[PATCH 6.12 230/265] nfc: nci: free skb on nci_transceive early error paths

Greg Kroah-Hartman
2026-03-12T20:28:40Z

From: Jakub Kicinski <kuba@kernel.org>

[ Upstream commit 7bd4b0c4779f978a6528c9b7937d2ca18e936e2c ]

nci_transceive() takes ownership of the skb passed by the caller,
but the -EPROTO, -EINVAL, and -EBUSY error paths return without
freeing it.

Due to issues clearing NCI_DATA_EXCHANGE fixed by subsequent changes
the nci/nci_dev selftest hits the error path occasionally in NIPA,
and kmemleak detects leaks:

unreferenced object 0xff11000015ce6a40 (size 640):
comm "nci_dev", pid 3954, jiffies 4295441246
hex dump (first 32 bytes):
6b 6b 6b 6b 00 a4 00 0c 02 e1 03 6b 6b 6b 6b 6b kkkk.......kkkkk
6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
backtrace (crc 7c40cc2a):
kmem_cache_alloc_node_noprof+0x492/0x630
__alloc_skb+0x11e/0x5f0
alloc_skb_with_frags+0xc6/0x8f0
sock_alloc_send_pskb+0x326/0x3f0
nfc_alloc_send_skb+0x94/0x1d0
rawsock_sendmsg+0x162/0x4c0
do_syscall_64+0x117/0xfc0

Fixes: 6a2968aaf50c ("NFC: basic NCI protocol implementation")
Reviewed-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20260303162346.2071888-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/nfc/nci/core.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index 3c42b149c729c..18ff1c23769ae 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -1024,18 +1024,23 @@ static int nci_transceive(struct nfc_dev *nfc_dev, struct nfc_target *target,
struct nci_conn_info *conn_info;

conn_info = ndev->rf_conn_info;
- if (!conn_info)
+ if (!conn_info) {
+ kfree_skb(skb);
return -EPROTO;
+ }

pr_debug("target_idx %d, len %d\n", target->idx, skb->len);

if (!ndev->target_active_prot) {
pr_err("unable to exchange data, no active target\n");
+ kfree_skb(skb);
return -EINVAL;
}

- if (test_and_set_bit(NCI_DATA_EXCHANGE, &ndev->flags))
+ if (test_and_set_bit(NCI_DATA_EXCHANGE, &ndev->flags)) {
+ kfree_skb(skb);
return -EBUSY;
+ }

/* store cb and context to be used on receiving data */
conn_info->data_exchange_cb = cb;
--
2.51.0