[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20211118070202.2739158-1-jordy@pwning.systems>
Date: Thu, 18 Nov 2021 08:02:00 +0100
From: Jordy Zomer <jordy@...ing.systems>
To: linux-kernel@...r.kernel.org
Cc: Jordy Zomer <jordy@...ing.systems>,
Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
wengjianfeng <wengjianfeng@...ong.com>,
"David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org
Subject: [PATCH v2] nfc: st-nci: Fix potential buffer overflows in EVT_TRANSACTION
It appears that there are some buffer overflows in EVT_TRANSACTION.
This happens because the length parameters that are passed to memcpy
come directly from skb->data and are not guarded in any way.
It would be nice if someone can review and test this patch because
I don't own the hardware :)
EDIT: Changed comment style and double newlines
Signed-off-by: Jordy Zomer <jordy@...ing.systems>
---
drivers/nfc/st-nci/se.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/nfc/st-nci/se.c b/drivers/nfc/st-nci/se.c
index 7764b1a4c3cf..8e2ac8a3d199 100644
--- a/drivers/nfc/st-nci/se.c
+++ b/drivers/nfc/st-nci/se.c
@@ -335,6 +335,11 @@ static int st_nci_hci_connectivity_event_received(struct nci_dev *ndev,
return -ENOMEM;
transaction->aid_len = skb->data[1];
+
+ /* Checking if the length of the AID is valid */
+ if (transaction->aid_len > sizeof(transaction->aid))
+ return -EINVAL;
+
memcpy(transaction->aid, &skb->data[2], transaction->aid_len);
/* Check next byte is PARAMETERS tag (82) */
@@ -343,6 +348,16 @@ static int st_nci_hci_connectivity_event_received(struct nci_dev *ndev,
return -EPROTO;
transaction->params_len = skb->data[transaction->aid_len + 3];
+
+ /*
+ * check if the length of the parameters is valid
+ * we can't use sizeof(transaction->params) because it's
+ * a flexible array member so we have to check if params_len
+ * is bigger than the space allocated for the array
+ */
+ if (transaction->params_len > ((skb->len - 2) - sizeof(struct nfc_evt_transaction)))
+ return -EINVAL;
+
memcpy(transaction->params, skb->data +
transaction->aid_len + 4, transaction->params_len);
--
2.27.0
Powered by blists - more mailing lists