[PATCH net] nfc: nci: fix out-of-bounds read in activation parameter parsing

[PATCH net] nfc: nci: fix out-of-bounds read in activation parameter parsing

[Muhammad Bilal]

nci_extract_activation_params_iso_dep() and
nci_extract_activation_params_nfc_dep() receive a pointer into the
RF_INTF_ACTIVATED_NTF notification but are not told how many bytes
remain.  Each reads a one-byte length field (rats_res_len,
attrib_res_len, atr_res_len or atr_req_len) and then memcpy()s that many
bytes from the packet.  The length is clamped to the destination size,
but it is never checked against the remaining activation-parameter data,
so a notification whose length field is larger than the data present
reads past the end of the buffer.

The sibling nci_extract_rf_params_*() helpers were recently given a
data_len argument and matching remaining-length checks, but the
activation-parameter helpers were not updated.

Pass the remaining length down and validate each field against it before
copying, as the rf_params helpers do.

Fixes: ac2068384034 ("NFC: Parse NCI NFC-DEP activation params")
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Bilal <meatuni001@gmail.com>
---
 net/nfc/nci/ntf.c | 36 ++++++++++++++++++++++++++++++------
 1 file changed, 30 insertions(+), 6 deletions(-)

diff --git a/net/nfc/nci/ntf.c b/net/nfc/nci/ntf.c
index c96512bb86531..63aa0a78472b1 100644
--- a/net/nfc/nci/ntf.c
+++ b/net/nfc/nci/ntf.c
@@ -525,7 +525,7 @@ static int nci_rf_discover_ntf_packet(struct nci_dev *ndev,
 
 static int nci_extract_activation_params_iso_dep(struct nci_dev *ndev,
 						 struct nci_rf_intf_activated_ntf *ntf,
-						 const __u8 *data)
+						 const __u8 *data, ssize_t data_len)
 {
 	struct activation_params_nfca_poll_iso_dep *nfca_poll;
 	struct activation_params_nfcb_poll_iso_dep *nfcb_poll;
@@ -533,9 +533,14 @@ static int nci_extract_activation_params_iso_dep(struct nci_dev *ndev,
 	switch (ntf->activation_rf_tech_and_mode) {
 	case NCI_NFC_A_PASSIVE_POLL_MODE:
 		nfca_poll = &ntf->activation_params.nfca_poll_iso_dep;
+		if (data_len < 1)
+			return NCI_STATUS_RF_PROTOCOL_ERROR;
 		nfca_poll->rats_res_len = min_t(__u8, *data++, NFC_ATS_MAXSIZE);
+		data_len--;
 		pr_debug("rats_res_len %d\n", nfca_poll->rats_res_len);
 		if (nfca_poll->rats_res_len > 0) {
+			if (data_len < nfca_poll->rats_res_len)
+				return NCI_STATUS_RF_PROTOCOL_ERROR;
 			memcpy(nfca_poll->rats_res,
 			       data, nfca_poll->rats_res_len);
 		}
@@ -543,9 +548,14 @@ static int nci_extract_activation_params_iso_dep(struct nci_dev *ndev,
 
 	case NCI_NFC_B_PASSIVE_POLL_MODE:
 		nfcb_poll = &ntf->activation_params.nfcb_poll_iso_dep;
+		if (data_len < 1)
+			return NCI_STATUS_RF_PROTOCOL_ERROR;
 		nfcb_poll->attrib_res_len = min_t(__u8, *data++, 50);
+		data_len--;
 		pr_debug("attrib_res_len %d\n", nfcb_poll->attrib_res_len);
 		if (nfcb_poll->attrib_res_len > 0) {
+			if (data_len < nfcb_poll->attrib_res_len)
+				return NCI_STATUS_RF_PROTOCOL_ERROR;
 			memcpy(nfcb_poll->attrib_res,
 			       data, nfcb_poll->attrib_res_len);
 		}
@@ -562,7 +572,7 @@ static int nci_extract_activation_params_iso_dep(struct nci_dev *ndev,
 
 static int nci_extract_activation_params_nfc_dep(struct nci_dev *ndev,
 						 struct nci_rf_intf_activated_ntf *ntf,
-						 const __u8 *data)
+						 const __u8 *data, ssize_t data_len)
 {
 	struct activation_params_poll_nfc_dep *poll;
 	struct activation_params_listen_nfc_dep *listen;
@@ -571,21 +581,33 @@ static int nci_extract_activation_params_nfc_dep(struct nci_dev *ndev,
 	case NCI_NFC_A_PASSIVE_POLL_MODE:
 	case NCI_NFC_F_PASSIVE_POLL_MODE:
 		poll = &ntf->activation_params.poll_nfc_dep;
+		if (data_len < 1)
+			return NCI_STATUS_RF_PROTOCOL_ERROR;
 		poll->atr_res_len = min_t(__u8, *data++,
 					  NFC_ATR_RES_MAXSIZE - 2);
+		data_len--;
 		pr_debug("atr_res_len %d\n", poll->atr_res_len);
-		if (poll->atr_res_len > 0)
+		if (poll->atr_res_len > 0) {
+			if (data_len < poll->atr_res_len)
+				return NCI_STATUS_RF_PROTOCOL_ERROR;
 			memcpy(poll->atr_res, data, poll->atr_res_len);
+		}
 		break;
 
 	case NCI_NFC_A_PASSIVE_LISTEN_MODE:
 	case NCI_NFC_F_PASSIVE_LISTEN_MODE:
 		listen = &ntf->activation_params.listen_nfc_dep;
+		if (data_len < 1)
+			return NCI_STATUS_RF_PROTOCOL_ERROR;
 		listen->atr_req_len = min_t(__u8, *data++,
 					    NFC_ATR_REQ_MAXSIZE - 2);
+		data_len--;
 		pr_debug("atr_req_len %d\n", listen->atr_req_len);
-		if (listen->atr_req_len > 0)
+		if (listen->atr_req_len > 0) {
+			if (data_len < listen->atr_req_len)
+				return NCI_STATUS_RF_PROTOCOL_ERROR;
 			memcpy(listen->atr_req, data, listen->atr_req_len);
+		}
 		break;
 
 	default:
@@ -806,12 +828,14 @@ static int nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev,
 		switch (ntf.rf_interface) {
 		case NCI_RF_INTERFACE_ISO_DEP:
 			err = nci_extract_activation_params_iso_dep(ndev,
-								    &ntf, data);
+								    &ntf, data,
+								    ntf.activation_params_len);
 			break;
 
 		case NCI_RF_INTERFACE_NFC_DEP:
 			err = nci_extract_activation_params_nfc_dep(ndev,
-								    &ntf, data);
+								    &ntf, data,
+								    ntf.activation_params_len);
 			break;
 
 		case NCI_RF_INTERFACE_FRAME:
-- 
2.54.0