Merge pull request #244 from poettering/sdbus-suppress-local

sd-bus: suppress installing local bus matches server side

6 files changed, 88 insertions, 13 deletions

diff --git a/src/libsystemd/sd-bus/bus-internal.h b/src/libsystemd/sd-bus/bus-internal.h
index 88c058889a..c3e20ee1bf 100644
--- a/src/libsystemd/sd-bus/bus-internal.h
+++ b/src/libsystemd/sd-bus/bus-internal.h
@@ -141,6 +141,7 @@ struct sd_bus_slot {
         void *userdata;
         BusSlotType type:5;
         bool floating:1;
+        bool match_added:1;
         char *description;
 
         LIST_FIELDS(sd_bus_slot, slots);
diff --git a/src/libsystemd/sd-bus/bus-match.c b/src/libsystemd/sd-bus/bus-match.c
index 7c5264fad4..132b37526e 100644
--- a/src/libsystemd/sd-bus/bus-match.c
+++ b/src/libsystemd/sd-bus/bus-match.c
@@ -1149,3 +1149,40 @@ void bus_match_dump(struct bus_match_node *node, unsigned level) {
         for (c = node->child; c; c = c->next)
                 bus_match_dump(c, level + 1);
 }
+
+enum bus_match_scope bus_match_get_scope(const struct bus_match_component *components, unsigned n_components) {
+        bool found_driver = false;
+        unsigned i;
+
+        if (n_components <= 0)
+                return BUS_MATCH_GENERIC;
+
+        assert(components);
+
+        /* Checks whether the specified match can only match the
+         * pseudo-service for local messages, which we detect by
+         * sender, interface or path. If a match is not restricted to
+         * local messages, then we check if it only matches on the
+         * driver. */
+
+        for (i = 0; i < n_components; i++) {
+                const struct bus_match_component *c = components + i;
+
+                if (c->type == BUS_MATCH_SENDER) {
+                        if (streq_ptr(c->value_str, "org.freedesktop.DBus.Local"))
+                                return BUS_MATCH_LOCAL;
+
+                        if (streq_ptr(c->value_str, "org.freedesktop.DBus"))
+                                found_driver = true;
+                }
+
+                if (c->type == BUS_MATCH_INTERFACE && streq_ptr(c->value_str, "org.freedesktop.DBus.Local"))
+                        return BUS_MATCH_LOCAL;
+
+                if (c->type == BUS_MATCH_PATH && streq_ptr(c->value_str, "/org/freedesktop/DBus/Local"))
+                        return BUS_MATCH_LOCAL;
+        }
+
+        return found_driver ? BUS_MATCH_DRIVER : BUS_MATCH_GENERIC;
+
+}
diff --git a/src/libsystemd/sd-bus/bus-match.h b/src/libsystemd/sd-bus/bus-match.h
index af5f65d073..56516be9fa 100644
--- a/src/libsystemd/sd-bus/bus-match.h
+++ b/src/libsystemd/sd-bus/bus-match.h
@@ -73,6 +73,12 @@ struct bus_match_component {
         char *value_str;
 };
 
+enum bus_match_scope {
+        BUS_MATCH_GENERIC,
+        BUS_MATCH_LOCAL,
+        BUS_MATCH_DRIVER,
+};
+
 int bus_match_run(sd_bus *bus, struct bus_match_node *root, sd_bus_message *m);
 
 int bus_match_add(struct bus_match_node *root, struct bus_match_component *components, unsigned n_components, struct match_callback *callback);
@@ -90,3 +96,5 @@ enum bus_match_node_type bus_match_node_type_from_string(const char *k, size_t n
 int bus_match_parse(const char *match, struct bus_match_component **_components, unsigned *_n_components);
 void bus_match_parse_free(struct bus_match_component *components, unsigned n_components);
 char *bus_match_to_string(struct bus_match_component *components, unsigned n_components);
+
+enum bus_match_scope bus_match_get_scope(const struct bus_match_component *components, unsigned n_components);
diff --git a/src/libsystemd/sd-bus/bus-slot.c b/src/libsystemd/sd-bus/bus-slot.c
index 8060e9882c..c452477566 100644
--- a/src/libsystemd/sd-bus/bus-slot.c
+++ b/src/libsystemd/sd-bus/bus-slot.c
@@ -89,7 +89,7 @@ void bus_slot_disconnect(sd_bus_slot *slot) {
 
         case BUS_MATCH_CALLBACK:
 
-                if (slot->bus->bus_client)
+                if (slot->match_added)
                         bus_remove_match_internal(slot->bus, slot->match_callback.match_string, slot->match_callback.cookie);
 
                 slot->bus->match_callbacks_modified = true;
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index 2805b29839..0881b4779a 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -2952,22 +2952,35 @@ _public_ int sd_bus_add_match(
         s->match_callback.cookie = ++bus->match_cookie;
 
         if (bus->bus_client) {
+                enum bus_match_scope scope;
 
-                if (!bus->is_kernel) {
-                        /* When this is not a kernel transport, we
-                         * store the original match string, so that we
-                         * can use it to remove the match again */
+                scope = bus_match_get_scope(components, n_components);
 
-                        s->match_callback.match_string = strdup(match);
-                        if (!s->match_callback.match_string) {
-                                r = -ENOMEM;
-                                goto finish;
+                /* Do not install server-side matches for matches
+                 * against the local service, interface or bus
+                 * path. Also, when on kdbus don't install driver
+                 * matches server side. */
+                if (scope == BUS_MATCH_GENERIC ||
+                    (!bus->is_kernel && scope == BUS_MATCH_DRIVER)) {
+
+                        if (!bus->is_kernel) {
+                                /* When this is not a kernel transport, we
+                                 * store the original match string, so that we
+                                 * can use it to remove the match again */
+
+                                s->match_callback.match_string = strdup(match);
+                                if (!s->match_callback.match_string) {
+                                        r = -ENOMEM;
+                                        goto finish;
+                                }
                         }
-                }
 
-                r = bus_add_match_internal(bus, s->match_callback.match_string, components, n_components, s->match_callback.cookie);
-                if (r < 0)
-                        goto finish;
+                        r = bus_add_match_internal(bus, s->match_callback.match_string, components, n_components, s->match_callback.cookie);
+                        if (r < 0)
+                                goto finish;
+
+                        s->match_added = true;
+                }
         }
 
         bus->match_callbacks_modified = true;
diff --git a/src/libsystemd/sd-bus/test-bus-match.c b/src/libsystemd/sd-bus/test-bus-match.c
index 40c67046da..a1687b1c7b 100644
--- a/src/libsystemd/sd-bus/test-bus-match.c
+++ b/src/libsystemd/sd-bus/test-bus-match.c
@@ -77,6 +77,15 @@ static int match_add(sd_bus_slot *slots, struct bus_match_node *root, const char
         return r;
 }
 
+static void test_match_scope(const char *match, enum bus_match_scope scope) {
+        struct bus_match_component *components = NULL;
+        unsigned n_components = 0;
+
+        assert_se(bus_match_parse(match, &components, &n_components) >= 0);
+        assert_se(bus_match_get_scope(components, n_components) == scope);
+        bus_match_parse_free(components, n_components);
+}
+
 int main(int argc, char *argv[]) {
         struct bus_match_node root = {
                 .type = BUS_MATCH_ROOT,
@@ -142,5 +151,12 @@ int main(int argc, char *argv[]) {
 
         bus_match_free(&root);
 
+        test_match_scope("interface='foobar'", BUS_MATCH_GENERIC);
+        test_match_scope("", BUS_MATCH_GENERIC);
+        test_match_scope("interface='org.freedesktop.DBus.Local'", BUS_MATCH_LOCAL);
+        test_match_scope("sender='org.freedesktop.DBus.Local'", BUS_MATCH_LOCAL);
+        test_match_scope("member='gurke',path='/org/freedesktop/DBus/Local'", BUS_MATCH_LOCAL);
+        test_match_scope("arg2='piep',sender='org.freedesktop.DBus',member='waldo'", BUS_MATCH_DRIVER);
+
         return 0;
 }