[PATCH 4.19 01/86] Bluetooth: refactor malicious adv data check

Greg Kroah-Hartman
2022-02-07T11:23:14Z

From: Brian Gix <brian.gix@intel.com>

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

--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5391,6 +5391,11 @@ static void hci_le_adv_report_evt(struct
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];
@@ -5402,11 +5407,6 @@ static void hci_le_adv_report_evt(struct
}

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);