From: Jordy Zomer <jordy@pwning.systems>
To: linux-kernel@vger.kernel.org
Cc: Jordy Zomer <jordy@pwning.systems>,
Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org
Subject: [PATCH v2] nfc: st21nfca: Fix potential buffer overflows in EVT_TRANSACTION
Date: Thu, 18 Nov 2021 08:04:23 +0100 [thread overview]
Message-ID: <20211118070426.2739243-1-jordy@pwning.systems> (raw)
In-Reply-To: <20211117171706.2731410-1-jordy@pwning.systems>
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 the comment styles and removed double newlines
Signed-off-by: Jordy Zomer <jordy@pwning.systems>
---
drivers/nfc/st21nfca/se.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/nfc/st21nfca/se.c b/drivers/nfc/st21nfca/se.c
index a43fc4117fa5..5e036768b2a1 100644
--- a/drivers/nfc/st21nfca/se.c
+++ b/drivers/nfc/st21nfca/se.c
@@ -316,6 +316,11 @@ int st21nfca_connectivity_event_received(struct nfc_hci_dev *hdev, u8 host,
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);
@@ -325,6 +330,16 @@ int st21nfca_connectivity_event_received(struct nfc_hci_dev *hdev, u8 host,
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
next prev parent reply other threads:[~2021-11-18 7:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-17 17:17 [PATCH] nfc: st21nfca: Fix potential buffer overflows in EVT_TRANSACTION Jordy Zomer
2021-11-18 7:04 ` Jordy Zomer [this message]
2021-11-18 7:40 ` [PATCH v2] " Krzysztof Kozlowski
2022-01-11 16:44 ` [PATCH v3] " Jordy Zomer
2022-01-12 10:07 ` Krzysztof Kozlowski
2022-01-12 17:25 ` Jakub Kicinski
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