From f7d92f11bd33a6eb49c7c812255ef4ab13681f0f Mon Sep 17 00:00:00 2001 From: Ian Ray Date: Mon, 2 Mar 2026 18:32:37 +0200 Subject: [PATCH] net: nfc: nci: Fix zero-length proprietary notifications NCI NFC controllers may have proprietary OIDs with zero-length payload. One example is: drivers/nfc/nxp-nci/core.c, NXP_NCI_RF_TXLDO_ERROR_NTF. Allow a zero length payload in proprietary notifications *only*. Before: -- >8 -- kernel: nci: nci_recv_frame: len 3 -- >8 -- After: -- >8 -- kernel: nci: nci_recv_frame: len 3 kernel: nci: nci_ntf_packet: NCI RX: MT=ntf, PBF=0, GID=0x1, OID=0x23, plen=0 kernel: nci: nci_ntf_packet: unknown ntf opcode 0x123 kernel: nfc nfc0: NFC: RF transmitter couldn't start. Bad power and/or configuration? -- >8 -- After fixing the hardware: -- >8 -- kernel: nci: nci_recv_frame: len 27 kernel: nci: nci_ntf_packet: NCI RX: MT=ntf, PBF=0, GID=0x1, OID=0x5, plen=24 kernel: nci: nci_rf_intf_activated_ntf_packet: rf_discovery_id 1 -- >8 -- Fixes: d24b03535e5e ("nfc: nci: Fix uninit-value in nci_dev_up and nci_ntf_packet") Signed-off-by: Ian Ray Link: https://patch.msgid.link/20260302163238.140576-1-ian.ray@gehealthcare.com Signed-off-by: Jakub Kicinski --- net/nfc/nci/core.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c index 6e9b76e2cc56..e95eef85971f 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -1482,10 +1482,20 @@ static bool nci_valid_size(struct sk_buff *skb) unsigned int hdr_size = NCI_CTRL_HDR_SIZE; if (skb->len < hdr_size || - !nci_plen(skb->data) || skb->len < hdr_size + nci_plen(skb->data)) { return false; } + + if (!nci_plen(skb->data)) { + /* Allow zero length in proprietary notifications (0x20 - 0x3F). */ + if (nci_opcode_oid(nci_opcode(skb->data)) >= 0x20 && + nci_mt(skb->data) == NCI_MT_NTF_PKT) + return true; + + /* Disallow zero length otherwise. */ + return false; + } + return true; }