-/*

- Derived from source code of TrueCrypt 7.1a, which is

- Copyright (c) 2008-2012 TrueCrypt Developers Association and which is governed

- by the TrueCrypt License 3.0.

-

- Modifications and additions to the original source code (contained in this file)

- and all other portions of this file are Copyright (c) 2013-2016 IDRIX

- and are governed by the Apache License 2.0 the full text of which is

- contained in the file License.txt included in VeraCrypt binary and source

- code distribution packages.

-*/

-

-#include "Platform.h"

-#include "BootMemory.h"

-#include "BootConfig.h"

-#include "BootConsoleIo.h"

-#include "BootDebug.h"

-#include "BootDefs.h"

-#include "BootDiskIo.h"

-#include "BootEncryptedIo.h"

-#include "BootStrings.h"

-#include "IntFilter.h"

-

-static uint32 OriginalInt13Handler;

-static uint32 OriginalInt15Handler;

-

-static Registers IntRegisters;

-

-

-bool Int13Filter ()

-{

- CheckStack();

-

- Registers regs;

- memcpy (&regs, &IntRegisters, sizeof (regs));

- __asm sti

-

- static int ReEntryCount = -1;

- ++ReEntryCount;

-

- byte function = (byte) (regs.AX >> 8);

-

-#ifdef TC_TRACE_INT13

- DisableScreenOutput();

-

- PrintHex (function);

-

- Print (" EN:"); Print (ReEntryCount);

- Print (" SS:"); PrintHex (regs.SS);

-

- uint16 spdbg;

- __asm mov spdbg, sp

- PrintChar (' ');

- PrintHex (spdbg);

- PrintChar ('<'); PrintHex (TC_BOOT_LOADER_STACK_TOP);

-

-#endif

-

- bool passOriginalRequest = true;

-

- switch (function)

- {

- case 0x2: // Read sectors

- case 0x3: // Write sectors

- {

- byte drive = (byte) regs.DX;

-

- ChsAddress chs;

- chs.Cylinder = ((regs.CX << 2) & 0x300) | (regs.CX >> 8);

- chs.Head = regs.DX >> 8;

- chs.Sector = regs.CX & 0x3f;

-

- byte sectorCount = (byte) regs.AX;

-

-#ifdef TC_TRACE_INT13

- PrintVal (": Drive", drive - TC_FIRST_BIOS_DRIVE, false);

- Print (" Chs: "); Print (chs);

-#endif

-

- uint64 sector;

- if (drive == BootDrive)

- {

- if (!BootDriveGeometryValid)

- TC_THROW_FATAL_EXCEPTION;

-

- ChsToLba (BootDriveGeometry, chs, sector);

-#ifdef TC_TRACE_INT13

- PrintVal (" Sec", sector.LowPart, false);

-#endif

- }

-

-#ifdef TC_TRACE_INT13

- PrintVal (" Count", sectorCount, false);

- Print (" Buf: "); PrintHex (regs.ES); PrintChar (':'); PrintHex (regs.BX);

- PrintEndl();

-#endif

-

- if (ReEntryCount == 0 && drive == EncryptedVirtualPartition.Drive)

- {

- BiosResult result;

-

- if (function == 0x3)

- result = WriteEncryptedSectors (regs.ES, regs.BX, drive, sector, sectorCount);

- else

- result = ReadEncryptedSectors (regs.ES, regs.BX, drive, sector, sectorCount);

-

- __asm cli

-

- memcpy (&IntRegisters, &regs, sizeof (regs));

- IntRegisters.AX = (uint16) result << 8;

-

- if (result == BiosResultSuccess)

- {

- IntRegisters.AX |= sectorCount;

- IntRegisters.Flags &= ~TC_X86_CARRY_FLAG;

- }

- else

- IntRegisters.Flags |= TC_X86_CARRY_FLAG;

-

- passOriginalRequest = false;

- }

- }

- break;

-

- case 0x42: // Read sectors LBA

- case 0x43: // Write sectors LBA

- {

- byte drive = (byte) regs.DX;

-

- BiosLbaPacket lba;

- CopyMemory (regs.DS, regs.SI, (byte *) &lba, sizeof (lba));

-

-#ifdef TC_TRACE_INT13

- PrintVal (": Drive", drive - TC_FIRST_BIOS_DRIVE, false);

- PrintVal (" Sec", lba.Sector.LowPart, false);

- PrintVal (" Count", lba.SectorCount, false);

- PrintVal (" Buf", lba.Buffer, false, true);

- PrintEndl();

-#endif

-

- if (ReEntryCount == 0 && drive == EncryptedVirtualPartition.Drive)

- {

- BiosResult result;

-

- uint16 segment = (uint16) (lba.Buffer >> 16);

- uint16 offset = (uint16) lba.Buffer;

-

- if (function == 0x43)

- result = WriteEncryptedSectors (segment, offset, drive, lba.Sector, lba.SectorCount);

- else

- result = ReadEncryptedSectors (segment, offset, drive, lba.Sector, lba.SectorCount);

-

- __asm cli

-

- memcpy (&IntRegisters, &regs, sizeof (regs));

- IntRegisters.AX = (IntRegisters.AX & 0xff) | ((uint16) result << 8);

-

- if (result == BiosResultSuccess)

- IntRegisters.Flags &= ~TC_X86_CARRY_FLAG;

- else

- IntRegisters.Flags |= TC_X86_CARRY_FLAG;

-

- passOriginalRequest = false;

- }

- }

- break;

-

- default:

-#ifdef TC_TRACE_INT13

- PrintEndl();

-#endif

- break;

- }

-

-#ifdef TC_TRACE_INT13

- EnableScreenOutput();

-#endif

- --ReEntryCount;

-

- return passOriginalRequest;

-}

-

-

-#define TC_MAX_MEMORY_MAP_SIZE 80

-

-BiosMemoryMapEntry BiosMemoryMap[TC_MAX_MEMORY_MAP_SIZE];

-static size_t BiosMemoryMapSize;

-

-

-static void CreateBootLoaderMemoryMapEntry (BiosMemoryMapEntry *newMapEntry, uint32 bootLoaderStart)

-{

- newMapEntry->Type = 0x2;

- newMapEntry->BaseAddress.HighPart = 0;

- newMapEntry->BaseAddress.LowPart = bootLoaderStart;

- newMapEntry->Length.HighPart = 0;

- newMapEntry->Length.LowPart = TC_BOOT_MEMORY_REQUIRED * 1024UL;

-}

-

-

-static bool CreateNewBiosMemoryMap ()

-{

- // Create a new BIOS memory map presenting the memory area of the loader as reserved

-

- BiosMemoryMapSize = 0;

- BiosMemoryMapEntry entry;

- BiosMemoryMapEntry *newMapEntry = BiosMemoryMap;

-

- const BiosMemoryMapEntry *mapEnd = BiosMemoryMap + TC_MAX_MEMORY_MAP_SIZE;

-

- uint64 bootLoaderStart;

- bootLoaderStart.HighPart = 0;

-

- uint16 codeSeg;

- __asm mov codeSeg, cs

- bootLoaderStart.LowPart = GetLinearAddress (codeSeg, 0);

-

- uint64 bootLoaderEnd;

- bootLoaderEnd.HighPart = 0;

- bootLoaderEnd.LowPart = bootLoaderStart.LowPart + TC_BOOT_MEMORY_REQUIRED * 1024UL;

-

- bool loaderEntryInserted = false;

-

- if (GetFirstBiosMemoryMapEntry (entry))

- {

- do

- {

- uint64 entryEnd = entry.BaseAddress + entry.Length;

-

- if (entry.Type == 0x1 && RegionsIntersect (bootLoaderStart, TC_BOOT_MEMORY_REQUIRED * 1024UL, entry.BaseAddress, entryEnd - 1))

- {

- // Free map entry covers the boot loader area

-

- if (entry.BaseAddress < bootLoaderStart)

- {

- // Create free entry below the boot loader area

- if (newMapEntry >= mapEnd)

- goto mapOverflow;

-

- *newMapEntry = entry;

- newMapEntry->Length = bootLoaderStart - entry.BaseAddress;

- ++newMapEntry;

- }

-

- if (!loaderEntryInserted)

- {

- // Create reserved entry for the boot loader if it has not been done yet

- if (newMapEntry >= mapEnd)

- goto mapOverflow;

-

- CreateBootLoaderMemoryMapEntry (newMapEntry, bootLoaderStart.LowPart);

- ++newMapEntry;

- loaderEntryInserted = true;

- }

-

- if (bootLoaderEnd < entryEnd)

- {

- // Create free entry above the boot loader area

- if (newMapEntry >= mapEnd)

- goto mapOverflow;

-

- newMapEntry->Type = 0x1;

- newMapEntry->BaseAddress = bootLoaderEnd;

- newMapEntry->Length = entryEnd - bootLoaderEnd;

- ++newMapEntry;

- }

- }

- else

- {

- if (newMapEntry >= mapEnd)

- goto mapOverflow;

-

- if (!loaderEntryInserted && entry.BaseAddress > bootLoaderStart)

- {

- // Create reserved entry for the boot loader if it has not been done yet

- CreateBootLoaderMemoryMapEntry (newMapEntry, bootLoaderStart.LowPart);

- ++newMapEntry;

- loaderEntryInserted = true;

- }

-

- // Copy map entry

- *newMapEntry++ = entry;

- }

-

- } while (GetNextBiosMemoryMapEntry (entry));

- }

-

- BiosMemoryMapSize = newMapEntry - BiosMemoryMap;

- return true;

-

-mapOverflow:

- size_t overSize = 0;

- while (GetNextBiosMemoryMapEntry (entry))

- {

- ++overSize;

- }

-

- PrintErrorNoEndl ("MMP:");

- Print (overSize);

- PrintEndl();

-

- return false;

-}

-

-

-bool Int15Filter ()

-{

- CheckStack();

-

-#ifdef TC_TRACE_INT15

- DisableScreenOutput();

-

- Print ("15-");

- PrintHex (IntRegisters.AX);

-

- Print (" SS:"); PrintHex (IntRegisters.SS);

-

- uint16 spdbg;

- __asm mov spdbg, sp

- PrintChar (' ');

- PrintHex (spdbg);

- PrintChar ('<'); PrintHex (TC_BOOT_LOADER_STACK_TOP);

-

- Print (" EAX:"); PrintHex (IntRegisters.EAX);

- Print (" EBX:"); PrintHex (IntRegisters.EBX);

- Print (" ECX:"); PrintHex (IntRegisters.ECX);

- Print (" EDX:"); PrintHex (IntRegisters.EDX);

- Print (" DI:"); PrintHex (IntRegisters.DI);

- PrintEndl();

-

-#endif

-

- if (IntRegisters.EBX >= BiosMemoryMapSize)

- {

- IntRegisters.Flags |= TC_X86_CARRY_FLAG;

- IntRegisters.EBX = 0;

- IntRegisters.AX = -1;

- }

- else

- {

- CopyMemory ((byte *) &BiosMemoryMap[IntRegisters.EBX], IntRegisters.ES, IntRegisters.DI, sizeof (BiosMemoryMap[0]));

-

- IntRegisters.Flags &= ~TC_X86_CARRY_FLAG;

- IntRegisters.EAX = 0x534D4150UL;

-

- ++IntRegisters.EBX;

- if (IntRegisters.EBX >= BiosMemoryMapSize)

- IntRegisters.EBX = 0;

-

- IntRegisters.ECX = sizeof (BiosMemoryMap[0]);

- }

-

- if (IntRegisters.EBX == 0 && !(BootSectorFlags & TC_BOOT_CFG_FLAG_WINDOWS_VISTA_OR_LATER))

- {

- // Uninstall filter when the modified map has been issued three times to prevent

- // problems with hardware drivers on some notebooks running Windows XP.

-

- static int CompleteMapIssueCount = 0;

- if (++CompleteMapIssueCount >= 3)

- {

- __asm

- {

- cli

- push es

-

- lea si, OriginalInt15Handler

- xor ax, ax

- mov es, ax

- mov di, 0x15 * 4

-

- mov ax, [si]

- mov es:[di], ax

- mov ax, [si + 2]

- mov es:[di + 2], ax

-

- pop es

- sti

- }

- }

- }

-

-#ifdef TC_TRACE_INT15

- BiosMemoryMapEntry entry;

- CopyMemory (IntRegisters.ES, IntRegisters.DI, (byte *) &entry, sizeof (entry));

- PrintHex (entry.Type); PrintChar (' ');

- PrintHex (entry.BaseAddress); PrintChar (' ');

- PrintHex (entry.Length); PrintChar (' ');

- PrintHex (entry.BaseAddress + entry.Length); PrintEndl();

-

- Print ("EAX:"); PrintHex (IntRegisters.EAX);

- Print (" EBX:"); PrintHex (IntRegisters.EBX);

- Print (" ECX:"); PrintHex (IntRegisters.ECX);

- Print (" EDX:"); PrintHex (IntRegisters.EDX);

- Print (" DI:"); PrintHex (IntRegisters.DI);

- Print (" FL:"); PrintHex (IntRegisters.Flags);

- PrintEndl (2);

-#endif

-

-#ifdef TC_TRACE_INT15

- EnableScreenOutput();

-#endif

- return false;

-}

-

-

-void IntFilterEntry ()

-{

- // No automatic variables should be used in this scope as SS may change

- static uint16 OrigStackPointer;

- static uint16 OrigStackSegment;

-

- __asm

- {

- pushf

- pushad

-

- cli

- mov cs:IntRegisters.DI, di

-

- lea di, cs:IntRegisters.EAX

- TC_ASM_EMIT4 (66,2E,89,05) // mov [cs:di], eax

- lea di, cs:IntRegisters.EBX

- TC_ASM_EMIT4 (66,2E,89,1D) // mov [cs:di], ebx

- lea di, cs:IntRegisters.ECX

- TC_ASM_EMIT4 (66,2E,89,0D) // mov [cs:di], ecx

- lea di, cs:IntRegisters.EDX

- TC_ASM_EMIT4 (66,2E,89,15) // mov [cs:di], edx

-

- mov ax, [bp + 8]

- mov cs:IntRegisters.Flags, ax

-

- mov cs:IntRegisters.SI, si

- mov si, [bp + 2] // Int number

-

- mov cs:IntRegisters.DS, ds

- mov cs:IntRegisters.ES, es

- mov cs:IntRegisters.SS, ss

-

- // Compiler assumes SS == DS - use our stack if this condition is not met

- mov ax, ss

- mov bx, cs

- cmp ax, bx

- jz stack_ok

-

- mov cs:OrigStackPointer, sp

- mov cs:OrigStackSegment, ss

- mov ax, cs

- mov ss, ax

- mov sp, TC_BOOT_LOADER_STACK_TOP

-

- stack_ok:

- // DS = CS

- push ds

- push es

- mov ax, cs

- mov ds, ax

- mov es, ax

-

- push si // Int number

-

- // Filter request

- cmp si, 0x15

- je filter15

- cmp si, 0x13

- jne $

-

- call Int13Filter

- jmp s0

-

- filter15:

- call Int15Filter

-

- s0:

- pop si // Int number

- pop es

- pop ds

-

- // Restore original SS:SP if our stack is empty

- cli

- mov bx, TC_BOOT_LOADER_STACK_TOP

- cmp bx, sp

- jnz stack_in_use

-

- mov ss, cs:OrigStackSegment

- mov sp, cs:OrigStackPointer

- stack_in_use:

-

- test ax, ax // passOriginalRequest

- jnz pass_request

-

- // Return results of filtered request

- popad

- popf

- mov ax, cs:IntRegisters.Flags

- mov [bp + 8], ax

- leave

-

- lea di, cs:IntRegisters.EAX

- TC_ASM_EMIT4 (66,2E,8B,05) // mov eax, [cs:di]

- lea di, cs:IntRegisters.EBX

- TC_ASM_EMIT4 (66,2E,8B,1D) // mov ebx, [cs:di]

- lea di, cs:IntRegisters.ECX

- TC_ASM_EMIT4 (66,2E,8B,0D) // mov ecx, [cs:di]

- lea di, cs:IntRegisters.EDX

- TC_ASM_EMIT4 (66,2E,8B,15) // mov edx, [cs:di]

-

- mov di, cs:IntRegisters.DI

- mov si, cs:IntRegisters.SI

- mov es, cs:IntRegisters.ES

- mov ds, cs:IntRegisters.DS

-

- sti

- add sp, 2

- iret

-

- // Pass original request

- pass_request:

- sti

- cmp si, 0x15

- je pass15

- cmp si, 0x13

- jne $

-

- popad

- popf

- leave

- add sp, 2

- jmp cs:OriginalInt13Handler

-

- pass15:

- popad

- popf

- leave

- add sp, 2

- jmp cs:OriginalInt15Handler

- }

-}

-

-

-void Int13FilterEntry ()

-{

- __asm

- {

- leave

- push 0x13

- jmp IntFilterEntry

- }

-}

-

-

-static void Int15FilterEntry ()

-{

- __asm

- {

- pushf

- cmp ax, 0xe820 // Get system memory map

- je filter

-

- popf

- leave

- jmp cs:OriginalInt15Handler

-

- filter:

- leave

- push 0x15

- jmp IntFilterEntry

- }

-}

-

-

-bool InstallInterruptFilters ()

-{

-

-#ifndef TC_WINDOWS_BOOT_RESCUE_DISK_MODE

-

- // If the filters have already been installed, it usually indicates stack corruption

- // and a consequent reentry of this routine without a system reset.

-

- uint32 currentInt13Handler;

- CopyMemory (0, 0x13 * 4, &currentInt13Handler, sizeof (currentInt13Handler));

-

- if (currentInt13Handler == (uint32) Int13FilterEntry)

- {

- PrintError ("Memory corrupted");

- Print (TC_BOOT_STR_UPGRADE_BIOS);

-

- GetKeyboardChar();

- return true;

- }

-

-#endif

-

- if (!CreateNewBiosMemoryMap())

- return false;

-

- __asm

- {

- cli

- push es

-

- // Save original INT 13 handler

- xor ax, ax

- mov es, ax

-

- mov si, 0x13 * 4

- lea di, OriginalInt13Handler

-

- mov ax, es:[si]

- mov [di], ax

- mov ax, es:[si + 2]

- mov [di + 2], ax

-

- // Install INT 13 filter

- lea ax, Int13FilterEntry

- mov es:[si], ax

- mov es:[si + 2], cs

-

- // Save original INT 15 handler

- mov si, 0x15 * 4

- lea di, OriginalInt15Handler

-

- mov ax, es:[si]

- mov [di], ax

- mov ax, es:[si + 2]

- mov [di + 2], ax

-

- // Install INT 15 filter

- lea ax, Int15FilterEntry

- mov es:[si], ax

- mov es:[si + 2], cs

-

- // If the BIOS does not support system memory map (INT15 0xe820),

- // set amount of available memory to CS:0000 - 0:0000

- cmp BiosMemoryMapSize, 1

- jg mem_map_ok

- mov ax, cs

- shr ax, 10 - 4 // CS * 16 / 1024

- mov es:[0x413], ax // = KBytes available

- mem_map_ok:

-

- pop es

- sti

- }

-

- return true;

-}