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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Itay Iellin <ieitayie@gmail.com>,
        Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Subject: [PATCH 4.19 07/15] Bluetooth: Fix the creation of hdev->name
Date:   Fri, 13 May 2022 16:23:29 +0200
Message-Id: <20220513142228.113538429@linuxfoundation.org>
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From: Itay Iellin <ieitayie@gmail.com>

commit 103a2f3255a95991252f8f13375c3a96a75011cd upstream.

Set a size limit of 8 bytes of the written buffer to "hdev->name"
including the terminating null byte, as the size of "hdev->name" is 8
bytes. If an id value which is greater than 9999 is allocated,
then the "snprintf(hdev->name, sizeof(hdev->name), "hci%d", id)"
function call would lead to a truncation of the id value in decimal
notation.

Set an explicit maximum id parameter in the id allocation function call.
The id allocation function defines the maximum allocated id value as the
maximum id parameter value minus one. Therefore, HCI_MAX_ID is defined
as 10000.

Signed-off-by: Itay Iellin <ieitayie@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/net/bluetooth/hci_core.h |    3 +++
 net/bluetooth/hci_core.c         |    6 +++---
 2 files changed, 6 insertions(+), 3 deletions(-)

--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -34,6 +34,9 @@
 /* HCI priority */
 #define HCI_PRIO_MAX	7
 
+/* HCI maximum id value */
+#define HCI_MAX_ID 10000
+
 /* HCI Core structures */
 struct inquiry_data {
 	bdaddr_t	bdaddr;
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -3180,10 +3180,10 @@ int hci_register_dev(struct hci_dev *hde
 	 */
 	switch (hdev->dev_type) {
 	case HCI_PRIMARY:
-		id = ida_simple_get(&hci_index_ida, 0, 0, GFP_KERNEL);
+		id = ida_simple_get(&hci_index_ida, 0, HCI_MAX_ID, GFP_KERNEL);
 		break;
 	case HCI_AMP:
-		id = ida_simple_get(&hci_index_ida, 1, 0, GFP_KERNEL);
+		id = ida_simple_get(&hci_index_ida, 1, HCI_MAX_ID, GFP_KERNEL);
 		break;
 	default:
 		return -EINVAL;
@@ -3192,7 +3192,7 @@ int hci_register_dev(struct hci_dev *hde
 	if (id < 0)
 		return id;
 
-	sprintf(hdev->name, "hci%d", id);
+	snprintf(hdev->name, sizeof(hdev->name), "hci%d", id);
 	hdev->id = id;
 
 	BT_DBG("%p name %s bus %d", hdev, hdev->name, hdev->bus);