From 2de0e6a71ceb056e17e4684dce8b7640367996f9 Mon Sep 17 00:00:00 2001 From: Pavel Skripkin Date: Mon, 1 Nov 2021 10:12:12 +0300 Subject: [PATCH] Bluetooth: stop proccessing malicious adv data [ Upstream commit 3a56ef719f0b9682afb8a86d64b2399e36faa4e6 ] 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 Signed-off-by: Sasha Levin --- net/bluetooth/hci_event.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 0bca035bf2dc..50d1d62c15ec 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -5780,7 +5780,8 @@ 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, @@ -5790,6 +5791,11 @@ 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);