From: Pavel Skripkin <paskripkin@gmail.com>
To: marcel@holtmann.org, johan.hedberg@gmail.com,
luiz.dentz@gmail.com, davem@davemloft.net, kuba@kernel.org
Cc: linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
Pavel Skripkin <paskripkin@gmail.com>,
syzbot+e3fcb9c4f3c2a931dc40@syzkaller.appspotmail.com
Subject: [PATCH] Bluetooth: stop proccessing malicious adv data
Date: Mon, 1 Nov 2021 10:12:12 +0300 [thread overview]
Message-ID: <20211101071212.15355-1-paskripkin@gmail.com> (raw)
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 <paskripkin@gmail.com>
---
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);
--
2.33.1
next reply other threads:[~2021-11-01 7:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-01 7:12 Pavel Skripkin [this message]
2021-11-16 5:02 ` [PATCH] Bluetooth: stop proccessing malicious adv data Pavel Skripkin
2021-11-16 13:55 ` Marcel Holtmann
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