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feat: Move fingerprint match members to fingerprint for ease of access by using context receivers

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oSumAtrIX
2024-11-04 02:24:16 +01:00
parent 7f55868e6f
commit 0746c22743
9 changed files with 324 additions and 217 deletions
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115
docs/2_2_1_fingerprinting.md
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@@ -117,15 +117,19 @@ With this information, the original code can be reconstructed:
```java
package com.some.app.ads;
<accessFlags> class AdsLoader {
public final boolean <methodName>(boolean <parameter>) {
<accessFlags>
class AdsLoader {
public final boolean <methodName>(boolean <parameter>)
{
// ...
var userStatus = "pro";
// ...
return <returnValue>;
return <returnValue >;
}
}
```
@@ -134,13 +138,14 @@ Using that fingerprint, this method can be matched uniquely from all other metho
> [!TIP]
> A fingerprint should contain information about a method likely to remain the same across updates.
> A method's name is not included in the fingerprint because it will likely change with each update in an obfuscated app.
> In contrast, the return type, access flags, parameters, patterns of opcodes, and strings are likely to remain the same.
> A method's name is not included in the fingerprint because it will likely change with each update in an obfuscated
> app.
> In contrast, the return type, access flags, parameters, patterns of opcodes, and strings are likely to remain the
> same.
## 🔨 How to use fingerprints
A fingerprint is matched to a method,
once the `match` property of the fingerprint is accessed in a patch's `execute` scope:
After declaring a fingerprint, it can be used in a patch to find the method it matches to:
```kt
val fingerprint = fingerprint {
@@ -149,52 +154,34 @@ val fingerprint = fingerprint {
val patch = bytecodePatch {
execute {
val match = fingerprint.match!!
fingerprint.method
}
}
```
The fingerprint won't be matched again, if it has already been matched once.
This makes it useful, to share fingerprints between multiple patches, and let the first patch match the fingerprint:
The fingerprint won't be matched again, if it has already been matched once, for performance reasons.
This makes it useful, to share fingerprints between multiple patches,
and let the first executing patch match the fingerprint:
```kt
// Either of these two patches will match the fingerprint first and the other patch can reuse the match:
val mainActivityPatch1 = bytecodePatch {
execute {
val match = mainActivityOnCreateFingerprint.match!!
mainActivityOnCreateFingerprint.method
}
}
val mainActivityPatch2 = bytecodePatch {
execute {
val match = mainActivityOnCreateFingerprint.match!!
}
}
```
A fingerprint match can also be delegated to a variable for convenience without the need to check for `null`:
```kt
val fingerprint = fingerprint {
// ...
}
val patch = bytecodePatch {
execute {
// Alternative to fingerprint.match ?: throw PatchException("No match found")
val match by fingerprint.match
try {
match.method
} catch (e: PatchException) {
// Handle the exception for example.
}
mainActivityOnCreateFingerprint.method
}
}
```
> [!WARNING]
> If the fingerprint can not be matched to any method, the match of a fingerprint is `null`. If such a match is delegated
> to a variable, accessing it will raise an exception.
> If the fingerprint can not be matched to any method,
> accessing certain properties of the fingerprint will raise an exception.
> Instead, the `orNull` properties can be used to return `null` if no match is found.
> [!TIP]
> If a fingerprint has an opcode pattern, you can use the `fuzzyPatternScanThreshhold` parameter of the `opcode`
@@ -211,47 +198,43 @@ val patch = bytecodePatch {
> )
>}
> ```
>
The match of a fingerprint contains references to the original method and class definition of the method:
```kt
class Match(
val originalMethod: Method,
val originalClassDef: ClassDef,
val patternMatch: Match.PatternMatch?,
val stringMatches: List<Match.StringMatch>?,
// ...
) {
val classDef by lazy { /* ... */ }
val method by lazy { /* ... */ }
The following properties can be accessed in a fingerprint:
// ...
}
```
- `originalClassDef`: The original class definition the fingerprint matches to.
- `originalClassDefOrNull`: The original class definition the fingerprint matches to.
- `originalMethod`: The original method the fingerprint matches to.
- `originalMethodOrNull`: The original method the fingerprint matches to.
- `classDef`: The class the fingerprint matches to.
- `classDefOrNull`: The class the fingerprint matches to.
- `method`: The method the fingerprint matches to. If no match is found, an exception is raised.
- `methodOrNull`: The method the fingerprint matches to.
The `classDef` and `method` properties can be used to make changes to the class or method.
They are lazy properties, so they are only computed
and will effectively replace the original method or class definition when accessed.
The difference between the `original` and non-`original` properties is that the `original` properties return the
original class or method definition, while the non-`original` properties return a mutable copy of the class or method.
The mutable copies can be modified. They are lazy properties, so they are only computed
and only then will effectively replace the `original` method or class definition when accessed.
> [!TIP]
> If only read-only access to the class or method is needed,
> the `originalClassDef` and `originalMethod` properties can be used,
> If only read-only access to the class or method is needed,
> the `originalClassDef` and `originalMethod` properties should be used,
> to avoid making a mutable copy of the class or method.
## 🏹 Manually matching fingerprints
By default, a fingerprint is matched automatically against all classes when the `match` property is accessed.
By default, a fingerprint is matched automatically against all classes
when one of the fingerprint's properties is accessed.
Instead, the fingerprint can be matched manually using various overloads of a fingerprint's `match` function:
- In a **list of classes**, if the fingerprint can match in a known subset of classes
If you have a known list of classes you know the fingerprint can match in,
you can match the fingerprint on the list of classes:
you can match the fingerprint on the list of classes:
```kt
execute {
val match = showAdsFingerprint.match(classes) ?: throw PatchException("No match found")
val match = showAdsFingerprint(classes)
}
```
@@ -263,23 +246,24 @@ you can match the fingerprint on the list of classes:
execute {
val adsLoaderClass = classes.single { it.name == "Lcom/some/app/ads/Loader;" }
val match = showAdsFingerprint.match(context, adsLoaderClass) ?: throw PatchException("No match found")
val match = showAdsFingerprint.match(adsLoaderClass)
}
```
Another common usecase is to use a fingerprint to reduce the search space of a method to a single class.
```kt
execute {
// Match showAdsFingerprint in the class of the ads loader found by adsLoaderClassFingerprint.
val match by showAdsFingerprint.match(adsLoaderClassFingerprint.match!!.classDef)
val match = showAdsFingerprint.match(adsLoaderClassFingerprint.classDef)
}
```
- Match a **single method**, to extract certain information about it
The match of a fingerprint contains useful information about the method,
such as the start and end index of an opcode pattern or the indices of the instructions with certain string references.
such as the start and end index of an opcode pattern or the indices of the instructions with certain string
references.
A fingerprint can be leveraged to extract such information from a method instead of manually figuring it out:
```kt
@@ -288,14 +272,19 @@ you can match the fingerprint on the list of classes:
strings("free", "trial")
}
currentPlanFingerprint.match(adsFingerprintMatch.method)?.let { match ->
currentPlanFingerprint.match(adsFingerprint.method).let { match ->
match.stringMatches.forEach { match ->
println("The index of the string '${match.string}' is ${match.index}")
}
} ?: throw PatchException("No match found")
}
}
```
> [!WARNING]
> If the fingerprint can not be matched to any method, calling `match` will raise an
> exception.
> Instead, the `orNull` overloads can be used to return `null` if no match is found.
> [!TIP]
> To see real-world examples of fingerprints,
> check out the repository for [ReVanced Patches](https://github.com/revanced/revanced-patches).

13
docs/4_apis.md
View File

@@ -46,17 +46,17 @@ The `navigate(Method)` function allows you to navigate method calls recursively
```kt
execute {
// Sequentially navigate to the instructions at index 1 within 'someMethod'.
val method = navigate(someMethod).at(1).original() // original() returns the original immutable method.
val method = navigate(someMethod).to(1).original() // original() returns the original immutable method.
// Further navigate to the second occurrence where the instruction's opcode is 'INVOKEVIRTUAL'.
// stop() returns the mutable copy of the method.
val method = navigate(someMethod).at(2) { instruction -> instruction.opcode == Opcode.INVOKEVIRTUAL }.stop()
val method = navigate(someMethod).to(2) { instruction -> instruction.opcode == Opcode.INVOKEVIRTUAL }.stop()
// Alternatively, to stop(), you can delegate the method to a variable.
val method by navigate(someMethod).at(1)
val method by navigate(someMethod).to(1)
// You can chain multiple calls to at() to navigate deeper into the method.
val method by navigate(someMethod).at(1).at(2, 3, 4).at(5)
val method by navigate(someMethod).to(1).to(2, 3, 4).to(5)
}
```
@@ -85,7 +85,7 @@ execute {
The `document` function is used to read and write DOM files.
```kt
execute {
execute {
document("res/values/strings.xml").use { document ->
val element = doc.createElement("string").apply {
textContent = "Hello, World!"
@@ -112,5 +112,6 @@ ReVanced Patcher is a powerful library to patch Android applications, offering a
that outlive app updates. Patches make up ReVanced; without you, the community of patch developers,
ReVanced would not be what it is today. We hope that this documentation has been helpful to you
and are excited to see what you will create with ReVanced Patcher. If you have any questions or need help,
talk to us on one of our platforms linked on [revanced.app](https://revanced.app) or open an issue in case of a bug or feature request,
talk to us on one of our platforms linked on [revanced.app](https://revanced.app) or open an issue in case of a bug or
feature request,
ReVanced