The Tor Browser: security/sandbox/win/src/sidestep/mini_disassembler.h@6474c204b198 (annotated)

security/sandbox/win/src/sidestep/mini_disassembler.h@6474c204b198 (annotated)

security/sandbox/win/src/sidestep/mini_disassembler.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 // Definition of MiniDisassembler.
 #ifndef SANDBOX_SRC_SIDESTEP_MINI_DISASSEMBLER_H__
 #define SANDBOX_SRC_SIDESTEP_MINI_DISASSEMBLER_H__
 #include "sandbox/win/src/sidestep/mini_disassembler_types.h"
 namespace sidestep {
 // This small disassembler is very limited
 // in its functionality, and in fact does only the bare minimum required by the
 // preamble patching utility.  It may be useful for other purposes, however.
 //
 // The limitations include at least the following:
 //  -# No support for coprocessor opcodes, MMX, etc.
 //  -# No machine-readable identification of opcodes or decoding of
 //     assembly parameters. The name of the opcode (as a string) is given,
 //     however, to aid debugging.
 //
 // You may ask what this little disassembler actually does, then?  The answer is
 // that it does the following, which is exactly what the patching utility needs:
 //  -# Indicates if opcode is a jump (any kind) or a return (any kind)
 //     because this is important for the patching utility to determine if
 //     a function is too short or there are jumps too early in it for it
 //     to be preamble patched.
 //  -# The opcode length is always calculated, so that the patching utility
 //     can figure out where the next instruction starts, and whether it
 //     already has enough instructions to replace with the absolute jump
 //     to the patching code.
 //
 // The usage is quite simple; just create a MiniDisassembler and use its
 // Disassemble() method.
 //
 // If you would like to extend this disassembler, please refer to the
 // IA-32 Intel Architecture Software Developer's Manual Volume 2:
 // Instruction Set Reference for information about operand decoding
 // etc.
 class MiniDisassembler {
  public:
   // Creates a new instance and sets defaults.
   //
   // operand_default_32_bits: If true, the default operand size is
   // set to 32 bits, which is the default under Win32. Otherwise it is 16 bits.
   // address_default_32_bits: If true, the default address size is
   // set to 32 bits, which is the default under Win32. Otherwise it is 16 bits.
   MiniDisassembler(bool operand_default_32_bits,
                    bool address_default_32_bits);
   // Equivalent to MiniDisassembler(true, true);
   MiniDisassembler();
   // Attempts to disassemble a single instruction starting from the
   // address in memory it is pointed to.
   //
   // start: Address where disassembly should start.
   // instruction_bytes: Variable that will be incremented by
   // the length in bytes of the instruction.
   // Returns enItJump, enItReturn or enItGeneric on success.  enItUnknown
   // if unable to disassemble, enItUnused if this seems to be an unused
   // opcode. In the last two (error) cases, cbInstruction will be set
   // to 0xffffffff.
   //
   // Postcondition: This instance of the disassembler is ready to be used again,
   // with unchanged defaults from creation time.
   InstructionType Disassemble(unsigned char* start,
                               unsigned int* instruction_bytes);
  private:
   // Makes the disassembler ready for reuse.
   void Initialize();
   // Sets the flags for address and operand sizes.
   // Returns Number of prefix bytes.
   InstructionType ProcessPrefixes(unsigned char* start, unsigned int* size);
   // Sets the flag for whether we have ModR/M, and increments
   // operand_bytes_ if any are specifies by the opcode directly.
   // Returns Number of opcode bytes.
   InstructionType ProcessOpcode(unsigned char* start,
                                 unsigned int table,
                                 unsigned int* size);
   // Checks the type of the supplied operand.  Increments
   // operand_bytes_ if it directly indicates an immediate etc.
   // operand.  Asserts have_modrm_ if the operand specifies
   // a ModR/M byte.
   bool ProcessOperand(int flag_operand);
   // Increments operand_bytes_ by size specified by ModR/M and
   // by SIB if present.
   // Returns 0 in case of error, 1 if there is just a ModR/M byte,
   // 2 if there is a ModR/M byte and a SIB byte.
   bool ProcessModrm(unsigned char* start, unsigned int* size);
   // Processes the SIB byte that it is pointed to.
   // start: Pointer to the SIB byte.
   // mod: The mod field from the ModR/M byte.
   // Returns 1 to indicate success (indicates 1 SIB byte)
   bool ProcessSib(unsigned char* start, unsigned char mod, unsigned int* size);
   // The instruction type we have decoded from the opcode.
   InstructionType instruction_type_;
   // Counts the number of bytes that is occupied by operands in
   // the current instruction (note: we don't care about how large
   // operands stored in registers etc. are).
   unsigned int operand_bytes_;
   // True iff there is a ModR/M byte in this instruction.
   bool have_modrm_;
   // True iff we need to decode the ModR/M byte (sometimes it just
   // points to a register, we can tell by the addressing mode).
   bool should_decode_modrm_;
   // Current operand size is 32 bits if true, 16 bits if false.
   bool operand_is_32_bits_;
   // Default operand size is 32 bits if true, 16 bits if false.
   bool operand_default_is_32_bits_;
   // Current address size is 32 bits if true, 16 bits if false.
   bool address_is_32_bits_;
   // Default address size is 32 bits if true, 16 bits if false.
   bool address_default_is_32_bits_;
   // Huge big opcode table based on the IA-32 manual, defined
   // in Ia32OpcodeMap.cpp
   static const OpcodeTable s_ia32_opcode_map_[];
   // Somewhat smaller table to help with decoding ModR/M bytes
   // when 16-bit addressing mode is being used.  Defined in
   // Ia32ModrmMap.cpp
   static const ModrmEntry s_ia16_modrm_map_[];
   // Somewhat smaller table to help with decoding ModR/M bytes
   // when 32-bit addressing mode is being used.  Defined in
   // Ia32ModrmMap.cpp
   static const ModrmEntry s_ia32_modrm_map_[];
   // Indicators of whether we got certain prefixes that certain
   // silly Intel instructions depend on in nonstandard ways for
   // their behaviors.
   bool got_f2_prefix_, got_f3_prefix_, got_66_prefix_;
 };
 };  // namespace sidestep
 #endif  // SANDBOX_SRC_SIDESTEP_MINI_DISASSEMBLER_H__

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security/sandbox/win/src/sidestep/mini_disassembler.h@6474c204b198 (annotated)

security/sandbox/win/src/sidestep/mini_disassembler.h