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MalwareSourceCode/Win32/Proof of Concepts/CheckKernelEATHook/CheckKernelHookDrv/CheckKernelHook/libdasm.c

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2022-04-12 01:00:13 +00:00
/*
* libdasm -- simple x86 disassembly library
* (c) 2004 - 2005 jt / nologin.org
*
*
* TODO:
* - more documentation
* - do more code validation
*
*/
#include <stdio.h>
#include <string.h>
#include "libdasm.h"
#include "tables.h"
// Endianess conversion routines (thanks Ero)
__inline__ BYTE FETCH8(BYTE *addr) {
// So far byte cast seems to work on all tested platforms
return *(BYTE *)addr;
}
__inline__ WORD FETCH16(BYTE *addr) {
#if defined __X86__
// Direct cast only for x86
return *(WORD *)addr;
#else
// Revert to memcpy
WORD val;
memcpy(&val, addr, 2);
#if defined __LITTLE_ENDIAN__
return val;
#else
return ((val & 0xff00) >> 8) |
((val & 0x00ff) << 8);
#endif // __LITTLE_ENDIAN__
#endif // __X86__
}
__inline__ DWORD FETCH32(BYTE *addr) {
#if defined __X86__
return *(DWORD *)addr;
#else
DWORD val;
memcpy(&val, addr, 4);
#if defined __LITTLE_ENDIAN__
return val;
#else
return ((val & (0xff000000)) >> 24) |
((val & (0x00ff0000)) >> 8) |
((val & (0x0000ff00)) << 8) |
((val & (0x000000ff)) << 24);
#endif // __LITTLE_ENDIAN__
#endif // __X86__
}
// Parse 2 and 3-byte opcodes
int get_real_instruction2(BYTE *addr, int *flags) {
switch (*addr) {
// opcode extensions for 2-byte opcodes
case 0x00:
// Clear extension
*flags &= 0xFFFFFF00;
*flags |= EXT_G6;
break;
case 0x01:
*flags &= 0xFFFFFF00;
*flags |= EXT_G7;
break;
case 0x71:
*flags &= 0xFFFFFF00;
*flags |= EXT_GC;
break;
case 0x72:
*flags &= 0xFFFFFF00;
*flags |= EXT_GD;
break;
case 0x73:
*flags &= 0xFFFFFF00;
*flags |= EXT_GE;
break;
case 0xae:
*flags &= 0xFFFFFF00;
*flags |= EXT_GF;
break;
case 0xba:
*flags &= 0xFFFFFF00;
*flags |= EXT_G8;
break;
case 0xc7:
*flags &= 0xFFFFFF00;
*flags |= EXT_G9;
break;
default:
break;
}
return 0;
}
// Parse instruction flags, get opcode index
int get_real_instruction(BYTE *addr, int *index, int *flags) {
switch (*addr) {
// 2-byte opcode
case 0x0f:
*index += 1;
*flags |= EXT_T2;
break;
// Prefix group 2
case 0x2e:
*index += 1;
// Clear previous flags from same group (undefined effect)
*flags &= 0xFF00FFFF;
*flags |= PREFIX_CS_OVERRIDE;
get_real_instruction(addr + 1, index, flags);
break;
case 0x36:
*index += 1;
*flags &= 0xFF00FFFF;
*flags |= PREFIX_SS_OVERRIDE;
get_real_instruction(addr + 1, index, flags);
break;
case 0x3e:
*index += 1;
*flags &= 0xFF00FFFF;
*flags |= PREFIX_DS_OVERRIDE;
get_real_instruction(addr + 1, index, flags);
break;
case 0x26:
*index += 1;
*flags &= 0xFF00FFFF;
*flags |= PREFIX_ES_OVERRIDE;
get_real_instruction(addr + 1, index, flags);
break;
case 0x64:
*index += 1;
*flags &= 0xFF00FFFF;
*flags |= PREFIX_FS_OVERRIDE;
get_real_instruction(addr + 1, index, flags);
break;
case 0x65:
*index += 1;
*flags &= 0xFF00FFFF;
*flags |= PREFIX_GS_OVERRIDE;
get_real_instruction(addr + 1, index, flags);
break;
// Prefix group 3 or 3-byte opcode
case 0x66:
// Do not clear flags from the same group!!!!
*index += 1;
*flags |= PREFIX_OPERAND_SIZE_OVERRIDE;
get_real_instruction(addr + 1, index, flags);
break;
// Prefix group 4
case 0x67:
// Do not clear flags from the same group!!!!
*index += 1;
*flags |= PREFIX_ADDR_SIZE_OVERRIDE;
get_real_instruction(addr + 1, index, flags);
break;
// Extension group 1
case 0x80:
case 0x81:
case 0x82:
case 0x83:
*flags |= EXT_G1;
break;
// Extension group 2
case 0xc0:
case 0xc1:
case 0xd0:
case 0xd1:
case 0xd2:
case 0xd3:
*flags |= EXT_G2;
break;
// Escape to co-processor
case 0xd8:
case 0xd9:
case 0xda:
case 0xdb:
case 0xdc:
case 0xdd:
case 0xde:
case 0xdf:
*index += 1;
*flags |= EXT_CP;
break;
// Prefix group 1 or 3-byte opcode
case 0xf0:
*index += 1;
*flags &= 0x00FFFFFF;
*flags |= PREFIX_LOCK;
get_real_instruction(addr + 1, index, flags);
break;
case 0xf2:
*index += 1;
*flags &= 0x00FFFFFF;
*flags |= PREFIX_REPNE;
get_real_instruction(addr + 1, index, flags);
break;
case 0xf3:
*index += 1;
*flags &= 0x00FFFFFF;
*flags |= PREFIX_REP;
get_real_instruction(addr + 1, index, flags);
break;
// Extension group 3
case 0xf6:
case 0xf7:
*flags |= EXT_G3;
break;
// Extension group 4
case 0xfe:
*flags |= EXT_G4;
break;
// Extension group 5
case 0xff:
*flags |= EXT_G5;
break;
default:
break;
}
return 0;
}
// Parse operand and fill OPERAND structure
int get_operand(PINST inst, int oflags, PINSTRUCTION instruction,
POPERAND op, BYTE *data, int offset, enum Mode mode, int iflags) {
BYTE *addr = data + offset;
int index = 0, sib = 0, scale = 0;
int reg = REG_NOP;
int basereg = REG_NOP;
int indexreg = REG_NOP;
int dispbytes = 0;
enum Mode pmode;
// Is this valid operand?
if (oflags == FLAGS_NONE) {
op->type = OPERAND_TYPE_NONE;
return 1;
}
// Copy flags
op->flags = oflags;
// Set operand registers
op->reg = REG_NOP;
op->basereg = REG_NOP;
op->indexreg = REG_NOP;
// Offsets
op->dispoffset = 0;
op->immoffset = 0;
// Parse modrm and sib
if (inst->modrm) {
// 32-bit mode
if (((mode == MODE_32) && (MASK_PREFIX_ADDR(iflags) == 0)) ||
((mode == MODE_16) && (MASK_PREFIX_ADDR(iflags) == 1)))
pmode = MODE_32;
else
pmode = MODE_16;
// Update length only once!
if (!instruction->length) {
instruction->modrm = *addr;
instruction->length += 1;
}
// Register
reg = MASK_MODRM_REG(*addr);
// Displacement bytes
// SIB can also specify additional displacement, see below
if (MASK_MODRM_MOD(*addr) == 0) {
if ((pmode == MODE_32) && (MASK_MODRM_RM(*addr) == REG_EBP))
dispbytes = 4;
if ((pmode == MODE_16) && (MASK_MODRM_RM(*addr) == REG_ESI))
dispbytes = 2;
} else if (MASK_MODRM_MOD(*addr) == 1) {
dispbytes = 1;
} else if (MASK_MODRM_MOD(*addr) == 2) {
dispbytes = (pmode == MODE_32) ? 4 : 2;
}
// Base and index registers
// 32-bit mode
if (pmode == MODE_32) {
if ((MASK_MODRM_RM(*addr) == REG_ESP) &&
(MASK_MODRM_MOD(*addr) != 3)) {
sib = 1;
instruction->sib = *(addr + 1);
// Update length only once!
if (instruction->length == 1) {
instruction->sib = *(addr + 1);
instruction->length += 1;
}
basereg = MASK_SIB_BASE( *(addr + 1));
indexreg = MASK_SIB_INDEX(*(addr + 1));
scale = MASK_SIB_SCALE(*(addr + 1)) * 2;
// Fix scale *8
if (scale == 6)
scale += 2;
// Special case where base=ebp and MOD = 0
if ((basereg == REG_EBP) && !MASK_MODRM_MOD(*addr)) {
basereg = REG_NOP;
dispbytes = 4;
}
if (indexreg == REG_ESP)
indexreg = REG_NOP;
} else {
if (!MASK_MODRM_MOD(*addr) && (MASK_MODRM_RM(*addr) == REG_EBP))
basereg = REG_NOP;
else
basereg = MASK_MODRM_RM(*addr);
}
// 16-bit
} else {
switch (MASK_MODRM_RM(*addr)) {
case 0:
basereg = REG_EBX;
indexreg = REG_ESI;
break;
case 1:
basereg = REG_EBX;
indexreg = REG_EDI;
break;
case 2:
basereg = REG_EBP;
indexreg = REG_ESI;
break;
case 3:
basereg = REG_EBP;
indexreg = REG_EDI;
break;
case 4:
basereg = REG_ESI;
indexreg = REG_NOP;
break;
case 5:
basereg = REG_EDI;
indexreg = REG_NOP;
break;
case 6:
if (!MASK_MODRM_MOD(*addr))
basereg = REG_NOP;
else
basereg = REG_EBP;
indexreg = REG_NOP;
break;
case 7:
basereg = REG_EBX;
indexreg = REG_NOP;
break;
}
if (MASK_MODRM_MOD(*addr) == 3) {
basereg = MASK_MODRM_RM(*addr);
indexreg = REG_NOP;
}
}
}
// Operand addressing mode -specific parsing
switch (MASK_AM(oflags)) {
// Register encoded in instruction
case AM_REG:
op->type = OPERAND_TYPE_REGISTER;
op->reg = MASK_REG(oflags);
break;
// Register/memory encoded in MODRM
case AM_M:
if (MASK_MODRM_MOD(*addr) == 3)
return 0;
goto skip_rest;
case AM_R:
if (MASK_MODRM_MOD(*addr) != 3)
return 0;
skip_rest:
case AM_Q:
case AM_W:
case AM_E:
op->type = OPERAND_TYPE_MEMORY;
op->dispbytes = dispbytes;
instruction->dispbytes = dispbytes;
op->basereg = basereg;
op->indexreg = indexreg;
op->scale = scale;
index = (sib) ? 1 : 0;
if (dispbytes)
op->dispoffset = index + 1 + offset;
switch (dispbytes) {
case 0:
break;
case 1:
op->displacement = FETCH8(addr + 1 + index);
// Always sign-extend
if (op->displacement >= 0x80)
op->displacement |= 0xffffff00;
break;
case 2:
op->displacement = FETCH16(addr + 1 + index);
// Malformed opcode
if (op->displacement < 0x80)
return 0;
break;
case 4:
op->displacement = FETCH32(addr + 1 + index);
// XXX: problems with [index*scale + disp] addressing
//if (op->displacement < 0x80)
// return 0;
break;
}
// MODRM defines register
if ((basereg != REG_NOP) && (MASK_MODRM_MOD(*addr) == 3)) {
op->type = OPERAND_TYPE_REGISTER;
op->reg = basereg;
}
break;
// Immediate byte 1 encoded in instruction
case AM_I1:
op->type = OPERAND_TYPE_IMMEDIATE;
op->immbytes = 1;
op->immediate = 1;
break;
// Immediate value
case AM_J:
op->type = OPERAND_TYPE_IMMEDIATE;
// Always sign-extend
oflags |= F_s;
case AM_I:
op->type = OPERAND_TYPE_IMMEDIATE;
index = (inst->modrm) ? 1 : 0;
index += (sib) ? 1 : 0;
index += instruction->immbytes;
index += instruction->dispbytes;
op->immoffset = index + offset;
// 32-bit mode
if (((mode == MODE_32) && (MASK_PREFIX_OPERAND(iflags) == 0)) ||
((mode == MODE_16) && (MASK_PREFIX_OPERAND(iflags) == 1)))
mode = MODE_32;
else
mode = MODE_16;
switch (MASK_OT(oflags)) {
case OT_b:
op->immbytes = 1;
op->immediate = FETCH8(addr + index);
if ((op->immediate >= 0x80) &&
(MASK_FLAGS(oflags) == F_s))
op->immediate |= 0xffffff00;
break;
case OT_v:
op->immbytes = (mode == MODE_32) ?
4 : 2;
op->immediate = (mode == MODE_32) ?
FETCH32(addr + index) :
FETCH16(addr + index);
break;
case OT_w:
op->immbytes = 2;
op->immediate = FETCH16(addr + index);
break;
}
instruction->immbytes += op->immbytes;
break;
// 32-bit or 48-bit address
case AM_A:
op->type = OPERAND_TYPE_IMMEDIATE;
// 32-bit mode
if (((mode == MODE_32) && (MASK_PREFIX_OPERAND(iflags) == 0)) ||
((mode == MODE_16) && (MASK_PREFIX_OPERAND(iflags) == 1)))
mode = MODE_32;
else
mode = MODE_16;
op->dispbytes = (mode == MODE_32) ? 6 : 4;
op->displacement = (mode == MODE_32) ?
FETCH32(addr) : FETCH16(addr);
op->section = FETCH16(addr + op->dispbytes - 2);
instruction->dispbytes = op->dispbytes;
instruction->sectionbytes = 2;
break;
// Plain displacement without MODRM/SIB
case AM_O:
op->type = OPERAND_TYPE_MEMORY;
switch (MASK_OT(oflags)) {
case OT_b:
op->dispbytes = 1;
op->displacement = FETCH8(addr);
break;
case OT_v:
op->dispbytes = (mode == MODE_32) ? 4 : 2;
op->displacement = (mode == MODE_32) ?
FETCH32(addr) : FETCH16(addr);
break;
}
instruction->dispbytes = op->dispbytes;
op->dispoffset = offset;
break;
// General-purpose register encoded in MODRM
case AM_G:
op->type = OPERAND_TYPE_REGISTER;
op->reg = reg;
break;
// control register encoded in MODRM
case AM_C:
// debug register encoded in MODRM
case AM_D:
// Segment register encoded in MODRM
case AM_S:
// TEST register encoded in MODRM
case AM_T:
// MMX register encoded in MODRM
case AM_P:
// XMM register encoded in MODRM
case AM_V:
op->type = OPERAND_TYPE_REGISTER;
op->reg = MASK_MODRM_REG(instruction->modrm);
break;
}
return 1;
}
// Print operand string
#if !defined NOSTR
int get_operand_string(INSTRUCTION *inst, OPERAND *op,
enum Format format, DWORD offset, char *string, int length) {
enum Mode mode;
int regtype = 0;
DWORD tmp;
memset(string, 0, length);
if (op->type == OPERAND_TYPE_REGISTER) {
// 32-bit mode
if (((inst->mode == MODE_32) && (MASK_PREFIX_OPERAND(inst->flags) == 0)) ||
((inst->mode == MODE_16) && (MASK_PREFIX_OPERAND(inst->flags) == 1)))
mode = MODE_32;
else
mode = MODE_16;
if (format == FORMAT_ATT)
snprintf(string + strlen(string), length - strlen(string), "%%");
// Determine register type
switch (MASK_AM(op->flags)) {
case AM_REG:
if (MASK_FLAGS(op->flags) == F_r)
regtype = REG_SEGMENT;
else if (MASK_FLAGS(op->flags) == F_f)
regtype = REG_FPU;
else
regtype = REG_GEN_DWORD;
break;
case AM_E:
case AM_G:
case AM_R:
regtype = REG_GEN_DWORD;
break;
// control register encoded in MODRM
case AM_C:
regtype = REG_CONTROL;
break;
// debug register encoded in MODRM
case AM_D:
regtype = REG_DEBUG;
break;
// Segment register encoded in MODRM
case AM_S:
regtype = REG_SEGMENT;
break;
// TEST register encoded in MODRM
case AM_T:
regtype = REG_TEST;
break;
// MMX register encoded in MODRM
case AM_P:
case AM_Q:
regtype = REG_MMX;
break;
// XMM register encoded in MODRM
case AM_V:
case AM_W:
regtype = REG_XMM;
break;
}
if (regtype == REG_GEN_DWORD) {
switch (MASK_OT(op->flags)) {
case OT_b:
snprintf(string + strlen(string), length - strlen(string),
"%s", reg_table[REG_GEN_BYTE][op->reg]);
break;
case OT_v:
snprintf(string + strlen(string), length - strlen(string),
"%s", (mode == MODE_32) ?
reg_table[REG_GEN_DWORD][op->reg] :
reg_table[REG_GEN_WORD][op->reg]);
break;
case OT_w:
snprintf(string + strlen(string), length - strlen(string),
"%s", reg_table[REG_GEN_WORD][op->reg]);
break;
case OT_d:
snprintf(string + strlen(string), length - strlen(string),
"%s", reg_table[REG_GEN_DWORD][op->reg]);
break;
}
} else
snprintf(string + strlen(string), length - strlen(string),
"%s", reg_table[regtype][op->reg]);
} else if (op->type == OPERAND_TYPE_MEMORY) {
// 32-bit mode
if (((inst->mode == MODE_32) && (MASK_PREFIX_ADDR(inst->flags) == 0)) ||
((inst->mode == MODE_16) && (MASK_PREFIX_ADDR(inst->flags) == 1)))
mode = MODE_32;
else
mode = MODE_16;
// Segment register prefix (only in memory operands)
if (MASK_PREFIX_G2(inst->flags)) {
if (format == FORMAT_ATT)
snprintf(string + strlen(string),
length - strlen(string), "%%");
snprintf(string + strlen(string), length - strlen(string),
"%s:", reg_table[REG_SEGMENT][(MASK_PREFIX_G2(inst->flags)) - 1]);
}
// Displacement in ATT
if (op->dispbytes && (format == FORMAT_ATT))
snprintf(string + strlen(string), length - strlen(string),
"0x%x", op->displacement);
// Open memory addressing brackets
snprintf(string + strlen(string), length - strlen(string),
"%s", (format == FORMAT_ATT) ? "(" : "[");
// Base register
if (op->basereg != REG_NOP) {
snprintf(string + strlen(string), length - strlen(string),
"%s%s", (format == FORMAT_ATT) ? "%" : "",
(mode == MODE_32) ?
reg_table[REG_GEN_DWORD][op->basereg] :
reg_table[REG_GEN_WORD][op->basereg]);
}
// Index register
if (op->indexreg != REG_NOP) {
if (op->basereg != REG_NOP)
snprintf(string + strlen(string), length - strlen(string),
"%s%s", (format == FORMAT_ATT) ? ",%" : "+",
(mode == MODE_32) ?
reg_table[REG_GEN_DWORD][op->indexreg] :
reg_table[REG_GEN_WORD][op->indexreg]);
else
snprintf(string + strlen(string), length - strlen(string),
"%s%s", (format == FORMAT_ATT) ? "%" : "",
(mode == MODE_32) ?
reg_table[REG_GEN_DWORD][op->indexreg] :
reg_table[REG_GEN_WORD][op->indexreg]);
switch (op->scale) {
case 2:
snprintf(string + strlen(string), length - strlen(string),
"%s", (format == FORMAT_ATT) ?
",2" : "*2");
break;
case 4:
snprintf(string + strlen(string), length - strlen(string),
"%s", (format == FORMAT_ATT) ?
",4" : "*4");
break;
case 8:
snprintf(string + strlen(string), length - strlen(string),
"%s", (format == FORMAT_ATT) ?
",8" : "*8");
break;
}
}
// INTEL displacement
if (inst->dispbytes && (format != FORMAT_ATT)) {
if ((op->basereg != REG_NOP) || (op->indexreg != REG_NOP)) {
// Negative displacement
if (op->displacement & (1<<(op->dispbytes*8-1))) {
tmp = op->displacement;
switch (op->dispbytes) {
case 1:
tmp = ~tmp & 0xff;
break;
case 2:
tmp = ~tmp & 0xffff;
break;
case 4:
tmp = ~tmp;
break;
}
snprintf(string + strlen(string),
length - strlen(string),
"-0x%x", tmp + 1);
// Positive displacement
} else
snprintf(string + strlen(string),
length - strlen(string),
"+0x%x", op->displacement);
// Plain displacement
} else {
snprintf(string + strlen(string),
length - strlen(string),
"0x%x", op->displacement);
}
}
// Close memory addressing brackets
snprintf(string + strlen(string), length - strlen(string),
"%s", (format == FORMAT_ATT) ? ")" : "]");
} else if (op->type == OPERAND_TYPE_IMMEDIATE) {
// 32-bit mode
if (((inst->mode == MODE_32) && (MASK_PREFIX_OPERAND(inst->flags) == 0)) ||
((inst->mode == MODE_16) && (MASK_PREFIX_OPERAND(inst->flags) == 1)))
mode = MODE_32;
else
mode = MODE_16;
switch (MASK_AM(op->flags)) {
case AM_J:
snprintf(string + strlen(string), length - strlen(string),
"0x%x", op->immediate + inst->length + offset);
break;
case AM_I1:
case AM_I:
if (format == FORMAT_ATT)
snprintf(string + strlen(string), length - strlen(string), "$");
snprintf(string + strlen(string), length - strlen(string),
"0x%x", op->immediate);
break;
// 32-bit or 48-bit address
case AM_A:
snprintf(string + strlen(string), length - strlen(string),
"%s0x%x:%s0x%x",
(format == FORMAT_ATT) ? "$" : "",
op->section,
(format == FORMAT_ATT) ? "$" : "",
op->displacement);
break;
}
} else
return 0;
return 1;
}
#endif
// Fetch instruction
int get_instruction(PINSTRUCTION inst, BYTE *addr, enum Mode mode) {
PINST ptr;
int index = 0;
int flags = 0;
const char *ext = NULL;
memset(inst, 0, sizeof(INSTRUCTION));
// Parse flags, skip prefixes etc.
get_real_instruction(addr, &index, &flags);
// Select instruction table
// FPU opcodes
if (MASK_EXT(flags) == EXT_CP) {
if (*(addr + index) < 0xc0) {
// MODRM byte adds the additional byte
index--;
inst->fpuindex = *(addr + index) - 0xd8;
inst->opcode = *(addr + index + 1);
ptr = &inst_table4[inst->fpuindex]
[MASK_MODRM_REG(inst->opcode)];
} else {
inst->fpuindex = *(addr + index - 1) - 0xd8;
inst->opcode = *(addr + index);
ptr = &inst_table4[inst->fpuindex]
[inst->opcode - 0xb8];
}
// 2 or 3-byte opcodes
} else if (MASK_EXT(flags) == EXT_T2) {
inst->opcode = *(addr + index);
get_real_instruction2(addr + index, &flags);
// 3-byte opcode tables
// prefix 0x66
if (MASK_PREFIX_OPERAND(flags) == 1) {
ptr = &inst_table3_66[inst->opcode];
// prefix 0xf2
} else if (MASK_PREFIX_G1(flags) == 2) {
ptr = &inst_table3_f2[inst->opcode];
// prefix 0xf3
} else if (MASK_PREFIX_G1(flags) == 3) {
ptr = &inst_table3_f3[inst->opcode];
// normal 2-byte opcode table
} else {
ptr = &inst_table2[inst->opcode];
}
// extension group 3 "test" (<-- stupid hack)
} else if ((MASK_EXT(flags) == EXT_G3) &&
!MASK_MODRM_REG(*(addr + index + 1))) {
inst->opcode = *(addr + index);
ptr = &inst_table_test[inst->opcode - 0xf6];
// finally, the default 1-byte opcode table
} else {
inst->opcode = *(addr + index);
ptr = &inst_table1[inst->opcode];
}
// Illegal instruction
if (!ptr->mnemonic) return 0;
// Copy instruction type
inst->type = ptr->type;
// Pointer to instruction table
inst->ptr = ptr;
// Index points now to first byte after prefixes/escapes
index++;
// Opcode extensions
if (MASK_EXT(flags) && (MASK_EXT(flags) < EXT_T2)) {
inst->extindex = MASK_MODRM_REG(*(addr + index));
ext = ext_name_table[(MASK_EXT(flags)) - 1][inst->extindex];
if (ext == NULL)
return 0;
/*
* Copy instruction type from extension table
* except for groups 12-14. These are special groups
* that are either MMX/SSE instructions. For these,
* just use the type in INST structure.
*
*/
if ((MASK_EXT(flags) < 12) || (MASK_EXT(flags) > 14))
inst->type =
ext_type_table[(MASK_EXT(flags)) - 1][inst->extindex];
}
// Parse operands
if (!get_operand(ptr, ptr->flags1, inst, &inst->op1, addr, index,
mode, flags))
return 0;
if (!get_operand(ptr, ptr->flags2, inst, &inst->op2, addr, index,
mode, flags))
return 0;
if (!get_operand(ptr, ptr->flags3, inst, &inst->op3, addr, index,
mode, flags))
return 0;
// Add modrm/sib, displacement and immediate bytes in size
inst->length += index + inst->immbytes + inst->dispbytes;
// Copy addressing mode
inst->mode = mode;
// Copy instruction flags
inst->flags = flags;
return inst->length;
}
// Print instruction mnemonic
#if !defined NOSTR
int get_mnemonic_string(INSTRUCTION *inst, enum Format format, char *string, int length) {
const char *ext;
memset(string, 0, length);
// Segment override
if (MASK_PREFIX_G2(inst->flags) &&
(inst->op1.type != OPERAND_TYPE_MEMORY) &&
(inst->op2.type != OPERAND_TYPE_MEMORY))
snprintf(string + strlen(string), length - strlen(string),
"%s ", reg_table[REG_SEGMENT][(MASK_PREFIX_G2(inst->flags)) - 1]);
// Rep, lock etc.
if (MASK_PREFIX_G1(inst->flags) &&
(MASK_EXT(inst->flags) != EXT_T2))
snprintf(string + strlen(string), length - strlen(string),
"%s", rep_table[(MASK_PREFIX_G1(inst->flags)) - 1]);
// Opcode extensions
if (MASK_EXT(inst->flags) &&
(MASK_EXT(inst->flags) != EXT_T2) &&
(MASK_EXT(inst->flags) != EXT_CP)) {
ext = ext_name_table[(MASK_EXT(inst->flags)) - 1][inst->extindex];
snprintf(string + strlen(string), length - strlen(string),
"%s", ext);
} else {
snprintf(string + strlen(string), length - strlen(string),
"%s", inst->ptr->mnemonic);
}
// memory operation size in immediate to memory operations
// XXX: also, register -> memory operations when size is different
if (inst->ptr->modrm && (MASK_MODRM_MOD(inst->modrm) != 3) &&
(MASK_AM(inst->op2.flags) == AM_I)) {
switch (MASK_OT(inst->op1.flags)) {
case OT_b:
snprintf(string + strlen(string), length - strlen(string),
"%s", (format == FORMAT_ATT) ?
"b" : " byte");
break;
case OT_w:
snprintf(string + strlen(string), length - strlen(string),
"%s", (format == FORMAT_ATT) ?
"w" : " word");
break;
case OT_d:
snprintf(string + strlen(string), length - strlen(string),
"%s", (format == FORMAT_ATT) ?
"l" : " dword");
break;
case OT_v:
if (((inst->mode == MODE_32) && (MASK_PREFIX_OPERAND(inst->flags) == 0)) ||
((inst->mode == MODE_16) && (MASK_PREFIX_OPERAND(inst->flags) == 1)))
snprintf(string + strlen(string), length - strlen(string),
"%s", (format == FORMAT_ATT) ?
"l" : " dword");
else
snprintf(string + strlen(string), length - strlen(string),
"%s", (format == FORMAT_ATT) ?
"w" : " word");
break;
}
}
return 1;
}
// Print operands
int get_operands_string(INSTRUCTION *inst, enum Format format, DWORD offset,
char *string, int length) {
if (format == FORMAT_ATT) {
if (inst->op3.type != OPERAND_TYPE_NONE) {
get_operand_string(inst, &inst->op3, format, offset,
string + strlen(string), length - strlen(string));
snprintf(string + strlen(string), length - strlen(string), ",");
}
if (inst->op2.type != OPERAND_TYPE_NONE) {
get_operand_string(inst, &inst->op2, format, offset,
string + strlen(string), length - strlen(string));
snprintf(string + strlen(string), length - strlen(string), ",");
}
if (inst->op1.type != OPERAND_TYPE_NONE)
get_operand_string(inst, &inst->op1, format, offset,
string + strlen(string), length - strlen(string));
} else if (format == FORMAT_INTEL) {
if (inst->op1.type != OPERAND_TYPE_NONE)
get_operand_string(inst, &inst->op1, format, offset,
string + strlen(string), length - strlen(string));
if (inst->op2.type != OPERAND_TYPE_NONE) {
snprintf(string + strlen(string), length - strlen(string), ",");
get_operand_string(inst, &inst->op2, format, offset,
string + strlen(string), length - strlen(string));
}
if (inst->op3.type != OPERAND_TYPE_NONE) {
snprintf(string + strlen(string), length - strlen(string), ",");
get_operand_string(inst, &inst->op3, format, offset,
string + strlen(string), length - strlen(string));
}
} else
return 0;
return 1;
}
// Print instruction mnemonic, prefixes and operands
int get_instruction_string(INSTRUCTION *inst, enum Format format, DWORD offset,
char *string, int length) {
// Print the actual instruction string with possible prefixes etc.
get_mnemonic_string(inst, format, string, length);
snprintf(string + strlen(string), length - strlen(string), " ");
// Print operands
if (!get_operands_string(inst, format, offset,
string + strlen(string), length - strlen(string)))
return 0;
return 1;
}
#endif
// Helper functions
int get_register_type(POPERAND op) {
if (op->type != OPERAND_TYPE_REGISTER)
return 0;
switch (MASK_AM(op->flags)) {
case AM_REG:
if (MASK_FLAGS(op->flags) == F_r)
return REGISTER_TYPE_SEGMENT;
else if (MASK_FLAGS(op->flags) == F_f)
return REGISTER_TYPE_FPU;
else
return REGISTER_TYPE_GEN;
case AM_E:
case AM_G:
case AM_R:
return REGISTER_TYPE_GEN;
case AM_C:
return REGISTER_TYPE_CONTROL;
case AM_D:
return REGISTER_TYPE_DEBUG;
case AM_S:
return REGISTER_TYPE_SEGMENT;
case AM_T:
return REGISTER_TYPE_TEST;
case AM_P:
case AM_Q:
return REGISTER_TYPE_MMX;
case AM_V:
case AM_W:
return REGISTER_TYPE_XMM;
default:
break;
}
return 0;
}
int get_operand_type(POPERAND op) {
return op->type;
}
int get_operand_register(POPERAND op) {
return op->reg;
}
int get_operand_basereg(POPERAND op) {
return op->basereg;
}
int get_operand_indexreg(POPERAND op) {
return op->indexreg;
}
int get_operand_scale(POPERAND op) {
return op->scale;
}
int get_operand_immediate(POPERAND op, DWORD *imm) {
if (op->immbytes) {
*imm = op->immediate;
return 1;
} else
return 0;
}
int get_operand_displacement(POPERAND op, DWORD *disp) {
if (op->dispbytes) {
*disp = op->displacement;
return 1;
} else
return 0;
}
// XXX: note that source and destination are not always literal
POPERAND get_source_operand(PINSTRUCTION inst) {
if (inst->op2.type != OPERAND_TYPE_NONE)
return &inst->op2;
else
return NULL;
}
POPERAND get_destination_operand(PINSTRUCTION inst) {
if (inst->op1.type != OPERAND_TYPE_NONE)
return &inst->op1;
else
return NULL;
}
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