From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: Marcel Holtmann <marcel@holtmann.org>,
Johan Hedberg <johan.hedberg@gmail.com>,
Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
linux-bluetooth@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Lin Ma <linma@zju.edu.cn>,
netdev@vger.kernel.org,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Subject: [PATCH] Bluetooth: call lock_sock() outside of spinlock section
Date: Sun, 27 Jun 2021 22:11:34 +0900 [thread overview]
Message-ID: <20210627131134.5434-1-penguin-kernel@I-love.SAKURA.ne.jp> (raw)
syzbot is hitting might_sleep() warning at hci_sock_dev_event() due to
calling lock_sock() with rw spinlock held [1]. Defer calling lock_sock()
via sock_hold().
Link: https://syzkaller.appspot.com/bug?extid=a5df189917e79d5e59c9 [1]
Reported-by: syzbot <syzbot+a5df189917e79d5e59c9@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Tested-by: syzbot <syzbot+a5df189917e79d5e59c9@syzkaller.appspotmail.com>
Fixes: e305509e678b3a4a ("Bluetooth: use correct lock to prevent UAF of hdev object")
---
net/bluetooth/hci_sock.c | 24 ++++++++++++++++++++++--
1 file changed, 22 insertions(+), 2 deletions(-)
diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index eed0dd066e12..64e54ab0892f 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -759,19 +759,39 @@ void hci_sock_dev_event(struct hci_dev *hdev, int event)
if (event == HCI_DEV_UNREG) {
struct sock *sk;
+restart:
/* Detach sockets from device */
read_lock(&hci_sk_list.lock);
sk_for_each(sk, &hci_sk_list.head) {
+ /* hci_sk_list.lock is preventing hci_sock_release()
+ * from calling bt_sock_unlink().
+ */
+ if (hci_pi(sk)->hdev != hdev || sk_unhashed(sk))
+ continue;
+ /* Take a ref because we can't call lock_sock() with
+ * hci_sk_list.lock held.
+ */
+ sock_hold(sk);
+ read_unlock(&hci_sk_list.lock);
lock_sock(sk);
- if (hci_pi(sk)->hdev == hdev) {
+ /* Since hci_sock_release() might have already called
+ * bt_sock_unlink() while waiting for lock_sock(),
+ * use sk_hashed(sk) for checking that bt_sock_unlink()
+ * is not yet called.
+ */
+ if (sk_hashed(sk) && hci_pi(sk)->hdev == hdev) {
hci_pi(sk)->hdev = NULL;
sk->sk_err = EPIPE;
sk->sk_state = BT_OPEN;
sk->sk_state_change(sk);
-
hci_dev_put(hdev);
}
release_sock(sk);
+ sock_put(sk);
+ /* Restarting is safe, for hci_pi(sk)->hdev is now NULL
+ * if condition met and will "continue;" otherwise.
+ */
+ goto restart;
}
read_unlock(&hci_sk_list.lock);
}
--
2.18.4
next reply other threads:[~2021-06-27 13:12 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-27 13:11 Tetsuo Handa [this message]
2021-07-07 9:43 ` [PATCH v2] Bluetooth: call lock_sock() outside of spinlock section Tetsuo Handa
2021-07-07 18:20 ` Luiz Augusto von Dentz
2021-07-07 23:33 ` Tetsuo Handa
2021-07-08 1:00 ` LinMa
2021-07-09 13:50 ` Tetsuo Handa
2021-07-10 13:34 ` Tetsuo Handa
2021-07-13 11:27 ` [PATCH v3] " Tetsuo Handa
2021-07-14 19:20 ` Luiz Augusto von Dentz
2021-07-15 3:03 ` LinMa
2021-07-16 3:47 ` Desmond Cheong Zhi Xi
2021-07-16 4:11 ` Desmond Cheong Zhi Xi
2021-07-16 14:48 ` Tetsuo Handa
2021-07-16 15:26 ` LinMa
2021-07-17 15:41 ` Yet Another Patch for CVE-2021-3573 LinMa
2021-07-17 15:45 ` LinMa
2021-07-22 9:36 ` [PATCH v3] Bluetooth: call lock_sock() outside of spinlock section Tetsuo Handa
2021-07-22 4:47 ` LinMa
2021-07-22 5:16 ` Tetsuo Handa
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