Patch "Bluetooth: stop proccessing malicious adv data" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    Bluetooth: stop proccessing malicious adv data

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     bluetooth-stop-proccessing-malicious-adv-data.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 759209074f8aefd79d7a835c410d558ee33a23f1
Author: Pavel Skripkin <paskripkin@xxxxxxxxx>
Date:   Mon Nov 1 10:12:12 2021 +0300

    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@xxxxxxxxxxxxxxxxxxxxxxxxx
    Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
    Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 9f52145bb7b76..7ffcca9ae82a1 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5661,7 +5661,8 @@ 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,
@@ -5671,6 +5672,11 @@ 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);