From 186982901a3b2868c3a6e32929b2eea52360c624 Mon Sep 17 00:00:00 2001
From: matthieu <matthieu@openbsd.org>
Date: Sat, 14 Oct 2017 09:33:48 +0000
Subject: [PATCH] MFC: dbe: Unvalidated variable-length request in
 ProcDbeGetVisualInfo (CVE-2017-12177)

v2: Protect against integer overflow (Alan Coopersmith)
---
 xserver/dbe/dbe.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/xserver/dbe/dbe.c b/xserver/dbe/dbe.c
index 23f7e164d..f31766f31 100644
--- a/xserver/dbe/dbe.c
+++ b/xserver/dbe/dbe.c
@@ -574,6 +574,9 @@ ProcDbeGetVisualInfo(ClientPtr client)
     XdbeScreenVisualInfo *pScrVisInfo;
 
     REQUEST_AT_LEAST_SIZE(xDbeGetVisualInfoReq);
+    if (stuff->n > UINT32_MAX / sizeof(CARD32))
+        return BadLength;
+    REQUEST_FIXED_SIZE(xDbeGetVisualInfoReq, stuff->n * sizeof(CARD32));
 
     if (stuff->n > UINT32_MAX / sizeof(DrawablePtr))
         return BadAlloc;
@@ -924,7 +927,7 @@ SProcDbeSwapBuffers(ClientPtr client)
 
     swapl(&stuff->n);
     if (stuff->n > UINT32_MAX / sizeof(DbeSwapInfoRec))
-        return BadAlloc;
+        return BadLength;
     REQUEST_FIXED_SIZE(xDbeSwapBuffersReq, stuff->n * sizeof(xDbeSwapInfo));
 
     if (stuff->n != 0) {