From 0d60d8df6f493bb46bf5db40d39dd60a1bafdd4e Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
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 <edumazet@google.com>
Cc: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Cc: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240223123208.3543319-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
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 <uapi/linux/dpll.h>
#include <linux/device.h>
#include <linux/netlink.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
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
}