Commit fd1c0eb4 authored by Duoming Zhou's avatar Duoming Zhou Committed by Liu Jian
Browse files

ax25: Use kernel universal linked list to implement ax25_dev_list 

stable inclusion
from stable-v6.6.33
commit 39da6f09e110d60423a75ea1d0a8c6f5c63e2d9e
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA6S8I
CVE: CVE-2024-38602

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=39da6f09e110d60423a75ea1d0a8c6f5c63e2d9e



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

[ Upstream commit a7d6e36b9ad052926ba2ecba3a59d8bb67dabcb4 ]

The origin ax25_dev_list implements its own single linked list,
which is complicated and error-prone. For example, when deleting
the node of ax25_dev_list in ax25_dev_device_down(), we have to
operate on the head node and other nodes separately.

This patch uses kernel universal linked list to replace original
ax25_dev_list, which make the operation of ax25_dev_list easier.

We should do "dev->ax25_ptr = ax25_dev;" and "dev->ax25_ptr = NULL;"
while holding the spinlock, otherwise the ax25_dev_device_up() and
ax25_dev_device_down() could race.

Suggested-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: default avatarDuoming Zhou <duoming@zju.edu.cn>
Reviewed-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/85bba3af651ca0e1a519da8d0d715b949891171c.1715247018.git.duoming@zju.edu.cn


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Stable-dep-of: b505e0319852 ("ax25: Fix reference count leak issues of ax25_dev")
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarLiu Jian <liujian56@huawei.com>
parent ed2d630b

include/net/ax25.h

+1 −2
Original line number Diff line number Diff line
@@ -216,7 +216,7 @@ typedef struct { 
struct ctl_table;



typedef struct ax25_dev {

	struct ax25_dev		*next;

	struct list_head	list;



	struct net_device	*dev;

	netdevice_tracker	dev_tracker;
@@ -330,7 +330,6 @@ int ax25_addr_size(const ax25_digi *); 
void ax25_digi_invert(const ax25_digi *, ax25_digi *);



/* ax25_dev.c */

extern ax25_dev *ax25_dev_list;

extern spinlock_t ax25_dev_lock;



#if IS_ENABLED(CONFIG_AX25)

net/ax25/ax25_dev.c

+15 −25
Original line number Diff line number Diff line
@@ -22,11 +22,12 @@ 
#include <net/sock.h>

#include <linux/uaccess.h>

#include <linux/fcntl.h>

#include <linux/list.h>

#include <linux/mm.h>

#include <linux/interrupt.h>

#include <linux/init.h>



ax25_dev *ax25_dev_list;

static LIST_HEAD(ax25_dev_list);

DEFINE_SPINLOCK(ax25_dev_lock);



ax25_dev *ax25_addr_ax25dev(ax25_address *addr)
@@ -34,7 +35,7 @@ ax25_dev *ax25_addr_ax25dev(ax25_address *addr) 
	ax25_dev *ax25_dev, *res = NULL;



	spin_lock_bh(&ax25_dev_lock);

	for (ax25_dev = ax25_dev_list; ax25_dev != NULL; ax25_dev = ax25_dev->next)

	list_for_each_entry(ax25_dev, &ax25_dev_list, list)

		if (ax25cmp(addr, (const ax25_address *)ax25_dev->dev->dev_addr) == 0) {

			res = ax25_dev;

			ax25_dev_hold(ax25_dev);
@@ -59,7 +60,6 @@ void ax25_dev_device_up(struct net_device *dev) 
	}



	refcount_set(&ax25_dev->refcount, 1);

	dev->ax25_ptr     = ax25_dev;

	ax25_dev->dev     = dev;

	netdev_hold(dev, &ax25_dev->dev_tracker, GFP_KERNEL);

	ax25_dev->forward = NULL;
@@ -85,8 +85,8 @@ void ax25_dev_device_up(struct net_device *dev) 
#endif



	spin_lock_bh(&ax25_dev_lock);

	ax25_dev->next = ax25_dev_list;

	ax25_dev_list  = ax25_dev;

	list_add(&ax25_dev->list, &ax25_dev_list);

	dev->ax25_ptr     = ax25_dev;

	spin_unlock_bh(&ax25_dev_lock);

	ax25_dev_hold(ax25_dev);
@@ -111,32 +111,25 @@ void ax25_dev_device_down(struct net_device *dev) 
	/*

	 *	Remove any packet forwarding that points to this device.

	 */

	for (s = ax25_dev_list; s != NULL; s = s->next)

	list_for_each_entry(s, &ax25_dev_list, list)

		if (s->forward == dev)

			s->forward = NULL;



	if ((s = ax25_dev_list) == ax25_dev) {

		ax25_dev_list = s->next;

		goto unlock_put;

	}



	while (s != NULL && s->next != NULL) {

		if (s->next == ax25_dev) {

			s->next = ax25_dev->next;

	list_for_each_entry(s, &ax25_dev_list, list) {

		if (s == ax25_dev) {

			list_del(&s->list);

			goto unlock_put;

		}



		s = s->next;

	}

	spin_unlock_bh(&ax25_dev_lock);

	dev->ax25_ptr = NULL;

	spin_unlock_bh(&ax25_dev_lock);

	ax25_dev_put(ax25_dev);

	return;



unlock_put:

	dev->ax25_ptr = NULL;

	spin_unlock_bh(&ax25_dev_lock);

	ax25_dev_put(ax25_dev);

	dev->ax25_ptr = NULL;

	netdev_put(dev, &ax25_dev->dev_tracker);

	ax25_dev_put(ax25_dev);

}
@@ -200,16 +193,13 @@ struct net_device *ax25_fwd_dev(struct net_device *dev) 
 */

void __exit ax25_dev_free(void)

{

	ax25_dev *s, *ax25_dev;

	ax25_dev *s, *n;



	spin_lock_bh(&ax25_dev_lock);

	ax25_dev = ax25_dev_list;

	while (ax25_dev != NULL) {

		s        = ax25_dev;

		netdev_put(ax25_dev->dev, &ax25_dev->dev_tracker);

		ax25_dev = ax25_dev->next;

	list_for_each_entry_safe(s, n, &ax25_dev_list, list) {

		netdev_put(s->dev, &s->dev_tracker);

		list_del(&s->list);

		kfree(s);

	}

	ax25_dev_list = NULL;

	spin_unlock_bh(&ax25_dev_lock);

}