From patchwork Wed Nov 17 17:17:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jordy Zomer X-Patchwork-Id: 12625097 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D322BC433EF for ; Wed, 17 Nov 2021 17:17:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4D6161B3A for ; Wed, 17 Nov 2021 17:17:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239327AbhKQRUQ (ORCPT ); Wed, 17 Nov 2021 12:20:16 -0500 Received: from h2.fbrelay.privateemail.com ([131.153.2.43]:59763 "EHLO h2.fbrelay.privateemail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229585AbhKQRUP (ORCPT ); Wed, 17 Nov 2021 12:20:15 -0500 Received: from MTA-13-4.privateemail.com (mta-13-1.privateemail.com [198.54.122.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by h1.fbrelay.privateemail.com (Postfix) with ESMTPS id 5946A80AFB; Wed, 17 Nov 2021 12:17:15 -0500 (EST) Received: from mta-13.privateemail.com (localhost [127.0.0.1]) by mta-13.privateemail.com (Postfix) with ESMTP id 8557F18000A1; Wed, 17 Nov 2021 12:17:13 -0500 (EST) Received: from localhost.localdomain (unknown [10.20.151.206]) by mta-13.privateemail.com (Postfix) with ESMTPA id 10EA918000AB; Wed, 17 Nov 2021 12:17:11 -0500 (EST) From: Jordy Zomer To: linux-kernel@vger.kernel.org Cc: Jordy Zomer , Krzysztof Kozlowski , Jakub Kicinski , netdev@vger.kernel.org Subject: [PATCH] nfc: st21nfca: Fix potential buffer overflows in EVT_TRANSACTION Date: Wed, 17 Nov 2021 18:17:03 +0100 Message-Id: <20211117171706.2731410-1-jordy@pwning.systems> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org 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 :) Signed-off-by: Jordy Zomer --- drivers/nfc/st21nfca/se.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/nfc/st21nfca/se.c b/drivers/nfc/st21nfca/se.c index a43fc4117fa5..e3483aca3280 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 +330,14 @@ 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);