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// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// disassembler_x86.h: Basic x86 bytecode disassembler
//
// Provides a simple disassembler which wraps libdisasm. This allows simple
// tests to be run against bytecode to test for various properties.
//
// Author: Cris Neckar
#ifndef GOOGLE_BREAKPAD_PROCESSOR_DISASSEMBLER_X86_H_
#define GOOGLE_BREAKPAD_PROCESSOR_DISASSEMBLER_X86_H_
#include <stddef.h>
#include <sys/types.h>
#include "google_breakpad/common/breakpad_types.h"
namespace libdis {
#include "third_party/libdisasm/libdis.h"
}
namespace google_breakpad {
enum {
DISX86_NONE = 0x0,
DISX86_BAD_BRANCH_TARGET = 0x1,
DISX86_BAD_ARGUMENT_PASSED = 0x2,
DISX86_BAD_WRITE = 0x4,
DISX86_BAD_BLOCK_WRITE = 0x8,
DISX86_BAD_READ = 0x10,
DISX86_BAD_BLOCK_READ = 0x20,
DISX86_BAD_COMPARISON = 0x40
};
class DisassemblerX86 {
public:
// TODO(cdn): Modify this class to take a MemoryRegion instead of just
// a raw buffer. This will make it easier to use this on arbitrary
// minidumps without first copying out the code segment.
DisassemblerX86(const uint8_t *bytecode, uint32_t, uint32_t);
~DisassemblerX86();
// This walks to the next instruction in the memory region and
// sets flags based on the type of instruction and previous state
// including any registers marked as bad through setBadRead()
// or setBadWrite(). This method can be called in a loop to
// disassemble until the end of a region.
uint32_t NextInstruction();
// Indicates whether the current disassembled instruction was valid.
bool currentInstructionValid() { return instr_valid_; }
// Returns the current instruction as defined in libdis.h,
// or NULL if the current instruction is not valid.
const libdis::x86_insn_t* currentInstruction() {
return instr_valid_ ? ¤t_instr_ : NULL;
}
// Returns the type of the current instruction as defined in libdis.h.
libdis::x86_insn_group currentInstructionGroup() {
return current_instr_.group;
}
// Indicates whether a return instruction has been encountered.
bool endOfBlock() { return end_of_block_; }
// The flags set so far for the disassembly.
uint16_t flags() { return flags_; }
// This sets an indicator that the register used to determine
// src or dest for the current instruction is tainted. These can
// be used after examining the current instruction to indicate,
// for example that a bad read or write occurred and the pointer
// stored in the register is currently invalid.
bool setBadRead();
bool setBadWrite();
protected:
const uint8_t *bytecode_;
uint32_t size_;
uint32_t virtual_address_;
uint32_t current_byte_offset_;
uint32_t current_inst_offset_;
bool instr_valid_;
libdis::x86_insn_t current_instr_;
// TODO(cdn): Maybe also track an expression's index register.
// ex: mov eax, [ebx + ecx]; ebx is base, ecx is index.
bool register_valid_;
libdis::x86_reg_t bad_register_;
bool pushed_bad_value_;
bool end_of_block_;
uint16_t flags_;
};
} // namespace google_breakpad
#endif // GOOGLE_BREAKPAD_PROCESSOR_DISASSEMBLER_X86_H_
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