filter: new object to run the port/device filter logic

This new object allows configuring the filter rules applied to the
device ports. By default, for now, it implements the same rules as the
MMKernelDevice is_candidate() method, which is obsoleted.

1 files changed, 207 insertions, 0 deletions

diff --git a/src/mm-filter.c b/src/mm-filter.c
new file mode 100644
index 00000000..68bd2231
--- /dev/null
+++ b/src/mm-filter.c
@@ -0,0 +1,207 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details:
+ *
+ * Copyright (C) 2017 Aleksander Morgado <aleksander@aleksander.es>
+ */
+
+#include <config.h>
+#include <string.h>
+
+#include "mm-daemon-enums-types.h"
+#include "mm-filter.h"
+#include "mm-log.h"
+
+G_DEFINE_TYPE (MMFilter, mm_filter, G_TYPE_OBJECT)
+
+enum {
+    PROP_0,
+    PROP_ENABLED_RULES,
+    LAST_PROP
+};
+
+struct _MMFilterPrivate {
+    MMFilterRule enabled_rules;
+};
+
+/*****************************************************************************/
+
+gboolean
+mm_filter_port (MMFilter        *self,
+                MMKernelDevice  *port,
+                gboolean         manual_scan)
+{
+    const gchar *subsystem;
+    const gchar *name;
+
+    subsystem = mm_kernel_device_get_subsystem (port);
+    name      = mm_kernel_device_get_name      (port);
+
+    /* If this is a virtual device, don't allow it */
+    if ((self->priv->enabled_rules & MM_FILTER_RULE_VIRTUAL) &&
+        (!mm_kernel_device_get_physdev_sysfs_path (port))) {
+        mm_dbg ("[filter] (%s/%s) port filtered: virtual device", subsystem, name);
+        return FALSE;
+    }
+
+    /* If this is a net device, we always allow it */
+    if ((self->priv->enabled_rules & MM_FILTER_RULE_NET) &&
+        (g_strcmp0 (subsystem, "net") == 0)) {
+        mm_dbg ("[filter] (%s/%s) port allowed: net device", subsystem, name);
+        return TRUE;
+    }
+
+    /* If this is a cdc-wdm device, we always allow it */
+    if ((self->priv->enabled_rules & MM_FILTER_RULE_CDC_WDM) &&
+        (g_strcmp0 (subsystem, "usb") == 0 || g_strcmp0 (subsystem, "usbmisc") == 0) &&
+        (name && g_str_has_prefix (name, "cdc-wdm"))) {
+        mm_dbg ("[filter] (%s/%s) port allowed: cdc-wdm device", subsystem, name);
+        return TRUE;
+    }
+
+    /* If this is a tty device, we may allow it */
+    if ((self->priv->enabled_rules & MM_FILTER_RULE_TTY) &&
+        (g_strcmp0 (subsystem, "tty") == 0)) {
+        const gchar *physdev_subsystem;
+
+        /* Filter out virtual consoles (e.g. tty0, tty1, tty2...) */
+        if ((self->priv->enabled_rules & MM_FILTER_RULE_TTY_VIRTUAL_CONSOLE) &&
+            (name && strncmp (name, "tty", 3) == 0) &&
+            (g_ascii_isdigit (name[3]))) {
+            mm_dbg ("[filter] (%s/%s) port filtered: virtual console", subsystem, name);
+            return FALSE;
+        }
+
+        /* Ignore blacklisted tty devices. */
+        if ((self->priv->enabled_rules & MM_FILTER_RULE_TTY_BLACKLIST) &&
+            (mm_kernel_device_get_global_property_as_boolean (port, "ID_MM_DEVICE_IGNORE"))) {
+            mm_dbg ("[filter] (%s/%s): port filtered: device is blacklisted", subsystem, name);
+            return FALSE;
+        }
+
+        /* Is the device in the manual-only greylist? If so, return if this is an
+         * automatic scan. */
+        if ((self->priv->enabled_rules & MM_FILTER_RULE_TTY_MANUAL_SCAN_ONLY) &&
+            (!manual_scan && mm_kernel_device_get_global_property_as_boolean (port, "ID_MM_DEVICE_MANUAL_SCAN_ONLY"))) {
+            mm_dbg ("[filter] (%s/%s): port filtered: device probed only in manual scan", subsystem, name);
+            return FALSE;
+        }
+
+        /* If the physdev is a 'platform' or 'pnp' device that's not whitelisted, ignore it */
+        physdev_subsystem = mm_kernel_device_get_physdev_subsystem (port);
+        if ((self->priv->enabled_rules & MM_FILTER_RULE_TTY_PLATFORM_DRIVER) &&
+            (!g_strcmp0 (physdev_subsystem, "platform") || !g_strcmp0 (physdev_subsystem, "pnp")) &&
+            (!mm_kernel_device_get_global_property_as_boolean (port, "ID_MM_PLATFORM_DRIVER_PROBE"))) {
+            mm_dbg ("[filter] (%s/%s): port filtered: port's parent platform driver is not whitelisted", subsystem, name);
+            return FALSE;
+        }
+
+        /* Otherwise, TTY probed */
+        return TRUE;
+    }
+
+    /* Otherwise forbidden */
+    mm_dbg ("[filter] (%s/%s) port filtered: forbidden port type", subsystem, name);
+    return FALSE;
+}
+
+/*****************************************************************************/
+
+MMFilter *
+mm_filter_new (MMFilterRule enabled_rules)
+{
+    MMFilter *self;
+
+    self = g_object_new (MM_TYPE_FILTER,
+                         MM_FILTER_ENABLED_RULES, enabled_rules,
+                         NULL);
+
+#define RULE_ENABLED_STR(flag) ((self->priv->enabled_rules & flag) ? "yes" : "no")
+
+    mm_dbg ("[filter] created");
+    mm_dbg ("[filter]   virtual devices forbidden:  %s", RULE_ENABLED_STR (MM_FILTER_RULE_VIRTUAL));
+    mm_dbg ("[filter]   net devices allowed:        %s", RULE_ENABLED_STR (MM_FILTER_RULE_NET));
+    mm_dbg ("[filter]   cdc-wdm devices allowed:    %s", RULE_ENABLED_STR (MM_FILTER_RULE_CDC_WDM));
+    mm_dbg ("[filter]   tty devices allowed:        %s", RULE_ENABLED_STR (MM_FILTER_RULE_TTY));
+    if (self->priv->enabled_rules & MM_FILTER_RULE_TTY) {
+        mm_dbg ("[filter]       virtual consoles filtered: %s", RULE_ENABLED_STR (MM_FILTER_RULE_TTY_VIRTUAL_CONSOLE));
+        mm_dbg ("[filter]       blacklist applied:         %s", RULE_ENABLED_STR (MM_FILTER_RULE_TTY_BLACKLIST));
+        mm_dbg ("[filter]       manual scan only applied:  %s", RULE_ENABLED_STR (MM_FILTER_RULE_TTY_MANUAL_SCAN_ONLY));
+        mm_dbg ("[filter]       platform driver check:     %s", RULE_ENABLED_STR (MM_FILTER_RULE_TTY_PLATFORM_DRIVER));
+    }
+
+#undef RULE_ENABLED_STR
+
+    return self;
+}
+
+static void
+set_property (GObject      *object,
+              guint         prop_id,
+              const GValue *value,
+              GParamSpec   *pspec)
+{
+    MMFilter *self = MM_FILTER (object);
+
+    switch (prop_id) {
+    case PROP_ENABLED_RULES:
+        self->priv->enabled_rules = g_value_get_flags (value);
+        break;
+    default:
+        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+        break;
+    }
+}
+
+static void
+get_property (GObject    *object,
+              guint       prop_id,
+              GValue     *value,
+              GParamSpec *pspec)
+{
+    MMFilter *self = MM_FILTER (object);
+
+    switch (prop_id) {
+    case PROP_ENABLED_RULES:
+        g_value_set_flags (value, self->priv->enabled_rules);
+        break;
+    default:
+        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+        break;
+    }
+}
+
+static void
+mm_filter_init (MMFilter *self)
+{
+    self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self, MM_TYPE_FILTER, MMFilterPrivate);
+}
+
+static void
+mm_filter_class_init (MMFilterClass *klass)
+{
+    GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+    g_type_class_add_private (object_class, sizeof (MMFilterPrivate));
+
+    /* Virtual methods */
+    object_class->set_property = set_property;
+    object_class->get_property = get_property;
+
+    g_object_class_install_property (
+        object_class, PROP_ENABLED_RULES,
+        g_param_spec_flags (MM_FILTER_ENABLED_RULES,
+                            "Enabled rules",
+                            "Mask of rules enabled in the filter",
+                            MM_TYPE_FILTER_RULE,
+                            MM_FILTER_RULE_NONE,
+                            G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));
+}