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NDSCart: correctly restrict reading the DSi region on DSi carts

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This commit is contained in:
Arisotura 2021-07-22 21:37:34 +02:00
parent ab48461dc5
commit cd4ef575ee
2 changed files with 21 additions and 8 deletions
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27
src/NDSCart.cpp
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@ -193,6 +193,7 @@ CartCommon::CartCommon(u8* rom, u32 len, u32 chipid)
u8 unitcode = ROM[0x12];
IsDSi = (unitcode & 0x02) != 0;
DSiBase = *(u16*)&ROM[0x92] << 19;
}
CartCommon::~CartCommon()
@ -203,12 +204,14 @@ void CartCommon::Reset()
{
CmdEncMode = 0;
DataEncMode = 0;
DSiMode = false;
}
void CartCommon::SetupDirectBoot()
{
CmdEncMode = 2;
DataEncMode = 2;
DSiMode = false; // TODO!!
}
void CartCommon::DoSavestate(Savestate* file)
@ -217,6 +220,7 @@ void CartCommon::DoSavestate(Savestate* file)
file->Var32(&CmdEncMode);
file->Var32(&DataEncMode);
file->Bool32(&DSiMode);
}
void CartCommon::LoadSave(const char* path, u32 type)
@ -266,13 +270,15 @@ int CartCommon::ROMCommandStart(u8* cmd, u8* data, u32 len)
case 0x3C:
CmdEncMode = 1;
Key1_InitKeycode(false, *(u32*)&ROM[0xC], 2, 2);
DSiMode = false;
return 0;
case 0x3D:
if (IsDSi)
{
CmdEncMode = 11;
CmdEncMode = 1;
Key1_InitKeycode(true, *(u32*)&ROM[0xC], 1, 2);
DSiMode = true;
}
return 0;
@ -280,7 +286,7 @@ int CartCommon::ROMCommandStart(u8* cmd, u8* data, u32 len)
return 0;
}
}
else if (CmdEncMode == 1 || CmdEncMode == 11)
else if (CmdEncMode == 1)
{
// decrypt the KEY1 command as needed
// (KEY2 commands do not need decrypted because KEY2 is handled entirely by hardware,
@ -309,14 +315,13 @@ int CartCommon::ROMCommandStart(u8* cmd, u8* data, u32 len)
case 0x20:
{
u32 addr = (cmddec[2] & 0xF0) << 8;
if (CmdEncMode == 11)
if (DSiMode)
{
// the DSi region starts with 0x3000 unreadable bytes
// similarly to how the DS region starts at 0x1000 with 0x3000 unreadable bytes
// these contain data for KEY1 crypto
u32 dsiregion = *(u16*)&ROM[0x92] << 19;
addr -= 0x1000;
addr += dsiregion;
addr += DSiBase;
}
ReadROM(addr, 0x1000, data, 0);
}
@ -597,9 +602,15 @@ void CartRetail::ReadROM_B7(u32 addr, u32 len, u8* data, u32 offset)
if (addr < 0x8000)
addr = 0x8000 + (addr & 0x1FF);
// TODO: protect DSi secure area
// also protect DSi region if not unlocked
// and other security shenanigans
if (IsDSi && (addr >= DSiBase))
{
// for DSi carts:
// * in DSi mode: block the first 0x3000 bytes of the DSi area
// * in DS mode: block the entire DSi area
if ((!DSiMode) || (addr < (DSiBase+0x3000)))
addr = 0x8000 + (addr & 0x1FF);
}
memcpy(data+offset, ROM+addr, len);
}

2
src/NDSCart.h
View File

@ -56,6 +56,8 @@ protected:
u32 ROMLength;
u32 ChipID;
bool IsDSi;
bool DSiMode;
u32 DSiBase;
u32 CmdEncMode;
u32 DataEncMode;