FAILED: patch "[PATCH] nfc: nci: fix uninit-value in the RF discover/activated NTF" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 8cbe06c1e699c0a165dae5093a2550e65f914818
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026082417-repent-kilometer-e0ba@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8cbe06c1e699c0a165dae5093a2550e65f914818 Mon Sep 17 00:00:00 2001
From: Samuel Page <[email protected]>
Date: Fri, 26 Jun 2026 10:03:01 +0100
Subject: [PATCH] nfc: nci: fix uninit-value in the RF discover/activated NTF
handlers

nci_rf_discover_ntf_packet() and nci_rf_intf_activated_ntf_packet() each parse a notification into an on-stack struct (nci_rf_discover_ntf / nci_rf_intf_activated_ntf) that is not initialised. The RF technology-specific parameters are only extracted when rf_tech_specific_params_len is non-zero, so a notification that reports a zero length leaves the rf_tech_specific_params union uninitialised - and both handlers then pass it to nci_add_new_protocol(), which reads it:

- discover: nci_add_new_target() -> nci_add_new_protocol();
- activated: nci_target_auto_activated() -> nci_add_new_protocol().

nci_add_new_protocol() uses nfca_poll->nfcid1_len as both a branch condition and a memcpy() length and copies nfcid1/sens_res/sel_res into ndev->targets, which is later exposed to user space via NFC_CMD_GET_TARGET.

  BUG: KMSAN: uninit-value in nci_add_new_protocol+0x624/0x6c0
   nci_add_new_protocol+0x624/0x6c0
   nci_ntf_packet+0x25b2/0x3c30
   nci_rx_work+0x318/0x5d0
   process_scheduled_works+0x84b/0x17a0
   worker_thread+0xc10/0x11b0
   kthread+0x376/0x500
  Local variable ntf.i created at:
   nci_ntf_packet+0xbc2/0x3c30

Zero-initialise both on-stack notifications so the union reads back as zero when no technology-specific parameters are present.

index 87f76a29f0ec..f5c9a8ab7ec1 100644
@@ -440,7 +440,7 @@ void nci_clear_target_list(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;
+	struct nci_rf_discover_ntf ntf = {};
 	const __u8 *data;
 	bool add_target = true;
 

@@ -710,7 +710,7 @@ 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;
+	struct nci_rf_intf_activated_ntf ntf = {};
 	const __u8 *data;
 	int err = NCI_STATUS_OK;
 

From: Samuel Page <[email protected]>

[ Upstream commit 8cbe06c1e699c0a165dae5093a2550e65f914818 ]

nci_rf_discover_ntf_packet() and nci_rf_intf_activated_ntf_packet() each parse a notification into an on-stack struct (nci_rf_discover_ntf / nci_rf_intf_activated_ntf) that is not initialised. The RF technology-specific parameters are only extracted when rf_tech_specific_params_len is non-zero, so a notification that reports a zero length leaves the rf_tech_specific_params union uninitialised - and both handlers then pass it to nci_add_new_protocol(), which reads it:

- discover: nci_add_new_target() -> nci_add_new_protocol();
- activated: nci_target_auto_activated() -> nci_add_new_protocol().

nci_add_new_protocol() uses nfca_poll->nfcid1_len as both a branch condition and a memcpy() length and copies nfcid1/sens_res/sel_res into ndev->targets, which is later exposed to user space via NFC_CMD_GET_TARGET.

  BUG: KMSAN: uninit-value in nci_add_new_protocol+0x624/0x6c0
   nci_add_new_protocol+0x624/0x6c0
   nci_ntf_packet+0x25b2/0x3c30
   nci_rx_work+0x318/0x5d0
   process_scheduled_works+0x84b/0x17a0
   worker_thread+0xc10/0x11b0
   kthread+0x376/0x500
  Local variable ntf.i created at:
   nci_ntf_packet+0xbc2/0x3c30

Zero-initialise both on-stack notifications so the union reads back as zero when no technology-specific parameters are present.

---
 net/nfc/nci/ntf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index f8b20cddd5c96..a3d9cb70f3d2c 100644
@@ -310,7 +310,7 @@ void nci_clear_target_list(struct nci_dev *ndev)
 static void nci_rf_discover_ntf_packet(struct nci_dev *ndev,
 				       struct sk_buff *skb)
 {
-	struct nci_rf_discover_ntf ntf;
+	struct nci_rf_discover_ntf ntf = {};
 	__u8 *data = skb->data;
 	bool add_target = true;
 

@@ -511,7 +511,7 @@ static void nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev,
 					     struct sk_buff *skb)
 {
 	struct nci_conn_info    *conn_info;
-	struct nci_rf_intf_activated_ntf ntf;
+	struct nci_rf_intf_activated_ntf ntf = {};
 	__u8 *data = skb->data;
 	int err = NCI_STATUS_OK;
 

2.53.0