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From:   Niels Dossche <dossche.niels@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Cc:     Marcel Holtmann <marcel@holtmann.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        Ankit Navik <ankit.p.navik@intel.com>,
        Niels Dossche <dossche.niels@gmail.com>
Subject: [PATCH] Bluetooth: protect le accept and resolv lists with hdev->lock
Date:   Sat, 23 Apr 2022 00:31:17 +0200
Message-Id: <20220422223116.70026-1-dossche.niels@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Concurrent operations from events on le_{accept,resolv}_list are
currently unprotected by hdev->lock.
Most existing code do already protect the lists with that lock.
This can be observed in hci_debugfs and hci_sync.
Add the protection for these events too.

Fixes: b950aa88638c ("Bluetooth: Add definitions and track LE resolve list modification")
Fixes: 0f36b589e4ee ("Bluetooth: Track LE white list modification via HCI commands")
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
---

Note:
I am currently working on a static analyser to detect missing locks
using type-based static analysis as my master's thesis
in order to obtain my master's degree.
If you would like to have more details, please let me know.
This was a reported case. I manually verified the report by looking
at the code, so that I do not send wrong information or patches.
After concluding that this seems to be a true positive, I created
this patch. This was compile-tested and runtime-tested on x86_64.
This issue was found on Linux v5.17.4.

 net/bluetooth/hci_event.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index abaabfae19cc..f314eb0bf284 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -1835,7 +1835,9 @@ static u8 hci_cc_le_clear_accept_list(struct hci_dev *hdev, void *data,
 	if (rp->status)
 		return rp->status;
 
+	hci_dev_lock(hdev);
 	hci_bdaddr_list_clear(&hdev->le_accept_list);
+	hci_dev_unlock(hdev);
 
 	return rp->status;
 }
@@ -1855,8 +1857,10 @@ static u8 hci_cc_le_add_to_accept_list(struct hci_dev *hdev, void *data,
 	if (!sent)
 		return rp->status;
 
+	hci_dev_lock(hdev);
 	hci_bdaddr_list_add(&hdev->le_accept_list, &sent->bdaddr,
 			    sent->bdaddr_type);
+	hci_dev_unlock(hdev);
 
 	return rp->status;
 }
@@ -1876,8 +1880,10 @@ static u8 hci_cc_le_del_from_accept_list(struct hci_dev *hdev, void *data,
 	if (!sent)
 		return rp->status;
 
+	hci_dev_lock(hdev);
 	hci_bdaddr_list_del(&hdev->le_accept_list, &sent->bdaddr,
 			    sent->bdaddr_type);
+	hci_dev_unlock(hdev);
 
 	return rp->status;
 }
@@ -1949,9 +1955,11 @@ static u8 hci_cc_le_add_to_resolv_list(struct hci_dev *hdev, void *data,
 	if (!sent)
 		return rp->status;
 
+	hci_dev_lock(hdev);
 	hci_bdaddr_list_add_with_irk(&hdev->le_resolv_list, &sent->bdaddr,
 				sent->bdaddr_type, sent->peer_irk,
 				sent->local_irk);
+	hci_dev_unlock(hdev);
 
 	return rp->status;
 }
@@ -1971,8 +1979,10 @@ static u8 hci_cc_le_del_from_resolv_list(struct hci_dev *hdev, void *data,
 	if (!sent)
 		return rp->status;
 
+	hci_dev_lock(hdev);
 	hci_bdaddr_list_del_with_irk(&hdev->le_resolv_list, &sent->bdaddr,
 			    sent->bdaddr_type);
+	hci_dev_unlock(hdev);
 
 	return rp->status;
 }
@@ -1987,7 +1997,9 @@ static u8 hci_cc_le_clear_resolv_list(struct hci_dev *hdev, void *data,
 	if (rp->status)
 		return rp->status;
 
+	hci_dev_lock(hdev);
 	hci_bdaddr_list_clear(&hdev->le_resolv_list);
+	hci_dev_unlock(hdev);
 
 	return rp->status;
 }
-- 
2.35.2