From: Pavel Skripkin Date: Mon, 1 Nov 2021 07:12:12 +0000 (+0300) Subject: Bluetooth: stop proccessing malicious adv data X-Git-Tag: block-5.17-2022-01-21~91^2~428^2~9 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=3a56ef719f0b9682afb8a86d64b2399e36faa4e6;p=linux-block.git Bluetooth: stop proccessing malicious adv data Syzbot reported slab-out-of-bounds read in hci_le_adv_report_evt(). The problem was in missing validaion check. We should check if data is not malicious and we can read next data block. If we won't check ptr validness, code can read a way beyond skb->end and it can cause problems, of course. Fixes: e95beb414168 ("Bluetooth: hci_le_adv_report_evt code refactoring") Reported-and-tested-by: syzbot+e3fcb9c4f3c2a931dc40@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin Signed-off-by: Marcel Holtmann --- diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index d4b75a6cfeee..5471fbf38873 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -5906,7 +5906,8 @@ static void hci_le_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb) struct hci_ev_le_advertising_info *ev = ptr; s8 rssi; - if (ev->length <= HCI_MAX_AD_LENGTH) { + 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, @@ -5916,6 +5917,11 @@ static void hci_le_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb) } ptr += sizeof(*ev) + ev->length + 1; + + if (ptr > (void *) skb_tail_pointer(skb) - sizeof(*ev)) { + bt_dev_err(hdev, "Malicious advertising data. Stopping processing"); + break; + } } hci_dev_unlock(hdev);