From: Duoming Zhou <duoming@zju.edu.cn> stable inclusion from stable-v6.6.33 commit 965d940fb7414b310a22666503d2af69459c981b category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA6SG4 CVE: CVE-2024-38554 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- [ Upstream commit 36e56b1b002bb26440403053f19f9e1a8bc075b2 ] There is a reference count leak issue of the object "net_device" in ax25_dev_device_down(). When the ax25 device is shutting down, the ax25_dev_device_down() drops the reference count of net_device one or zero times depending on if we goto unlock_put or not, which will cause memory leak. In order to solve the above issue, decrease the reference count of net_device after dev->ax25_ptr is set to null. Fixes: d01ffb9eee4a ("ax25: add refcount in ax25_dev to avoid UAF bugs") Suggested-by: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org> Link: https://lore.kernel.org/r/7ce3b23a40d9084657ba1125432f0ecc380cbc80.171524701... Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Conflicts: net/ax25/ax25_dev.c [The conflict occurs because the commit a7d6e36b9ad0("ax25: Use kernel universal linked list to implement ax25_dev_list") is not merged] Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com> --- net/ax25/ax25_dev.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c index 282ec581c072..6f4ccb735653 100644 --- a/net/ax25/ax25_dev.c +++ b/net/ax25/ax25_dev.c @@ -128,10 +128,6 @@ void ax25_dev_device_down(struct net_device *dev) s = s->next; } - spin_unlock_bh(&ax25_dev_lock); - dev->ax25_ptr = NULL; - ax25_dev_put(ax25_dev); - return; unlock_put: spin_unlock_bh(&ax25_dev_lock); -- 2.34.1