Merge branch 'kvm-ghcb-for-7.2' into HEAD

Merge the final part of the GHCB 7.2 fixes at
https://lore.kernel.org/kvm/20260529183549.1104619-1-pbonzini@redhat.com/.

Patches 1-17 have already been included in Linux 7.1; these are minor
cleanups, and fixes for behaviors that are suboptimal or contradicting
the specification.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 47 insertions, 22 deletions

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 18826d4b9c0b..f1799c6a6f87 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -472,9 +472,13 @@ static struct sock *sco_get_sock_listen(bdaddr_t *src)
 			sk1 = sk;
 	}
 
+	sk = sk ? sk : sk1;
+	if (sk)
+		sock_hold(sk);
+
 	read_unlock(&sco_sk_list.lock);
 
-	return sk ? sk : sk1;
+	return sk;
 }
 
 static void sco_sock_destruct(struct sock *sk)
@@ -498,6 +502,8 @@ static void sco_sock_cleanup_listen(struct sock *parent)
 	while ((sk = bt_accept_dequeue(parent, NULL))) {
 		sco_sock_close(sk);
 		sco_sock_kill(sk);
+		/* Drop the reference handed back by bt_accept_dequeue(). */
+		sock_put(sk);
 	}
 
 	parent->sk_state  = BT_CLOSED;
@@ -515,11 +521,13 @@ static void sco_sock_kill(struct sock *sk)
 	BT_DBG("sk %p state %d", sk, sk->sk_state);
 
 	/* Sock is dead, so set conn->sk to NULL to avoid possible UAF */
+	lock_sock(sk);
 	if (sco_pi(sk)->conn) {
 		sco_conn_lock(sco_pi(sk)->conn);
 		sco_pi(sk)->conn->sk = NULL;
 		sco_conn_unlock(sco_pi(sk)->conn);
 	}
+	release_sock(sk);
 
 	/* Kill poor orphan */
 	bt_sock_unlink(&sco_sk_list, sk);
@@ -759,8 +767,13 @@ static int sco_sock_accept(struct socket *sock, struct socket *newsock,
 		}
 
 		ch = bt_accept_dequeue(sk, newsock);
-		if (ch)
+		if (ch) {
+			/* Drop the bridging ref from bt_accept_dequeue();
+			 * the grafted socket keeps ch alive from here.
+			 */
+			sock_put(ch);
 			break;
+		}
 
 		if (!timeo) {
 			err = -EAGAIN;
@@ -1365,40 +1378,51 @@ static int sco_sock_release(struct socket *sock)
 
 static void sco_conn_ready(struct sco_conn *conn)
 {
-	struct sock *parent;
-	struct sock *sk = conn->sk;
+	struct sock *parent, *sk;
+
+	sco_conn_lock(conn);
+	sk = sco_sock_hold(conn);
+	sco_conn_unlock(conn);
 
 	BT_DBG("conn %p", conn);
 
 	if (sk) {
 		lock_sock(sk);
-		sco_sock_clear_timer(sk);
-		sk->sk_state = BT_CONNECTED;
-		sk->sk_state_change(sk);
+
+		/* conn->sk may have become NULL if racing with sk close, but
+		 * due to held hdev->lock, it can't become different sk.
+		 */
+		if (conn->sk) {
+			sco_sock_clear_timer(sk);
+			sk->sk_state = BT_CONNECTED;
+			sk->sk_state_change(sk);
+		}
+
 		release_sock(sk);
+		sock_put(sk);
 	} else {
-		sco_conn_lock(conn);
-
-		if (!conn->hcon) {
-			sco_conn_unlock(conn);
+		if (!conn->hcon)
 			return;
-		}
+
+		lockdep_assert_held(&conn->hcon->hdev->lock);
 
 		parent = sco_get_sock_listen(&conn->hcon->src);
-		if (!parent) {
-			sco_conn_unlock(conn);
+		if (!parent)
 			return;
-		}
 
 		lock_sock(parent);
 
+		sco_conn_lock(conn);
+
+		/* hdev->lock guarantees conn->sk == NULL still here */
+
+		if (parent->sk_state != BT_LISTEN)
+			goto release;
+
 		sk = sco_sock_alloc(sock_net(parent), NULL,
 				    BTPROTO_SCO, GFP_ATOMIC, 0);
-		if (!sk) {
-			release_sock(parent);
-			sco_conn_unlock(conn);
-			return;
-		}
+		if (!sk)
+			goto release;
 
 		sco_sock_init(sk, parent);
 
@@ -1417,9 +1441,10 @@ static void sco_conn_ready(struct sco_conn *conn)
 		/* Wake up parent */
 		parent->sk_data_ready(parent);
 
-		release_sock(parent);
-
+release:
 		sco_conn_unlock(conn);
+		release_sock(parent);
+		sock_put(parent);
 	}
 }