From aa4154894c216f31665b691836efe85fdad387ae Mon Sep 17 00:00:00 2001
From: Ivan Baravy <dunkaist@gmail.com>
Date: Tue, 31 May 2022 07:27:00 +0000
Subject: [PATCH] [kernel] Add is_string_userspace func, like
 is_region_userspace

git-svn-id: svn://kolibrios.org@9823 a494cfbc-eb01-0410-851d-a64ba20cac60
---
 kernel/trunk/core/dll.inc    | 16 ++++++++--------
 kernel/trunk/core/memory.inc |  4 ++--
 kernel/trunk/kernel.asm      | 24 ++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/kernel/trunk/core/dll.inc b/kernel/trunk/core/dll.inc
index e303aa5fce..7dfd66d6bc 100644
--- a/kernel/trunk/core/dll.inc
+++ b/kernel/trunk/core/dll.inc
@@ -287,17 +287,17 @@ align 4
 proc get_coff_sym stdcall, pSym:dword,count:dword, sz_sym:dword
 
 @@:
-        stdcall strncmp, [pSym], [sz_sym], 8
+        stdcall strncmp, [pSym], [sz_sym], sizeof.COFF_SYM.Name
         test    eax, eax
         jz      .ok
-        add     [pSym], 18
+        add     [pSym], sizeof.COFF_SYM
         dec     [count]
         jnz     @b
         xor     eax, eax
         ret
 .ok:
         mov     eax, [pSym]
-        mov     eax, [eax+8]
+        mov     eax, [eax+COFF_SYM.Value]
         ret
 endp
 
@@ -964,7 +964,7 @@ proc load_library stdcall, file_name:dword, encoding:dword
         movzx   ecx, [edx + COFF_HEADER.nSections]
         xor     ebx, ebx
 
-        add     edx, 20
+        add     edx, sizeof.COFF_HEADER
 @@:
         call    coff_get_align
         add     ebx, eax
@@ -1045,7 +1045,7 @@ proc load_library stdcall, file_name:dword, encoding:dword
         movzx   ecx, [edx + COFF_HEADER.nSections]
         lea     ecx, [ecx*5]
         lea     edi, [edi + ecx*8+20]
-        add     edx, 20
+        add     edx, sizeof.COFF_HEADER
 @@:
         movzx   eax, [edx + COFF_SECTION.NumReloc]
         lea     eax, [eax*5]
@@ -1097,7 +1097,7 @@ proc load_library stdcall, file_name:dword, encoding:dword
 ; fixup symbols
         mov     edx, ebx
         mov     eax, [ebx + COFF_HEADER.nSymbols]
-        add     edx, 20
+        add     edx, sizeof.COFF_HEADER
         mov     ecx, [esi + DLLDESCR.symbols_num]
         lea     ecx, [ecx*9]
         add     ecx, ecx
@@ -1184,7 +1184,7 @@ proc load_library stdcall, file_name:dword, encoding:dword
         shr     ecx, 12
 .map_pages_loop:
         mov     eax, [page_tabs + ecx*4]
-        and     eax, not 0xFFF
+        and     eax, -PAGE_SIZE
         or      al, PG_UR
         xchg    eax, [page_tabs + edx*4]
         test    al, 1
@@ -1194,7 +1194,7 @@ proc load_library stdcall, file_name:dword, encoding:dword
         invlpg  [ebx+edi]
         inc     ecx
         inc     edx
-        add     edi, 0x1000
+        add     edi, PAGE_SIZE
         cmp     edi, [esi + DLLDESCR.size]
         jb      .map_pages_loop
 
diff --git a/kernel/trunk/core/memory.inc b/kernel/trunk/core/memory.inc
index 344227f3a8..63b3819be2 100644
--- a/kernel/trunk/core/memory.inc
+++ b/kernel/trunk/core/memory.inc
@@ -1141,8 +1141,8 @@ f68:
 .18:
         mov     eax, edx
 .19:
-        cmp     ecx, OS_BASE
-        jae     .fail
+        stdcall is_string_userspace, ecx
+        jnz     .fail
         stdcall load_library, ecx, eax
         mov     [esp + SYSCALL_STACK._eax], eax
         ret
diff --git a/kernel/trunk/kernel.asm b/kernel/trunk/kernel.asm
index bce6dbbe7a..1efb31b1c5 100644
--- a/kernel/trunk/kernel.asm
+++ b/kernel/trunk/kernel.asm
@@ -4820,6 +4820,30 @@ proc is_region_userspace stdcall, base:dword, len:dword
         ret 
 endp
 
+align 4
+; @brief Check whether given string lays in userspace memory, i.e. below OS_BASE
+; @param base Base address of string
+; @return ZF = 1 if string in userspace memory,
+;         zf = 0 otherwise
+proc is_string_userspace stdcall, base:dword
+        push    eax ecx edi
+        xor     eax, eax
+        mov     edi, [base]
+
+        mov     ecx, OS_BASE-1
+        sub     ecx, edi
+        jb      .done           ; zf
+        inc     ecx
+        cmp     ecx, 0x10000    ; don't allow strings larger than 64k?
+        jbe     @f
+        mov     ecx, 0x10000
+@@:
+        repnz scasb
+.done:
+        pop     edi ecx eax
+        ret
+endp
+
 if ~ lang eq sp
 diff16 "end of .text segment",0,$
 end if