From: Luca Boccassi <bluca@debian.org>
Date: Thu, 20 Apr 2023 00:24:42 +0000 (+0100)
Subject: sd-bus: check for pid change before closing
X-Git-Tag: v254-rc1~634^2~4
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7d9f6034a93c695c939bb6ae3a626727d5683523;p=thirdparty%2Fsystemd.git

sd-bus: check for pid change before closing

If we try to close after a fork, the FDs will have been cloned
too and we'll assert. This can happen for example in PAM modules.

Avoid the macro and define ref/unref by hand to do the same check.
---

diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index 40dadf67a88..f4f2e350f3c 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -1779,6 +1779,8 @@ _public_ void sd_bus_close(sd_bus *bus) {
 _public_ sd_bus *sd_bus_close_unref(sd_bus *bus) {
         if (!bus)
                 return NULL;
+        if (bus_pid_changed(bus))
+                return NULL;
 
         sd_bus_close(bus);
 
@@ -1788,6 +1790,8 @@ _public_ sd_bus *sd_bus_close_unref(sd_bus *bus) {
 _public_ sd_bus* sd_bus_flush_close_unref(sd_bus *bus) {
         if (!bus)
                 return NULL;
+        if (bus_pid_changed(bus))
+                return NULL;
 
         /* Have to do this before flush() to prevent hang */
         bus_kill_exec(bus);
@@ -1805,7 +1809,30 @@ void bus_enter_closing(sd_bus *bus) {
         bus_set_state(bus, BUS_CLOSING);
 }
 
-DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_bus, sd_bus, bus_free);
+/* Define manually so we can add the PID check */
+_public_ sd_bus *sd_bus_ref(sd_bus *bus) {
+        if (!bus)
+                return NULL;
+        if (bus_pid_changed(bus))
+                return NULL;
+
+        bus->n_ref++;
+
+        return bus;
+}
+
+_public_ sd_bus* sd_bus_unref(sd_bus *bus) {
+        if (!bus)
+                return NULL;
+        if (bus_pid_changed(bus))
+                return NULL;
+
+        assert(bus->n_ref > 0);
+        if (--bus->n_ref > 0)
+                return NULL;
+
+        return bus_free(bus);
+}
 
 _public_ int sd_bus_is_open(sd_bus *bus) {
         if (!bus)