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x64Emitter: Check end of allocated space when emitting code.

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This commit is contained in:
Admiral H. Curtiss
2020-05-02 00:42:29 +02:00
parent c36ae84b96
commit 5b52b3e9cb
10 changed files with 125 additions and 17 deletions
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73
Source/Core/Common/x64Emitter.cpp
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@ -101,9 +101,11 @@ enum class FloatOp
Invalid = -1,
};
void XEmitter::SetCodePtr(u8* ptr)
void XEmitter::SetCodePtr(u8* ptr, u8* end, bool write_failed)
{
code = ptr;
m_code_end = end;
m_write_failed = write_failed;
}
const u8* XEmitter::GetCodePtr() const
@ -116,31 +118,76 @@ u8* XEmitter::GetWritableCodePtr()
return code;
}
const u8* XEmitter::GetCodeEnd() const
{
return m_code_end;
}
u8* XEmitter::GetWritableCodeEnd()
{
return m_code_end;
}
void XEmitter::Write8(u8 value)
{
if (code >= m_code_end)
{
code = m_code_end;
m_write_failed = true;
return;
}
*code++ = value;
}
void XEmitter::Write16(u16 value)
{
if (code + sizeof(u16) > m_code_end)
{
code = m_code_end;
m_write_failed = true;
return;
}
std::memcpy(code, &value, sizeof(u16));
code += sizeof(u16);
}
void XEmitter::Write32(u32 value)
{
if (code + sizeof(u32) > m_code_end)
{
code = m_code_end;
m_write_failed = true;
return;
}
std::memcpy(code, &value, sizeof(u32));
code += sizeof(u32);
}
void XEmitter::Write64(u64 value)
{
if (code + sizeof(u64) > m_code_end)
{
code = m_code_end;
m_write_failed = true;
return;
}
std::memcpy(code, &value, sizeof(u64));
code += sizeof(u64);
}
void XEmitter::ReserveCodeSpace(int bytes)
{
if (code + bytes > m_code_end)
{
code = m_code_end;
m_write_failed = true;
return;
}
for (int i = 0; i < bytes; i++)
*code++ = 0xCC;
}
@ -454,6 +501,13 @@ FixupBranch XEmitter::CALL()
branch.ptr = code + 5;
Write8(0xE8);
Write32(0);
// If we couldn't write the full call instruction, indicate that in the returned FixupBranch by
// setting the branch's address to null. This will prevent a later SetJumpTarget() from writing to
// invalid memory.
if (HasWriteFailed())
branch.ptr = nullptr;
return branch;
}
@ -473,6 +527,13 @@ FixupBranch XEmitter::J(bool force5bytes)
Write8(0xE9);
Write32(0);
}
// If we couldn't write the full jump instruction, indicate that in the returned FixupBranch by
// setting the branch's address to null. This will prevent a later SetJumpTarget() from writing to
// invalid memory.
if (HasWriteFailed())
branch.ptr = nullptr;
return branch;
}
@ -493,6 +554,13 @@ FixupBranch XEmitter::J_CC(CCFlags conditionCode, bool force5bytes)
Write8(0x80 + conditionCode);
Write32(0);
}
// If we couldn't write the full jump instruction, indicate that in the returned FixupBranch by
// setting the branch's address to null. This will prevent a later SetJumpTarget() from writing to
// invalid memory.
if (HasWriteFailed())
branch.ptr = nullptr;
return branch;
}
@ -518,6 +586,9 @@ void XEmitter::J_CC(CCFlags conditionCode, const u8* addr)
void XEmitter::SetJumpTarget(const FixupBranch& branch)
{
if (!branch.ptr)
return;
if (branch.type == FixupBranch::Type::Branch8Bit)
{
s64 distance = (s64)(code - branch.ptr);