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([187.13.30.172]) by smtp.gmail.com with ESMTPSA id ada2fe7eead31-7b39b15808esm8107452137.5.2026.09.27.20.57.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 27 Sep 2026 20:58:01 -0700 (PDT) From: Aldo Ariel Panzardo To: david@ixit.cz, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: horms@kernel.org, oe-linux-nfc@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, syzbot+ci3c472c63e196fe9e@syzkaller.appspotmail.com, Aldo Ariel Panzardo , Sashiko Subject: [PATCH net v3] nfc: llcp: prevent resource leak on repeated connect after DM Date: Mon, 28 Sep 2026 00:57:49 -0300 Message-ID: <20260928035749.2305913-1-qwe.aldo@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260925184857.357926-1-qwe.aldo@gmail.com> References: <20260925184857.357926-1-qwe.aldo@gmail.com> Precedence: bulk X-Mailing-List: oe-linux-nfc@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit A rejected asynchronous connect leaves a local reference, SAP allocation, service name and device reference on a closed socket. Release them before retrying connect. The device pointer alone does not prove ownership: bind() puts its temporary device reference while retaining the pointer. When device teardown closes a bound socket, the retry cleanup would put that device again. Clear the pointer when a bound or listening socket becomes closed, and after a connected socket's device reference is put. Do the same when DM closes a bound or listening socket. A DM rejected connect keeps its device reference until the retry cleanup, so retain that put there. Fixes: d646960f7986 ("NFC: Initial LLCP support") Reported-by: Sashiko Link: https://ci.syzbot.org/findings/64002827-5231-4183-bfca-0d91bded8543/syz_repro Cc: stable@vger.kernel.org Signed-off-by: Aldo Ariel Panzardo --- v3: Clear non-owning or already released device pointers on close, while preserving the device put for rejected asynchronous connects. net/nfc/llcp_core.c | 12 +++++++++++- net/nfc/llcp_sock.c | 17 +++++++++++++++++ 2 files changed, 28 insertions(+), 1 deletion(-) diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c index 199543c47eef..6382aacca69a 100644 --- a/net/nfc/llcp_core.c +++ b/net/nfc/llcp_core.c @@ -95,8 +95,14 @@ nfc_llcp_socket_purge(llcp_sock); - if (sk->sk_state == LLCP_CONNECTED) + if (sk->sk_state == LLCP_CONNECTED) { nfc_put_device(llcp_sock->dev); + llcp_sock->dev = NULL; + } else if (sk->sk_state == LLCP_BOUND || + sk->sk_state == LLCP_LISTEN) { + /* bind() already dropped its temporary device reference. */ + llcp_sock->dev = NULL; + } if (sk->sk_state == LLCP_LISTEN) { struct nfc_llcp_sock *lsk, *n; @@ -1330,6 +1336,10 @@ if (connecting) nfc_llcp_sock_unlink(&local->connecting_sockets, sk); + /* Bound and listening sockets do not own a device reference. */ + if (sk->sk_state == LLCP_BOUND || sk->sk_state == LLCP_LISTEN) + llcp_sock->dev = NULL; + sk->sk_err = ENXIO; sk->sk_state = LLCP_CLOSED; sk->sk_state_change(sk); diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c index 1e5ee4bcde68..9d76c12aee01 100644 --- a/net/nfc/llcp_sock.c +++ b/net/nfc/llcp_sock.c @@ -713,6 +713,23 @@ if (sk->sk_state == LLCP_CONNECTING) { ret = -EINPROGRESS; goto error; + } + + if (sk->sk_state == LLCP_CLOSED) { + /* Release resources retained by a previous failed connection. */ + if (llcp_sock->local) { + if (llcp_sock->reserved_ssap < LLCP_SAP_MAX) + nfc_llcp_put_ssap(llcp_sock->local, llcp_sock->ssap); + nfc_llcp_local_put(llcp_sock->local); + } + if (llcp_sock->dev) + nfc_put_device(llcp_sock->dev); + kfree(llcp_sock->service_name); + llcp_sock->local = NULL; + llcp_sock->dev = NULL; + llcp_sock->service_name = NULL; + llcp_sock->service_name_len = 0; + llcp_sock->reserved_ssap = LLCP_SAP_MAX; } dev = nfc_get_device(addr->dev_idx); -- 2.43.0