forked from ReVanced/revanced-patcher
-
Notifications
You must be signed in to change notification settings - Fork 0
/
ExampleBytecodePatch.kt
169 lines (153 loc) Β· 7.22 KB
/
ExampleBytecodePatch.kt
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
package app.revanced.patcher.usage.bytecode.patch
import app.revanced.patcher.annotation.Description
import app.revanced.patcher.annotation.Name
import app.revanced.patcher.annotation.Version
import app.revanced.patcher.data.implementation.BytecodeData
import app.revanced.patcher.extensions.addInstructions
import app.revanced.patcher.extensions.or
import app.revanced.patcher.patch.annotations.Patch
import app.revanced.patcher.patch.implementation.BytecodePatch
import app.revanced.patcher.patch.implementation.misc.PatchResult
import app.revanced.patcher.patch.implementation.misc.PatchResultSuccess
import app.revanced.patcher.usage.bytecode.signatures.ExampleSignature
import app.revanced.patcher.usage.resource.annotation.ExampleResourceCompatibility
import app.revanced.patcher.util.proxy.mutableTypes.MutableField.Companion.toMutable
import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod.Companion.toMutable
import app.revanced.patcher.util.smali.toInstruction
import app.revanced.patcher.util.smali.toInstructions
import com.google.common.collect.ImmutableList
import org.jf.dexlib2.AccessFlags
import org.jf.dexlib2.Format
import org.jf.dexlib2.Opcode
import org.jf.dexlib2.builder.MutableMethodImplementation
import org.jf.dexlib2.builder.instruction.BuilderInstruction11x
import org.jf.dexlib2.builder.instruction.BuilderInstruction21c
import org.jf.dexlib2.iface.instruction.formats.Instruction21c
import org.jf.dexlib2.immutable.ImmutableField
import org.jf.dexlib2.immutable.ImmutableMethod
import org.jf.dexlib2.immutable.ImmutableMethodImplementation
import org.jf.dexlib2.immutable.reference.ImmutableFieldReference
import org.jf.dexlib2.immutable.reference.ImmutableStringReference
import org.jf.dexlib2.immutable.value.ImmutableFieldEncodedValue
import org.jf.dexlib2.util.Preconditions
@Patch
@Name("example-bytecode-patch")
@Description("Example demonstration of a bytecode patch.")
@ExampleResourceCompatibility
@Version("0.0.1")
class ExampleBytecodePatch : BytecodePatch(
listOf(
ExampleSignature
)
) {
// This function will be executed by the patcher.
// You can treat it as a constructor
override fun execute(data: BytecodeData): PatchResult {
// Get the resolved method for the signature from the resolver cache
val result = signatures.first().result!!
// Get the implementation for the resolved method
val implementation = result.method.implementation!!
// Let's modify it, so it prints "Hello, ReVanced! Editing bytecode."
// Get the start index of our opcode pattern.
// This will be the index of the instruction with the opcode CONST_STRING.
val startIndex = result.scanResult.startIndex
implementation.replaceStringAt(startIndex, "Hello, ReVanced! Editing bytecode.")
// Get the class in which the method matching our signature is defined in.
val mainClass = data.findClass {
it.type == result.definingClassProxy.immutableClass.type
}!!.resolve()
// Add a new method returning a string
mainClass.methods.add(
ImmutableMethod(
result.definingClassProxy.immutableClass.type,
"returnHello",
null,
"Ljava/lang/String;",
AccessFlags.PRIVATE or AccessFlags.STATIC,
null,
null,
ImmutableMethodImplementation(
1,
ImmutableList.of(
BuilderInstruction21c(
Opcode.CONST_STRING,
0,
ImmutableStringReference("Hello, ReVanced! Adding bytecode.")
),
BuilderInstruction11x(Opcode.RETURN_OBJECT, 0)
),
null,
null
)
).toMutable()
)
// Add a field in the main class
// We will use this field in our method below to call println on
// The field holds the Ljava/io/PrintStream->out; field
mainClass.fields.add(
ImmutableField(
mainClass.type,
"dummyField",
"Ljava/io/PrintStream;",
AccessFlags.PRIVATE or AccessFlags.STATIC,
ImmutableFieldEncodedValue(
ImmutableFieldReference(
"Ljava/lang/System;",
"out",
"Ljava/io/PrintStream;"
)
),
null,
null
).toMutable()
)
// store the fields initial value into the first virtual register
implementation.replaceInstruction(
0,
"sget-object v0, LTestClass;->dummyField:Ljava/io/PrintStream;".toInstruction()
)
// Now let's create a new call to our method and print the return value!
// You can also use the smali compiler to create instructions.
// For this sake of example I reuse the TestClass field dummyField inside the virtual register 0.
//
// Control flow instructions are not supported as of now.
val instructions = """
invoke-static { }, LTestClass;->returnHello()Ljava/lang/String;
move-result-object v1
invoke-virtual { v0, v1 }, Ljava/io/PrintStream;->println(Ljava/lang/String;)V
""".trimIndent().toInstructions()
implementation.addInstructions(startIndex + 2, instructions)
// Finally, tell the patcher that this patch was a success.
// You can also return PatchResultError with a message.
// If an exception is thrown inside this function,
// a PatchResultError will be returned with the error message.
return PatchResultSuccess()
}
/**
* Replace the string for an instruction at the given index with a new one.
* @param index The index of the instruction to replace the string for
* @param string The replacing string
*/
private fun MutableMethodImplementation.replaceStringAt(index: Int, string: String) {
val instruction = this.instructions[index]
// Utility method of dexlib2
Preconditions.checkFormat(instruction.opcode, Format.Format21c)
// Cast this to an instruction of the format 21c
// The instruction format can be found in the docs at
// https://source.android.com/devices/tech/dalvik/dalvik-bytecode
val strInstruction = instruction as Instruction21c
// In our case we want an instruction with the opcode CONST_STRING
// The format is 21c, so we create a new BuilderInstruction21c
// This instruction will hold the string reference constant in the virtual register of the original instruction
// For that a reference to the string is needed. It can be created with an ImmutableStringReference.
// At last, use the method replaceInstruction to replace it at the given index startIndex.
this.replaceInstruction(
index,
BuilderInstruction21c(
Opcode.CONST_STRING,
strInstruction.registerA,
ImmutableStringReference(string)
)
)
}
}