[glib/2528-dbus-message-truncation: 3/3] gdbusmessage: Remove arbitrary restriction on minimum D-Bus blob length

[Philip Withnall <pwithnall src gnome org>]

commit 1f8390c0027ea217a906d94e18837a486c98d680
Author: Philip Withnall <pwithnall endlessos org>
Date:   Tue Nov 23 12:57:29 2021 +0000

    gdbusmessage: Remove arbitrary restriction on minimum D-Bus blob length
    
    The code in `g_dbus_message_new_from_blob()` has now been fixed to
    correctly error out on all truncated messages, so there’s no need for an
    arbitrary programmer error if the input is too short to contain a valid
    D-Bus message header.
    
    Signed-off-by: Philip Withnall <pwithnall endlessos org>
    
    Helps: #2528

 gio/gdbusmessage.c              | 1 -
 gio/tests/gdbus-serialization.c | 6 ++----
 2 files changed, 2 insertions(+), 5 deletions(-)
---
diff --git a/gio/gdbusmessage.c b/gio/gdbusmessage.c
index cbd9e087c..0b803bc30 100644
--- a/gio/gdbusmessage.c
+++ b/gio/gdbusmessage.c
@@ -2168,7 +2168,6 @@ g_dbus_message_new_from_blob (guchar                *blob,
 
   g_return_val_if_fail (blob != NULL, NULL);
   g_return_val_if_fail (error == NULL || *error == NULL, NULL);
-  g_return_val_if_fail (blob_len >= 12, NULL);
 
   message = g_dbus_message_new ();
 
diff --git a/gio/tests/gdbus-serialization.c b/gio/tests/gdbus-serialization.c
index df1c63ca2..4f0634cf1 100644
--- a/gio/tests/gdbus-serialization.c
+++ b/gio/tests/gdbus-serialization.c
@@ -1512,10 +1512,8 @@ test_message_parse_truncated (void)
 
   g_clear_object (&message);
 
-  /* 12 bytes is the minimum size of the D-Bus message header. Anything less
-   * than that is rejected as a programming error by
-   * g_dbus_message_new_from_blob(). */
-  for (gsize i = 12; i < size; i++)
+  /* Try parsing all possible prefixes of the full @blob. */
+  for (gsize i = 0; i < size; i++)
     {
       message2 = g_dbus_message_new_from_blob (blob, i, G_DBUS_CAPABILITY_FLAGS_NONE, &error);
       g_assert_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT);