[PATCH 09/15] Bluetooth: HCI: Use skb_pull_data to parse LE Advertising Report event

Luiz Augusto von Dentz
2021-12-01T00:03:34Z

This uses skb_pull_data to check the LE Advertising Report events
received have the minimum required length.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
include/net/bluetooth/hci.h | 7 ++++++-
net/bluetooth/hci_event.c | 39 +++++++++++++++++++++++--------------
2 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 9e721e6efef3..c005b1ccdbc5 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -2445,13 +2445,18 @@ struct hci_ev_le_conn_complete {

#define HCI_EV_LE_ADVERTISING_REPORT 0x02
struct hci_ev_le_advertising_info {
- __u8 evt_type;
+ __u8 type;
__u8 bdaddr_type;
bdaddr_t bdaddr;
__u8 length;
__u8 data[];
} __packed;

+struct hci_ev_le_advertising_report {
+ __u8 num;
+ struct hci_ev_le_advertising_info info[];
+} __packed;
+
#define HCI_EV_LE_CONN_UPDATE_COMPLETE 0x03
struct hci_ev_le_conn_update_complete {
__u8 status;
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index d30e77f66376..42ffd5df6d4b 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -6564,31 +6564,40 @@ static void process_adv_report(struct hci_dev *hdev, u8 type, bdaddr_t *bdaddr,

static void hci_le_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb)
{
- u8 num_reports = skb->data[0];
- void *ptr = &skb->data[1];
+ struct hci_ev_le_advertising_report *ev;
+
+ ev = hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_ADVERTISING_REPORT,
+ sizeof(*ev));
+ if (!ev)
+ return;
+
+ if (!ev->num)
+ return;

hci_dev_lock(hdev);

- while (num_reports--) {
- struct hci_ev_le_advertising_info *ev = ptr;
+ while (ev->num--) {
+ struct hci_ev_le_advertising_info *info;
s8 rssi;

- if (ptr > (void *)skb_tail_pointer(skb) - sizeof(*ev)) {
- bt_dev_err(hdev, "Malicious advertising data.");
+ info = hci_le_ev_skb_pull(hdev, skb,
+ HCI_EV_LE_ADVERTISING_REPORT,
+ sizeof(*info));
+ if (!info)
break;
- }

- if (ev->length <= HCI_MAX_AD_LENGTH &&
- ev->data + ev->length <= skb_tail_pointer(skb)) {
- rssi = ev->data[ev->length];
- process_adv_report(hdev, ev->evt_type, &ev->bdaddr,
- ev->bdaddr_type, NULL, 0, rssi,
- ev->data, ev->length, false);
+ if (!hci_le_ev_skb_pull(hdev, skb, HCI_EV_LE_ADVERTISING_REPORT,
+ info->length + 1))
+ break;
+
+ if (info->length <= HCI_MAX_AD_LENGTH) {
+ rssi = info->data[info->length];
+ process_adv_report(hdev, info->type, &info->bdaddr,
+ info->bdaddr_type, NULL, 0, rssi,
+ info->data, info->length, false);
} else {
bt_dev_err(hdev, "Dropping invalid advertising data");
}
-
- ptr += sizeof(*ev) + ev->length + 1;
}

hci_dev_unlock(hdev);
--
2.33.1