bus-proxyd: make policy checks optional

Retrieve the bus owner creds, and when the uid matches the current user's
uid and is non-null, don't check the bus policy.

1 files changed, 25 insertions, 4 deletions

diff --git a/src/bus-proxyd/bus-proxyd.c b/src/bus-proxyd/bus-proxyd.c
index 3fc341eaed..c5aeaacf42 100644
--- a/src/bus-proxyd/bus-proxyd.c
+++ b/src/bus-proxyd/bus-proxyd.c
@@ -475,6 +475,9 @@ static int process_policy(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *polic
         assert(b);
         assert(m);
 
+        if (!policy)
+                return 0;
+
         if (b->is_kernel) {
 
                 /* The message came from the kernel, and is sent to our legacy client. */
@@ -849,7 +852,7 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *polic
                 if (r < 0)
                         return synthetic_reply_method_errno(m, r, NULL);
 
-                if (!policy_check_own(policy, ucred, name))
+                if (policy && !policy_check_own(policy, ucred, name))
                         return synthetic_reply_method_errno(m, -EPERM, NULL);
 
                 if (!service_name_is_valid(name))
@@ -1022,7 +1025,7 @@ static int process_hello(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *policy
                 return -EIO;
         }
 
-        if (!policy_check_hello(policy, ucred)) {
+        if (policy && !policy_check_hello(policy, ucred)) {
                 log_error("Policy denied HELLO");
                 return -EPERM;
         }
@@ -1133,6 +1136,7 @@ static int patch_sender(sd_bus *a, sd_bus_message *m) {
 
 int main(int argc, char *argv[]) {
 
+        _cleanup_bus_creds_unref_ sd_bus_creds *bus_creds = NULL;
         _cleanup_bus_close_unref_ sd_bus *a = NULL, *b = NULL;
         sd_id128_t server_id;
         int r, in_fd, out_fd;
@@ -1251,6 +1255,12 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
+        r = sd_bus_get_owner_creds(a, SD_BUS_CREDS_UID, &bus_creds);
+        if (r < 0) {
+                log_error("Failed to get bus creds: %s", strerror(-r));
+                goto finish;
+        }
+
         r = sd_bus_new(&b);
         if (r < 0) {
                 log_error("Failed to allocate bus: %s", strerror(-r));
@@ -1410,13 +1420,21 @@ int main(int argc, char *argv[]) {
                 }
 
                 if (m) {
+                        Policy *p = NULL;
+                        uid_t uid;
+
+                        assert_se(sd_bus_creds_get_uid(bus_creds, &uid) == 0);
+
+                        if (uid == 0 || uid != ucred.uid)
+                                p = &policy;
+
                         /* We officially got EOF, let's quit */
                         if (sd_bus_message_is_signal(m, "org.freedesktop.DBus.Local", "Disconnected")) {
                                 r = 0;
                                 goto finish;
                         }
 
-                        k = process_hello(a, b, m, &policy, &ucred, &got_hello);
+                        k = process_hello(a, b, m, p, &ucred, &got_hello);
                         if (k < 0) {
                                 r = k;
                                 log_error("Failed to process HELLO: %s", strerror(-r));
@@ -1426,7 +1444,7 @@ int main(int argc, char *argv[]) {
                         if (k > 0)
                                 r = k;
                         else {
-                                k = process_driver(a, b, m, &policy, &ucred);
+                                k = process_driver(a, b, m, p, &ucred);
                                 if (k < 0) {
                                         r = k;
                                         log_error("Failed to process driver calls: %s", strerror(-r));
@@ -1448,6 +1466,9 @@ int main(int argc, char *argv[]) {
                                                 if (k == -ECONNRESET)
                                                         r = 0;
                                                 else {
+
+                                                k = process_policy(a, b, m, p, &ucred);
+                                                if (k < 0) {
                                                         r = k;
                                                         log_error("Failed to send message: %s", strerror(-r));
                                                 }