From da3163d11b42fa81b2b0ae337e288d58e3649a9c Mon Sep 17 00:00:00 2001
From: Doczom <Doczom@kolibrios.org>
Date: Sun, 9 May 2021 13:27:00 +0000
Subject: [PATCH] fixed vulnerability (reading kernel memory from userspace) in
 sysfn 47

git-svn-id: svn://kolibrios.org@8713 a494cfbc-eb01-0410-851d-a64ba20cac60
---
 kernel/trunk/kernel.asm | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/kernel/trunk/kernel.asm b/kernel/trunk/kernel.asm
index 5b21513082..b4e6671545 100644
--- a/kernel/trunk/kernel.asm
+++ b/kernel/trunk/kernel.asm
@@ -1409,6 +1409,19 @@ sys_outport:
         ret
 
 display_number:
+; add check pointers
+        test    bl, bl
+        jz      @f
+        stdcall is_region_userspace, ecx, 1
+        jnz     @f
+        ret
+@@:
+        test    esi, 0x08000000
+        jz      @f
+        stdcall is_region_userspace, edi, 1
+        jnz     @f
+        ret
+@@:
 ;It is not optimization
         mov     eax, ebx
         mov     ebx, ecx