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From: Brian Gix <brian.gix@intel.com>
To: linux-bluetooth@vger.kernel.org
Cc: marcel@holtmann.org, paskripkin@gmail.com,
	Brian Gix <brian.gix@intel.com>
Subject: [PATCH v2] Bluetooth: refactor malicious adv data check
Date: Wed, 24 Nov 2021 12:16:28 -0800	[thread overview]
Message-ID: <20211124201628.405647-1-brian.gix@intel.com> (raw)

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>
---
 net/bluetooth/hci_event.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index efc5458b1345..dee4ef22fc88 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5920,6 +5920,11 @@ 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];
@@ -5931,11 +5936,6 @@ 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);
-- 
2.31.1


             reply	other threads:[~2021-11-24 20:16 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-24 20:16 Brian Gix [this message]
2021-11-24 20:46 ` [PATCH v2] Bluetooth: refactor malicious adv data check Marcel Holtmann

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