[PATCH v2] ieee802154: hwsim: Fix memory leak in hwsim_add_one

[PATCH v2] ieee802154: hwsim: Fix memory leak in hwsim_add_one

[Dongliang Mu]

No matter from hwsim_remove or hwsim_del_radio_nl, hwsim_del fails to
remove the entry in the edges list. Take the example below, phy0, phy1
and e0 will be deleted, resulting in e1 not freed and accessed in the
future.

              hwsim_phys
                  |
    ------------------------------
    |                            |
phy0 (edges)                 phy1 (edges)
   ----> e1 (idx = 1)             ----> e0 (idx = 0)

Fix this by deleting and freeing all the entries in the edges list
between hwsim_edge_unsubscribe_me and list_del(&phy->list).

Reported-by: syzbot+b80c9959009a9325cdff@syzkaller.appspotmail.com
Fixes: 1c9f4a3fce77 ("ieee802154: hwsim: fix rcu handling")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
---
v1->v2: add rcu_read_lock for the deletion operation according to Pavel Skripkin

 drivers/net/ieee802154/mac802154_hwsim.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ieee802154/mac802154_hwsim.c b/drivers/net/ieee802154/mac802154_hwsim.c
index da9135231c07..cf659361a3fb 100644
--- a/drivers/net/ieee802154/mac802154_hwsim.c
+++ b/drivers/net/ieee802154/mac802154_hwsim.c
@@ -824,12 +824,17 @@ static int hwsim_add_one(struct genl_info *info, struct device *dev,
 static void hwsim_del(struct hwsim_phy *phy)
 {
 	struct hwsim_pib *pib;
+	struct hwsim_edge *e;
 
 	hwsim_edge_unsubscribe_me(phy);
 
 	list_del(&phy->list);
 
 	rcu_read_lock();
+	list_for_each_entry_rcu(e, &phy->edges, list) {
+		list_del_rcu(&e->list);
+		hwsim_free_edge(e);
+	}
 	pib = rcu_dereference(phy->pib);
 	rcu_read_unlock();
 
-- 
2.25.1

Re: [PATCH v2] ieee802154: hwsim: Fix memory leak in hwsim_add_one

[Alexander Aring]

Hi,

On Tue, 15 Jun 2021 at 22:09, Dongliang Mu <mudongliangabcd@gmail.com> wrote:
>
> No matter from hwsim_remove or hwsim_del_radio_nl, hwsim_del fails to
> remove the entry in the edges list. Take the example below, phy0, phy1
> and e0 will be deleted, resulting in e1 not freed and accessed in the
> future.
>
>               hwsim_phys
>                   |
>     ------------------------------
>     |                            |
> phy0 (edges)                 phy1 (edges)
>    ----> e1 (idx = 1)             ----> e0 (idx = 0)
>
> Fix this by deleting and freeing all the entries in the edges list
> between hwsim_edge_unsubscribe_me and list_del(&phy->list).
>
> Reported-by: syzbot+b80c9959009a9325cdff@syzkaller.appspotmail.com
> Fixes: 1c9f4a3fce77 ("ieee802154: hwsim: fix rcu handling")
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>

Acked-by: Alexander Aring <aahringo@redhat.com>

Thanks!

Re: [PATCH v2] ieee802154: hwsim: Fix memory leak in hwsim_add_one

[Stefan Schmidt]

Hello.

On 22.06.21 20:29, Alexander Aring wrote:
> Hi,
> 
> On Tue, 15 Jun 2021 at 22:09, Dongliang Mu <mudongliangabcd@gmail.com> wrote:
>>
>> No matter from hwsim_remove or hwsim_del_radio_nl, hwsim_del fails to
>> remove the entry in the edges list. Take the example below, phy0, phy1
>> and e0 will be deleted, resulting in e1 not freed and accessed in the
>> future.
>>
>>                hwsim_phys
>>                    |
>>      ------------------------------
>>      |                            |
>> phy0 (edges)                 phy1 (edges)
>>     ----> e1 (idx = 1)             ----> e0 (idx = 0)
>>
>> Fix this by deleting and freeing all the entries in the edges list
>> between hwsim_edge_unsubscribe_me and list_del(&phy->list).
>>
>> Reported-by: syzbot+b80c9959009a9325cdff@syzkaller.appspotmail.com
>> Fixes: 1c9f4a3fce77 ("ieee802154: hwsim: fix rcu handling")
>> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> 
> Acked-by: Alexander Aring <aahringo@redhat.com>
> 
> Thanks!


This patch has been applied to the wpan tree and will be
part of the next pull request to net. Thanks!

regards
Stefan Schmidt