* [PATCH v2] net/rose: Fix Use-After-Free in rose_ioctl
@ 2023-12-06 4:13 Hyunwoo Kim
2023-12-06 10:33 ` Eric Dumazet
0 siblings, 1 reply; 4+ messages in thread
From: Hyunwoo Kim @ 2023-12-06 4:13 UTC (permalink / raw)
To: ralf, edumazet; +Cc: v4bel, imv4bel, davem, kuba, pabeni, linux-hams, netdev
Because rose_ioctl() accesses sk->sk_receive_queue
without holding a sk->sk_receive_queue.lock, it can
cause a race with rose_accept().
A use-after-free for skb occurs with the following flow.
```
rose_ioctl() -> skb_peek()
rose_accept() -> skb_dequeue() -> kfree_skb()
```
Add sk->sk_receive_queue.lock to rose_ioctl() to fix this issue.
Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
---
v1 -> v2: Use sk->sk_receive_queue.lock instead of lock_sock.
---
net/rose/af_rose.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
index 0cc5a4e19900..841c238de222 100644
--- a/net/rose/af_rose.c
+++ b/net/rose/af_rose.c
@@ -1316,8 +1316,10 @@ static int rose_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
struct sk_buff *skb;
long amount = 0L;
/* These two are safe on a single CPU system as only user tasks fiddle here */
+ spin_lock(&sk->sk_receive_queue.lock);
if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
amount = skb->len;
+ spin_unlock(&sk->sk_receive_queue.lock);
return put_user(amount, (unsigned int __user *) argp);
}
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] net/rose: Fix Use-After-Free in rose_ioctl
2023-12-06 4:13 [PATCH v2] net/rose: Fix Use-After-Free in rose_ioctl Hyunwoo Kim
@ 2023-12-06 10:33 ` Eric Dumazet
2023-12-06 10:52 ` Hyunwoo Kim
0 siblings, 1 reply; 4+ messages in thread
From: Eric Dumazet @ 2023-12-06 10:33 UTC (permalink / raw)
To: Hyunwoo Kim; +Cc: ralf, imv4bel, davem, kuba, pabeni, linux-hams, netdev
On Wed, Dec 6, 2023 at 5:13 AM Hyunwoo Kim <v4bel@theori.io> wrote:
>
> Because rose_ioctl() accesses sk->sk_receive_queue
> without holding a sk->sk_receive_queue.lock, it can
> cause a race with rose_accept().
> A use-after-free for skb occurs with the following flow.
> ```
> rose_ioctl() -> skb_peek()
> rose_accept() -> skb_dequeue() -> kfree_skb()
> ```
> Add sk->sk_receive_queue.lock to rose_ioctl() to fix this issue.
>
Please add a Fixes: tag
> Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
> ---
> v1 -> v2: Use sk->sk_receive_queue.lock instead of lock_sock.
> ---
> net/rose/af_rose.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
> index 0cc5a4e19900..841c238de222 100644
> --- a/net/rose/af_rose.c
> +++ b/net/rose/af_rose.c
> @@ -1316,8 +1316,10 @@ static int rose_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
> struct sk_buff *skb;
> long amount = 0L;
> /* These two are safe on a single CPU system as only user tasks fiddle here */
> + spin_lock(&sk->sk_receive_queue.lock);
You need interrupt safety here.
sk_receive_queue can be fed from interrupt, that would potentially deadlock.
> if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
> amount = skb->len;
> + spin_unlock(&sk->sk_receive_queue.lock);
> return put_user(amount, (unsigned int __user *) argp);
> }
>
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] net/rose: Fix Use-After-Free in rose_ioctl
2023-12-06 10:33 ` Eric Dumazet
@ 2023-12-06 10:52 ` Hyunwoo Kim
2023-12-06 10:56 ` Eric Dumazet
0 siblings, 1 reply; 4+ messages in thread
From: Hyunwoo Kim @ 2023-12-06 10:52 UTC (permalink / raw)
To: Eric Dumazet
Cc: ralf, imv4bel, davem, kuba, pabeni, linux-hams, netdev, v4bel
Dear,
On Wed, Dec 06, 2023 at 11:33:15AM +0100, Eric Dumazet wrote:
> On Wed, Dec 6, 2023 at 5:13 AM Hyunwoo Kim <v4bel@theori.io> wrote:
> >
> > Because rose_ioctl() accesses sk->sk_receive_queue
> > without holding a sk->sk_receive_queue.lock, it can
> > cause a race with rose_accept().
> > A use-after-free for skb occurs with the following flow.
> > ```
> > rose_ioctl() -> skb_peek()
> > rose_accept() -> skb_dequeue() -> kfree_skb()
> > ```
> > Add sk->sk_receive_queue.lock to rose_ioctl() to fix this issue.
> >
>
> Please add a Fixes: tag
>
> > Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
> > ---
> > v1 -> v2: Use sk->sk_receive_queue.lock instead of lock_sock.
> > ---
> > net/rose/af_rose.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
> > index 0cc5a4e19900..841c238de222 100644
> > --- a/net/rose/af_rose.c
> > +++ b/net/rose/af_rose.c
> > @@ -1316,8 +1316,10 @@ static int rose_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
> > struct sk_buff *skb;
> > long amount = 0L;
> > /* These two are safe on a single CPU system as only user tasks fiddle here */
> > + spin_lock(&sk->sk_receive_queue.lock);
>
> You need interrupt safety here.
>
> sk_receive_queue can be fed from interrupt, that would potentially deadlock.
I want to change spin_lock to spin_lock_irqsave, is this okay?
Regards,
Hyunwoo Kim
>
> > if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
> > amount = skb->len;
> > + spin_unlock(&sk->sk_receive_queue.lock);
> > return put_user(amount, (unsigned int __user *) argp);
> > }
> >
> > --
> > 2.25.1
> >
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] net/rose: Fix Use-After-Free in rose_ioctl
2023-12-06 10:52 ` Hyunwoo Kim
@ 2023-12-06 10:56 ` Eric Dumazet
0 siblings, 0 replies; 4+ messages in thread
From: Eric Dumazet @ 2023-12-06 10:56 UTC (permalink / raw)
To: Hyunwoo Kim; +Cc: ralf, imv4bel, davem, kuba, pabeni, linux-hams, netdev
On Wed, Dec 6, 2023 at 11:52 AM Hyunwoo Kim <v4bel@theori.io> wrote:
>
> Dear,
>
> On Wed, Dec 06, 2023 at 11:33:15AM +0100, Eric Dumazet wrote:
> > On Wed, Dec 6, 2023 at 5:13 AM Hyunwoo Kim <v4bel@theori.io> wrote:
> > >
> > > Because rose_ioctl() accesses sk->sk_receive_queue
> > > without holding a sk->sk_receive_queue.lock, it can
> > > cause a race with rose_accept().
> > > A use-after-free for skb occurs with the following flow.
> > > ```
> > > rose_ioctl() -> skb_peek()
> > > rose_accept() -> skb_dequeue() -> kfree_skb()
> > > ```
> > > Add sk->sk_receive_queue.lock to rose_ioctl() to fix this issue.
> > >
> >
> > Please add a Fixes: tag
> >
> > > Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
> > > ---
> > > v1 -> v2: Use sk->sk_receive_queue.lock instead of lock_sock.
> > > ---
> > > net/rose/af_rose.c | 2 ++
> > > 1 file changed, 2 insertions(+)
> > >
> > > diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
> > > index 0cc5a4e19900..841c238de222 100644
> > > --- a/net/rose/af_rose.c
> > > +++ b/net/rose/af_rose.c
> > > @@ -1316,8 +1316,10 @@ static int rose_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
> > > struct sk_buff *skb;
> > > long amount = 0L;
> > > /* These two are safe on a single CPU system as only user tasks fiddle here */
> > > + spin_lock(&sk->sk_receive_queue.lock);
> >
> > You need interrupt safety here.
> >
> > sk_receive_queue can be fed from interrupt, that would potentially deadlock.
>
> I want to change spin_lock to spin_lock_irqsave, is this okay?
Either spin_lock_irq() or spin_lock_irqsave() will work.
>
>
> Regards,
> Hyunwoo Kim
>
> >
> > > if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
> > > amount = skb->len;
> > > + spin_unlock(&sk->sk_receive_queue.lock);
> > > return put_user(amount, (unsigned int __user *) argp);
> > > }
> > >
> > > --
> > > 2.25.1
> > >
^ permalink raw reply [flat|nested] 4+ messages in thread
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2023-12-06 4:13 [PATCH v2] net/rose: Fix Use-After-Free in rose_ioctl Hyunwoo Kim
2023-12-06 10:33 ` Eric Dumazet
2023-12-06 10:52 ` Hyunwoo Kim
2023-12-06 10:56 ` Eric Dumazet
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