logind: open up most bus calls for unpriviliged processes, using PolicyKit

Also, allow clients to alter their own objects without any further
priviliges. i.e. this allows clients to kill and lock their own sessions
without involving PK.

2 files changed, 33 insertions, 2 deletions

diff --git a/src/libsystemd/sd-bus/bus-util.c b/src/libsystemd/sd-bus/bus-util.c
index 52d4ebe611..3bd6b8db9a 100644
--- a/src/libsystemd/sd-bus/bus-util.c
+++ b/src/libsystemd/sd-bus/bus-util.c
@@ -190,11 +190,33 @@ int bus_name_has_owner(sd_bus *c, const char *name, sd_bus_error *error) {
         return has_owner;
 }
 
+static int check_good_user(sd_bus_message *m, uid_t good_user) {
+        _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
+        uid_t sender_uid;
+        int r;
+
+        assert(m);
+
+        if (good_user == UID_INVALID)
+                return 0;
+
+        r = sd_bus_query_sender_creds(m, SD_BUS_CREDS_EUID, &creds);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_creds_get_euid(creds, &sender_uid);
+        if (r < 0)
+                return r;
+
+        return sender_uid == good_user;
+}
+
 int bus_verify_polkit(
                 sd_bus_message *call,
                 int capability,
                 const char *action,
                 bool interactive,
+                uid_t good_user,
                 bool *_challenge,
                 sd_bus_error *e) {
 
@@ -203,6 +225,10 @@ int bus_verify_polkit(
         assert(call);
         assert(action);
 
+        r = check_good_user(call, good_user);
+        if (r != 0)
+                return r;
+
         r = sd_bus_query_sender_privilege(call, capability);
         if (r < 0)
                 return r;
@@ -330,6 +356,7 @@ int bus_verify_polkit_async(
                 int capability,
                 const char *action,
                 bool interactive,
+                uid_t good_user,
                 Hashmap **registry,
                 sd_bus_error *error) {
 
@@ -347,6 +374,10 @@ int bus_verify_polkit_async(
         assert(action);
         assert(registry);
 
+        r = check_good_user(call, good_user);
+        if (r != 0)
+                return r;
+
 #ifdef ENABLE_POLKIT
         q = hashmap_get(*registry, call);
         if (q) {
diff --git a/src/libsystemd/sd-bus/bus-util.h b/src/libsystemd/sd-bus/bus-util.h
index e8a97cef9e..e9efa3597c 100644
--- a/src/libsystemd/sd-bus/bus-util.h
+++ b/src/libsystemd/sd-bus/bus-util.h
@@ -70,9 +70,9 @@ int bus_name_has_owner(sd_bus *c, const char *name, sd_bus_error *error);
 
 int bus_check_peercred(sd_bus *c);
 
-int bus_verify_polkit(sd_bus_message *call, int capability, const char *action, bool interactive, bool *_challenge, sd_bus_error *e);
+int bus_verify_polkit(sd_bus_message *call, int capability, const char *action, bool interactive, uid_t good_user, bool *_challenge, sd_bus_error *e);
 
-int bus_verify_polkit_async(sd_bus_message *call, int capability, const char *action, bool interactive, Hashmap **registry, sd_bus_error *error);
+int bus_verify_polkit_async(sd_bus_message *call, int capability, const char *action, bool interactive, uid_t good_user, Hashmap **registry, sd_bus_error *error);
 void bus_verify_polkit_async_registry_free(Hashmap *registry);
 
 int bus_open_system_systemd(sd_bus **_bus);