From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f46.google.com (mail-ej1-f46.google.com [209.85.218.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BEE35282F39 for ; Sun, 21 Jun 2026 16:23:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.46 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782059002; cv=none; b=KcoVVPuFbzJchLDkewKeYyUsDUgKfh3cpDqU+IIGXzfuh0QsRnkKF7dbzH7CVOU/t5VqQrpjV1nzXCj12yPptd247BLkd7fcMVGQXVqGqqxxKtqj4HUFQ4O1tlZ2N5RPNG1AC6BA2dyiBU40HCHjHTq1RnWWCljoSEizBWHWBR8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782059002; c=relaxed/simple; bh=9D3krCGzGGlRpYwm56oiCtazTMOUWfsdff/eOQAoLCc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=qKeGD2gRuTLH3LcMvYvQ8ZCVNtGY8YE/dyyMC/hQITx093dG0sFvtdGaIGJL1LZdAaTyr98mkEBp8rk9tJ7p4Nv6LZbEowgIwzWJMrjveoo3hkJvrPCL8BgC/sE56Fy+Ya73/oDElFxnxWCIntVgHhcT/Irqx17q6sgx5turMa0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=FxpgSqxr; arc=none smtp.client-ip=209.85.218.46 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="FxpgSqxr" Received: by mail-ej1-f46.google.com with SMTP id a640c23a62f3a-bed2195323cso547516066b.1 for ; Sun, 21 Jun 2026 09:23:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1782058999; x=1782663799; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=bybjcRHpNKQC6YvGZ5klSk+Kw3IBZ+UA74h0Z6azPxw=; b=FxpgSqxrnao4Vm8hwmKmqnK2juuVgYq2RXc97q9qUqRJPYC9JZbXDSaIVENzznvWIS KPbm3j+tZoTTmXRNPGeQ1eb24v0nki5bL6Rb7Ej0T1DDLB//PWyZPtwDtU9SIw8EBdk6 E+cioNtbyiDUAomJvc7saJkW7rhuX9SnJrFV5RCjeqowN5sW+2a/eP/S7jFxCJAsrxSs lxVZdcSRJbLH4oG5b+2SNDBx5TaxNvTD6ZcTfuQwATCIb1qALJJbQznwop+PuzWk5YBW QKtVVvV1H5mG1lP4cjhBMH89x0UrCwGLvb0fl9xRd3hLE6lNfDB2VT6/wnxBtWqTTDp8 Zhuw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782058999; x=1782663799; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=bybjcRHpNKQC6YvGZ5klSk+Kw3IBZ+UA74h0Z6azPxw=; b=MX2bkl2as6fZQAFYYzWieVqBmhhTl6Qfg4/mrx3p0YnKV53+TGddVF6k+8kVG/TECm MakgdqJAg4L+FxAOQFxn1UlD8IWw38ty9El7sHiXM1GFo/qK1EipZdFg+37F9VEuDXjL Fe9pGAt9XytoqJK0EK/7Ubp+Pqre2zthUVsupI0N37AkOv0dtaH8lkNlSUwnUfvo97Av WNxEgT0VRlR+OBiiVIsoZScSMwF9ZGx+YvqsBjPyqTN2GPDFXwuipX57v6NQCT/Au9ZN 1C3SvRXyxgjBsJXGuWRCHo1h8tFdqA8O1vIb/UdQskxtLNgQ6X2xP6jDWQmQ6n3cfpGC BF4g== X-Gm-Message-State: AOJu0Yz4fYQMdczpG7JMdsWEZPS/+htTzGGJ3642/4fijxNoQ9ytu83y ns3i0ofWHQRPTFHW/6YhS1cCS0xpaKDp603fwylifCofLmJCwrgaW0UQgLsP6ezxlfd5cA== X-Gm-Gg: AfdE7cmCKCIh2HZu9ZNW3+Dqe5uIiOFoBfRVcQd+LlKldVHd05YLgWDAs00A5eiYce3 93GKoNwfEWuRkPpmSHZgcutyOTFwttLWh+fc180yED3IfkmcLIzH9ggO+qbR9Vgj92rnmzmShAO RrtiCqAJP0g66MmIxJYhrUOMmDL/XskTaVdAM0a7+X4WC0Dbz3hFYXOuFqBrbKJv3V5kwCgWt8X 8ZA7MS0zX0G9QXjb1Efppp3EFMdn6cLOjPIHsn6BT9lCUCfd1l4C6+vAe6voaPTyovALRc/Xcx+ vfWkqXs9wPeY6Zd7xBaQdKYPo1qXXGg9iPu6eHrihNc+HyAbSTaMThNGKtzV3D6mDOMvT4xuEzs zjmNw+B41uuNF7a72l6HdP9e/Cpf1/+qt3dVqKXfyxWU3z0Xe4LaQnAVUWSaTFWeohYIJhET0Sy EjyAoB8xc2ebzY53E/gvP8AwKIJJuJlsNbrBi4ZWtONVjUsvelrz8Ji/cM/jetJzE= X-Received: by 2002:a17:907:3f89:b0:bf0:550:d9f with SMTP id a640c23a62f3a-c0b743ac8e1mr482252966b.31.1782058998924; Sun, 21 Jun 2026 09:23:18 -0700 (PDT) Received: from node ([202.47.63.86]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c0c5ef8acaesm216907366b.27.2026.06.21.09.23.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 21 Jun 2026 09:23:17 -0700 (PDT) From: Muhammad Bilal To: linux-bluetooth@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Marcel Holtmann , Luiz Augusto von Dentz , Iulia Tanasescu , Muhammad Bilal , stable@vger.kernel.org Subject: [PATCH] Bluetooth: ISO: avoid NULL deref of conn in iso_conn_big_sync() Date: Sun, 21 Jun 2026 21:23:05 +0500 Message-ID: <20260621162305.219763-1-meatuni001@gmail.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit iso_conn_big_sync() drops the socket lock to call hci_get_route() and then re-acquires it, but dereferences iso_pi(sk)->conn->hcon afterwards without re-checking that conn is still valid. While the lock is dropped, the connection can be torn down under the same socket lock: iso_disconn_cfm() -> iso_conn_del() -> iso_chan_del() sets iso_pi(sk)->conn to NULL (and the broadcast teardown path can also clear conn->hcon on its own). When iso_conn_big_sync() re-acquires the lock and reads conn->hcon, conn may be NULL, causing a NULL pointer dereference (hcon is the first member of struct iso_conn). This path is reached from iso_sock_recvmsg() for a PA-sync broadcast sink socket (BT_SK_DEFER_SETUP | BT_SK_PA_SYNC), so the dropped-lock window can race with connection teardown driven by controller events. Re-validate iso_pi(sk)->conn and its hcon after re-acquiring the socket lock and bail out if the connection went away, as already done in the sibling iso_sock_rebind_bc(). Fixes: 7a17308c17880d ("Bluetooth: iso: Fix circular lock in iso_conn_big_sync") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal --- net/bluetooth/iso.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c index 3abd8111dda83..7186e8d88c757 100644 --- a/net/bluetooth/iso.c +++ b/net/bluetooth/iso.c @@ -1589,6 +1589,7 @@ static void iso_conn_big_sync(struct sock *sk) { int err; struct hci_dev *hdev; + struct iso_conn *conn; bdaddr_t src, dst; u8 src_type; @@ -1611,8 +1612,17 @@ static void iso_conn_big_sync(struct sock *sk) hci_dev_lock(hdev); lock_sock(sk); + /* The socket lock was dropped for hci_get_route(), so the connection + * may have been torn down meanwhile: iso_chan_del() clears conn and + * the broadcast teardown path can clear conn->hcon on its own. Check + * both before dereferencing conn->hcon. + */ + conn = iso_pi(sk)->conn; + if (!conn || !conn->hcon) + goto unlock; + if (!test_and_set_bit(BT_SK_BIG_SYNC, &iso_pi(sk)->flags)) { - err = hci_conn_big_create_sync(hdev, iso_pi(sk)->conn->hcon, + err = hci_conn_big_create_sync(hdev, conn->hcon, &iso_pi(sk)->qos, iso_pi(sk)->sync_handle, iso_pi(sk)->bc_num_bis, @@ -1621,6 +1631,7 @@ static void iso_conn_big_sync(struct sock *sk) bt_dev_err(hdev, "hci_big_create_sync: %d", err); } +unlock: release_sock(sk); hci_dev_unlock(hdev); hci_dev_put(hdev); -- 2.54.0