| Message ID | 20231204065657.GA16054@ubuntu (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net/rose: Fix Use-After-Free in rose_ioctl | expand |
On Mon, Dec 4, 2023 at 7:57 AM Hyunwoo Kim <v4bel@theori.io> wrote: > > Because rose_ioctl() accesses sk->sk_receive_queue > without holding a lock_sock, 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 lock_sock to rose_ioctl() to fix this issue. > > Signed-off-by: Hyunwoo Kim <v4bel@theori.io> > --- > 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..5fe9db64b6df 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 */ > + lock_sock(sk); This is not correct. You will have to lock sk->sk_receive_queue.lock instead. Look at rose_recvmsg() for the reason why locking the socket itself is not helping. > if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) > amount = skb->len; > + release_sock(sk); > return put_user(amount, (unsigned int __user *) argp); > } > > -- > 2.25.1 >
diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c index 0cc5a4e19900..5fe9db64b6df 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 */ + lock_sock(sk); if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) amount = skb->len; + release_sock(sk); return put_user(amount, (unsigned int __user *) argp); }
Because rose_ioctl() accesses sk->sk_receive_queue without holding a lock_sock, 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 lock_sock to rose_ioctl() to fix this issue. Signed-off-by: Hyunwoo Kim <v4bel@theori.io> --- net/rose/af_rose.c | 2 ++ 1 file changed, 2 insertions(+)