Re: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in __lock_sock

syzbot
2023-11-23T03:19:08Z

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Subject: [bluetooth?] KASAN: slab-use-after-free Read in __lock_sock
Author: eadavis@qq.com

please test uaf in __lock_sock

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git 8de1e7afcc1c

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index c736186aba26..3d76352d3e79 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -270,6 +270,7 @@ static int sco_connect(struct sock *sk)
goto unlock;
}

+ hci_conn_get(hcon);
conn = sco_conn_add(hcon);
if (!conn) {
hci_conn_drop(hcon);
@@ -300,7 +301,6 @@ static int sco_connect(struct sock *sk)

unlock:
hci_dev_unlock(hdev);
- hci_dev_put(hdev);
return err;
}

@@ -438,12 +438,13 @@ static void __sco_sock_close(struct sock *sk)
case BT_CONNECTED:
case BT_CONFIG:
if (sco_pi(sk)->conn->hcon) {
+ struct hci_conn *hcon = sco_pi(sk)->conn->hcon;
sk->sk_state = BT_DISCONN;
sco_sock_set_timer(sk, SCO_DISCONN_TIMEOUT);
sco_conn_lock(sco_pi(sk)->conn);
- hci_conn_drop(sco_pi(sk)->conn->hcon);
sco_pi(sk)->conn->hcon = NULL;
sco_conn_unlock(sco_pi(sk)->conn);
+ hci_conn_put(hcon);
} else
sco_chan_del(sk, ECONNRESET);
break;