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Fixed inaccurate relative operands on decoding 

Resolves #13
This commit is contained in:
Joel Höner 2017-04-09 20:55:49 +02:00
parent 0376376b83
commit 3b47ed4a9a
1 changed files with 14 additions and 1 deletions
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15
src/Decoder.c
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@ -524,7 +524,7 @@ static ZydisStatus ZydisDecodeOperandImmediate(ZydisInstructionDecoder* decoder,
case 32:
{
uint32_t data[4] = { 0, 0, 0, 0 };
for (int i = sizeof(data) / sizeof(data[0]); i > 0; --i)
for (int i = ZYDIS_ARRAY_SIZE(data); i > 0; --i)
{
ZYDIS_CHECK(ZydisInputNext(decoder, info, (uint8_t*)&data[i - 1]));
}
@ -1255,6 +1255,7 @@ static ZydisStatus ZydisDecodeOperand(ZydisInstructionDecoder* decoder, ZydisIns
case ZYDIS_SEM_OPERAND_TYPE_REL8:
info->attributes |= ZYDIS_ATTRIB_IS_RELATIVE;
operand->imm.isRelative = ZYDIS_TRUE;
// Intentional fallthrough.
case ZYDIS_SEM_OPERAND_TYPE_IMM8:
operand->size = 8;
operand->imm.isSigned = ZYDIS_TRUE;
@ -1266,6 +1267,7 @@ static ZydisStatus ZydisDecodeOperand(ZydisInstructionDecoder* decoder, ZydisIns
case ZYDIS_SEM_OPERAND_TYPE_REL16:
info->attributes |= ZYDIS_ATTRIB_IS_RELATIVE;
operand->imm.isRelative = ZYDIS_TRUE;
// Intentional fallthrough.
case ZYDIS_SEM_OPERAND_TYPE_IMM16:
operand->size = 16;
operand->imm.isSigned = ZYDIS_TRUE;
@ -1280,6 +1282,7 @@ static ZydisStatus ZydisDecodeOperand(ZydisInstructionDecoder* decoder, ZydisIns
case ZYDIS_SEM_OPERAND_TYPE_REL64:
info->attributes |= ZYDIS_ATTRIB_IS_RELATIVE;
operand->imm.isRelative = ZYDIS_TRUE;
// Intentional fallthrough.
case ZYDIS_SEM_OPERAND_TYPE_IMM64:
operand->size = 64;
operand->imm.isSigned = ZYDIS_TRUE;
@ -2383,6 +2386,16 @@ ZydisStatus ZydisDecoderDecodeInstructionEx(ZydisInstructionDecoder* decoder,
}
}
// For relative operands, apply instruction length offset.
for (size_t i = 0; i < info->operandCount; ++i)
{
if (info->operands[i].type == ZYDIS_OPERAND_TYPE_IMMEDIATE &&
info->operands[i].imm.isRelative)
{
info->operands[i].imm.value.sqword += info->length;
}
}
// Replace XCHG rAX, rAX with NOP alias
if (info->mnemonic == ZYDIS_MNEMONIC_XCHG)
{