From 8cdec40083e218bc96e8d50881785c953e1c7d12 Mon Sep 17 00:00:00 2001
From: matt335672 <30179339+matt335672@users.noreply.github.com>
Date: Tue, 23 Jan 2024 16:55:48 +0000
Subject: [PATCH] Don't enable GFX if client doesn't support 32 BPP

mstsc.exe indicates it supports GFX in the early capability flags, even
if it not able to support 32 BPP. This results in a session failure
if a RDPGFX_CAPS_CONFIRM_PDU is sent on the EGFX virtual channel.
---
 libxrdp/xrdp_sec.c | 14 ++++++++++++--
 xrdp/xrdp_mm.c     |  3 +--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/libxrdp/xrdp_sec.c b/libxrdp/xrdp_sec.c
index 6c2057aeb1..bc3551fd5d 100644
--- a/libxrdp/xrdp_sec.c
+++ b/libxrdp/xrdp_sec.c
@@ -2138,15 +2138,25 @@ xrdp_sec_process_mcs_data_CS_CORE(struct xrdp_sec *self, struct stream *s)
     {
         client_info->bpp = 32;
     }
+#ifdef XRDP_RFXCODEC
     if (earlyCapabilityFlags & RNS_UD_CS_SUPPORT_DYNVC_GFX_PROTOCOL)
     {
-        LOG(LOG_LEVEL_INFO, "client supports gfx protocol");
-        self->rdp_layer->client_info.gfx = 1;
+        if (client_info->bpp < 32)
+        {
+            LOG(LOG_LEVEL_WARNING,
+                "client requested gfx protocol with insufficient color depth");
+        }
+        else
+        {
+            LOG(LOG_LEVEL_INFO, "client supports gfx protocol");
+            self->rdp_layer->client_info.gfx = 1;
+        }
     }
     else
     {
         LOG_DEVEL(LOG_LEVEL_INFO, "client DOES NOT support gfx");
     }
+#endif
     if (!s_check_rem(s, 64))
     {
         return 0;
diff --git a/xrdp/xrdp_mm.c b/xrdp/xrdp_mm.c
index 62082022cc..6d6279f1ef 100644
--- a/xrdp/xrdp_mm.c
+++ b/xrdp/xrdp_mm.c
@@ -1484,8 +1484,7 @@ int
 egfx_initialize(struct xrdp_mm *self)
 {
     LOG_DEVEL(LOG_LEVEL_TRACE, "egfx_initialize");
-    if (!(self->wm->client_info->mcs_early_capability_flags
-            & RNS_UD_CS_SUPPORT_DYNVC_GFX_PROTOCOL))
+    if (!(self->wm->client_info->gfx))
     {
         return 0;
     }