From: Brian Gix <brian.gix@intel.com>
Date: Wed, 24 Nov 2021 20:16:28 +0000 (-0800)
Subject: Bluetooth: refactor malicious adv data check
X-Git-Tag: v4.4.302~25
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=305e92f525450f3e1b5f5c9dc7eadb152d66a082;p=thirdparty%2Fkernel%2Fstable.git

Bluetooth: refactor malicious adv data check

commit 899663be5e75dc0174dc8bda0b5e6826edf0b29a upstream.

Check for out-of-bound read was being performed at the end of while
num_reports loop, and would fill journal with false positives. Added
check to beginning of loop processing so that it doesn't get checked
after ptr has been advanced.

Signed-off-by: Brian Gix <brian.gix@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: syphyr <syphyr@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 05ccd2bcd9e46..a557543ad29f3 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4940,6 +4940,11 @@ 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 (ptr > (void *)skb_tail_pointer(skb) - sizeof(*ev)) {
+			bt_dev_err(hdev, "Malicious advertising data.");
+			break;
+		}
+
 		if (ev->length <= HCI_MAX_AD_LENGTH &&
 		    ev->data + ev->length <= skb_tail_pointer(skb)) {
 			rssi = ev->data[ev->length];
@@ -4951,11 +4956,6 @@ 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);