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Date: Tue, 19 Nov 2019 06:13:26 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Ido Schimmel <idosch@...lanox.com>,
Jiri Pirko <jiri@...lanox.com>,
"David S. Miller" <davem@...emloft.net>
Subject: [PATCH 4.19 009/422] devlink: disallow reload operation during device cleanup
From: Jiri Pirko <jiri@...lanox.com>
[ 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 <idosch@...lanox.com>
Fixes: 2d8dc5bbf4e7 ("devlink: Add support for reload")
Signed-off-by: Jiri Pirko <jiri@...lanox.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/net/ethernet/mellanox/mlx4/main.c | 3 ++
drivers/net/ethernet/mellanox/mlxsw/core.c | 4 ++
drivers/net/netdevsim/netdev.c | 5 +++
include/net/devlink.h | 3 ++
net/core/devlink.c | 39 ++++++++++++++++++++++++++++-
5 files changed, 53 insertions(+), 1 deletion(-)
--- 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
if (ret)
goto err_params_unregister;
+ devlink_reload_enable(devlink);
pci_save_state(pdev);
return 0;
@@ -4093,6 +4094,8 @@ static void mlx4_remove_one(struct pci_d
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;
--- a/drivers/net/ethernet/mellanox/mlxsw/core.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.c
@@ -1054,6 +1054,8 @@ int mlxsw_core_bus_device_register(const
if (err)
goto err_driver_init;
}
+ if (!reload)
+ devlink_reload_enable(devlink);
return 0;
@@ -1088,6 +1090,8 @@ void mlxsw_core_bus_device_unregister(st
{
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
--- a/drivers/net/netdevsim/netdev.c
+++ b/drivers/net/netdevsim/netdev.c
@@ -23,6 +23,7 @@
#include <net/pkt_cls.h>
#include <net/rtnetlink.h>
#include <net/switchdev.h>
+#include <net/devlink.h>
#include "netdevsim.h"
@@ -221,6 +222,8 @@ static int nsim_init(struct net_device *
goto err_unreg_dev;
nsim_ipsec_init(ns);
+ if (ns->devlink)
+ devlink_reload_enable(ns->devlink);
return 0;
@@ -243,6 +246,8 @@ static void nsim_uninit(struct net_devic
{
struct netdevsim *ns = netdev_priv(dev);
+ if (ns->devlink)
+ devlink_reload_disable(ns->devlink);
nsim_ipsec_teardown(ns);
nsim_devlink_teardown(ns);
debugfs_remove_recursive(ns->ddir);
--- 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);
};
@@ -477,6 +478,8 @@ 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,
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -2643,7 +2643,7 @@ static int devlink_nl_cmd_reload(struct
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);
@@ -3889,6 +3889,8 @@ EXPORT_SYMBOL_GPL(devlink_register);
void devlink_unregister(struct devlink *devlink)
{
mutex_lock(&devlink_mutex);
+ WARN_ON(devlink->ops->reload &&
+ devlink->reload_enabled);
devlink_notify(devlink, DEVLINK_CMD_DEL);
list_del(&devlink->list);
mutex_unlock(&devlink_mutex);
@@ -3896,6 +3898,41 @@ void devlink_unregister(struct devlink *
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
*
* @devlink: devlink
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