From c7a8498e4254de97349a9867e41b79e17d38b298 Mon Sep 17 00:00:00 2001
From: "Rustem Gimadutdinov (rgimad)" <rustem.gimadutdinov@gmail.com>
Date: Thu, 22 Apr 2021 19:59:52 +0000
Subject: [PATCH] fixed vulnerability (reading kernel memory from userspace) in
 sysfn25

git-svn-id: svn://kolibrios.org@8675 a494cfbc-eb01-0410-851d-a64ba20cac60
---
 kernel/trunk/kernel.asm | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/kernel/trunk/kernel.asm b/kernel/trunk/kernel.asm
index 7e7d70e583..5b21513082 100644
--- a/kernel/trunk/kernel.asm
+++ b/kernel/trunk/kernel.asm
@@ -5420,6 +5420,14 @@ syscall_putarea_backgr:
         mov     esi, ecx
 ; ecx - size x, edx - size y
         mov     ebp, edx
+        
+        lea     ebp, [ebp*4]
+        imul    ebp, esi
+        stdcall is_region_userspace, edi, ebp
+        jz      .exit
+ 
+        mov     ebp, edx
+
         dec     ebp
         shl     ebp, 2
 
@@ -5477,6 +5485,7 @@ align 4
         dec     edx
         jnz     .start_y
 
+.exit:
         popad
         ret
 ;-----------------------------------------------------------------------------