chiark / gitweb /
bus-proxyd: enforce policy for method calls
[elogind.git] / src / bus-proxyd / bus-proxyd.c
index 5d58cd2af4d33b44a0f208918898e03a7a89b3e3..1106986e996cfb303c84b0218da195a59eeb689f 100644 (file)
@@ -51,6 +51,8 @@ static char *arg_command_line_buffer = NULL;
 static bool arg_drop_privileges = false;
 static char **arg_configuration = NULL;
 
+static Hashmap *names_hash = NULL;
+
 static int help(void) {
 
         printf("%s [OPTIONS...]\n\n"
@@ -186,7 +188,7 @@ static int rename_service(sd_bus *a, sd_bus *b) {
         assert(a);
         assert(b);
 
-        r = sd_bus_get_peer_creds(b, SD_BUS_CREDS_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_CMDLINE|SD_BUS_CREDS_COMM, &creds);
+        r = sd_bus_get_owner_creds(b, SD_BUS_CREDS_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_CMDLINE|SD_BUS_CREDS_COMM, &creds);
         if (r < 0)
                 return r;
 
@@ -309,48 +311,6 @@ static int synthesize_name_acquired(sd_bus *a, sd_bus *b, sd_bus_message *m) {
         return sd_bus_send(b, n, NULL);
 }
 
-static int process_policy(sd_bus *a, sd_bus *b, sd_bus_message *m) {
-        _cleanup_bus_message_unref_ sd_bus_message *n = NULL;
-        int r;
-
-        assert(a);
-        assert(b);
-        assert(m);
-
-        if (!a->is_kernel)
-                return 0;
-
-        if (!sd_bus_message_is_method_call(m, "org.freedesktop.DBus.Properties", "GetAll"))
-                return 0;
-
-        if (!streq_ptr(m->path, "/org/gnome/DisplayManager/Slave"))
-                return 0;
-
-        r = sd_bus_message_new_method_errorf(m, &n, SD_BUS_ERROR_ACCESS_DENIED, "gdm, you are stupid");
-        if (r < 0)
-                return r;
-
-        r = bus_message_append_sender(n, "org.freedesktop.DBus");
-        if (r < 0) {
-                log_error("Failed to append sender to gdm reply: %s", strerror(-r));
-                return r;
-        }
-
-        r = bus_seal_synthetic_message(b, n);
-        if (r < 0) {
-                log_error("Failed to seal gdm reply: %s", strerror(-r));
-                return r;
-        }
-
-        r = sd_bus_send(b, n, NULL);
-        if (r < 0) {
-                log_error("Failed to send gdm reply: %s", strerror(-r));
-                return r;
-        }
-
-        return 1;
-}
-
 static int synthetic_driver_send(sd_bus *b, sd_bus_message *m) {
         int r;
 
@@ -454,7 +414,7 @@ static int get_creds_by_name(sd_bus *bus, const char *name, uint64_t mask, sd_bu
 
         assert_return(service_name_is_valid(name), -EINVAL);
 
-        r = sd_bus_get_owner(bus, name, mask, &c);
+        r = sd_bus_get_name_creds(bus, name, mask, &c);
         if (r == -ESRCH || r == -ENXIO)
                 return sd_bus_error_setf(error, SD_BUS_ERROR_NAME_HAS_NO_OWNER, "Name %s is currently not owned by anyone.", name);
         if (r < 0)
@@ -507,7 +467,31 @@ static int peer_is_privileged(sd_bus *bus, sd_bus_message *m) {
         return false;
 }
 
-static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
+static int process_policy(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *policy, const struct ucred *ucred) {
+        int r;
+        char **names_strv;
+
+        assert(a);
+        assert(b);
+        assert(m);
+
+        if (a->is_kernel)
+                return 0;
+
+        r = sd_bus_creds_get_well_known_names(&m->creds, &names_strv);
+        if (r < 0)
+                return r;
+
+        if (!policy_check_recv(policy, ucred, names_hash, m->header->type, m->path, m->interface, m->member))
+                return -EPERM;
+
+        if (!policy_check_send(policy, ucred, names_strv, m->header->type, m->path, m->interface, m->member))
+                return -EPERM;
+
+        return 0;
+}
+
+static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *policy, const struct ucred *ucred) {
         int r;
 
         assert(a);
@@ -644,28 +628,31 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
 
         } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "GetConnectionSELinuxSecurityContext")) {
                 _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 
-                r = get_creds_by_message(a, m, SD_BUS_CREDS_SELINUX_CONTEXT, &creds, NULL);
+                r = get_creds_by_message(a, m, SD_BUS_CREDS_SELINUX_CONTEXT, &creds, &error);
                 if (r < 0)
-                        return synthetic_reply_method_errno(m, r, NULL);
+                        return synthetic_reply_method_errno(m, r, &error);
 
                 return synthetic_reply_method_return(m, "y", creds->label, strlen(creds->label));
 
         } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "GetConnectionUnixProcessID")) {
                 _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 
-                r = get_creds_by_message(a, m, SD_BUS_CREDS_PID, &creds, NULL);
+                r = get_creds_by_message(a, m, SD_BUS_CREDS_PID, &creds, &error);
                 if (r < 0)
-                        return synthetic_reply_method_errno(m, r, NULL);
+                        return synthetic_reply_method_errno(m, r, &error);
 
                 return synthetic_reply_method_return(m, "u", (uint32_t) creds->pid);
 
         } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "GetConnectionUnixUser")) {
                 _cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
 
-                r = get_creds_by_message(a, m, SD_BUS_CREDS_UID, &creds, NULL);
+                r = get_creds_by_message(a, m, SD_BUS_CREDS_UID, &creds, &error);
                 if (r < 0)
-                        return synthetic_reply_method_errno(m, r, NULL);
+                        return synthetic_reply_method_errno(m, r, &error);
 
                 return synthetic_reply_method_return(m, "u", (uint32_t) creds->uid);
 
@@ -673,7 +660,7 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
                 sd_id128_t server_id;
                 char buf[SD_ID128_STRING_MAX];
 
-                r = sd_bus_get_server_id(a, &server_id);
+                r = sd_bus_get_owner_id(a, &server_id);
                 if (r < 0)
                         return synthetic_reply_method_errno(m, r, NULL);
 
@@ -730,8 +717,10 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
         } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "ListQueuedOwners")) {
                 struct kdbus_cmd_name_list cmd = {};
                 struct kdbus_name_list *name_list;
-                struct kdbus_cmd_name *name;
+                struct kdbus_cmd_free cmd_free;
+                struct kdbus_name_info *name;
                 _cleanup_strv_free_ char **owners = NULL;
+                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
                 char *arg0;
                 int err = 0;
 
@@ -742,6 +731,14 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
                 if (!service_name_is_valid(arg0))
                         return synthetic_reply_method_errno(m, -EINVAL, NULL);
 
+                r = sd_bus_get_name_creds(a, arg0, 0, NULL);
+                if (r == -ESRCH || r == -ENXIO) {
+                        sd_bus_error_setf(&error, SD_BUS_ERROR_NAME_HAS_NO_OWNER, "Could not get owners of name '%s': no such name.", arg0);
+                        return synthetic_reply_method_errno(m, r, &error);
+                }
+                if (r < 0)
+                        return synthetic_reply_method_errno(m, r, NULL);
+
                 cmd.flags = KDBUS_NAME_LIST_QUEUED;
                 r = ioctl(a->input_fd, KDBUS_CMD_NAME_LIST, &cmd);
                 if (r < 0)
@@ -755,8 +752,8 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
                         char *n;
 
                         KDBUS_ITEM_FOREACH(item, name, items)
-                                if (item->type == KDBUS_ITEM_NAME)
-                                        entry_name = item->str;
+                                if (item->type == KDBUS_ITEM_OWNED_NAME)
+                                        entry_name = item->name.name;
 
                         if (!streq_ptr(entry_name, arg0))
                                 continue;
@@ -773,7 +770,10 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
                         }
                 }
 
-                r = ioctl(a->input_fd, KDBUS_CMD_FREE, &cmd.offset);
+                cmd_free.flags = 0;
+                cmd_free.offset = cmd.offset;
+
+                r = ioctl(a->input_fd, KDBUS_CMD_FREE, &cmd_free);
                 if (r < 0)
                         return synthetic_reply_method_errno(m, r, NULL);
 
@@ -795,7 +795,7 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
                 if (streq(name, "org.freedesktop.DBus"))
                         return synthetic_reply_method_return(m, "b", true);
 
-                r = sd_bus_get_owner(a, name, 0, NULL);
+                r = sd_bus_get_name_creds(a, name, 0, NULL);
                 if (r < 0 && r != -ESRCH && r != -ENXIO)
                         return synthetic_reply_method_errno(m, r, NULL);
 
@@ -821,6 +821,8 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
                         return synthetic_reply_method_errno(m, r, NULL);
                 }
 
+                hashmap_remove(names_hash, name);
+
                 return synthetic_reply_method_return(m, "u", BUS_NAME_RELEASED);
 
         } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "ReloadConfig")) {
@@ -832,18 +834,30 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
 
         } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "RequestName")) {
                 const char *name;
-                uint32_t flags;
+                uint32_t flags, param;
+                bool in_queue;
 
                 r = sd_bus_message_read(m, "su", &name, &flags);
                 if (r < 0)
                         return synthetic_reply_method_errno(m, r, NULL);
 
+                if (!policy_check_own(policy, ucred, name))
+                        return synthetic_reply_method_errno(m, -EPERM, NULL);
+
                 if (!service_name_is_valid(name))
                         return synthetic_reply_method_errno(m, -EINVAL, NULL);
                 if ((flags & ~(BUS_NAME_ALLOW_REPLACEMENT|BUS_NAME_REPLACE_EXISTING|BUS_NAME_DO_NOT_QUEUE)) != 0)
                         return synthetic_reply_method_errno(m, -EINVAL, NULL);
 
-                r = sd_bus_request_name(a, name, flags);
+                param = 0;
+                if (flags & BUS_NAME_ALLOW_REPLACEMENT)
+                        param |= SD_BUS_NAME_ALLOW_REPLACEMENT;
+                if (flags & BUS_NAME_REPLACE_EXISTING)
+                        param |= SD_BUS_NAME_REPLACE_EXISTING;
+                if (!(flags & BUS_NAME_DO_NOT_QUEUE))
+                        param |= SD_BUS_NAME_QUEUE;
+
+                r = sd_bus_request_name(a, name, param);
                 if (r < 0) {
                         if (r == -EEXIST)
                                 return synthetic_reply_method_return(m, "u", BUS_NAME_EXISTS);
@@ -852,7 +866,13 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
                         return synthetic_reply_method_errno(m, r, NULL);
                 }
 
-                if (r == 0)
+                in_queue = (r == 0);
+
+                r = hashmap_put(names_hash, name, NULL);
+                if (r < 0)
+                        return synthetic_reply_method_errno(m, r, NULL);
+
+                if (in_queue)
                         return synthetic_reply_method_return(m, "u", BUS_NAME_IN_QUEUE);
 
                 return synthetic_reply_method_return(m, "u", BUS_NAME_PRIMARY_OWNER);
@@ -871,7 +891,7 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
                 if (flags != 0)
                         return synthetic_reply_method_errno(m, -EINVAL, NULL);
 
-                r = sd_bus_get_owner(a, name, 0, NULL);
+                r = sd_bus_get_name_creds(a, name, 0, NULL);
                 if (r >= 0 || streq(name, "org.freedesktop.DBus"))
                         return synthetic_reply_method_return(m, "u", BUS_START_REPLY_ALREADY_RUNNING);
                 if (r != -ESRCH)
@@ -962,7 +982,7 @@ static int process_driver(sd_bus *a, sd_bus *b, sd_bus_message *m) {
         }
 }
 
-static int process_hello(sd_bus *a, sd_bus *b, sd_bus_message *m, bool *got_hello) {
+static int process_hello(sd_bus *a, sd_bus *b, sd_bus_message *m, Policy *policy, const struct ucred *ucred, bool *got_hello) {
         _cleanup_bus_message_unref_ sd_bus_message *n = NULL;
         bool is_hello;
         int r;
@@ -994,6 +1014,11 @@ static int process_hello(sd_bus *a, sd_bus *b, sd_bus_message *m, bool *got_hell
                 return -EIO;
         }
 
+        if (!policy_check_hello(policy, ucred)) {
+                log_error("Policy denied HELLO");
+                return -EPERM;
+        }
+
         *got_hello = true;
 
         if (!a->is_kernel)
@@ -1142,8 +1167,8 @@ int main(int argc, char *argv[]) {
                 sd_is_socket(out_fd, AF_UNIX, 0, 0) > 0;
 
         if (is_unix) {
-                getpeercred(in_fd, &ucred);
-                getpeersec(in_fd, &peersec);
+                (void) getpeercred(in_fd, &ucred);
+                (void) getpeersec(in_fd, &peersec);
         }
 
         if (arg_drop_privileges) {
@@ -1162,13 +1187,19 @@ int main(int argc, char *argv[]) {
                         goto finish;
         }
 
+        names_hash = hashmap_new(&string_hash_ops);
+        if (!names_hash) {
+                log_oom();
+                goto finish;
+        }
+
         r = sd_bus_new(&a);
         if (r < 0) {
                 log_error("Failed to allocate bus: %s", strerror(-r));
                 goto finish;
         }
 
-        r = sd_bus_set_name(a, "sd-proxy");
+        r = sd_bus_set_description(a, "sd-proxy");
         if (r < 0) {
                 log_error("Failed to set bus name: %s", strerror(-r));
                 goto finish;
@@ -1206,7 +1237,7 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
-        r = sd_bus_get_server_id(a, &server_id);
+        r = sd_bus_get_owner_id(a, &server_id);
         if (r < 0) {
                 log_error("Failed to get server ID: %s", strerror(-r));
                 goto finish;
@@ -1377,7 +1408,7 @@ int main(int argc, char *argv[]) {
                                 goto finish;
                         }
 
-                        k = process_hello(a, b, m, &got_hello);
+                        k = process_hello(a, b, m, &policy, &ucred, &got_hello);
                         if (k < 0) {
                                 r = k;
                                 log_error("Failed to process HELLO: %s", strerror(-r));
@@ -1387,14 +1418,7 @@ int main(int argc, char *argv[]) {
                         if (k > 0)
                                 r = k;
                         else {
-                                k = process_policy(a, b, m);
-                                if (k < 0) {
-                                        r = k;
-                                        log_error("Failed to process policy: %s", strerror(-r));
-                                        goto finish;
-                                }
-
-                                k = process_driver(a, b, m);
+                                k = process_driver(a, b, m, &policy, &ucred);
                                 if (k < 0) {
                                         r = k;
                                         log_error("Failed to process driver calls: %s", strerror(-r));
@@ -1404,6 +1428,13 @@ int main(int argc, char *argv[]) {
                                 if (k > 0)
                                         r = k;
                                 else {
+                                        k = process_policy(a, b, m, &policy, &ucred);
+                                        if (k < 0) {
+                                                r = k;
+                                                log_error("Failed to process policy: %s", strerror(-r));
+                                                goto finish;
+                                        }
+
                                         k = sd_bus_send(a, m, NULL);
                                         if (k < 0) {
                                                 if (k == -ECONNRESET)
@@ -1490,6 +1521,7 @@ finish:
 
         policy_free(&policy);
         strv_free(arg_configuration);
+        hashmap_free(names_hash);
         free(arg_address);
 
         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;