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[71.56.157.77]) by smtp.gmail.com with ESMTPSA id y14sm3538573pfe.107.2020.10.16.11.09.58 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Oct 2020 11:09:58 -0700 (PDT) From: Luiz Augusto von Dentz To: linux-bluetooth@vger.kernel.org Subject: [PATCH 1/2] Bluetooth: Fix not checking advertisement bondaries Date: Fri, 16 Oct 2020 11:09:55 -0700 Message-Id: <20201016180956.707681-1-luiz.dentz@gmail.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org From: Luiz Augusto von Dentz When receiving advertisements check if the length is actually within the skb, this also make use of skb_pull to advance on the skb->data instead of a custom ptr that way skb->len shall always indicates how much data is remaining and can be used to perform checks if there is enough data to parse. Fixes: a2ec905d1e160a33b2e210e45ad30445ef26ce0e ("Bluetooth: fix kernel oops in store_pending_adv_report") Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/hci_event.c | 72 ++++++++++++++++++++++++++++++--------- 1 file changed, 55 insertions(+), 17 deletions(-) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index a4c3703f2e94..ae31d227730b 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -5599,24 +5599,40 @@ 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]; hci_dev_lock(hdev); + skb_pull(skb, sizeof(num_reports)); + while (num_reports--) { - struct hci_ev_le_advertising_info *ev = ptr; + struct hci_ev_le_advertising_info *ev; s8 rssi; - if (ev->length <= HCI_MAX_AD_LENGTH) { - 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); - } else { - bt_dev_err(hdev, "Dropping invalid advertising data"); + if (skb->len < sizeof(*ev)) { + bt_dev_err(hdev, "Malformed advertising report"); + break; + } + + ev = (void *) skb->data; + skb_pull(skb, sizeof(*ev)); + + if (skb->len < ev->length || ev->length > HCI_MAX_AD_LENGTH) { + bt_dev_err(hdev, "Malformed advertising data"); + break; } - ptr += sizeof(*ev) + ev->length + 1; + skb_pull(skb, ev->length); + + if (skb->len < sizeof(rssi)) { + bt_dev_err(hdev, "Malformed advertising rssi"); + break; + } + + rssi = get_unaligned(skb->data); + + process_adv_report(hdev, ev->evt_type, &ev->bdaddr, + ev->bdaddr_type, NULL, 0, rssi, + ev->data, ev->length, false); } hci_dev_unlock(hdev); @@ -5669,15 +5685,31 @@ static u8 ext_evt_type_to_legacy(struct hci_dev *hdev, u16 evt_type) static void hci_le_ext_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb) { u8 num_reports = skb->data[0]; - void *ptr = &skb->data[1]; hci_dev_lock(hdev); + skb_pull(skb, sizeof(num_reports)); + while (num_reports--) { - struct hci_ev_le_ext_adv_report *ev = ptr; + struct hci_ev_le_ext_adv_report *ev; u8 legacy_evt_type; u16 evt_type; + if (skb->len < sizeof(*ev)) { + bt_dev_err(hdev, "Malformed ext advertising report"); + break; + } + + ev = (void *) skb->data; + skb_pull(skb, sizeof(*ev)); + + if (skb->len < ev->length || ev->length > HCI_MAX_AD_LENGTH) { + bt_dev_err(hdev, "Malformed ext advertising data"); + break; + } + + skb_pull(skb, ev->length); + evt_type = __le16_to_cpu(ev->evt_type); legacy_evt_type = ext_evt_type_to_legacy(hdev, evt_type); if (legacy_evt_type != LE_ADV_INVALID) { @@ -5687,7 +5719,6 @@ static void hci_le_ext_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb) !(evt_type & LE_EXT_ADV_LEGACY_PDU)); } - ptr += sizeof(*ev) + ev->length; } hci_dev_unlock(hdev); @@ -5873,19 +5904,26 @@ static void hci_le_direct_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb) { u8 num_reports = skb->data[0]; - void *ptr = &skb->data[1]; hci_dev_lock(hdev); + skb_pull(skb, sizeof(num_reports)); + while (num_reports--) { - struct hci_ev_le_direct_adv_info *ev = ptr; + struct hci_ev_le_direct_adv_info *ev; + + if (skb->len < sizeof(*ev)) { + bt_dev_err(hdev, "Malformed direct advertising"); + break; + } + + ev = (void *) skb->data; + skb_pull(skb, sizeof(*ev)); process_adv_report(hdev, ev->evt_type, &ev->bdaddr, ev->bdaddr_type, &ev->direct_addr, ev->direct_addr_type, ev->rssi, NULL, 0, false); - - ptr += sizeof(*ev); } hci_dev_unlock(hdev); -- 2.26.2