From: Jordy Zomer <jordy@pwning.systems>
Date: Tue, 11 Jan 2022 16:44:51 +0000 (+0100)
Subject: nfc: st21nfca: Fix potential buffer overflows in EVT_TRANSACTION
X-Git-Tag: v4.14.274~18
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d908d2776464a8021a1f63eba6e7417fbe7653c9;p=thirdparty%2Fkernel%2Fstable.git

nfc: st21nfca: Fix potential buffer overflows in EVT_TRANSACTION

commit 4fbcc1a4cb20fe26ad0225679c536c80f1648221 upstream.

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.

Signed-off-by: Jordy Zomer <jordy@pwning.systems>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Denis Efremov <denis.e.efremov@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/nfc/st21nfca/se.c b/drivers/nfc/st21nfca/se.c
index eac608a457f03..475f8a67856d0 100644
--- a/drivers/nfc/st21nfca/se.c
+++ b/drivers/nfc/st21nfca/se.c
@@ -330,6 +330,11 @@ 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);
 
@@ -339,6 +344,11 @@ int st21nfca_connectivity_event_received(struct nfc_hci_dev *hdev, u8 host,
 			return -EPROTO;
 
 		transaction->params_len = skb->data[transaction->aid_len + 3];
+
+		/* Total size is allocated (skb->len - 2) minus fixed array members */
+		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);