net/nfc/hci/core.c | 5 +++++ net/nfc/nci/hci.c | 5 +++++ 2 files changed, 10 insertions(+)
nfc_hci_recv_from_llc() and nci_hci_data_received_cb() cast skb->data
to struct hcp_packet and read the message header byte without checking
that enough data is present in the linear sk_buff area. A malicious NFC
peer can send a 1-byte HCP frame that passes through the SHDLC layer
and reaches these functions, causing an out-of-bounds heap read.
Fix this by adding pskb_may_pull() before each cast to ensure the full
2-byte HCP header is pulled into the linear area before it is accessed.
Fixes: 8b8d2e08bf0d ("NFC: HCI support")
Fixes: 11f54f228643 ("NFC: nci: Add HCI over NCI protocol support")
Cc: stable@vger.kernel.org
Signed-off-by: Ashutosh Desai <ashutoshdesai993@gmail.com>
---
V3 -> V4: add Fixes tags
V2 -> V3: drop redundant checks from nfc_hci_msg_rx_work/nci_hci_msg_rx_work,
remove incorrect Suggested-by tag
V1 -> V2: switch skb->len check to pskb_may_pull
v3: https://lore.kernel.org/netdev/20260413024329.3293075-1-ashutoshdesai993@gmail.com/
v2: https://lore.kernel.org/netdev/20260409150825.2217133-1-ashutoshdesai993@gmail.com/
v1: https://lore.kernel.org/netdev/20260408223113.2009304-1-ashutoshdesai993@gmail.com/
net/nfc/hci/core.c | 5 +++++
net/nfc/nci/hci.c | 5 +++++
2 files changed, 10 insertions(+)
diff --git a/net/nfc/hci/core.c b/net/nfc/hci/core.c
index 0d33c81a15fe..cd9cf6c94a50 100644
--- a/net/nfc/hci/core.c
+++ b/net/nfc/hci/core.c
@@ -904,6 +904,11 @@ static void nfc_hci_recv_from_llc(struct nfc_hci_dev *hdev, struct sk_buff *skb)
* unblock waiting cmd context. Otherwise, enqueue to dispatch
* in separate context where handler can also execute command.
*/
+if (!pskb_may_pull(hcp_skb, NFC_HCI_HCP_HEADER_LEN)) {
+kfree_skb(hcp_skb);
+return;
+}
+
packet = (struct hcp_packet *)hcp_skb->data;
type = HCP_MSG_GET_TYPE(packet->message.header);
if (type == NFC_HCI_HCP_RESPONSE) {
diff --git a/net/nfc/nci/hci.c b/net/nfc/nci/hci.c
index 40ae8e5a7ec7..6e633da257d1 100644
--- a/net/nfc/nci/hci.c
+++ b/net/nfc/nci/hci.c
@@ -482,6 +482,11 @@ void nci_hci_data_received_cb(void *context,
* unblock waiting cmd context. Otherwise, enqueue to dispatch
* in separate context where handler can also execute command.
*/
+if (!pskb_may_pull(hcp_skb, NCI_HCI_HCP_HEADER_LEN)) {
+kfree_skb(hcp_skb);
+return;
+}
+
packet = (struct nci_hcp_packet *)hcp_skb->data;
type = NCI_HCP_MSG_GET_TYPE(packet->message.header);
if (type == NCI_HCI_HCP_RESPONSE) {
--
2.34.1
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