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 BDE2CC433EF for ; Thu, 18 Nov 2021 07:04:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A7207619E5 for ; Thu, 18 Nov 2021 07:04:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243537AbhKRHHl (ORCPT ); Thu, 18 Nov 2021 02:07:41 -0500 Received: from mta-13-4.privateemail.com ([198.54.127.109]:58969 "EHLO MTA-13-4.privateemail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241348AbhKRHHk (ORCPT ); Thu, 18 Nov 2021 02:07:40 -0500 Received: from mta-13.privateemail.com (localhost [127.0.0.1]) by mta-13.privateemail.com (Postfix) with ESMTP id 5482418000A4; Thu, 18 Nov 2021 02:04:40 -0500 (EST) Received: from localhost.localdomain (unknown [10.20.151.236]) by mta-13.privateemail.com (Postfix) with ESMTPA id B26F018000B7; Thu, 18 Nov 2021 02:04:38 -0500 (EST) From: Jordy Zomer To: linux-kernel@vger.kernel.org Cc: Jordy Zomer , Krzysztof Kozlowski , Jakub Kicinski , 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 Message-Id: <20211118070426.2739243-1-jordy@pwning.systems> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211117171706.2731410-1-jordy@pwning.systems> References: <20211117171706.2731410-1-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 the comment styles and removed double newlines Signed-off-by: Jordy Zomer --- 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