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 8ABD1C433F5 for ; Thu, 18 Nov 2021 07:02:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6EF6461B51 for ; Thu, 18 Nov 2021 07:02:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243533AbhKRHF2 (ORCPT ); Thu, 18 Nov 2021 02:05:28 -0500 Received: from mta-13-4.privateemail.com ([198.54.127.109]:47279 "EHLO MTA-13-4.privateemail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243524AbhKRHF1 (ORCPT ); Thu, 18 Nov 2021 02:05:27 -0500 Received: from mta-13.privateemail.com (localhost [127.0.0.1]) by mta-13.privateemail.com (Postfix) with ESMTP id 5003F18000BA; Thu, 18 Nov 2021 02:02:27 -0500 (EST) Received: from localhost.localdomain (unknown [10.20.151.247]) by mta-13.privateemail.com (Postfix) with ESMTPA id 59D27180009F; Thu, 18 Nov 2021 02:02:25 -0500 (EST) From: Jordy Zomer To: linux-kernel@vger.kernel.org Cc: Jordy Zomer , Krzysztof Kozlowski , wengjianfeng , "David S. Miller" , Jakub Kicinski , netdev@vger.kernel.org Subject: [PATCH v2] nfc: st-nci: Fix potential buffer overflows in EVT_TRANSACTION Date: Thu, 18 Nov 2021 08:02:00 +0100 Message-Id: <20211118070202.2739158-1-jordy@pwning.systems> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211117171554.2731340-1-jordy@pwning.systems> References: <20211117171554.2731340-1-jordy@pwning.systems> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Virus-Scanned: ClamAV using ClamSMTP Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.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 :) EDIT: Changed comment style and double newlines Signed-off-by: Jordy Zomer --- 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