diff --git a/system/base/glib2/files/0002-gthreadedresolver-Fix-race-between-source-callbacks-.patch b/system/base/glib2/files/0002-gthreadedresolver-Fix-race-between-source-callbacks-.patch new file mode 100644 index 00000000..17de85b1 --- /dev/null +++ b/system/base/glib2/files/0002-gthreadedresolver-Fix-race-between-source-callbacks-.patch @@ -0,0 +1,158 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: Philip Withnall +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 + +Fixes: #3105 +--- + gio/gthreadedresolver.c | 43 +++++++++++++++++++++++++++++++++++------ + 1 file changed, 37 insertions(+), 6 deletions(-) + +diff --git a/gio/gthreadedresolver.c b/gio/gthreadedresolver.c +index 2d94531bfda3..c7a567549f28 100644 +--- a/gio/gthreadedresolver.c ++++ b/gio/gthreadedresolver.c +@@ -1422,85 +1422,116 @@ 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); + g_clear_pointer (&data->timeout_source, g_source_unref); + + g_mutex_unlock (&data->lock); + + if (should_return) + g_task_return_new_error (task, G_IO_ERROR, G_IO_ERROR_TIMED_OUT, + _("Socket I/O timed out")); + + /* Signal completion of the task. */ + g_mutex_lock (&data->lock); + data->has_returned = TRUE; + g_cond_broadcast (&data->cond); + g_mutex_unlock (&data->lock); + ++ g_object_unref (task); ++ + return G_SOURCE_REMOVE; + } + + /* Will be called in the GLib worker thread, so must lock all accesses to shared + * data. */ + 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)); + should_return = g_atomic_int_compare_and_exchange (&data->will_return, NOT_YET, CANCELLED); + g_clear_pointer (&data->cancellable_source, g_source_unref); + + g_mutex_unlock (&data->lock); + + if (should_return) + g_task_return_error_if_cancelled (task); + + /* Signal completion of the task. */ + g_mutex_lock (&data->lock); + data->has_returned = TRUE; + 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) + { + LookupData *data = g_task_get_task_data (task); + guint timeout_ms = g_resolver_get_timeout (G_RESOLVER (self)); + GCancellable *cancellable = g_task_get_cancellable (task); + + g_mutex_lock (&data->lock); + + g_thread_pool_push (self->thread_pool, g_object_ref (task), NULL); + + 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) ()); + } + diff --git a/system/base/glib2/pspec.xml b/system/base/glib2/pspec.xml index b2b820eb..c7bd1389 100644 --- a/system/base/glib2/pspec.xml +++ b/system/base/glib2/pspec.xml @@ -28,6 +28,7 @@ noisy-glib-compile-schemas.diff glib-2.68.2-skip_warnings-1.patch glib2.patch + 0002-gthreadedresolver-Fix-race-between-source-callbacks-.patch multilib.diff @@ -141,6 +142,13 @@ + + 2023-10-13 + 2.78.0 + Rebuild. + Mustafa Cinasal + muscnsl@gmail.com + 2023-09-08 2.78.0