netdev - [PATCH v2] nfc: st21nfca: Fix potential buffer overflows in EVT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 18 Nov 2021 08:04:23 +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>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org
Subject: [PATCH v2] nfc: st21nfca: 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 the comment styles and removed double newlines

Signed-off-by: Jordy Zomer <jordy@...ing.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