In cm_work_handler, it calls destory_cm_id() to release
the initial reference of cm_id_priv taken by iw_create_cm_id()
and free the cm_id_priv. After destory_cm_id(), iwcm_deref_id
(cm_id_priv) will be called and cause a use after free.
Fixes: 59c68ac31e15a ("iw_cm: free cm_id resources on the last deref")
Signed-off-by: Lv Yunlong <[email protected]>
---
drivers/infiniband/core/iwcm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
index da8adadf4755..cb6b4ac45e21 100644
--- a/drivers/infiniband/core/iwcm.c
+++ b/drivers/infiniband/core/iwcm.c
@@ -1035,8 +1035,10 @@ static void cm_work_handler(struct work_struct *_work)
if (!test_bit(IWCM_F_DROP_EVENTS, &cm_id_priv->flags)) {
ret = process_event(cm_id_priv, &levent);
- if (ret)
+ if (ret) {
destroy_cm_id(&cm_id_priv->id);
+ return;
+ }
} else
pr_debug("dropping event %d\n", levent.event);
if (iwcm_deref_id(cm_id_priv))
--
2.25.1
On Wed, Mar 10, 2021 at 06:21:53PM -0800, Lv Yunlong wrote:
> In cm_work_handler, it calls destory_cm_id() to release
> the initial reference of cm_id_priv taken by iw_create_cm_id()
> and free the cm_id_priv. After destory_cm_id(), iwcm_deref_id
> (cm_id_priv) will be called and cause a use after free.
>
> Fixes: 59c68ac31e15a ("iw_cm: free cm_id resources on the last deref")
> Signed-off-by: Lv Yunlong <[email protected]>
> ---
> drivers/infiniband/core/iwcm.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
> index da8adadf4755..cb6b4ac45e21 100644
> --- a/drivers/infiniband/core/iwcm.c
> +++ b/drivers/infiniband/core/iwcm.c
> @@ -1035,8 +1035,10 @@ static void cm_work_handler(struct work_struct *_work)
>
> if (!test_bit(IWCM_F_DROP_EVENTS, &cm_id_priv->flags)) {
> ret = process_event(cm_id_priv, &levent);
> - if (ret)
> + if (ret) {
> destroy_cm_id(&cm_id_priv->id);
> + return;
The destroy_cm_id() is called to free ->id and not cm_id_priv. This "return"
leaks cm_id_priv now and what "a use after free" do you see?
> + }
> } else
> pr_debug("dropping event %d\n", levent.event);
> if (iwcm_deref_id(cm_id_priv))
> --
> 2.25.1
>
>
In the implementation of destory_cm_id(), it restores cm_id_priv by
"cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);".
And the last line of destory_cm_id() calls "(void)iwcm_deref_id(cm_id_priv);"
to free the cm_id_priv.
> -----原始邮件-----
> 发件人: "Leon Romanovsky" <[email protected]>
> 发送时间: 2021-03-11 17:22:03 (星期四)
> 收件人: "Lv Yunlong" <[email protected]>
> 抄送: [email protected], [email protected], [email protected], [email protected]
> 主题: Re: [PATCH] infiniband/core: Fix a use after free in cm_work_handler
>
> On Wed, Mar 10, 2021 at 06:21:53PM -0800, Lv Yunlong wrote:
> > In cm_work_handler, it calls destory_cm_id() to release
> > the initial reference of cm_id_priv taken by iw_create_cm_id()
> > and free the cm_id_priv. After destory_cm_id(), iwcm_deref_id
> > (cm_id_priv) will be called and cause a use after free.
> >
> > Fixes: 59c68ac31e15a ("iw_cm: free cm_id resources on the last deref")
> > Signed-off-by: Lv Yunlong <[email protected]>
> > ---
> > drivers/infiniband/core/iwcm.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
> > index da8adadf4755..cb6b4ac45e21 100644
> > --- a/drivers/infiniband/core/iwcm.c
> > +++ b/drivers/infiniband/core/iwcm.c
> > @@ -1035,8 +1035,10 @@ static void cm_work_handler(struct work_struct *_work)
> >
> > if (!test_bit(IWCM_F_DROP_EVENTS, &cm_id_priv->flags)) {
> > ret = process_event(cm_id_priv, &levent);
> > - if (ret)
> > + if (ret) {
> > destroy_cm_id(&cm_id_priv->id);
> > + return;
>
> The destroy_cm_id() is called to free ->id and not cm_id_priv. This "return"
> leaks cm_id_priv now and what "a use after free" do you see?
>
> > + }
> > } else
> > pr_debug("dropping event %d\n", levent.event);
> > if (iwcm_deref_id(cm_id_priv))
> > --
> > 2.25.1
> >
> >
On Thu, Mar 11, 2021 at 06:29:19PM +0800, [email protected] wrote:
> In the implementation of destory_cm_id(), it restores cm_id_priv by
> "cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);".
>
> And the last line of destory_cm_id() calls "(void)iwcm_deref_id(cm_id_priv);"
> to free the cm_id_priv.
It is not enough to see double call to iwcm_deref_id() because it is
protected with refcount to claim use-after-free. Did you hit the BUG_ON()
for the second call to iwcm_deref_id()?
And please don't do top-posting.
Thanks
>
>
> > -----原始邮件-----
> > 发件人: "Leon Romanovsky" <[email protected]>
> > 发送时间: 2021-03-11 17:22:03 (星期四)
> > 收件人: "Lv Yunlong" <[email protected]>
> > 抄送: [email protected], [email protected], [email protected], [email protected]
> > 主题: Re: [PATCH] infiniband/core: Fix a use after free in cm_work_handler
> >
> > On Wed, Mar 10, 2021 at 06:21:53PM -0800, Lv Yunlong wrote:
> > > In cm_work_handler, it calls destory_cm_id() to release
> > > the initial reference of cm_id_priv taken by iw_create_cm_id()
> > > and free the cm_id_priv. After destory_cm_id(), iwcm_deref_id
> > > (cm_id_priv) will be called and cause a use after free.
> > >
> > > Fixes: 59c68ac31e15a ("iw_cm: free cm_id resources on the last deref")
> > > Signed-off-by: Lv Yunlong <[email protected]>
> > > ---
> > > drivers/infiniband/core/iwcm.c | 4 +++-
> > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
> > > index da8adadf4755..cb6b4ac45e21 100644
> > > --- a/drivers/infiniband/core/iwcm.c
> > > +++ b/drivers/infiniband/core/iwcm.c
> > > @@ -1035,8 +1035,10 @@ static void cm_work_handler(struct work_struct *_work)
> > >
> > > if (!test_bit(IWCM_F_DROP_EVENTS, &cm_id_priv->flags)) {
> > > ret = process_event(cm_id_priv, &levent);
> > > - if (ret)
> > > + if (ret) {
> > > destroy_cm_id(&cm_id_priv->id);
> > > + return;
> >
> > The destroy_cm_id() is called to free ->id and not cm_id_priv. This "return"
> > leaks cm_id_priv now and what "a use after free" do you see?
> >
> > > + }
> > > } else
> > > pr_debug("dropping event %d\n", levent.event);
> > > if (iwcm_deref_id(cm_id_priv))
> > > --
> > > 2.25.1
> > >
> > >
> -----原始邮件-----
> 发件人: "Leon Romanovsky" <[email protected]>
> 发送时间: 2021-03-11 19:05:03 (星期四)
> 收件人: [email protected]
> 抄送: [email protected], [email protected], [email protected], [email protected]
> 主题: Re: Re: [PATCH] infiniband/core: Fix a use after free in cm_work_handler
>
> On Thu, Mar 11, 2021 at 06:29:19PM +0800, [email protected] wrote:
> > In the implementation of destory_cm_id(), it restores cm_id_priv by
> > "cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);".
> >
> > And the last line of destory_cm_id() calls "(void)iwcm_deref_id(cm_id_priv);"
> > to free the cm_id_priv.
>
> It is not enough to see double call to iwcm_deref_id() because it is
> protected with refcount to claim use-after-free. Did you hit the BUG_ON()
> for the second call to iwcm_deref_id()?
>
> And please don't do top-posting.
>
> Thanks
>
> >
> >
> > > -----原始邮件-----
> > > 发件人: "Leon Romanovsky" <[email protected]>
> > > 发送时间: 2021-03-11 17:22:03 (星期四)
> > > 收件人: "Lv Yunlong" <[email protected]>
> > > 抄送: [email protected], [email protected], [email protected], [email protected]
> > > 主题: Re: [PATCH] infiniband/core: Fix a use after free in cm_work_handler
> > >
> > > On Wed, Mar 10, 2021 at 06:21:53PM -0800, Lv Yunlong wrote:
> > > > In cm_work_handler, it calls destory_cm_id() to release
> > > > the initial reference of cm_id_priv taken by iw_create_cm_id()
> > > > and free the cm_id_priv. After destory_cm_id(), iwcm_deref_id
> > > > (cm_id_priv) will be called and cause a use after free.
> > > >
> > > > Fixes: 59c68ac31e15a ("iw_cm: free cm_id resources on the last deref")
> > > > Signed-off-by: Lv Yunlong <[email protected]>
> > > > ---
> > > > drivers/infiniband/core/iwcm.c | 4 +++-
> > > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
> > > > index da8adadf4755..cb6b4ac45e21 100644
> > > > --- a/drivers/infiniband/core/iwcm.c
> > > > +++ b/drivers/infiniband/core/iwcm.c
> > > > @@ -1035,8 +1035,10 @@ static void cm_work_handler(struct work_struct *_work)
> > > >
> > > > if (!test_bit(IWCM_F_DROP_EVENTS, &cm_id_priv->flags)) {
> > > > ret = process_event(cm_id_priv, &levent);
> > > > - if (ret)
> > > > + if (ret) {
> > > > destroy_cm_id(&cm_id_priv->id);
> > > > + return;
> > >
> > > The destroy_cm_id() is called to free ->id and not cm_id_priv. This "return"
> > > leaks cm_id_priv now and what "a use after free" do you see?
> > >
> > > > + }
> > > > } else
> > > > pr_debug("dropping event %d\n", levent.event);
> > > > if (iwcm_deref_id(cm_id_priv))
> > > > --
> > > > 2.25.1
> > > >
> > > >
I'm not familiar with debug the kernel, sorry.This problem was
reported by my code analyzer and reviewed by myself.
But i think as long as destroy_cm_id() is called, iwcm_deref_id() will be called twice.
Then "BUG_ON(atomic_read(&cm_id_priv->refcount)==0);" in iwcm_deref_id() will be triggered.
Is it not a true problem?
On Thu, Mar 11, 2021 at 08:03:23PM +0800, [email protected] wrote:
>
>
>
> > -----原始邮件-----
> > 发件人: "Leon Romanovsky" <[email protected]>
> > 发送时间: 2021-03-11 19:05:03 (星期四)
> > 收件人: [email protected]
> > 抄送: [email protected], [email protected], [email protected], [email protected]
> > 主题: Re: Re: [PATCH] infiniband/core: Fix a use after free in cm_work_handler
> >
> > On Thu, Mar 11, 2021 at 06:29:19PM +0800, [email protected] wrote:
> > > In the implementation of destory_cm_id(), it restores cm_id_priv by
> > > "cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);".
> > >
> > > And the last line of destory_cm_id() calls "(void)iwcm_deref_id(cm_id_priv);"
> > > to free the cm_id_priv.
> >
> > It is not enough to see double call to iwcm_deref_id() because it is
> > protected with refcount to claim use-after-free. Did you hit the BUG_ON()
> > for the second call to iwcm_deref_id()?
> >
> > And please don't do top-posting.
> >
> > Thanks
> >
> > >
> > >
> > > > -----原始邮件-----
> > > > 发件人: "Leon Romanovsky" <[email protected]>
> > > > 发送时间: 2021-03-11 17:22:03 (星期四)
> > > > 收件人: "Lv Yunlong" <[email protected]>
> > > > 抄送: [email protected], [email protected], [email protected], [email protected]
> > > > 主题: Re: [PATCH] infiniband/core: Fix a use after free in cm_work_handler
> > > >
> > > > On Wed, Mar 10, 2021 at 06:21:53PM -0800, Lv Yunlong wrote:
> > > > > In cm_work_handler, it calls destory_cm_id() to release
> > > > > the initial reference of cm_id_priv taken by iw_create_cm_id()
> > > > > and free the cm_id_priv. After destory_cm_id(), iwcm_deref_id
> > > > > (cm_id_priv) will be called and cause a use after free.
> > > > >
> > > > > Fixes: 59c68ac31e15a ("iw_cm: free cm_id resources on the last deref")
> > > > > Signed-off-by: Lv Yunlong <[email protected]>
> > > > > ---
> > > > > drivers/infiniband/core/iwcm.c | 4 +++-
> > > > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
> > > > > index da8adadf4755..cb6b4ac45e21 100644
> > > > > --- a/drivers/infiniband/core/iwcm.c
> > > > > +++ b/drivers/infiniband/core/iwcm.c
> > > > > @@ -1035,8 +1035,10 @@ static void cm_work_handler(struct work_struct *_work)
> > > > >
> > > > > if (!test_bit(IWCM_F_DROP_EVENTS, &cm_id_priv->flags)) {
> > > > > ret = process_event(cm_id_priv, &levent);
> > > > > - if (ret)
> > > > > + if (ret) {
> > > > > destroy_cm_id(&cm_id_priv->id);
> > > > > + return;
> > > >
> > > > The destroy_cm_id() is called to free ->id and not cm_id_priv. This "return"
> > > > leaks cm_id_priv now and what "a use after free" do you see?
> > > >
> > > > > + }
> > > > > } else
> > > > > pr_debug("dropping event %d\n", levent.event);
> > > > > if (iwcm_deref_id(cm_id_priv))
> > > > > --
> > > > > 2.25.1
> > > > >
> > > > >
>
> I'm not familiar with debug the kernel, sorry.This problem was
> reported by my code analyzer and reviewed by myself.
>
> But i think as long as destroy_cm_id() is called, iwcm_deref_id() will be called twice.
> Then "BUG_ON(atomic_read(&cm_id_priv->refcount)==0);" in iwcm_deref_id() will be triggered.
>
> Is it not a true problem?
I don't know, this is I'm trying to understand here.
Thanks