diff options
Diffstat (limited to 'src/Boot/Windows/BootDiskIo.cpp')
| -rw-r--r-- | src/Boot/Windows/BootDiskIo.cpp | 487 |
1 files changed, 487 insertions, 0 deletions
diff --git a/src/Boot/Windows/BootDiskIo.cpp b/src/Boot/Windows/BootDiskIo.cpp new file mode 100644 index 00000000..84e888e0 --- /dev/null +++ b/src/Boot/Windows/BootDiskIo.cpp @@ -0,0 +1,487 @@ +/*
+ Copyright (c) 2008-2011 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 "Bios.h"
+#include "BootConsoleIo.h"
+#include "BootConfig.h"
+#include "BootDebug.h"
+#include "BootDefs.h"
+#include "BootDiskIo.h"
+#include "BootStrings.h"
+
+
+byte SectorBuffer[TC_LB_SIZE];
+
+#ifdef TC_BOOT_DEBUG_ENABLED
+static bool SectorBufferInUse = false;
+
+void AcquireSectorBuffer ()
+{
+ if (SectorBufferInUse)
+ TC_THROW_FATAL_EXCEPTION;
+
+ SectorBufferInUse = true;
+}
+
+
+void ReleaseSectorBuffer ()
+{
+ SectorBufferInUse = false;
+}
+
+#endif
+
+
+bool IsLbaSupported (byte drive)
+{
+ static byte CachedDrive = TC_INVALID_BIOS_DRIVE;
+ static bool CachedStatus;
+ uint16 result = 0;
+
+ if (CachedDrive == drive)
+ goto ret;
+
+ __asm
+ {
+ mov bx, 0x55aa
+ mov dl, drive
+ mov ah, 0x41
+ int 0x13
+ jc err
+ mov result, bx
+ err:
+ }
+
+ CachedDrive = drive;
+ CachedStatus = (result == 0xaa55);
+ret:
+ return CachedStatus;
+}
+
+
+void PrintDiskError (BiosResult error, bool write, byte drive, const uint64 *sector, const ChsAddress *chs)
+{
+ PrintEndl();
+ Print (write ? "Write" : "Read"); Print (" error:");
+ Print (error);
+ Print (" Drive:");
+ Print (drive ^ 0x80);
+
+ if (sector)
+ {
+ Print (" Sector:");
+ Print (*sector);
+ }
+
+ if (chs)
+ {
+ Print (" CHS:");
+ Print (*chs);
+ }
+
+ PrintEndl();
+ Beep();
+}
+
+
+void Print (const ChsAddress &chs)
+{
+ Print (chs.Cylinder);
+ PrintChar ('/');
+ Print (chs.Head);
+ PrintChar ('/');
+ Print (chs.Sector);
+}
+
+
+void PrintSectorCountInMB (const uint64 §orCount)
+{
+ Print (sectorCount >> (TC_LB_SIZE_BIT_SHIFT_DIVISOR + 2)); Print (" MB ");
+}
+
+
+BiosResult ReadWriteSectors (bool write, uint16 bufferSegment, uint16 bufferOffset, byte drive, const ChsAddress &chs, byte sectorCount, bool silent)
+{
+ CheckStack();
+
+ byte cylinderLow = (byte) chs.Cylinder;
+ byte sector = chs.Sector;
+ sector |= byte (chs.Cylinder >> 2) & 0xc0;
+ byte function = write ? 0x03 : 0x02;
+
+ BiosResult result;
+ byte tryCount = TC_MAX_BIOS_DISK_IO_RETRIES;
+
+ do
+ {
+ result = BiosResultSuccess;
+
+ __asm
+ {
+ push es
+ mov ax, bufferSegment
+ mov es, ax
+ mov bx, bufferOffset
+ mov dl, drive
+ mov ch, cylinderLow
+ mov si, chs
+ mov dh, [si].Head
+ mov cl, sector
+ mov al, sectorCount
+ mov ah, function
+ int 0x13
+ jnc ok // If CF=0, ignore AH to prevent issues caused by potential bugs in BIOSes
+ mov result, ah
+ ok:
+ pop es
+ }
+
+ if (result == BiosResultEccCorrected)
+ result = BiosResultSuccess;
+
+ // Some BIOSes report I/O errors prematurely in some cases
+ } while (result != BiosResultSuccess && --tryCount != 0);
+
+ if (!silent && result != BiosResultSuccess)
+ PrintDiskError (result, write, drive, nullptr, &chs);
+
+ return result;
+}
+
+
+BiosResult ReadWriteSectors (bool write, byte *buffer, byte drive, const ChsAddress &chs, byte sectorCount, bool silent)
+{
+ uint16 codeSeg;
+ __asm mov codeSeg, cs
+ return ReadWriteSectors (write, codeSeg, (uint16) buffer, drive, chs, sectorCount, silent);
+}
+
+
+BiosResult ReadSectors (byte *buffer, byte drive, const ChsAddress &chs, byte sectorCount, bool silent)
+{
+ return ReadWriteSectors (false, buffer, drive, chs, sectorCount, silent);
+}
+
+
+BiosResult WriteSectors (byte *buffer, byte drive, const ChsAddress &chs, byte sectorCount, bool silent)
+{
+ return ReadWriteSectors (true, buffer, drive, chs, sectorCount, silent);
+}
+
+
+static BiosResult ReadWriteSectors (bool write, BiosLbaPacket &dapPacket, byte drive, const uint64 §or, uint16 sectorCount, bool silent)
+{
+ CheckStack();
+
+ if (!IsLbaSupported (drive))
+ {
+ DriveGeometry geometry;
+
+ BiosResult result = GetDriveGeometry (drive, geometry, silent);
+ if (result != BiosResultSuccess)
+ return result;
+
+ ChsAddress chs;
+ LbaToChs (geometry, sector, chs);
+ return ReadWriteSectors (write, (uint16) (dapPacket.Buffer >> 16), (uint16) dapPacket.Buffer, drive, chs, sectorCount, silent);
+ }
+
+ dapPacket.Size = sizeof (dapPacket);
+ dapPacket.Reserved = 0;
+ dapPacket.SectorCount = sectorCount;
+ dapPacket.Sector = sector;
+
+ byte function = write ? 0x43 : 0x42;
+
+ BiosResult result;
+ byte tryCount = TC_MAX_BIOS_DISK_IO_RETRIES;
+
+ do
+ {
+ result = BiosResultSuccess;
+
+ __asm
+ {
+ mov bx, 0x55aa
+ mov dl, drive
+ mov si, [dapPacket]
+ mov ah, function
+ xor al, al
+ int 0x13
+ jnc ok // If CF=0, ignore AH to prevent issues caused by potential bugs in BIOSes
+ mov result, ah
+ ok:
+ }
+
+ if (result == BiosResultEccCorrected)
+ result = BiosResultSuccess;
+
+ // Some BIOSes report I/O errors prematurely in some cases
+ } while (result != BiosResultSuccess && --tryCount != 0);
+
+ if (!silent && result != BiosResultSuccess)
+ PrintDiskError (result, write, drive, §or);
+
+ return result;
+}
+
+
+static BiosResult ReadWriteSectors (bool write, byte *buffer, byte drive, const uint64 §or, uint16 sectorCount, bool silent)
+{
+ BiosLbaPacket dapPacket;
+ dapPacket.Buffer = (uint32) buffer;
+ return ReadWriteSectors (write, dapPacket, drive, sector, sectorCount, silent);
+}
+
+
+BiosResult ReadWriteSectors (bool write, uint16 bufferSegment, uint16 bufferOffset, byte drive, const uint64 §or, uint16 sectorCount, bool silent)
+{
+ BiosLbaPacket dapPacket;
+ dapPacket.Buffer = ((uint32) bufferSegment << 16) | bufferOffset;
+ return ReadWriteSectors (write, dapPacket, drive, sector, sectorCount, silent);
+}
+
+BiosResult ReadSectors (uint16 bufferSegment, uint16 bufferOffset, byte drive, const uint64 §or, uint16 sectorCount, bool silent)
+{
+ return ReadWriteSectors (false, bufferSegment, bufferOffset, drive, sector, sectorCount, silent);
+}
+
+
+BiosResult ReadSectors (byte *buffer, byte drive, const uint64 §or, uint16 sectorCount, bool silent)
+{
+ BiosResult result;
+ uint16 codeSeg;
+ __asm mov codeSeg, cs
+
+ result = ReadSectors (BootStarted ? codeSeg : TC_BOOT_LOADER_ALT_SEGMENT, (uint16) buffer, drive, sector, sectorCount, silent);
+
+ // Alternative segment is used to prevent memory corruption caused by buggy BIOSes
+ if (!BootStarted)
+ CopyMemory (TC_BOOT_LOADER_ALT_SEGMENT, (uint16) buffer, buffer, sectorCount * TC_LB_SIZE);
+
+ return result;
+}
+
+
+BiosResult WriteSectors (byte *buffer, byte drive, const uint64 §or, uint16 sectorCount, bool silent)
+{
+ return ReadWriteSectors (true, buffer, drive, sector, sectorCount, silent);
+}
+
+
+BiosResult GetDriveGeometry (byte drive, DriveGeometry &geometry, bool silent)
+{
+ CheckStack();
+
+ byte maxCylinderLow, maxHead, maxSector;
+ BiosResult result;
+ __asm
+ {
+ push es
+ mov dl, drive
+ mov ah, 0x08
+ int 0x13
+
+ mov result, ah
+ mov maxCylinderLow, ch
+ mov maxSector, cl
+ mov maxHead, dh
+ pop es
+ }
+
+ if (result == BiosResultSuccess)
+ {
+ geometry.Cylinders = (maxCylinderLow | (uint16 (maxSector & 0xc0) << 2)) + 1;
+ geometry.Heads = maxHead + 1;
+ geometry.Sectors = maxSector & ~0xc0;
+ }
+ else if (!silent)
+ {
+ Print ("Drive ");
+ Print (drive ^ 0x80);
+ Print (" not found: ");
+ PrintErrorNoEndl ("");
+ Print (result);
+ PrintEndl();
+ }
+
+ return result;
+}
+
+
+void ChsToLba (const DriveGeometry &geometry, const ChsAddress &chs, uint64 &lba)
+{
+ lba.HighPart = 0;
+ lba.LowPart = (uint32 (chs.Cylinder) * geometry.Heads + chs.Head) * geometry.Sectors + chs.Sector - 1;
+}
+
+
+void LbaToChs (const DriveGeometry &geometry, const uint64 &lba, ChsAddress &chs)
+{
+ chs.Sector = (byte) ((lba.LowPart % geometry.Sectors) + 1);
+ uint32 ch = lba.LowPart / geometry.Sectors;
+ chs.Head = (byte) (ch % geometry.Heads);
+ chs.Cylinder = (uint16) (ch / geometry.Heads);
+}
+
+
+void PartitionEntryMBRToPartition (const PartitionEntryMBR &partEntry, Partition &partition)
+{
+ partition.Active = partEntry.BootIndicator == 0x80;
+ partition.EndSector.HighPart = 0;
+ partition.EndSector.LowPart = partEntry.StartLBA + partEntry.SectorCountLBA - 1;
+ partition.SectorCount.HighPart = 0;
+ partition.SectorCount.LowPart = partEntry.SectorCountLBA;
+ partition.StartSector.HighPart = 0;
+ partition.StartSector.LowPart = partEntry.StartLBA;
+ partition.Type = partEntry.Type;
+}
+
+
+BiosResult ReadWriteMBR (bool write, byte drive, bool silent)
+{
+ uint64 mbrSector;
+ mbrSector.HighPart = 0;
+ mbrSector.LowPart = 0;
+
+ if (write)
+ return WriteSectors (SectorBuffer, drive, mbrSector, 1, silent);
+
+ return ReadSectors (SectorBuffer, drive, mbrSector, 1, silent); // Uses alternative segment
+}
+
+
+BiosResult GetDrivePartitions (byte drive, Partition *partitionArray, size_t partitionArrayCapacity, size_t &partitionCount, bool activeOnly, Partition *findPartitionFollowingThis, bool silent)
+{
+ Partition *followingPartition;
+ Partition tmpPartition;
+
+ if (findPartitionFollowingThis)
+ {
+ assert (partitionArrayCapacity == 1);
+ partitionArrayCapacity = 0xff;
+ followingPartition = partitionArray;
+ partitionArray = &tmpPartition;
+
+ followingPartition->Drive = TC_INVALID_BIOS_DRIVE;
+ followingPartition->StartSector.LowPart = 0xFFFFffffUL;
+ }
+
+ AcquireSectorBuffer();
+ BiosResult result = ReadWriteMBR (false, drive, silent);
+ ReleaseSectorBuffer();
+
+ partitionCount = 0;
+
+ MBR *mbr = (MBR *) SectorBuffer;
+ if (result != BiosResultSuccess || mbr->Signature != 0xaa55)
+ return result;
+
+ PartitionEntryMBR mbrPartitions[4];
+ memcpy (mbrPartitions, mbr->Partitions, sizeof (mbrPartitions));
+ size_t partitionArrayPos = 0, partitionNumber;
+
+ for (partitionNumber = 0;
+ partitionNumber < array_capacity (mbrPartitions) && partitionArrayPos < partitionArrayCapacity;
+ ++partitionNumber)
+ {
+ const PartitionEntryMBR &partEntry = mbrPartitions[partitionNumber];
+
+ if (partEntry.SectorCountLBA > 0)
+ {
+ Partition &partition = partitionArray[partitionArrayPos];
+ PartitionEntryMBRToPartition (partEntry, partition);
+
+ if (activeOnly && !partition.Active)
+ continue;
+
+ partition.Drive = drive;
+ partition.Number = partitionArrayPos;
+
+ if (partEntry.Type == 0x5 || partEntry.Type == 0xf) // Extended partition
+ {
+ if (IsLbaSupported (drive))
+ {
+ // Find all extended partitions
+ uint64 firstExtStartLBA = partition.StartSector;
+ uint64 extStartLBA = partition.StartSector;
+ MBR *extMbr = (MBR *) SectorBuffer;
+
+ while (partitionArrayPos < partitionArrayCapacity &&
+ (result = ReadSectors ((byte *) extMbr, drive, extStartLBA, 1, silent)) == BiosResultSuccess
+ && extMbr->Signature == 0xaa55)
+ {
+ if (extMbr->Partitions[0].SectorCountLBA > 0)
+ {
+ Partition &logPart = partitionArray[partitionArrayPos];
+ PartitionEntryMBRToPartition (extMbr->Partitions[0], logPart);
+ logPart.Drive = drive;
+
+ logPart.Number = partitionArrayPos;
+ logPart.Primary = false;
+
+ logPart.StartSector.LowPart += extStartLBA.LowPart;
+ logPart.EndSector.LowPart += extStartLBA.LowPart;
+
+ if (findPartitionFollowingThis)
+ {
+ if (logPart.StartSector.LowPart > findPartitionFollowingThis->EndSector.LowPart
+ && logPart.StartSector.LowPart < followingPartition->StartSector.LowPart)
+ {
+ *followingPartition = logPart;
+ }
+ }
+ else
+ ++partitionArrayPos;
+ }
+
+ // Secondary extended
+ if (extMbr->Partitions[1].Type != 0x5 && extMbr->Partitions[1].Type == 0xf
+ || extMbr->Partitions[1].SectorCountLBA == 0)
+ break;
+
+ extStartLBA.LowPart = extMbr->Partitions[1].StartLBA + firstExtStartLBA.LowPart;
+ }
+ }
+ }
+ else
+ {
+ partition.Primary = true;
+
+ if (findPartitionFollowingThis)
+ {
+ if (partition.StartSector.LowPart > findPartitionFollowingThis->EndSector.LowPart
+ && partition.StartSector.LowPart < followingPartition->StartSector.LowPart)
+ {
+ *followingPartition = partition;
+ }
+ }
+ else
+ ++partitionArrayPos;
+ }
+ }
+ }
+
+ partitionCount = partitionArrayPos;
+ return result;
+}
+
+
+bool GetActivePartition (byte drive)
+{
+ size_t partCount;
+
+ if (GetDrivePartitions (drive, &ActivePartition, 1, partCount, true) != BiosResultSuccess || partCount < 1)
+ {
+ ActivePartition.Drive = TC_INVALID_BIOS_DRIVE;
+ PrintError (TC_BOOT_STR_NO_BOOT_PARTITION);
+ return false;
+ }
+
+ return true;
+}
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