Blame SOURCES/wpa_supplicant-p2p-segfault-on-iface-removal.patch

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From b2ad4e6b24ed0271ca76cb27856def0a701fb778 Mon Sep 17 00:00:00 2001
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Message-Id: <b2ad4e6b24ed0271ca76cb27856def0a701fb778.1572271835.git.davide.caratti@gmail.com>
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From: Davide Caratti <davide.caratti@gmail.com>
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Date: Wed, 2 Oct 2019 14:08:41 +0200
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Subject: [PATCH] D-Bus: Fix P2P NULL dereference after interface removal
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When the P2P management interface is deleted, P2P is then disabled and
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global->p2p_init_wpa_s is set to NULL. After that, other interfaces can
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still trigger P2P functions (like wpas_p2p_find()) using D-Bus. This
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makes wpa_supplicant terminate with SIGSEGV, because it dereferences a
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NULL pointer. Fix this by adding proper checks, like it's done with
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wpa_cli.
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CC: Beniamino Galvani <bgalvani@redhat.com>
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CC: Benjamin Berg <benjamin@sipsolutions.net>
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Reported-by: Vladimir Benes <vbenes@redhat.com>
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Signed-off-by: Davide Caratti <davide.caratti@gmail.com>
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---
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 wpa_supplicant/dbus/dbus_new_handlers_p2p.c | 69 ++++++++++++++++++++-
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 1 file changed, 67 insertions(+), 2 deletions(-)
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diff --git a/wpa_supplicant/dbus/dbus_new_handlers_p2p.c b/wpa_supplicant/dbus/dbus_new_handlers_p2p.c
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index 8cdd88564..19715eb4c 100644
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--- a/wpa_supplicant/dbus/dbus_new_handlers_p2p.c
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+++ b/wpa_supplicant/dbus/dbus_new_handlers_p2p.c
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@@ -40,6 +40,14 @@ static int wpas_dbus_validate_dbus_ipaddr(struct wpa_dbus_dict_entry entry)
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 }
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+static dbus_bool_t no_p2p_mgmt_interface(DBusError *error)
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+{
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+	dbus_set_error_const(error, WPAS_DBUS_ERROR_IFACE_UNKNOWN,
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+			     "Could not find P2P mgmt interface");
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+	return FALSE;
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+}
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+
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+
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 /**
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  * Parses out the mac address from the peer object path.
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  * @peer_path - object path of the form
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@@ -78,6 +86,22 @@ wpas_dbus_error_persistent_group_unknown(DBusMessage *message)
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 }
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+/**
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+ * wpas_dbus_error_no_p2p_mgmt_iface - Return a new InterfaceUnknown error
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+ * message
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+ * @message: Pointer to incoming dbus message this error refers to
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+ * Returns: a dbus error message
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+ *
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+ * Convenience function to create and return an unknown interface error.
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+ */
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+static DBusMessage * wpas_dbus_error_no_p2p_mgmt_iface(DBusMessage *message)
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+{
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+	wpa_printf(MSG_DEBUG, "dbus: Could not find P2P mgmt interface");
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+	return dbus_message_new_error(message, WPAS_DBUS_ERROR_IFACE_UNKNOWN,
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+				      "Could not find P2P mgmt interface");
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+}
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+
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+
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 DBusMessage * wpas_dbus_handler_p2p_find(DBusMessage *message,
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 					 struct wpa_supplicant *wpa_s)
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 {
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@@ -145,6 +169,10 @@ DBusMessage * wpas_dbus_handler_p2p_find(DBusMessage *message,
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 	}
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 	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (!wpa_s) {
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+		reply = wpas_dbus_error_no_p2p_mgmt_iface(message);
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+		goto error_nop2p;
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+	}
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 	if (wpas_p2p_find(wpa_s, timeout, type, num_req_dev_types,
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 			  req_dev_types, NULL, 0, 0, NULL, freq))
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@@ -157,8 +185,9 @@ DBusMessage * wpas_dbus_handler_p2p_find(DBusMessage *message,
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 error_clear:
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 	wpa_dbus_dict_entry_clear(&entry);
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 error:
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-	os_free(req_dev_types);
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 	reply = wpas_dbus_error_invalid_args(message, entry.key);
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+error_nop2p:
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+	os_free(req_dev_types);
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 	return reply;
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 }
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@@ -166,7 +195,9 @@ error:
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 DBusMessage * wpas_dbus_handler_p2p_stop_find(DBusMessage *message,
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 					      struct wpa_supplicant *wpa_s)
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 {
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-	wpas_p2p_stop_find(wpa_s->global->p2p_init_wpa_s);
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+	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (wpa_s)
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+		wpas_p2p_stop_find(wpa_s);
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 	return NULL;
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 }
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@@ -185,6 +216,8 @@ DBusMessage * wpas_dbus_handler_p2p_rejectpeer(DBusMessage *message,
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 		return wpas_dbus_error_invalid_args(message, NULL);
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 	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (!wpa_s)
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+		return wpas_dbus_error_no_p2p_mgmt_iface(message);
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 	if (wpas_p2p_reject(wpa_s, peer_addr) < 0)
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 		return wpas_dbus_error_unknown_error(message,
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@@ -204,6 +237,8 @@ DBusMessage * wpas_dbus_handler_p2p_listen(DBusMessage *message,
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 		return wpas_dbus_error_no_memory(message);
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 	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (!wpa_s)
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+		return wpas_dbus_error_no_p2p_mgmt_iface(message);
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 	if (wpas_p2p_listen(wpa_s, (unsigned int) timeout)) {
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 		return dbus_message_new_error(message,
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@@ -245,6 +280,8 @@ DBusMessage * wpas_dbus_handler_p2p_extendedlisten(
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 	}
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 	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (!wpa_s)
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+		return wpas_dbus_error_no_p2p_mgmt_iface(message);
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 	if (wpas_p2p_ext_listen(wpa_s, period, interval))
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 		return wpas_dbus_error_unknown_error(
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@@ -350,6 +387,10 @@ DBusMessage * wpas_dbus_handler_p2p_group_add(DBusMessage *message,
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 	}
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 	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (!wpa_s) {
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+		reply = wpas_dbus_error_no_p2p_mgmt_iface(message);
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+		goto out;
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+	}
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 	if (pg_object_path != NULL) {
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 		char *net_id_str;
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@@ -433,6 +474,12 @@ static dbus_bool_t wpa_dbus_p2p_check_enabled(struct wpa_supplicant *wpa_s,
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 				     "P2P is not available for this interface");
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 		return FALSE;
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 	}
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+	if (!wpa_s->global->p2p_init_wpa_s) {
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+		if (out_reply)
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+			*out_reply = wpas_dbus_error_no_p2p_mgmt_iface(
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+				message);
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+		return no_p2p_mgmt_interface(error);
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+	}
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 	return TRUE;
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 }
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@@ -822,6 +869,8 @@ DBusMessage * wpas_dbus_handler_p2p_prov_disc_req(DBusMessage *message,
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 		return wpas_dbus_error_invalid_args(message, NULL);
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 	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (!wpa_s)
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+		return wpas_dbus_error_no_p2p_mgmt_iface(message);
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 	if (wpas_p2p_prov_disc(wpa_s, peer_addr, config_method,
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 			       WPAS_P2P_PD_FOR_GO_NEG, NULL) < 0)
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@@ -1882,6 +1931,8 @@ dbus_bool_t wpas_dbus_getter_p2p_peer_groups(
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 	wpa_s = peer_args->wpa_s;
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 	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (!wpa_s)
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+		return no_p2p_mgmt_interface(error);
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 	wpa_s_go = wpas_get_p2p_client_iface(wpa_s, info->p2p_device_addr);
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 	if (wpa_s_go) {
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@@ -1963,6 +2014,9 @@ dbus_bool_t wpas_dbus_getter_persistent_groups(
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 	dbus_bool_t success = FALSE;
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 	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (!wpa_s)
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+		return no_p2p_mgmt_interface(error);
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+
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 	if (!wpa_s->parent->dbus_new_path)
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 		return FALSE;
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@@ -2077,6 +2131,11 @@ DBusMessage * wpas_dbus_handler_add_persistent_group(
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 	dbus_message_iter_init(message, &iter);
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 	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (!wpa_s) {
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+		reply = wpas_dbus_error_no_p2p_mgmt_iface(message);
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+		goto err;
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+	}
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+
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 	if (wpa_s->parent->dbus_new_path)
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 		ssid = wpa_config_add_network(wpa_s->conf);
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 	if (ssid == NULL) {
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@@ -2159,6 +2218,10 @@ DBusMessage * wpas_dbus_handler_remove_persistent_group(
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 			      DBUS_TYPE_INVALID);
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 	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (!wpa_s) {
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+		reply = wpas_dbus_error_no_p2p_mgmt_iface(message);
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+		goto out;
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+	}
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 	/*
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 	 * Extract the network ID and ensure the network is actually a child of
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@@ -2235,6 +2298,8 @@ DBusMessage * wpas_dbus_handler_remove_all_persistent_groups(
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 	struct wpa_config *config;
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 	wpa_s = wpa_s->global->p2p_init_wpa_s;
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+	if (!wpa_s)
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+		return wpas_dbus_error_no_p2p_mgmt_iface(message);
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 	config = wpa_s->conf;
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 	ssid = config->ssid;
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-- 
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2.21.0
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