[rpms/glib2] cve-2026-58016-f44: gthreadedresolver: Fix race between source callbacks and finalize (fedora#2235890)

[Zephyr Lykos <git@mochaa.ws>]

A new commit has been pushed.

Repo   : rpms/glib2
Branch : cve-2026-58016-f44
Commit : 2eebf802dd2bd192e30d2acca9779821d35da967
Author : Zephyr Lykos <git@mochaa.ws>
Date   : 2023-09-27T16:31:55+08:00
Stats  : +136/-0 in 2 file(s)
URL    : https://src.fedoraproject.org/rpms/glib2/c/2eebf802dd2bd192e30d2acca9779821d35da967?branch=cve-2026-58016-f44

Log:
gthreadedresolver: Fix race between source callbacks and finalize (fedora#2235890)

---
diff --git a/glib2.spec b/glib2.spec
index 024b513..50c25c6 100644
--- a/glib2.spec
+++ b/glib2.spec
@@ -16,6 +16,10 @@ Patch:          gnutls-hmac.patch
 # the baremetal Docker is updated there i.e. lets be a little bit pragmatic...
 Patch:          gspawn-eperm.patch
 
+# https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3575
+# not released yet
+Patch:          gthreadedresolver-race.patch
+
 BuildRequires:  gcc
 BuildRequires:  gcc-c++
 BuildRequires:  gettext

diff --git a/gthreadedresolver-race.patch b/gthreadedresolver-race.patch
new file mode 100644
index 0000000..911b78c
--- /dev/null
+++ b/gthreadedresolver-race.patch
@@ -0,0 +1,132 @@
+From 82c764ce2e42f0d1032627dabcbd742d5f2bd8fa Mon Sep 17 00:00:00 2001
+From: Philip Withnall <philip@tecnocode.co.uk>
+Date: Mon, 11 Sep 2023 16:02:15 +0100
+Subject: [PATCH] gthreadedresolver: Fix race between source callbacks and
+ finalize
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+I had thought that because `g_source_destroy()` was called for the two
+sources (cancel and timeout) in the `GTask` finalize function for a
+threaded resolver operation, that it would be fine to use a plain
+pointer in the source callbacks to point to the `GTask`.
+
+That turns out to not be true: because the source callbacks are executed
+in the GLib worker thread, and the `GTask` can be finalized in another
+thread, it’s possible for a source callback (e.g. `cancelled_cb()`) to
+be scheduled in the worker thread, then for the `GTask` to be finalized,
+and then the source callback to continue execution and find itself
+doing a use-after-free.
+
+Fix that by using a weak ref to the `GTask` in the source callbacks,
+rather than a plain pointer.
+
+Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
+
+Fixes: #3105
+---
+ gio/gthreadedresolver.c | 43 +++++++++++++++++++++++++++++++++++------
+ 1 file changed, 37 insertions(+), 6 deletions(-)
+
+diff --git a/gio/gthreadedresolver.c b/gio/gthreadedresolver.c
+index 2d94531bfd..c7a567549f 100644
+--- a/gio/gthreadedresolver.c
++++ b/gio/gthreadedresolver.c
+@@ -1422,10 +1422,17 @@ lookup_records_finish (GResolver     *resolver,
+ static gboolean
+ timeout_cb (gpointer user_data)
+ {
+-  GTask *task = G_TASK (user_data);
+-  LookupData *data = g_task_get_task_data (task);
++  GWeakRef *weak_task = user_data;
++  GTask *task = NULL;  /* (owned) */
++  LookupData *data;
+   gboolean should_return;
+ 
++  task = g_weak_ref_get (weak_task);
++  if (task == NULL)
++    return G_SOURCE_REMOVE;
++
++  data = g_task_get_task_data (task);
++
+   g_mutex_lock (&data->lock);
+ 
+   should_return = g_atomic_int_compare_and_exchange (&data->will_return, NOT_YET, TIMED_OUT);
+@@ -1443,6 +1450,8 @@ timeout_cb (gpointer user_data)
+   g_cond_broadcast (&data->cond);
+   g_mutex_unlock (&data->lock);
+ 
++  g_object_unref (task);
++
+   return G_SOURCE_REMOVE;
+ }
+ 
+@@ -1452,10 +1461,17 @@ static gboolean
+ cancelled_cb (GCancellable *cancellable,
+               gpointer      user_data)
+ {
+-  GTask *task = G_TASK (user_data);
+-  LookupData *data = g_task_get_task_data (task);
++  GWeakRef *weak_task = user_data;
++  GTask *task = NULL;  /* (owned) */
++  LookupData *data;
+   gboolean should_return;
+ 
++  task = g_weak_ref_get (weak_task);
++  if (task == NULL)
++    return G_SOURCE_REMOVE;
++
++  data = g_task_get_task_data (task);
++
+   g_mutex_lock (&data->lock);
+ 
+   g_assert (g_cancellable_is_cancelled (cancellable));
+@@ -1473,9 +1489,18 @@ cancelled_cb (GCancellable *cancellable,
+   g_cond_broadcast (&data->cond);
+   g_mutex_unlock (&data->lock);
+ 
++  g_object_unref (task);
++
+   return G_SOURCE_REMOVE;
+ }
+ 
++static void
++weak_ref_clear_and_free (GWeakRef *weak_ref)
++{
++  g_weak_ref_clear (weak_ref);
++  g_free (weak_ref);
++}
++
+ static void
+ run_task_in_thread_pool_async (GThreadedResolver *self,
+                                GTask             *task)
+@@ -1490,17 +1515,23 @@ run_task_in_thread_pool_async (GThreadedResolver *self,
+ 
+   if (timeout_ms != 0)
+     {
++      GWeakRef *weak_task = g_new0 (GWeakRef, 1);
++      g_weak_ref_set (weak_task, task);
++
+       data->timeout_source = g_timeout_source_new (timeout_ms);
+       g_source_set_static_name (data->timeout_source, "[gio] threaded resolver timeout");
+-      g_source_set_callback (data->timeout_source, G_SOURCE_FUNC (timeout_cb), task, NULL);
++      g_source_set_callback (data->timeout_source, G_SOURCE_FUNC (timeout_cb), g_steal_pointer (&weak_task), (GDestroyNotify) weak_ref_clear_and_free);
+       g_source_attach (data->timeout_source, GLIB_PRIVATE_CALL (g_get_worker_context) ());
+     }
+ 
+   if (cancellable != NULL)
+     {
++      GWeakRef *weak_task = g_new0 (GWeakRef, 1);
++      g_weak_ref_set (weak_task, task);
++
+       data->cancellable_source = g_cancellable_source_new (cancellable);
+       g_source_set_static_name (data->cancellable_source, "[gio] threaded resolver cancellable");
+-      g_source_set_callback (data->cancellable_source, G_SOURCE_FUNC (cancelled_cb), task, NULL);
++      g_source_set_callback (data->cancellable_source, G_SOURCE_FUNC (cancelled_cb), g_steal_pointer (&weak_task), (GDestroyNotify) weak_ref_clear_and_free);
+       g_source_attach (data->cancellable_source, GLIB_PRIVATE_CALL (g_get_worker_context) ());
+     }
+ 
+-- 
+GitLab
+