Commit 9c328f54 authored by Deepak Sharma's avatar Deepak Sharma Committed by Paolo Abeni
Browse files

net: nfc: nci: Add parameter validation for packet data 

Syzbot reported an uninitialized value bug in nci_init_req, which was
introduced by commit 5aca7966 ("Merge tag
'perf-tools-fixes-for-v6.17-2025-09-16' of
git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools"

).

This bug arises due to very limited and poor input validation
that was done at nic_valid_size(). This validation only
validates the skb->len (directly reflects size provided at the
userspace interface) with the length provided in the buffer
itself (interpreted as NCI_HEADER). This leads to the processing
of memory content at the address assuming the correct layout
per what opcode requires there. This leads to the accesses to
buffer of `skb_buff->data` which is not assigned anything yet.

Following the same silent drop of packets of invalid sizes at
`nic_valid_size()`, add validation of the data in the respective
handlers and return error values in case of failure. Release
the skb if error values are returned from handlers in
`nci_nft_packet` and effectively do a silent drop

Possible TODO: because we silently drop the packets, the
call to `nci_request` will be waiting for completion of request
and will face timeouts. These timeouts can get excessively logged
in the dmesg. A proper handling of them may require to export
`nci_request_cancel` (or propagate error handling from the
nft packets handlers).

Reported-by: default avatar <syzbot+740e04c2a93467a0f8c8@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=740e04c2a93467a0f8c8


Fixes: 6a2968aa ("NFC: basic NCI protocol implementation")
Tested-by: default avatar <syzbot+740e04c2a93467a0f8c8@syzkaller.appspotmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDeepak Sharma <deepak.sharma.472935@gmail.com>
Reviewed-by: default avatarVadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/20250925132846.213425-1-deepak.sharma.472935@gmail.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 99e4c35e

net/nfc/nci/ntf.c

+99 −36
Original line number Diff line number Diff line
@@ -27,11 +27,16 @@ 


/* Handle NCI Notification packets */



static void nci_core_reset_ntf_packet(struct nci_dev *ndev,

static int nci_core_reset_ntf_packet(struct nci_dev *ndev,

				     const struct sk_buff *skb)

{

	/* Handle NCI 2.x core reset notification */

	const struct nci_core_reset_ntf *ntf = (void *)skb->data;

	const struct nci_core_reset_ntf *ntf;



	if (skb->len < sizeof(struct nci_core_reset_ntf))

		return -EINVAL;



	ntf = (struct nci_core_reset_ntf *)skb->data;



	ndev->nci_ver = ntf->nci_ver;

	pr_debug("nci_ver 0x%x, config_status 0x%x\n",
@@ -42,15 +47,22 @@ static void nci_core_reset_ntf_packet(struct nci_dev *ndev, 
		__le32_to_cpu(ntf->manufact_specific_info);



	nci_req_complete(ndev, NCI_STATUS_OK);



	return 0;

}



static void nci_core_conn_credits_ntf_packet(struct nci_dev *ndev,

static int nci_core_conn_credits_ntf_packet(struct nci_dev *ndev,

					    struct sk_buff *skb)

{

	struct nci_core_conn_credit_ntf *ntf = (void *) skb->data;

	struct nci_core_conn_credit_ntf *ntf;

	struct nci_conn_info *conn_info;

	int i;



	if (skb->len < sizeof(struct nci_core_conn_credit_ntf))

		return -EINVAL;



	ntf = (struct nci_core_conn_credit_ntf *)skb->data;



	pr_debug("num_entries %d\n", ntf->num_entries);



	if (ntf->num_entries > NCI_MAX_NUM_CONN)
@@ -68,7 +80,7 @@ static void nci_core_conn_credits_ntf_packet(struct nci_dev *ndev, 
		conn_info = nci_get_conn_info_by_conn_id(ndev,

							 ntf->conn_entries[i].conn_id);

		if (!conn_info)

			return;

			return 0;



		atomic_add(ntf->conn_entries[i].credits,

			   &conn_info->credits_cnt);
@@ -77,12 +89,19 @@ static void nci_core_conn_credits_ntf_packet(struct nci_dev *ndev, 
	/* trigger the next tx */

	if (!skb_queue_empty(&ndev->tx_q))

		queue_work(ndev->tx_wq, &ndev->tx_work);



	return 0;

}



static void nci_core_generic_error_ntf_packet(struct nci_dev *ndev,

static int nci_core_generic_error_ntf_packet(struct nci_dev *ndev,

					     const struct sk_buff *skb)

{

	__u8 status = skb->data[0];

	__u8 status;



	if (skb->len < 1)

		return -EINVAL;



	status = skb->data[0];



	pr_debug("status 0x%x\n", status);
@@ -91,12 +110,19 @@ static void nci_core_generic_error_ntf_packet(struct nci_dev *ndev, 
		   (the state remains the same) */

		nci_req_complete(ndev, status);

	}



	return 0;

}



static void nci_core_conn_intf_error_ntf_packet(struct nci_dev *ndev,

static int nci_core_conn_intf_error_ntf_packet(struct nci_dev *ndev,

					       struct sk_buff *skb)

{

	struct nci_core_intf_error_ntf *ntf = (void *) skb->data;

	struct nci_core_intf_error_ntf *ntf;



	if (skb->len < sizeof(struct nci_core_intf_error_ntf))

		return -EINVAL;



	ntf = (struct nci_core_intf_error_ntf *)skb->data;



	ntf->conn_id = nci_conn_id(&ntf->conn_id);
@@ -105,6 +131,8 @@ static void nci_core_conn_intf_error_ntf_packet(struct nci_dev *ndev, 
	/* complete the data exchange transaction, if exists */

	if (test_bit(NCI_DATA_EXCHANGE, &ndev->flags))

		nci_data_exchange_complete(ndev, NULL, ntf->conn_id, -EIO);



	return 0;

}



static const __u8 *
@@ -329,13 +357,18 @@ void nci_clear_target_list(struct nci_dev *ndev) 
	ndev->n_targets = 0;

}



static void nci_rf_discover_ntf_packet(struct nci_dev *ndev,

static int nci_rf_discover_ntf_packet(struct nci_dev *ndev,

				      const struct sk_buff *skb)

{

	struct nci_rf_discover_ntf ntf;

	const __u8 *data = skb->data;

	const __u8 *data;

	bool add_target = true;



	if (skb->len < sizeof(struct nci_rf_discover_ntf))

		return -EINVAL;



	data = skb->data;



	ntf.rf_discovery_id = *data++;

	ntf.rf_protocol = *data++;

	ntf.rf_tech_and_mode = *data++;
@@ -390,6 +423,8 @@ static void nci_rf_discover_ntf_packet(struct nci_dev *ndev, 
		nfc_targets_found(ndev->nfc_dev, ndev->targets,

				  ndev->n_targets);

	}



	return 0;

}



static int nci_extract_activation_params_iso_dep(struct nci_dev *ndev,
@@ -553,14 +588,19 @@ static int nci_store_ats_nfc_iso_dep(struct nci_dev *ndev, 
	return NCI_STATUS_OK;

}



static void nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev,

static int nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev,

					    const struct sk_buff *skb)

{

	struct nci_conn_info *conn_info;

	struct nci_rf_intf_activated_ntf ntf;

	const __u8 *data = skb->data;

	const __u8 *data;

	int err = NCI_STATUS_OK;



	if (skb->len < sizeof(struct nci_rf_intf_activated_ntf))

		return -EINVAL;



	data = skb->data;



	ntf.rf_discovery_id = *data++;

	ntf.rf_interface = *data++;

	ntf.rf_protocol = *data++;
@@ -667,7 +707,7 @@ static void nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev, 
	if (err == NCI_STATUS_OK) {

		conn_info = ndev->rf_conn_info;

		if (!conn_info)

			return;

			return 0;



		conn_info->max_pkt_payload_len = ntf.max_data_pkt_payload_size;

		conn_info->initial_num_credits = ntf.initial_num_credits;
@@ -721,19 +761,26 @@ static void nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev, 
				pr_err("error when signaling tm activation\n");

		}

	}



	return 0;

}



static void nci_rf_deactivate_ntf_packet(struct nci_dev *ndev,

static int nci_rf_deactivate_ntf_packet(struct nci_dev *ndev,

					const struct sk_buff *skb)

{

	const struct nci_conn_info *conn_info;

	const struct nci_rf_deactivate_ntf *ntf = (void *)skb->data;

	const struct nci_rf_deactivate_ntf *ntf;



	if (skb->len < sizeof(struct nci_rf_deactivate_ntf))

		return -EINVAL;



	ntf = (struct nci_rf_deactivate_ntf *)skb->data;



	pr_debug("entry, type 0x%x, reason 0x%x\n", ntf->type, ntf->reason);



	conn_info = ndev->rf_conn_info;

	if (!conn_info)

		return;

		return 0;



	/* drop tx data queue */

	skb_queue_purge(&ndev->tx_q);
@@ -765,14 +812,20 @@ static void nci_rf_deactivate_ntf_packet(struct nci_dev *ndev, 
	}



	nci_req_complete(ndev, NCI_STATUS_OK);



	return 0;

}



static void nci_nfcee_discover_ntf_packet(struct nci_dev *ndev,

static int nci_nfcee_discover_ntf_packet(struct nci_dev *ndev,

					 const struct sk_buff *skb)

{

	u8 status = NCI_STATUS_OK;

	const struct nci_nfcee_discover_ntf *nfcee_ntf =

				(struct nci_nfcee_discover_ntf *)skb->data;

	const struct nci_nfcee_discover_ntf *nfcee_ntf;



	if (skb->len < sizeof(struct nci_nfcee_discover_ntf))

		return -EINVAL;



	nfcee_ntf = (struct nci_nfcee_discover_ntf *)skb->data;



	/* NFCForum NCI 9.2.1 HCI Network Specific Handling

	 * If the NFCC supports the HCI Network, it SHALL return one,
@@ -783,6 +836,8 @@ static void nci_nfcee_discover_ntf_packet(struct nci_dev *ndev, 
	ndev->cur_params.id = nfcee_ntf->nfcee_id;



	nci_req_complete(ndev, status);



	return 0;

}



void nci_ntf_packet(struct nci_dev *ndev, struct sk_buff *skb)
@@ -809,35 +864,43 @@ void nci_ntf_packet(struct nci_dev *ndev, struct sk_buff *skb) 


	switch (ntf_opcode) {

	case NCI_OP_CORE_RESET_NTF:

		nci_core_reset_ntf_packet(ndev, skb);

		if (nci_core_reset_ntf_packet(ndev, skb))

			goto end;

		break;



	case NCI_OP_CORE_CONN_CREDITS_NTF:

		nci_core_conn_credits_ntf_packet(ndev, skb);

		if (nci_core_conn_credits_ntf_packet(ndev, skb))

			goto end;

		break;



	case NCI_OP_CORE_GENERIC_ERROR_NTF:

		nci_core_generic_error_ntf_packet(ndev, skb);

		if (nci_core_generic_error_ntf_packet(ndev, skb))

			goto end;

		break;



	case NCI_OP_CORE_INTF_ERROR_NTF:

		nci_core_conn_intf_error_ntf_packet(ndev, skb);

		if (nci_core_conn_intf_error_ntf_packet(ndev, skb))

			goto end;

		break;



	case NCI_OP_RF_DISCOVER_NTF:

		nci_rf_discover_ntf_packet(ndev, skb);

		if (nci_rf_discover_ntf_packet(ndev, skb))

			goto end;

		break;



	case NCI_OP_RF_INTF_ACTIVATED_NTF:

		nci_rf_intf_activated_ntf_packet(ndev, skb);

		if (nci_rf_intf_activated_ntf_packet(ndev, skb))

			goto end;

		break;



	case NCI_OP_RF_DEACTIVATE_NTF:

		nci_rf_deactivate_ntf_packet(ndev, skb);

		if (nci_rf_deactivate_ntf_packet(ndev, skb))

			goto end;

		break;



	case NCI_OP_NFCEE_DISCOVER_NTF:

		nci_nfcee_discover_ntf_packet(ndev, skb);

		if (nci_nfcee_discover_ntf_packet(ndev, skb))

			goto end;

		break;



	case NCI_OP_RF_NFCEE_ACTION_NTF: