivers/dpll/dpll_core.c +++ b/drivers/dpll/dpll_core.c @@ -564,7 +564,7 @@ void dpll_pin_put(struct dpll_pin *pin) xa_destroy(&pin->parent_refs); xa_erase(&dpll_pin_xa, pin->id); dpll_pin_prop_free(&pin->prop); - kfree(pin); + kfree_rcu(pin, rcu); } mutex_unlock(&dpll_lock); } diff --git a/drivers/dpll/dpll_core.h b/drivers/dpll/dpll_core.h index 717f715015c7..2b6d8ef1cdf3 100644 --- a/drivers/dpll/dpll_core.h +++ b/drivers/dpll/dpll_core.h @@ -47,6 +47,7 @@ struct dpll_device { * @prop: pin properties copied from the registerer * @rclk_dev_name: holds name of device when pin can recover clock from it * @refcount: refcount + * @rcu: rcu_head for kfree_rcu() **/ struct dpll_pin { u32 id; @@ -57,6 +58,7 @@ struct dpll_pin { struct xarray parent_refs; struct dpll_pin_properties prop; refcount_t refcount; + struct rcu_head rcu; }; /** diff --git a/include/linux/dpll.h b/include/linux/dpll.h index 9cf896ea1d41..4ec2fe9caf5a 100644 --- a/include/linux/dpll.h +++ b/include/linux/dpll.h @@ -10,6 +10,8 @@ #include #include #include +#include +#include struct dpll_device; struct dpll_pin; @@ -167,4 +169,13 @@ int dpll_device_change_ntf(struct dpll_device *dpll); int dpll_pin_change_ntf(struct dpll_pin *pin); +static inline struct dpll_pin *netdev_dpll_pin(const struct net_device *dev) +{ +#if IS_ENABLED(CONFIG_DPLL) + return rcu_dereference_rtnl(dev->dpll_pin); +#else + return NULL; +#endif +} + #endif diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index ef7bfbb98497..a9c973b92294 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2469,7 +2469,7 @@ struct net_device { struct devlink_port *devlink_port; #if IS_ENABLED(CONFIG_DPLL) - struct dpll_pin *dpll_pin; + struct dpll_pin __rcu *dpll_pin; #endif #if IS_ENABLED(CONFIG_PAGE_POOL) /** @page_pools: page pools created for this netdevice */ @@ -4035,15 +4035,6 @@ bool netdev_port_same_parent_id(struct net_device *a, struct net_device *b); void netdev_dpll_pin_set(struct net_device *dev, struct dpll_pin *dpll_pin); void netdev_dpll_pin_clear(struct net_device *dev); -static inline struct dpll_pin *netdev_dpll_pin(const struct net_device *dev) -{ -#if IS_ENABLED(CONFIG_DPLL) - return dev->dpll_pin; -#else - return NULL; -#endif -} - struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device *dev, bool *again); struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev, struct netdev_queue *txq, int *ret); diff --git a/net/core/dev.c b/net/core/dev.c index 73a021973007..0230391c78f7 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9078,7 +9078,7 @@ static void netdev_dpll_pin_assign(struct net_device *dev, struct dpll_pin *dpll { #if IS_ENABLED(CONFIG_DPLL) rtnl_lock(); - dev->dpll_pin = dpll_pin; + rcu_assign_pointer(dev->dpll_pin, dpll_pin); rtnl_unlock(); #endif }