From 476afb1d08513cb74cd1d28490c5e028c70f67c2 Mon Sep 17 00:00:00 2001
From: Colin Walters <walters@verbum.org>
Date: Wed, 15 Feb 2023 11:44:18 -0500
Subject: [PATCH] daemon: Use a socket in `/run`, require non-abstract

This fixes https://bugzilla.redhat.com/show_bug.cgi?id=2169622

The new glib changed to use non-abstract sockets by default,
which broke us because we'd slowly grown more isolation, specifically
the daemon has been using `PrivateTmp` for a while and we'd
been relying on abstract sockets to pierce that.

Change to use `/run` which should always be shared by client
and daemon.  While we're here, make it a well-known static path
because there can be only one transaction at a time.

We also do need to explicitly make the socket world-accessible
because that was the semantics of the previous abstract socket.

Also, plug leaks here by ensuring we call `g_dbus_server_stop()`.

(But really we should also change this to be crash safe, probably
 with a temporary directory, but that's a larger change)
---
 src/daemon/rpmostreed-transaction.cxx  | 26 ++++++++++++++++++++++----
 tests/vmcheck/test-cached-rpm-diffs.sh |  3 ++-
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/src/daemon/rpmostreed-transaction.cxx b/src/daemon/rpmostreed-transaction.cxx
index 6d184f9c..f50db494 100644
--- a/src/daemon/rpmostreed-transaction.cxx
+++ b/src/daemon/rpmostreed-transaction.cxx
@@ -31,6 +31,10 @@
 #include "rpmostreed-sysroot.h"
 #include "rpmostreed-transaction.h"
 
+// The well-known transaction socket path.  This used to be randomly
+// generated, but there's no point because there can be at most one transaction.
+#define CLIENT_TRANSACTION_PATH "/run/rpm-ostree-transaction.sock"
+
 struct _RpmostreedTransactionPrivate
 {
   GDBusMethodInvocation *invocation;
@@ -482,6 +486,10 @@ transaction_dispose (GObject *object)
   g_clear_object (&priv->invocation);
   g_clear_object (&priv->cancellable);
   g_clear_object (&priv->sysroot);
+  if (priv->server)
+    {
+      g_dbus_server_stop (priv->server);
+    }
   g_clear_object (&priv->server);
   g_clear_pointer (&priv->sysroot_path, g_free);
 
@@ -578,14 +586,24 @@ transaction_initable_init (GInitable *initable, GCancellable *cancellable, GErro
     priv->cancellable = (GCancellable *)g_object_ref (cancellable);
 
   /* Set up a private D-Bus server over which to emit
-   * progress and informational messages to the caller. */
-
+   * progress and informational messages to the caller.
+   * The socket needs to be non-abstract (for security reasons so it can't
+   * be accessed outside of our namespace)
+   * and it needs to be in `/run` so that it can be found by the client;
+   * the default daemon sandboxing uses PrivateTmp= implicitly.
+   */
   g_autofree char *guid = g_dbus_generate_guid ();
-  priv->server = g_dbus_server_new_sync ("unix:tmpdir=/tmp/rpm-ostree", G_DBUS_SERVER_FLAGS_NONE,
-                                         guid, NULL, cancellable, error);
+  if (unlink (CLIENT_TRANSACTION_PATH) < 0 && errno != ENOENT)
+    return glnx_throw_errno_prefix (error, "Failed to unlink %s", CLIENT_TRANSACTION_PATH);
+  g_autofree char *addr = g_strdup_printf ("unix:path=%s", CLIENT_TRANSACTION_PATH);
+  priv->server
+      = g_dbus_server_new_sync (addr, G_DBUS_SERVER_FLAGS_NONE, guid, NULL, cancellable, error);
   if (priv->server == NULL)
     return FALSE;
 
+  if (chmod (CLIENT_TRANSACTION_PATH, 0666) < 0)
+    return glnx_throw_errno_prefix (error, "Failed to chmod %s", CLIENT_TRANSACTION_PATH);
+
   g_signal_connect_object (priv->server, "new-connection",
                            G_CALLBACK (transaction_new_connection_cb), self,
                            static_cast<GConnectFlags> (0));
diff --git a/tests/vmcheck/test-cached-rpm-diffs.sh b/tests/vmcheck/test-cached-rpm-diffs.sh
index 05c0f3f0..55ab2424 100755
--- a/tests/vmcheck/test-cached-rpm-diffs.sh
+++ b/tests/vmcheck/test-cached-rpm-diffs.sh
@@ -68,7 +68,7 @@ run_transaction() {
   sig=$1; shift
   args=$1; shift
   cur=$(vm_get_journal_cursor)
-  vm_run_container --privileged -i -v /var/run/dbus:/var/run/dbus --net=host -- \
+  vm_run_container --privileged -i -v /run:/run/host/run -v /var/run/dbus:/var/run/dbus --net=host -- \
     /bin/bash << EOF
 set -xeuo pipefail
 dnf install -y python3-dbus
@@ -77,6 +77,7 @@ import dbus
 addr = dbus.SystemBus().call_blocking(
   "org.projectatomic.rpmostree1", "$ospath", "org.projectatomic.rpmostree1.OS",
   "$method", "$sig", ($args))
+addr = addr.replace("/run/", "/run/host/run/")
 t = dbus.connection.Connection(addr)
 t.call_blocking(
   "org.projectatomic.rpmostree1", "/",
-- 
2.39.0