From: Ruihan Li <lrh2000@xxxxxxxxxx> commit 2910431ab0e500dfc5df12299bb15eef0f30b43e upstream. If hci_conn_put(conn->parent) reduces conn->parent's reference count to zero, it can immediately deallocate conn->parent. At the same time, conn->link->list has its head in conn->parent, causing use-after-free problems in the latter list_del_rcu(&conn->link->list). This problem can be easily solved by reordering the two operations, i.e., first performing the list removal with list_del_rcu and then decreasing the refcnt with hci_conn_put. Reported-by: Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx> Closes: https://lore.kernel.org/linux-bluetooth/CABBYNZ+1kce8_RJrLNOXd_8=Mdpb=2bx4Nto-hFORk=qiOkoCg@xxxxxxxxxxxxxx/ Fixes: 06149746e720 ("Bluetooth: hci_conn: Add support for linking multiple hcon") Signed-off-by: Ruihan Li <lrh2000@xxxxxxxxxx> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/bluetooth/hci_conn.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -1107,12 +1107,12 @@ static void hci_conn_unlink(struct hci_c if (!conn->link) return; - hci_conn_put(conn->parent); - conn->parent = NULL; - list_del_rcu(&conn->link->list); synchronize_rcu(); + hci_conn_put(conn->parent); + conn->parent = NULL; + kfree(conn->link); conn->link = NULL; }
