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From 73d0aa81c2575a5c9ae77dcb94da919579014fc0 Mon Sep 17 00:00:00 2001
From: Philip Withnall <pwithnall@endlessos.org>
Date: Fri, 11 Aug 2023 04:13:02 +0000
Subject: [PATCH] gvariant-serialiser: Rework child size calculation
This reduces a few duplicate calls to `g_variant_type_info_query()` and
explains why they’re needed.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #2121
CVE: CVE-2023-32665
Upstream-Status: Backport from [https://gitlab.gnome.org/GNOME/glib/-/commit/73d0aa81c2575a5c9ae77dcb94da919579014fc0]
Signed-off-by: Siddharth Doshi <sdoshi@mvista.com>
---
glib/gvariant-serialiser.c | 31 +++++++++----------------------
1 file changed, 9 insertions(+), 22 deletions(-)
diff --git a/glib/gvariant-serialiser.c b/glib/gvariant-serialiser.c
index 6f9b366..fb75923 100644
--- a/glib/gvariant-serialiser.c
+++ b/glib/gvariant-serialiser.c
@@ -1007,14 +1007,18 @@ gvs_tuple_get_child (GVariantSerialised value,
child.depth = value.depth + 1;
offset_size = gvs_get_offset_size (value.size);
+ /* Ensure the size is set for fixed-sized children, or
+ * g_variant_serialised_check() will fail, even if we return
+ * (child.data == NULL) to indicate an error. */
+ if (member_info->ending_type == G_VARIANT_MEMBER_ENDING_FIXED)
+ g_variant_type_info_query (child.type_info, NULL, &child.size);
+
/* tuples are the only (potentially) fixed-sized containers, so the
* only ones that have to deal with the possibility of having %NULL
* data with a non-zero %size if errors occurred elsewhere.
*/
if G_UNLIKELY (value.data == NULL && value.size != 0)
{
- g_variant_type_info_query (child.type_info, NULL, &child.size);
-
/* this can only happen in fixed-sized tuples,
* so the child must also be fixed sized.
*/
@@ -1032,29 +1036,12 @@ gvs_tuple_get_child (GVariantSerialised value,
else
{
if (offset_size * (member_info->i + 1) > value.size)
- {
- /* if the child is fixed size, return its size.
- * if child is not fixed-sized, return size = 0.
- */
- g_variant_type_info_query (child.type_info, NULL, &child.size);
-
- return child;
- }
+ return child;
}
- gvs_tuple_get_member_bounds (value, index_, offset_size, &start, &end);
-
/* The child should not extend into the offset table. */
- if (index_ != g_variant_type_info_n_members (value.type_info) - 1)
- {
- GVariantSerialised last_child;
- last_child = gvs_tuple_get_child (value,
- g_variant_type_info_n_members (value.type_info) - 1);
- last_end = last_child.data + last_child.size - value.data;
- g_variant_type_info_unref (last_child.type_info);
- }
- else
- last_end = end;
+ gvs_tuple_get_member_bounds (value, index_, offset_size, &start, &end);
+ gvs_tuple_get_member_bounds (value, g_variant_type_info_n_members (value.type_info) - 1, offset_size, NULL, &last_end);
if (start < end && end <= value.size && end <= last_end)
{
--
2.24.4
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