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/***************************************************************************************************
Zyan Disassembler Library (Zydis)
Original Author : Joel Hoener
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
***************************************************************************************************/
/**
* @file
*
* This file implements fuzz target for decoder, formatter and various utility functions.
*/
#include "ZydisFuzzShared.h"
/* ============================================================================================== */
/* Enums and types */
/* ============================================================================================== */
/**
* Main fuzzer control block data structure.
*/
typedef struct ZydisFuzzControlBlock_
{
ZydisMachineMode machine_mode;
ZydisStackWidth stack_width;
ZyanBool decoder_mode[ZYDIS_DECODER_MODE_MAX_VALUE + 1];
ZydisFormatterStyle formatter_style;
ZyanU64 u64; // u64 used for all kind of non-overlapping purposes
ZyanUPointer formatter_properties[ZYDIS_FORMATTER_PROP_MAX_VALUE + 1];
char string[16];
ZyanU16 formatter_max_len;
} ZydisFuzzControlBlock;
/* ============================================================================================== */
/* Fuzz target */
/* ============================================================================================== */
// We disable enum sanitization here because we actually want Zydis to be tested with
// possibly invalid enum values in mind, thus need to be able to create them here.
ZYAN_NO_SANITIZE("enum")
int ZydisFuzzTarget(ZydisStreamRead read_fn, void* stream_ctx)
{
ZydisFuzzControlBlock control_block;
if (read_fn(
stream_ctx, (ZyanU8*)&control_block, sizeof(control_block)) != sizeof(control_block))
{
ZYDIS_MAYBE_FPUTS("Not enough bytes to fuzz\n", ZYAN_STDERR);
return EXIT_SUCCESS;
}
control_block.string[ZYAN_ARRAY_LENGTH(control_block.string) - 1] = 0;
ZydisDecoder decoder;
if (!ZYAN_SUCCESS(ZydisDecoderInit(&decoder, control_block.machine_mode,
control_block.stack_width)))
{
ZYDIS_MAYBE_FPUTS("Failed to initialize decoder\n", ZYAN_STDERR);
return EXIT_FAILURE;
}
for (int mode = 0; mode <= ZYDIS_DECODER_MODE_MAX_VALUE; ++mode)
{
if (!ZYAN_SUCCESS(ZydisDecoderEnableMode(&decoder, (ZydisDecoderMode)mode,
control_block.decoder_mode[mode] ? 1 : 0)))
{
ZYDIS_MAYBE_FPUTS("Failed to adjust decoder-mode\n", ZYAN_STDERR);
return EXIT_FAILURE;
}
}
ZydisFormatter formatter;
if (!ZYAN_SUCCESS(ZydisFormatterInit(&formatter, control_block.formatter_style)))
{
ZYDIS_MAYBE_FPUTS("Failed to initialize formatter\n", ZYAN_STDERR);
return EXIT_FAILURE;
}
for (int prop = 0; prop <= ZYDIS_FORMATTER_PROP_MAX_VALUE; ++prop)
{
switch (prop)
{
case ZYDIS_FORMATTER_PROP_DEC_PREFIX:
case ZYDIS_FORMATTER_PROP_DEC_SUFFIX:
case ZYDIS_FORMATTER_PROP_HEX_PREFIX:
case ZYDIS_FORMATTER_PROP_HEX_SUFFIX:
control_block.formatter_properties[prop] =
control_block.formatter_properties[prop] ? (ZyanUPointer)&control_block.string : 0;
break;
default:
break;
}
if (!ZYAN_SUCCESS(ZydisFormatterSetProperty(&formatter, (ZydisFormatterProperty)prop,
control_block.formatter_properties[prop])))
{
ZYDIS_MAYBE_FPUTS("Failed to set formatter-attribute\n", ZYAN_STDERR);
return EXIT_FAILURE;
}
}
ZyanU8 buffer[32];
ZyanUSize input_len = read_fn(stream_ctx, buffer, sizeof(buffer));
ZydisDecodedInstruction instruction;
ZydisDecodedOperand operands[ZYDIS_MAX_OPERAND_COUNT];
// Fuzz decoder.
ZyanStatus status = ZydisDecoderDecodeFull(&decoder, buffer, input_len, &instruction, operands);
if (!ZYAN_SUCCESS(status))
{
return EXIT_FAILURE;
}
ZydisValidateEnumRanges(&instruction, operands, instruction.operand_count);
// Fuzz formatter.
char format_buffer[256];
// Allow the control block to artificially restrict the buffer size.
ZyanUSize output_len = ZYAN_MIN(sizeof(format_buffer), control_block.formatter_max_len);
ZydisFormatterFormatInstruction(&formatter, &instruction, operands,
instruction.operand_count_visible, format_buffer, output_len, control_block.u64, ZYAN_NULL);
// Fuzz tokenizer.
const ZydisFormatterToken* token;
status = ZydisFormatterTokenizeInstruction(&formatter, &instruction, operands,
instruction.operand_count_visible, format_buffer, output_len, control_block.u64, &token,
ZYAN_NULL);
// Walk tokens.
while (ZYAN_SUCCESS(status))
{
ZydisTokenType type;
ZyanConstCharPointer value;
if (!ZYAN_SUCCESS(status = ZydisFormatterTokenGetValue(token, &type, &value)))
{
ZYDIS_MAYBE_FPUTS("Failed to get token value\n", ZYAN_STDERR);
break;
}
status = ZydisFormatterTokenNext(&token);
}
if (instruction.operand_count_visible > 0)
{
// Fuzz single operand formatting. We reuse rt-address for operand selection.
// It's casted to u8 because modulo is way cheaper on that.
ZyanU8 op_idx = (ZyanU8)control_block.u64 % instruction.operand_count_visible;
const ZydisDecodedOperand* op = &operands[op_idx];
ZydisFormatterFormatOperand(&formatter, &instruction, op, format_buffer, output_len,
control_block.u64, ZYAN_NULL);
// Fuzz single operand tokenization.
ZydisFormatterTokenizeOperand(&formatter, &instruction, op, format_buffer, output_len,
control_block.u64, &token, ZYAN_NULL);
// Address translation helper.
ZyanU64 abs_addr;
ZydisCalcAbsoluteAddress(&instruction, op, control_block.u64, &abs_addr);
}
// Mnemonic helpers.
ZydisMnemonicGetString((ZydisMnemonic)control_block.u64);
ZydisMnemonicGetStringWrapped((ZydisMnemonic)control_block.u64);
// Instruction segment helper.
# ifndef ZYDIS_DISABLE_SEGMENT
ZydisInstructionSegments segments;
ZydisGetInstructionSegments(&instruction, &segments);
# endif
// Feature enable check helper.
ZydisIsFeatureEnabled((ZydisFeature)control_block.u64);
// Register helpers.
ZydisRegisterEncode((ZydisRegisterClass)(control_block.u64 >> 8), (ZyanU8)control_block.u64);
ZydisRegisterGetId((ZydisRegister)control_block.u64);
ZydisRegisterGetClass((ZydisRegister)control_block.u64);
ZydisRegisterGetWidth(control_block.machine_mode, (ZydisRegister)control_block.u64);
ZydisRegisterGetLargestEnclosing(control_block.machine_mode, (ZydisRegister)control_block.u64);
ZydisRegisterGetString((ZydisRegister)control_block.u64);
ZydisRegisterGetStringWrapped((ZydisRegister)control_block.u64);
ZydisRegisterClassGetWidth(control_block.machine_mode, (ZydisRegisterClass)control_block.u64);
return EXIT_SUCCESS;
}
/* ============================================================================================== */
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