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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Subject: [PATCH] Bluetooth: HCI: Fix Set Extended (Scan Response) Data
Date:   Tue,  8 Jun 2021 11:44:57 -0700
Message-Id: <20210608184457.3069064-1-luiz.dentz@gmail.com>
MIME-Version: 1.0
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From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

These command do have variable length and the length can go up to 251,
so this changes the struct to not use a fixed size and then when
creating the PDU only the actual length of the data send to the
controller.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/hci.h      |  6 ++--
 include/net/bluetooth/hci_core.h |  8 ++---
 net/bluetooth/hci_request.c      | 51 ++++++++++++++++++--------------
 3 files changed, 37 insertions(+), 28 deletions(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 479adbde6db4..cfd4e40594d1 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -1775,13 +1775,15 @@ struct hci_cp_ext_adv_set {
 	__u8  max_events;
 } __packed;
 
+#define HCI_MAX_EXT_AD_LENGTH	251
+
 #define HCI_OP_LE_SET_EXT_ADV_DATA		0x2037
 struct hci_cp_le_set_ext_adv_data {
 	__u8  handle;
 	__u8  operation;
 	__u8  frag_pref;
 	__u8  length;
-	__u8  data[HCI_MAX_AD_LENGTH];
+	__u8  data[];
 } __packed;
 
 #define HCI_OP_LE_SET_EXT_SCAN_RSP_DATA		0x2038
@@ -1790,7 +1792,7 @@ struct hci_cp_le_set_ext_scan_rsp_data {
 	__u8  operation;
 	__u8  frag_pref;
 	__u8  length;
-	__u8  data[HCI_MAX_AD_LENGTH];
+	__u8  data[];
 } __packed;
 
 #define LE_SET_ADV_DATA_OP_COMPLETE	0x03
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 212f46806ce7..a53e94459ecd 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -228,9 +228,9 @@ struct adv_info {
 	__u16	remaining_time;
 	__u16	duration;
 	__u16	adv_data_len;
-	__u8	adv_data[HCI_MAX_AD_LENGTH];
+	__u8	adv_data[HCI_MAX_EXT_AD_LENGTH];
 	__u16	scan_rsp_len;
-	__u8	scan_rsp_data[HCI_MAX_AD_LENGTH];
+	__u8	scan_rsp_data[HCI_MAX_EXT_AD_LENGTH];
 	__s8	tx_power;
 	__u32   min_interval;
 	__u32   max_interval;
@@ -551,9 +551,9 @@ struct hci_dev {
 	DECLARE_BITMAP(dev_flags, __HCI_NUM_FLAGS);
 
 	__s8			adv_tx_power;
-	__u8			adv_data[HCI_MAX_AD_LENGTH];
+	__u8			adv_data[HCI_MAX_EXT_AD_LENGTH];
 	__u8			adv_data_len;
-	__u8			scan_rsp_data[HCI_MAX_AD_LENGTH];
+	__u8			scan_rsp_data[HCI_MAX_EXT_AD_LENGTH];
 	__u8			scan_rsp_data_len;
 
 	struct list_head	adv_instances;
diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c
index f7a9d97f3e84..1d14adc023e9 100644
--- a/net/bluetooth/hci_request.c
+++ b/net/bluetooth/hci_request.c
@@ -1716,30 +1716,33 @@ void __hci_req_update_scan_rsp_data(struct hci_request *req, u8 instance)
 		return;
 
 	if (ext_adv_capable(hdev)) {
-		struct hci_cp_le_set_ext_scan_rsp_data cp;
+		struct {
+			struct hci_cp_le_set_ext_scan_rsp_data cp;
+			u8 data[HCI_MAX_EXT_AD_LENGTH];
+		} pdu;
 
-		memset(&cp, 0, sizeof(cp));
+		memset(&pdu, 0, sizeof(pdu));
 
 		if (instance)
 			len = create_instance_scan_rsp_data(hdev, instance,
-							    cp.data);
+							    pdu.data);
 		else
-			len = create_default_scan_rsp_data(hdev, cp.data);
+			len = create_default_scan_rsp_data(hdev, pdu.data);
 
 		if (hdev->scan_rsp_data_len == len &&
-		    !memcmp(cp.data, hdev->scan_rsp_data, len))
+		    !memcmp(pdu.data, hdev->scan_rsp_data, len))
 			return;
 
-		memcpy(hdev->scan_rsp_data, cp.data, sizeof(cp.data));
+		memcpy(hdev->scan_rsp_data, pdu.data, len);
 		hdev->scan_rsp_data_len = len;
 
-		cp.handle = instance;
-		cp.length = len;
-		cp.operation = LE_SET_ADV_DATA_OP_COMPLETE;
-		cp.frag_pref = LE_SET_ADV_DATA_NO_FRAG;
+		pdu.cp.handle = instance;
+		pdu.cp.length = len;
+		pdu.cp.operation = LE_SET_ADV_DATA_OP_COMPLETE;
+		pdu.cp.frag_pref = LE_SET_ADV_DATA_NO_FRAG;
 
-		hci_req_add(req, HCI_OP_LE_SET_EXT_SCAN_RSP_DATA, sizeof(cp),
-			    &cp);
+		hci_req_add(req, HCI_OP_LE_SET_EXT_SCAN_RSP_DATA,
+			    sizeof(pdu.cp) + len, &pdu.cp);
 	} else {
 		struct hci_cp_le_set_scan_rsp_data cp;
 
@@ -1862,26 +1865,30 @@ void __hci_req_update_adv_data(struct hci_request *req, u8 instance)
 		return;
 
 	if (ext_adv_capable(hdev)) {
-		struct hci_cp_le_set_ext_adv_data cp;
+		struct {
+			struct hci_cp_le_set_ext_adv_data cp;
+			u8 data[HCI_MAX_EXT_AD_LENGTH];
+		} pdu;
 
-		memset(&cp, 0, sizeof(cp));
+		memset(&pdu, 0, sizeof(pdu));
 
-		len = create_instance_adv_data(hdev, instance, cp.data);
+		len = create_instance_adv_data(hdev, instance, pdu.data);
 
 		/* There's nothing to do if the data hasn't changed */
 		if (hdev->adv_data_len == len &&
-		    memcmp(cp.data, hdev->adv_data, len) == 0)
+		    memcmp(pdu.data, hdev->adv_data, len) == 0)
 			return;
 
-		memcpy(hdev->adv_data, cp.data, sizeof(cp.data));
+		memcpy(hdev->adv_data, pdu.data, len);
 		hdev->adv_data_len = len;
 
-		cp.length = len;
-		cp.handle = instance;
-		cp.operation = LE_SET_ADV_DATA_OP_COMPLETE;
-		cp.frag_pref = LE_SET_ADV_DATA_NO_FRAG;
+		pdu.cp.length = len;
+		pdu.cp.handle = instance;
+		pdu.cp.operation = LE_SET_ADV_DATA_OP_COMPLETE;
+		pdu.cp.frag_pref = LE_SET_ADV_DATA_NO_FRAG;
 
-		hci_req_add(req, HCI_OP_LE_SET_EXT_ADV_DATA, sizeof(cp), &cp);
+		hci_req_add(req, HCI_OP_LE_SET_EXT_ADV_DATA,
+			    sizeof(pdu.cp) + len, &pdu.cp);
 	} else {
 		struct hci_cp_le_set_adv_data cp;
 
-- 
2.31.1