From: Yuchao Zhang When an NCI_OP_CORE_CONN_CREATE_RSP packet is received, nci_core_conn_create_rsp_packet() parses it and creates a logical connection entry in ndev->conn_info_list. However, nci_core_conn_create_rsp_packet() suffers from several issues: 1. It does not verify that a connection creation command is currently pending. An unsolicited or delayed CORE_CONN_CREATE_RSP packet unconditionally creates a rogue connection and calls nci_req_complete(), prematurely completing unrelated in-flight requests. 2. It lacks bounds checking against sizeof(struct nci_core_conn_create_rsp) for the packet payload, leading to potential out-of-bounds reads. 3. It does not validate rsp->conn_id. Dynamic logical connections assigned by the NFCC must not use NCI_STATIC_RF_CONN_ID (0x00) or collide with any existing connection ID. 4. It inserts the new connection at the head of ndev->conn_info_list via list_add(). Because connection lookup (e.g. in nci_tx_work() and nci_data_exchange_complete()) uses first-match semantics, prepending allows a newly created connection with a duplicate ID to shadow the static RF connection or earlier connections. Furthermore, ndev->hci_dev->conn_info is mistakenly updated even when the destination type is not NCI_DESTINATION_NFCEE because cur_params.id and nfcee_id both default to 0. Fix this by: - Adding an NCI_CONN_CREATE_PENDING flag in enum nci_flag to track in-flight connection creation commands, and rejecting unsolicited or delayed responses. - Adding packet length verification before reading payload fields. - Rejecting responses that allocate NCI_STATIC_RF_CONN_ID or duplicate existing connection IDs. - Appending new connections with list_add_tail() instead of list_add(). - Restricting ndev->hci_dev->conn_info assignment to NFCEE destination types. Fixes: 736bb9577407 ("NFC: nci: Support logical connections management") Cc: stable@vger.kernel.org Signed-off-by: Yuchao Zhang --- include/net/nfc/nci_core.h | 1 + net/nfc/nci/core.c | 2 ++ net/nfc/nci/rsp.c | 37 ++++++++++++++++++++++++++++++------- 3 files changed, 33 insertions(+), 7 deletions(-) diff --git a/include/net/nfc/nci_core.h b/include/net/nfc/nci_core.h index 664d5058e66e..a4652ffc173d 100644 --- a/include/net/nfc/nci_core.h +++ b/include/net/nfc/nci_core.h @@ -31,6 +31,7 @@ enum nci_flag { NCI_DATA_EXCHANGE, NCI_DATA_EXCHANGE_TO, NCI_UNREG, + NCI_CONN_CREATE_PENDING, }; /* NCI device states */ diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c index 5f46c4b5720f..b5fa17f0524e 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -134,6 +134,7 @@ static int __nci_request(struct nci_dev *ndev, } ndev->req_status = ndev->req_result = 0; + clear_bit(NCI_CONN_CREATE_PENDING, &ndev->flags); return rc; } @@ -709,6 +710,7 @@ static void nci_core_conn_create_req(struct nci_dev *ndev, const void *opt) { const struct core_conn_create_data *data = opt; + set_bit(NCI_CONN_CREATE_PENDING, &ndev->flags); nci_send_cmd(ndev, NCI_OP_CORE_CONN_CREATE_CMD, data->length, data->cmd); } diff --git a/net/nfc/nci/rsp.c b/net/nfc/nci/rsp.c index b0ab4f5acbce..a56a7392ab5e 100644 --- a/net/nfc/nci/rsp.c +++ b/net/nfc/nci/rsp.c @@ -305,15 +305,37 @@ static void nci_nfcee_mode_set_rsp_packet(struct nci_dev *ndev, static void nci_core_conn_create_rsp_packet(struct nci_dev *ndev, const struct sk_buff *skb) { - __u8 status = skb->data[0]; struct nci_conn_info *conn_info = NULL; const struct nci_core_conn_create_rsp *rsp; + __u8 status; + + if (skb->len < 1) + return; + status = skb->data[0]; pr_debug("status 0x%x\n", status); + if (!test_and_clear_bit(NCI_CONN_CREATE_PENDING, &ndev->flags)) { + pr_warn_ratelimited("unexpected CORE_CONN_CREATE_RSP\n"); + return; + } + if (status == NCI_STATUS_OK) { + if (skb->len < sizeof(*rsp)) { + status = NCI_STATUS_SYNTAX_ERROR; + goto exit; + } + rsp = (struct nci_core_conn_create_rsp *)skb->data; + if (rsp->conn_id == NCI_STATIC_RF_CONN_ID || + nci_get_conn_info_by_conn_id(ndev, rsp->conn_id)) { + pr_warn_ratelimited("invalid or duplicate conn_id 0x%x\n", + rsp->conn_id); + status = NCI_STATUS_REJECTED; + goto exit; + } + conn_info = devm_kzalloc(&ndev->nfc_dev->dev, sizeof(*conn_info), GFP_KERNEL); if (!conn_info) { @@ -339,21 +361,22 @@ static void nci_core_conn_create_rsp_packet(struct nci_dev *ndev, */ INIT_LIST_HEAD(&conn_info->list); - list_add(&conn_info->list, &ndev->conn_info_list); + list_add_tail(&conn_info->list, &ndev->conn_info_list); - if (ndev->cur_params.id == ndev->hci_dev->nfcee_id) + if (conn_info->dest_type == NCI_DESTINATION_NFCEE && + ndev->cur_params.id == ndev->hci_dev->nfcee_id) ndev->hci_dev->conn_info = conn_info; - conn_info->conn_id = rsp->conn_id; conn_info->max_pkt_payload_len = rsp->max_ctrl_pkt_payload_len; atomic_set(&conn_info->credits_cnt, rsp->credits_cnt); } + nci_req_complete(ndev, status); + return; + free_conn_info: - if (status == NCI_STATUS_REJECTED) - devm_kfree(&ndev->nfc_dev->dev, conn_info); + devm_kfree(&ndev->nfc_dev->dev, conn_info); exit: - nci_req_complete(ndev, status); } -- 2.53.0