Return-path: Received: from mail-pl0-f68.google.com ([209.85.160.68]:37412 "EHLO mail-pl0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756615AbdLTTvj (ORCPT ); Wed, 20 Dec 2017 14:51:39 -0500 Received: by mail-pl0-f68.google.com with SMTP id s3so9608559plp.4 for ; Wed, 20 Dec 2017 11:51:39 -0800 (PST) From: Amit Pundir To: lkml , linux-wireless@vger.kernel.org Cc: Suren Baghdasaryan , Samuel Ortiz , Christophe Ricard , Andy Shevchenko , John Stultz , Dmitry Shmidt , Todd Kjos , Android Kernel Team Subject: [RFC][PATCH 2/4] NFC: st21nfca: Fix memory OOB and leak issues in connectivity events handler Date: Thu, 21 Dec 2017 01:21:22 +0530 Message-Id: <1513799484-12505-3-git-send-email-amit.pundir@linaro.org> (sfid-20171220_205149_538568_6B160C15) In-Reply-To: <1513799484-12505-1-git-send-email-amit.pundir@linaro.org> References: <1513799484-12505-1-git-send-email-amit.pundir@linaro.org> Sender: linux-wireless-owner@vger.kernel.org List-ID: From: Suren Baghdasaryan Overflow on memcpy is possible in kernel driver for st21nfca's NFC HCI layer when handling connectivity events if aid_len or params_len are bigger than the buffer size. Memory leak is possible when parameter tag is invalid. Signed-off-by: Suren Baghdasaryan Signed-off-by: Amit Pundir --- drivers/nfc/st21nfca/se.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/nfc/st21nfca/se.c b/drivers/nfc/st21nfca/se.c index 4bed9e842db3..acdce231e227 100644 --- a/drivers/nfc/st21nfca/se.c +++ b/drivers/nfc/st21nfca/se.c @@ -322,23 +322,33 @@ int st21nfca_connectivity_event_received(struct nfc_hci_dev *hdev, u8 host, * AID 81 5 to 16 * PARAMETERS 82 0 to 255 */ - if (skb->len < NFC_MIN_AID_LENGTH + 2 && + if (skb->len < NFC_MIN_AID_LENGTH + 2 || skb->data[0] != NFC_EVT_TRANSACTION_AID_TAG) return -EPROTO; + /* + * Buffer should have enough space for at least + * two tag fields + two length fields + aid_len (skb->data[1]) + */ + if (skb->len < skb->data[1] + 4) + return -EPROTO; + transaction = (struct nfc_evt_transaction *)devm_kzalloc(dev, skb->len - 2, GFP_KERNEL); transaction->aid_len = skb->data[1]; memcpy(transaction->aid, &skb->data[2], transaction->aid_len); + transaction->params_len = skb->data[transaction->aid_len + 3]; - /* Check next byte is PARAMETERS tag (82) */ + /* Check next byte is PARAMETERS tag (82) and the length field */ if (skb->data[transaction->aid_len + 2] != - NFC_EVT_TRANSACTION_PARAMS_TAG) + NFC_EVT_TRANSACTION_PARAMS_TAG || + skb->len < transaction->aid_len + transaction->params_len + 4) { + devm_kfree(dev, transaction); return -EPROTO; + } - transaction->params_len = skb->data[transaction->aid_len + 3]; memcpy(transaction->params, skb->data + transaction->aid_len + 4, transaction->params_len); -- 2.7.4