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-rw-r--r--Boot/Windows/IntFilter.cpp641
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diff --git a/Boot/Windows/IntFilter.cpp b/Boot/Windows/IntFilter.cpp
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+/*
+ Copyright (c) 2008 TrueCrypt Developers Association. All rights reserved.
+
+ Governed by the TrueCrypt License 3.0 the full text of which is contained in
+ the file License.txt included in TrueCrypt 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;
+}