linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jordy Zomer <jordy@pwning.systems>
To: jordy@pwning.systems
Cc: krzysztof.kozlowski@canonical.com, kuba@kernel.org,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH v3] nfc: st21nfca: Fix potential buffer overflows in EVT_TRANSACTION
Date: Tue, 11 Jan 2022 17:44:51 +0100	[thread overview]
Message-ID: <20220111164451.3232987-1-jordy@pwning.systems> (raw)
In-Reply-To: <20211117171706.2731410-1-jordy@pwning.systems>

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.

Signed-off-by: Jordy Zomer <jordy@pwning.systems>
---
 drivers/nfc/st21nfca/se.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/nfc/st21nfca/se.c b/drivers/nfc/st21nfca/se.c
index a43fc4117fa5..c922f10d0d7b 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 +330,11 @@ int st21nfca_connectivity_event_received(struct nfc_hci_dev *hdev, u8 host,
 			return -EPROTO;
 
 		transaction->params_len = skb->data[transaction->aid_len + 3];
+
+		/* Total size is allocated (skb->len - 2) minus fixed array members */
+		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


  parent reply	other threads:[~2022-01-11 16:45 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-17 17:17 [PATCH] nfc: st21nfca: Fix potential buffer overflows in EVT_TRANSACTION Jordy Zomer
2021-11-18  7:04 ` [PATCH v2] " Jordy Zomer
2021-11-18  7:40   ` Krzysztof Kozlowski
2022-01-11 16:44 ` Jordy Zomer [this message]
2022-01-12 10:07   ` [PATCH v3] " Krzysztof Kozlowski
2022-01-12 17:25     ` Jakub Kicinski

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220111164451.3232987-1-jordy@pwning.systems \
    --to=jordy@pwning.systems \
    --cc=krzysztof.kozlowski@canonical.com \
    --cc=kuba@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).