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CDImageDevice: Verify MSF of SUBQ before use
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@stenzek
stenzek committed Mar 23, 2024
1 parent 4d5c8cb commit 1f89203
Showing 1 changed file with 60 additions and 13 deletions.
73 changes: 60 additions & 13 deletions src/util/cd_image_device.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,9 @@
#include "assert.h"
#include "cd_image.h"

// TODO: Remove me..
#include "core/host.h"

#include "common/assert.h"
#include "common/error.h"
#include "common/log.h"
Expand Down Expand Up @@ -91,7 +94,8 @@ enum class SCSIReadMode : u8
}
}

[[maybe_unused]] static bool VerifySCSIReadData(std::span<const u8> buffer, SCSIReadMode mode)
[[maybe_unused]] static bool VerifySCSIReadData(std::span<const u8> buffer, SCSIReadMode mode,
CDImage::LBA expected_sector)
{
const u32 expected_size = SCSIReadCommandOutputSize(mode);
if (buffer.size() != expected_size)
Expand All @@ -100,33 +104,65 @@ enum class SCSIReadMode : u8
return false;
}

const CDImage::Position expected_pos = CDImage::Position::FromLBA(expected_sector);

if (mode == SCSIReadMode::Full)
{
// Validate subcode.
u8 deinterleaved_subcode[CDImage::ALL_SUBCODE_SIZE];
CDImage::SubChannelQ subq;
CDImage::DeinterleaveSubcode(buffer.data() + CDImage::RAW_SECTOR_SIZE, deinterleaved_subcode);
std::memcpy(&subq, &deinterleaved_subcode[CDImage::SUBCHANNEL_BYTES_PER_FRAME], sizeof(subq));

Log_DevFmt("SCSI full subcode read returned [{}] for {:02d}:{:02d}:{:02d}",
StringUtil::EncodeHex(subq.data.data(), static_cast<int>(subq.data.size())), expected_pos.minute,
expected_pos.second, expected_pos.frame);

if (!subq.IsCRCValid())
{
Log_WarningFmt("SCSI full subcode read returned invalid SubQ CRC (got {:02X} expected {:02X})", subq.crc,
CDImage::SubChannelQ::ComputeCRC(subq.data));
return false;
}

const CDImage::Position got_pos =
CDImage::Position::FromBCD(subq.absolute_minute_bcd, subq.absolute_second_bcd, subq.absolute_frame_bcd);
if (expected_pos != got_pos)
{
Log_WarningFmt(
"SCSI full subcode read returned invalid MSF (got {:02x}:{:02x}:{:02x}, expected {:02d}:{:02d}:{:02d})",
expected_pos.minute, expected_pos.second, expected_pos.frame, subq.absolute_minute_bcd,
subq.absolute_second_bcd, subq.absolute_frame_bcd);
return false;
}

return true;
}
else if (mode == SCSIReadMode::SubQOnly)
{
CDImage::SubChannelQ subq;
std::memcpy(&subq, buffer.data() + CDImage::RAW_SECTOR_SIZE, sizeof(subq));
Log_DevFmt("SCSI subq read returned [{}] for {:02d}:{:02d}:{:02d}",
StringUtil::EncodeHex(subq.data.data(), static_cast<int>(subq.data.size())), expected_pos.minute,
expected_pos.second, expected_pos.frame);

if (!subq.IsCRCValid())
{
Log_WarningFmt("SCSI subq read returned invalid SubQ CRC (got {:02X} expected {:02X})", subq.crc,
CDImage::SubChannelQ::ComputeCRC(subq.data));
return false;
}

const CDImage::Position got_pos =
CDImage::Position::FromBCD(subq.absolute_minute_bcd, subq.absolute_second_bcd, subq.absolute_frame_bcd);
if (expected_pos != got_pos)
{
Log_WarningFmt("SCSI subq read returned invalid MSF (got {:02x}:{:02x}:{:02x}, expected {:02d}:{:02d}:{:02d})",
expected_pos.minute, expected_pos.second, expected_pos.frame, subq.absolute_minute_bcd,
subq.absolute_second_bcd, subq.absolute_frame_bcd);
return false;
}

return true;
}
else // if (mode == SCSIReadMode::None || mode == SCSIReadMode::Raw)
Expand All @@ -136,6 +172,11 @@ enum class SCSIReadMode : u8
}
}

[[maybe_unused]] static bool ShouldTryReadingSubcode()
{
return !Host::GetBaseBoolSettingValue("CDROM", "IgnoreHostSubcode", false);
}

#if defined(_WIN32)

// The include order here is critical.
Expand Down Expand Up @@ -522,13 +563,15 @@ bool CDImageDeviceWin32::DetermineReadMode(bool try_sptd)
{
// Prefer raw reads if we can use them
const LBA track_1_lba = static_cast<LBA>(m_indices[m_tracks[0].first_index].file_offset);
const LBA track_1_subq_lba = track_1_lba + FRAMES_PER_SECOND * 2;
const bool check_subcode = ShouldTryReadingSubcode();

Log_DevPrint("Trying raw reads...");
if (DoRawRead(track_1_lba))
if (check_subcode && DoRawRead(track_1_lba))
{
// verify subcode
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), SCSIReadCommandOutputSize(SCSIReadMode::Full)),
SCSIReadMode::Full))
SCSIReadMode::Full, track_1_subq_lba))
{
Log_VerbosePrint("Using raw reads with full subcode");
m_scsi_read_mode = SCSIReadMode::None;
Expand All @@ -540,9 +583,9 @@ bool CDImageDeviceWin32::DetermineReadMode(bool try_sptd)
std::optional<u32> transfer_size;

Log_DevPrint("Trying SCSI read with full subcode...");
if ((transfer_size = DoSCSIRead(track_1_lba, SCSIReadMode::Full)).has_value())
if (check_subcode && (transfer_size = DoSCSIRead(track_1_lba, SCSIReadMode::Full)).has_value())
{
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::Full))
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::Full, track_1_subq_lba))
{
Log_VerbosePrint("Using SCSI reads with subcode");
m_scsi_read_mode = SCSIReadMode::Full;
Expand All @@ -552,9 +595,10 @@ bool CDImageDeviceWin32::DetermineReadMode(bool try_sptd)
}

Log_WarningPrint("Full subcode failed, trying SCSI read with only subq...");
if ((transfer_size = DoSCSIRead(track_1_lba, SCSIReadMode::SubQOnly)).has_value())
if (check_subcode && (transfer_size = DoSCSIRead(track_1_lba, SCSIReadMode::SubQOnly)).has_value())
{
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::SubQOnly))
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::SubQOnly,
track_1_subq_lba))
{
Log_VerbosePrint("Using SCSI reads with subq only");
m_scsi_read_mode = SCSIReadMode::SubQOnly;
Expand All @@ -567,7 +611,7 @@ bool CDImageDeviceWin32::DetermineReadMode(bool try_sptd)
Log_WarningPrint("Subq only failed failed, trying SCSI without subcode...");
if ((transfer_size = DoSCSIRead(track_1_lba, SCSIReadMode::Raw)).has_value())
{
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::Raw))
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::Raw, track_1_subq_lba))
{
Log_WarningPrint("Using SCSI raw reads, libcrypt games will not run correctly");
m_scsi_read_mode = SCSIReadMode::Raw;
Expand Down Expand Up @@ -990,12 +1034,14 @@ bool CDImageDeviceLinux::ReadSectorToBuffer(LBA lba)
bool CDImageDeviceLinux::DetermineReadMode(Error* error)
{
const LBA track_1_lba = static_cast<LBA>(m_indices[m_tracks[0].first_index].file_offset);
const LBA track_1_subq_lba = track_1_lba + FRAMES_PER_SECOND * 2;
const bool check_subcode = ShouldTryReadingSubcode();
std::optional<u32> transfer_size;

Log_DevPrint("Trying SCSI read with full subcode...");
if ((transfer_size = DoSCSIRead(track_1_lba, SCSIReadMode::Full)).has_value())
if (check_subcode && (transfer_size = DoSCSIRead(track_1_lba, SCSIReadMode::Full)).has_value())
{
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::Full))
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::Full, track_1_subq_lba))
{
Log_VerbosePrint("Using SCSI reads with subcode");
m_scsi_read_mode = SCSIReadMode::Full;
Expand All @@ -1004,9 +1050,10 @@ bool CDImageDeviceLinux::DetermineReadMode(Error* error)
}

Log_WarningPrint("Full subcode failed, trying SCSI read with only subq...");
if ((transfer_size = DoSCSIRead(track_1_lba, SCSIReadMode::SubQOnly)).has_value())
if (check_subcode && (transfer_size = DoSCSIRead(track_1_lba, SCSIReadMode::SubQOnly)).has_value())
{
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::SubQOnly))
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::SubQOnly,
track_1_subq_lba))
{
Log_VerbosePrint("Using SCSI reads with subq only");
m_scsi_read_mode = SCSIReadMode::SubQOnly;
Expand All @@ -1026,7 +1073,7 @@ bool CDImageDeviceLinux::DetermineReadMode(Error* error)
Log_WarningPrint("CDROMREADRAW failed, trying SCSI without subcode...");
if ((transfer_size = DoSCSIRead(track_1_lba, SCSIReadMode::Raw)).has_value())
{
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::Raw))
if (VerifySCSIReadData(std::span<u8>(m_buffer.data(), transfer_size.value()), SCSIReadMode::Raw, track_1_subq_lba))
{
Log_WarningPrint("Using SCSI raw reads, libcrypt games will not run correctly");
m_scsi_read_mode = SCSIReadMode::Raw;
Expand Down

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