From 07203788d3c87ff62f163695fc7bf4aec97fd340 Mon Sep 17 00:00:00 2001
From: Olivier Fourdan <ofourdan@redhat.com>
Date: Tue, 20 May 2025 15:18:19 +0200
Subject: [PATCH] randr: Check for overflow in RRChangeProviderProperty()

A client might send a request causing an integer overflow when computing
the total size to allocate in RRChangeProviderProperty().

To avoid the issue, check that total length in bytes won't exceed the
maximum integer value.

CVE-2025-49180

This issue was discovered by Nils Emmerich <nemmerich@ernw.de> and
reported by Julian Suleder via ERNW Vulnerability Disclosure.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2024>
(cherry picked from commit 3c3a4b767b16174d3213055947ea7f4f88e10ec6)
---
 randr/rrproviderproperty.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/randr/rrproviderproperty.c b/randr/rrproviderproperty.c
index 8be6fff86..7dc97476e 100644
--- a/randr/rrproviderproperty.c
+++ b/randr/rrproviderproperty.c
@@ -179,7 +179,8 @@ RRChangeProviderProperty(RRProviderPtr provider, Atom property, Atom type,
 
     if (mode == PropModeReplace || len > 0) {
         void *new_data = NULL, *old_data = NULL;
-
+        if (total_len > MAXINT / size_in_bytes)
+            return BadValue;
         total_size = total_len * size_in_bytes;
         new_value.data = (void *) malloc(total_size);
         if (!new_value.data && total_size) {