1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "courgette/disassembler.h"
6
7 #include <algorithm>
8 #include <string>
9 #include <vector>
10
11 #include "base/basictypes.h"
12 #include "base/logging.h"
13
14 #include "courgette/assembly_program.h"
15 #include "courgette/courgette.h"
16 #include "courgette/disassembler_elf_32_arm.h"
17 #include "courgette/disassembler_elf_32_x86.h"
18 #include "courgette/disassembler_win32_x64.h"
19 #include "courgette/disassembler_win32_x86.h"
20 #include "courgette/encoded_program.h"
21
22 namespace courgette {
23
24 ////////////////////////////////////////////////////////////////////////////////
25
DetectDisassembler(const void * buffer,size_t length)26 Disassembler* DetectDisassembler(const void* buffer, size_t length) {
27 Disassembler* disassembler = NULL;
28
29 disassembler = new DisassemblerWin32X86(buffer, length);
30 if (disassembler->ParseHeader())
31 return disassembler;
32 else
33 delete disassembler;
34
35 disassembler = new DisassemblerWin32X64(buffer, length);
36 if (disassembler->ParseHeader())
37 return disassembler;
38 else
39 delete disassembler;
40
41 disassembler = new DisassemblerElf32X86(buffer, length);
42 if (disassembler->ParseHeader())
43 return disassembler;
44 else
45 delete disassembler;
46
47 disassembler = new DisassemblerElf32ARM(buffer, length);
48 if (disassembler->ParseHeader())
49 return disassembler;
50 else
51 delete disassembler;
52
53 return NULL;
54 }
55
DetectExecutableType(const void * buffer,size_t length,ExecutableType * type,size_t * detected_length)56 Status DetectExecutableType(const void* buffer, size_t length,
57 ExecutableType* type,
58 size_t* detected_length) {
59
60 Disassembler* disassembler = DetectDisassembler(buffer, length);
61
62 if (disassembler) {
63 *type = disassembler->kind();
64 *detected_length = disassembler->length();
65 delete disassembler;
66 return C_OK;
67 }
68
69 // We failed to detect anything
70 *type = EXE_UNKNOWN;
71 *detected_length = 0;
72 return C_INPUT_NOT_RECOGNIZED;
73 }
74
ParseDetectedExecutable(const void * buffer,size_t length,AssemblyProgram ** output)75 Status ParseDetectedExecutable(const void* buffer, size_t length,
76 AssemblyProgram** output) {
77 *output = NULL;
78
79 Disassembler* disassembler = DetectDisassembler(buffer, length);
80
81 if (!disassembler) {
82 return C_INPUT_NOT_RECOGNIZED;
83 }
84
85 AssemblyProgram* program = new AssemblyProgram(disassembler->kind());
86
87 if (!disassembler->Disassemble(program)) {
88 delete program;
89 delete disassembler;
90 return C_DISASSEMBLY_FAILED;
91 }
92
93 delete disassembler;
94 *output = program;
95 return C_OK;
96 }
97
DeleteAssemblyProgram(AssemblyProgram * program)98 void DeleteAssemblyProgram(AssemblyProgram* program) {
99 delete program;
100 }
101
Disassembler(const void * start,size_t length)102 Disassembler::Disassembler(const void* start, size_t length)
103 : failure_reason_("uninitialized") {
104
105 start_ = reinterpret_cast<const uint8*>(start);
106 length_ = length;
107 end_ = start_ + length_;
108 };
109
~Disassembler()110 Disassembler::~Disassembler() {};
111
OffsetToPointer(size_t offset) const112 const uint8* Disassembler::OffsetToPointer(size_t offset) const {
113 assert(start_ + offset <= end_);
114 return start_ + offset;
115 }
116
Good()117 bool Disassembler::Good() {
118 failure_reason_ = NULL;
119 return true;
120 }
121
Bad(const char * reason)122 bool Disassembler::Bad(const char* reason) {
123 failure_reason_ = reason;
124 return false;
125 }
126
ReduceLength(size_t reduced_length)127 void Disassembler::ReduceLength(size_t reduced_length) {
128 if (reduced_length < length_)
129 length_ = reduced_length;
130 }
131
132 } // namespace courgette
133