From 7bd4b0c4779f978a6528c9b7937d2ca18e936e2c Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 3 Mar 2026 08:23:41 -0800 Subject: [PATCH 1/5] nfc: nci: free skb on nci_transceive early error paths 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 Link: https://patch.msgid.link/20260303162346.2071888-2-kuba@kernel.org Signed-off-by: Jakub Kicinski --- 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 e95eef85971f..e859b834c0f1 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -1035,18 +1035,23 @@ 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; From d42449d2c17cdf06d1f63268557450bd3f051e9a Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 3 Mar 2026 08:23:42 -0800 Subject: [PATCH 2/5] nfc: digital: free skb on digital_in_send error paths digital_in_send() takes ownership of the skb passed by the caller (nfc_data_exchange), make sure it's freed on all error paths. Found looking around the real driver for similar bugs to the one just fixed in nci. Fixes: 2c66daecc409 ("NFC Digital: Add NFC-A technology support") Reviewed-by: Joe Damato Link: https://patch.msgid.link/20260303162346.2071888-3-kuba@kernel.org Signed-off-by: Jakub Kicinski --- net/nfc/digital_core.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/nfc/digital_core.c b/net/nfc/digital_core.c index 3670bb33732e..7cb1e6aaae90 100644 --- a/net/nfc/digital_core.c +++ b/net/nfc/digital_core.c @@ -707,8 +707,10 @@ static int digital_in_send(struct nfc_dev *nfc_dev, struct nfc_target *target, int rc; data_exch = kzalloc_obj(*data_exch); - if (!data_exch) + if (!data_exch) { + kfree_skb(skb); return -ENOMEM; + } data_exch->cb = cb; data_exch->cb_context = cb_context; @@ -731,8 +733,10 @@ static int digital_in_send(struct nfc_dev *nfc_dev, struct nfc_target *target, data_exch); exit: - if (rc) + if (rc) { + kfree_skb(skb); kfree(data_exch); + } return rc; } From 66083581945bd5b8e99fe49b5aeb83d03f62d053 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 3 Mar 2026 08:23:43 -0800 Subject: [PATCH 3/5] nfc: nci: complete pending data exchange on device close In nci_close_device(), complete any pending data exchange before closing. The data exchange callback (e.g. rawsock_data_exchange_complete) holds a socket reference. NIPA occasionally hits this leak: unreferenced object 0xff1100000f435000 (size 2048): comm "nci_dev", pid 3954, jiffies 4295441245 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 27 00 01 40 00 00 00 00 00 00 00 00 00 00 00 00 '..@............ backtrace (crc ec2b3c5): __kmalloc_noprof+0x4db/0x730 sk_prot_alloc.isra.0+0xe4/0x1d0 sk_alloc+0x36/0x760 rawsock_create+0xd1/0x540 nfc_sock_create+0x11f/0x280 __sock_create+0x22d/0x630 __sys_socket+0x115/0x1d0 __x64_sys_socket+0x72/0xd0 do_syscall_64+0x117/0xfc0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Fixes: 38f04c6b1b68 ("NFC: protect nci_data_exchange transactions") Reviewed-by: Joe Damato Link: https://patch.msgid.link/20260303162346.2071888-4-kuba@kernel.org Signed-off-by: Jakub Kicinski --- net/nfc/nci/core.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c index e859b834c0f1..43d871525dbc 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -567,6 +567,10 @@ static int nci_close_device(struct nci_dev *ndev) flush_workqueue(ndev->cmd_wq); timer_delete_sync(&ndev->cmd_timer); timer_delete_sync(&ndev->data_timer); + if (test_bit(NCI_DATA_EXCHANGE, &ndev->flags)) + nci_data_exchange_complete(ndev, NULL, + ndev->cur_conn_id, + -ENODEV); mutex_unlock(&ndev->req_lock); return 0; } @@ -598,6 +602,11 @@ static int nci_close_device(struct nci_dev *ndev) flush_workqueue(ndev->cmd_wq); timer_delete_sync(&ndev->cmd_timer); + timer_delete_sync(&ndev->data_timer); + + if (test_bit(NCI_DATA_EXCHANGE, &ndev->flags)) + nci_data_exchange_complete(ndev, NULL, ndev->cur_conn_id, + -ENODEV); /* Clear flags except NCI_UNREG */ ndev->flags &= BIT(NCI_UNREG); From 0efdc02f4f6d52f8ca5d5889560f325a836ce0a8 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 3 Mar 2026 08:23:44 -0800 Subject: [PATCH 4/5] nfc: nci: clear NCI_DATA_EXCHANGE before calling completion callback Move clear_bit(NCI_DATA_EXCHANGE) before invoking the data exchange callback in nci_data_exchange_complete(). The callback (e.g. rawsock_data_exchange_complete) may immediately schedule another data exchange via schedule_work(tx_work). On a multi-CPU system, tx_work can run and reach nci_transceive() before the current nci_data_exchange_complete() clears the flag, causing test_and_set_bit(NCI_DATA_EXCHANGE) to return -EBUSY and the new transfer to fail. This causes intermittent flakes in nci/nci_dev in NIPA: # # RUN NCI.NCI1_0.t4t_tag_read ... # # t4t_tag_read: Test terminated by timeout # # FAIL NCI.NCI1_0.t4t_tag_read # not ok 3 NCI.NCI1_0.t4t_tag_read Fixes: 38f04c6b1b68 ("NFC: protect nci_data_exchange transactions") Reviewed-by: Joe Damato Link: https://patch.msgid.link/20260303162346.2071888-5-kuba@kernel.org Signed-off-by: Jakub Kicinski --- net/nfc/nci/data.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/net/nfc/nci/data.c b/net/nfc/nci/data.c index 78f4131af3cf..5f98c73db5af 100644 --- a/net/nfc/nci/data.c +++ b/net/nfc/nci/data.c @@ -33,7 +33,8 @@ void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb, conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id); if (!conn_info) { kfree_skb(skb); - goto exit; + clear_bit(NCI_DATA_EXCHANGE, &ndev->flags); + return; } cb = conn_info->data_exchange_cb; @@ -45,6 +46,12 @@ void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb, timer_delete_sync(&ndev->data_timer); clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags); + /* Mark the exchange as done before calling the callback. + * The callback (e.g. rawsock_data_exchange_complete) may + * want to immediately queue another data exchange. + */ + clear_bit(NCI_DATA_EXCHANGE, &ndev->flags); + if (cb) { /* forward skb to nfc core */ cb(cb_context, skb, err); @@ -54,9 +61,6 @@ void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb, /* no waiting callback, free skb */ kfree_skb(skb); } - -exit: - clear_bit(NCI_DATA_EXCHANGE, &ndev->flags); } /* ----------------- NCI TX Data ----------------- */ From d793458c45df2aed498d7f74145eab7ee22d25aa Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 3 Mar 2026 08:23:45 -0800 Subject: [PATCH 5/5] nfc: rawsock: cancel tx_work before socket teardown In rawsock_release(), cancel any pending tx_work and purge the write queue before orphaning the socket. rawsock_tx_work runs on the system workqueue and calls nfc_data_exchange which dereferences the NCI device. Without synchronization, tx_work can race with socket and device teardown when a process is killed (e.g. by SIGKILL), leading to use-after-free or leaked references. Set SEND_SHUTDOWN first so that if tx_work is already running it will see the flag and skip transmitting, then use cancel_work_sync to wait for any in-progress execution to finish, and finally purge any remaining queued skbs. Fixes: 23b7869c0fd0 ("NFC: add the NFC socket raw protocol") Reviewed-by: Joe Damato Link: https://patch.msgid.link/20260303162346.2071888-6-kuba@kernel.org Signed-off-by: Jakub Kicinski --- net/nfc/rawsock.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/net/nfc/rawsock.c b/net/nfc/rawsock.c index b049022399ae..f7d7a599fade 100644 --- a/net/nfc/rawsock.c +++ b/net/nfc/rawsock.c @@ -67,6 +67,17 @@ static int rawsock_release(struct socket *sock) if (sock->type == SOCK_RAW) nfc_sock_unlink(&raw_sk_list, sk); + if (sk->sk_state == TCP_ESTABLISHED) { + /* Prevent rawsock_tx_work from starting new transmits and + * wait for any in-progress work to finish. This must happen + * before the socket is orphaned to avoid a race where + * rawsock_tx_work runs after the NCI device has been freed. + */ + sk->sk_shutdown |= SEND_SHUTDOWN; + cancel_work_sync(&nfc_rawsock(sk)->tx_work); + rawsock_write_queue_purge(sk); + } + sock_orphan(sk); sock_put(sk);