Commit a12e91eb authored by Marco Pagani's avatar Marco Pagani Committed by Liu Chuang
Browse files

fpga: manager: add owner module and take its refcount 

mainline inclusion
from mainline-v6.10-rc1
commit 4d4d2d4346857bf778fafaa97d6f76bb1663e3c9
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA7YM1
CVE: CVE-2024-37021

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4d4d2d4346857bf778fafaa97d6f76bb1663e3c9



--------------------------------

The current implementation of the fpga manager assumes that the low-level
module registers a driver for the parent device and uses its owner pointer
to take the module's refcount. This approach is problematic since it can
lead to a null pointer dereference while attempting to get the manager if
the parent device does not have a driver.

To address this problem, add a module owner pointer to the fpga_manager
struct and use it to take the module's refcount. Modify the functions for
registering the manager to take an additional owner module parameter and
rename them to avoid conflicts. Use the old function names for helper
macros that automatically set the module that registers the manager as the
owner. This ensures compatibility with existing low-level control modules
and reduces the chances of registering a manager without setting the owner.

Also, update the documentation to keep it consistent with the new interface
for registering an fpga manager.

Other changes: opportunistically move put_device() from __fpga_mgr_get() to
fpga_mgr_get() and of_fpga_mgr_get() to improve code clarity since the
manager device is taken in these functions.

Fixes: 654ba4cc ("fpga manager: ensure lifetime with of_fpga_mgr_get")
Suggested-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: default avatarXu Yilun <yilun.xu@intel.com>
Signed-off-by: default avatarMarco Pagani <marpagan@redhat.com>
Acked-by: default avatarXu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20240305192926.84886-1-marpagan@redhat.com


Signed-off-by: default avatarXu Yilun <yilun.xu@linux.intel.com>

Conflicts:
	drivers/fpga/fpga-mgr.c
	include/linux/fpga/fpga-mgr.h
	Documentation/driver-api/fpga/fpga-mgr.rst
[Liu Chuang: add owner module.]
Signed-off-by: default avatarLiu Chuang <liuchuang40@huawei.com>
parent 223a7beb

drivers/fpga/fpga-mgr.c

+36 −26
Original line number Diff line number Diff line
@@ -444,20 +444,15 @@ static struct attribute *fpga_mgr_attrs[] = { 
};

ATTRIBUTE_GROUPS(fpga_mgr);



static struct fpga_manager *__fpga_mgr_get(struct device *dev)

static struct fpga_manager *__fpga_mgr_get(struct device *mgr_dev)

{

	struct fpga_manager *mgr;



	mgr = to_fpga_manager(dev);



	if (!try_module_get(dev->parent->driver->owner))

		goto err_dev;

	mgr = to_fpga_manager(mgr_dev);

	if (!try_module_get(mgr->mops_owner))

		mgr = ERR_PTR(-ENODEV);



	return mgr;



err_dev:

	put_device(dev);

	return ERR_PTR(-ENODEV);

}



static int fpga_mgr_dev_match(struct device *dev, const void *data)
@@ -473,12 +468,18 @@ static int fpga_mgr_dev_match(struct device *dev, const void *data) 
 */

struct fpga_manager *fpga_mgr_get(struct device *dev)

{

	struct device *mgr_dev = class_find_device(fpga_mgr_class, NULL, dev,

						   fpga_mgr_dev_match);

	struct fpga_manager *mgr;

	struct device *mgr_dev;



	mgr_dev = class_find_device(fpga_mgr_class, NULL, dev, fpga_mgr_dev_match);

	if (!mgr_dev)

		return ERR_PTR(-ENODEV);



	return __fpga_mgr_get(mgr_dev);

	mgr = __fpga_mgr_get(mgr_dev);

	if (IS_ERR(mgr))

		put_device(mgr_dev);



	return mgr;

}

EXPORT_SYMBOL_GPL(fpga_mgr_get);
@@ -491,13 +492,18 @@ EXPORT_SYMBOL_GPL(fpga_mgr_get); 
 */

struct fpga_manager *of_fpga_mgr_get(struct device_node *node)

{

	struct device *dev;

	struct fpga_manager *mgr;

	struct device *mgr_dev;



	dev = class_find_device_by_of_node(fpga_mgr_class, node);

	if (!dev)

	mgr_dev = class_find_device_by_of_node(fpga_mgr_class, node);

	if (!mgr_dev)

		return ERR_PTR(-ENODEV);



	return __fpga_mgr_get(dev);

	mgr = __fpga_mgr_get(mgr_dev);

	if (IS_ERR(mgr))

		put_device(mgr_dev);



	return mgr;

}

EXPORT_SYMBOL_GPL(of_fpga_mgr_get);
@@ -507,7 +513,7 @@ EXPORT_SYMBOL_GPL(of_fpga_mgr_get); 
 */

void fpga_mgr_put(struct fpga_manager *mgr)

{

	module_put(mgr->dev.parent->driver->owner);

	module_put(mgr->mops_owner);

	put_device(&mgr->dev);

}

EXPORT_SYMBOL_GPL(fpga_mgr_put);
@@ -546,20 +552,21 @@ void fpga_mgr_unlock(struct fpga_manager *mgr) 
EXPORT_SYMBOL_GPL(fpga_mgr_unlock);



/**

 * fpga_mgr_create - create and initialize a FPGA manager struct

 * __fpga_mgr_create - create and initialize a FPGA manager struct

 * @dev:	fpga manager device from pdev

 * @name:	fpga manager name

 * @mops:	pointer to structure of fpga manager ops

 * @priv:	fpga manager private data

 * @owner:	owner module containing the ops

 *

 * The caller of this function is responsible for freeing the struct with

 * fpga_mgr_free().  Using devm_fpga_mgr_create() instead is recommended.

 *

 * Return: pointer to struct fpga_manager or NULL

 */

struct fpga_manager *fpga_mgr_create(struct device *dev, const char *name,

struct fpga_manager *__fpga_mgr_create(struct device *dev, const char *name,

				     const struct fpga_manager_ops *mops,

				     void *priv)

				     void *priv, struct module *owner)

{

	struct fpga_manager *mgr;

	int id, ret;
@@ -586,6 +593,8 @@ struct fpga_manager *fpga_mgr_create(struct device *dev, const char *name, 


	mutex_init(&mgr->ref_mutex);



	mgr->mops_owner = owner;



	mgr->name = name;

	mgr->mops = mops;

	mgr->priv = priv;
@@ -610,7 +619,7 @@ struct fpga_manager *fpga_mgr_create(struct device *dev, const char *name, 


	return NULL;

}

EXPORT_SYMBOL_GPL(fpga_mgr_create);

EXPORT_SYMBOL_GPL(__fpga_mgr_create);



/**

 * fpga_mgr_free - free a FPGA manager created with fpga_mgr_create()
@@ -631,11 +640,12 @@ static void devm_fpga_mgr_release(struct device *dev, void *res) 
}



/**

 * devm_fpga_mgr_create - create and initialize a managed FPGA manager struct

 * __devm_fpga_mgr_create - create and initialize a managed FPGA manager struct

 * @dev:	fpga manager device from pdev

 * @name:	fpga manager name

 * @mops:	pointer to structure of fpga manager ops

 * @priv:	fpga manager private data

 * @owner:	owner module containing the ops

 *

 * This function is intended for use in a FPGA manager driver's probe function.

 * After the manager driver creates the manager struct with
@@ -647,9 +657,9 @@ static void devm_fpga_mgr_release(struct device *dev, void *res) 
 *

 * Return: pointer to struct fpga_manager or NULL

 */

struct fpga_manager *devm_fpga_mgr_create(struct device *dev, const char *name,

struct fpga_manager *__devm_fpga_mgr_create(struct device *dev, const char *name,

					  const struct fpga_manager_ops *mops,

					  void *priv)

					  void *priv, struct module *owner)

{

	struct fpga_manager **ptr, *mgr;
@@ -657,7 +667,7 @@ struct fpga_manager *devm_fpga_mgr_create(struct device *dev, const char *name, 
	if (!ptr)

		return NULL;



	mgr = fpga_mgr_create(dev, name, mops, priv);

	mgr = __fpga_mgr_create(dev, name, mops, priv, owner);

	if (!mgr) {

		devres_free(ptr);

	} else {
@@ -667,7 +677,7 @@ struct fpga_manager *devm_fpga_mgr_create(struct device *dev, const char *name, 


	return mgr;

}

EXPORT_SYMBOL_GPL(devm_fpga_mgr_create);

EXPORT_SYMBOL_GPL(__devm_fpga_mgr_create);



/**

 * fpga_mgr_register - register a FPGA manager

include/linux/fpga/fpga-mgr.h

+10 −4
Original line number Diff line number Diff line
@@ -162,6 +162,7 @@ struct fpga_compat_id { 
 * @state: state of fpga manager

 * @compat_id: FPGA manager id for compatibility check.

 * @mops: pointer to struct of fpga manager ops

 * @mops_owner: module containing the mops

 * @priv: low level driver private date

 */

struct fpga_manager {
@@ -171,6 +172,7 @@ struct fpga_manager { 
	enum fpga_mgr_states state;

	struct fpga_compat_id *compat_id;

	const struct fpga_manager_ops *mops;

	struct module *mops_owner;

	void *priv;

};
@@ -191,15 +193,19 @@ struct fpga_manager *fpga_mgr_get(struct device *dev); 


void fpga_mgr_put(struct fpga_manager *mgr);



struct fpga_manager *fpga_mgr_create(struct device *dev, const char *name,

#define fpga_mgr_create(dev, name, mops, priv) \

	__fpga_mgr_create(dev, name, mops, priv, THIS_MODULE)

struct fpga_manager *__fpga_mgr_create(struct device *dev, const char *name,

				     const struct fpga_manager_ops *mops,

				     void *priv);

				     void *priv, struct module *owner);

void fpga_mgr_free(struct fpga_manager *mgr);

int fpga_mgr_register(struct fpga_manager *mgr);

void fpga_mgr_unregister(struct fpga_manager *mgr);



struct fpga_manager *devm_fpga_mgr_create(struct device *dev, const char *name,

#define devm_fpga_mgr_create(dev, name, mops, priv) \

	__devm_fpga_mgr_create(dev, name, mops, priv, THIS_MODULE)

struct fpga_manager *__devm_fpga_mgr_create(struct device *dev, const char *name,

					  const struct fpga_manager_ops *mops,

					  void *priv);

					  void *priv, struct module *owner);



#endif /*_LINUX_FPGA_MGR_H */