fix(YouTube Music): Add Spoof client patch to fix playback

extensions/music/build.gradle.kts

@@ -0,0 +1 @@
+// Do not remove. Necessary for the extension plugin to be applied to the project.

extensions/music/src/main/AndroidManifest.xml

@@ -0,0 +1 @@
+<manifest/>

extensions/music/src/main/java/app/revanced/extension/music/spoof/SpoofClientPatch.java

@@ -0,0 +1,27 @@
+package app.revanced.extension.music.spoof;
+
+/**
+ * @noinspection unused
+ */
+public class SpoofClientPatch {
+    private static final int CLIENT_TYPE_ID = 26;
+    private static final String CLIENT_VERSION = "6.21";
+    private static final String DEVICE_MODEL = "iPhone16,2";
+    private static final String OS_VERSION = "17.7.2.21H221";
+
+    public static int getClientId() {
+        return CLIENT_TYPE_ID;
+    }
+
+    public static String getClientVersion() {
+        return CLIENT_VERSION;
+    }
+
+    public static String getClientModel() {
+        return DEVICE_MODEL;
+    }
+
+    public static String getOsVersion() {
+        return OS_VERSION;
+    }
+}

patches/api/patches.api

@@ -324,8 +324,12 @@ public final class app/revanced/patches/music/misc/gms/GmsCoreSupportPatchKt {
 	public static final fun getGmsCoreSupportPatch ()Lapp/revanced/patcher/patch/BytecodePatch;
 }
 
-public final class app/revanced/patches/music/misc/spoof/SpoofVideoStreamsPatchKt {
-	public static final fun getSpoofVideoStreamsPatch ()Lapp/revanced/patcher/patch/BytecodePatch;
+public final class app/revanced/patches/music/misc/spoof/SpoofClientPatchKt {
+	public static final fun getSpoofClientPatch ()Lapp/revanced/patcher/patch/BytecodePatch;
+}
+
+public final class app/revanced/patches/music/misc/spoof/UserAgentClientSpoofPatchKt {
+	public static final fun getUserAgentClientSpoofPatch ()Lapp/revanced/patcher/patch/BytecodePatch;
 }
 
 public final class app/revanced/patches/myexpenses/misc/pro/UnlockProPatchKt {
@@ -766,6 +770,10 @@ public final class app/revanced/patches/shared/misc/spoof/SpoofVideoStreamsPatch
 	public static synthetic fun spoofVideoStreamsPatch$default (Lkotlin/jvm/functions/Function1;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lapp/revanced/patcher/patch/BytecodePatch;
 }
 
+public final class app/revanced/patches/shared/misc/spoof/UserAgentClientSpoofPatchKt {
+	public static final fun userAgentClientSpoofPatch (Ljava/lang/String;)Lapp/revanced/patcher/patch/BytecodePatch;
+}
+
 public final class app/revanced/patches/solidexplorer2/functionality/filesize/RemoveFileSizeLimitPatchKt {
 	public static final fun getRemoveFileSizeLimitPatch ()Lapp/revanced/patcher/patch/BytecodePatch;
 }

patches/src/main/kotlin/app/revanced/patches/music/misc/extension/SharedExtensionPatch.kt

@@ -4,5 +4,6 @@ import app.revanced.patches.music.misc.extension.hooks.applicationInitHook
 import app.revanced.patches.shared.misc.extension.sharedExtensionPatch
 
 val sharedExtensionPatch = sharedExtensionPatch(
+    "music",
     applicationInitHook,
 )

patches/src/main/kotlin/app/revanced/patches/music/misc/gms/GmsCoreSupportPatch.kt

@@ -4,7 +4,7 @@ import app.revanced.patcher.patch.Option
 import app.revanced.patches.music.misc.extension.sharedExtensionPatch
 import app.revanced.patches.music.misc.gms.Constants.MUSIC_PACKAGE_NAME
 import app.revanced.patches.music.misc.gms.Constants.REVANCED_MUSIC_PACKAGE_NAME
-import app.revanced.patches.music.misc.spoof.spoofVideoStreamsPatch
+import app.revanced.patches.music.misc.spoof.spoofClientPatch
 import app.revanced.patches.shared.castContextFetchFingerprint
 import app.revanced.patches.shared.misc.gms.gmsCoreSupportPatch
 import app.revanced.patches.shared.primeMethodFingerprint
@@ -21,7 +21,7 @@ val gmsCoreSupportPatch = gmsCoreSupportPatch(
     extensionPatch = sharedExtensionPatch,
     gmsCoreSupportResourcePatchFactory = ::gmsCoreSupportResourcePatch,
 ) {
-    dependsOn(spoofVideoStreamsPatch)
+    dependsOn(spoofClientPatch)
 
     compatibleWith(MUSIC_PACKAGE_NAME)
 }

patches/src/main/kotlin/app/revanced/patches/music/misc/spoof/Fingerprints.kt

@@ -0,0 +1,39 @@
+package app.revanced.patches.music.misc.spoof
+
+import app.revanced.patcher.fingerprint
+import com.android.tools.smali.dexlib2.AccessFlags
+import com.android.tools.smali.dexlib2.Opcode
+
+internal val playerRequestConstructorFingerprint = fingerprint {
+    accessFlags(AccessFlags.PUBLIC, AccessFlags.CONSTRUCTOR)
+    strings("player")
+}
+
+/**
+ * Matches using the class found in [playerRequestConstructorFingerprint].
+ */
+internal val createPlayerRequestBodyFingerprint = fingerprint {
+    parameters("L")
+    returns("V")
+    opcodes(
+        Opcode.CHECK_CAST,
+        Opcode.IGET,
+        Opcode.AND_INT_LIT16,
+    )
+    strings("ms")
+}
+
+/**
+ * Used to get a reference to other clientInfo fields.
+ */
+internal val setClientInfoFieldsFingerprint = fingerprint {
+    returns("L")
+    strings("Google Inc.")
+}
+
+/**
+ * Used to get a reference to the clientInfo and clientInfo.clientVersion field.
+ */
+internal val setClientInfoClientVersionFingerprint = fingerprint {
+    strings("10.29")
+}

patches/src/main/kotlin/app/revanced/patches/music/misc/spoof/SpoofClientPatch.kt

@@ -0,0 +1,105 @@
+package app.revanced.patches.music.misc.spoof
+
+import app.revanced.patcher.extensions.InstructionExtensions.addInstruction
+import app.revanced.patcher.extensions.InstructionExtensions.addInstructions
+import app.revanced.patcher.extensions.InstructionExtensions.getInstruction
+import app.revanced.patcher.extensions.InstructionExtensions.instructions
+import app.revanced.patcher.patch.bytecodePatch
+import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod.Companion.toMutable
+import app.revanced.patches.music.misc.extension.sharedExtensionPatch
+import app.revanced.util.getReference
+import com.android.tools.smali.dexlib2.AccessFlags
+import com.android.tools.smali.dexlib2.Opcode
+import com.android.tools.smali.dexlib2.builder.MutableMethodImplementation
+import com.android.tools.smali.dexlib2.iface.instruction.OneRegisterInstruction
+import com.android.tools.smali.dexlib2.iface.reference.FieldReference
+import com.android.tools.smali.dexlib2.iface.reference.TypeReference
+import com.android.tools.smali.dexlib2.immutable.ImmutableMethod
+import com.android.tools.smali.dexlib2.immutable.ImmutableMethodParameter
+
+internal const val EXTENSION_CLASS_DESCRIPTOR =
+    "Lapp/revanced/extension/music/spoof/SpoofClientPatch;"
+
+// TODO: Replace this patch with spoofVideoStreamsPatch once possible.
+val spoofClientPatch = bytecodePatch(
+    name = "Spoof client",
+    description = "Spoofs the client to fix playback.",
+) {
+    compatibleWith("com.google.android.apps.youtube.music")
+
+    dependsOn(
+        sharedExtensionPatch,
+        // TODO: Add settingsPatch
+        userAgentClientSpoofPatch,
+    )
+
+    execute {
+        val playerRequestClass = playerRequestConstructorFingerprint.classDef
+
+        val createPlayerRequestBodyMatch = createPlayerRequestBodyFingerprint.match(playerRequestClass)
+
+        val clientInfoContainerClass = createPlayerRequestBodyMatch.method
+            .getInstruction(createPlayerRequestBodyMatch.patternMatch!!.startIndex)
+            .getReference<TypeReference>()!!.type
+
+        val clientInfoField = setClientInfoClientVersionFingerprint.method.instructions.first {
+            it.opcode == Opcode.IPUT_OBJECT && it.getReference<FieldReference>()!!.definingClass == clientInfoContainerClass
+        }.getReference<FieldReference>()!!
+
+        val setClientInfoFieldInstructions = setClientInfoFieldsFingerprint.method.instructions.filter {
+            (it.opcode == Opcode.IPUT_OBJECT || it.opcode == Opcode.IPUT) &&
+                it.getReference<FieldReference>()!!.definingClass == clientInfoField.type
+        }.map { it.getReference<FieldReference>()!! }
+
+        // Offsets are known for the fields in the clientInfo object.
+        val clientIdField = setClientInfoFieldInstructions[0]
+        val clientModelField = setClientInfoFieldInstructions[5]
+        val osVersionField = setClientInfoFieldInstructions[7]
+        val clientVersionField = setClientInfoClientVersionFingerprint.method
+            .getInstruction(setClientInfoClientVersionFingerprint.stringMatches!!.first().index + 1)
+            .getReference<FieldReference>()
+
+        // Helper method to spoof the client info.
+        val spoofClientInfoMethod = ImmutableMethod(
+            playerRequestClass.type,
+            "spoofClientInfo",
+            listOf(ImmutableMethodParameter(clientInfoContainerClass, null, null)),
+            "V",
+            AccessFlags.PRIVATE.value or AccessFlags.STATIC.value,
+            null,
+            null,
+            MutableMethodImplementation(3),
+        ).toMutable().also(playerRequestClass.methods::add).apply {
+            addInstructions(
+                """
+                    iget-object v0, p0, $clientInfoField
+
+                    invoke-static { }, $EXTENSION_CLASS_DESCRIPTOR->getClientId()I
+                    move-result v1
+                    iput v1, v0, $clientIdField
+
+                    invoke-static { }, $EXTENSION_CLASS_DESCRIPTOR->getClientModel()Ljava/lang/String;
+                    move-result-object v1
+                    iput-object v1, v0, $clientModelField
+
+                    invoke-static { }, $EXTENSION_CLASS_DESCRIPTOR->getClientVersion()Ljava/lang/String;
+                    move-result-object v1
+                    iput-object v1, v0, $clientVersionField
+
+                    invoke-static { }, $EXTENSION_CLASS_DESCRIPTOR->getOsVersion()Ljava/lang/String;
+                    move-result-object v1
+                    iput-object v1, v0, $osVersionField
+
+                    return-void
+                """,
+            )
+        }
+
+        createPlayerRequestBodyMatch.method.apply {
+            val checkCastIndex = createPlayerRequestBodyMatch.patternMatch!!.startIndex
+            val clientInfoContainerRegister = getInstruction<OneRegisterInstruction>(checkCastIndex).registerA
+
+            addInstruction(checkCastIndex + 1, "invoke-static {v$clientInfoContainerRegister}, $spoofClientInfoMethod")
+        }
+    }
+}

patches/src/main/kotlin/app/revanced/patches/music/misc/spoof/UserAgentClientSpoofPatch.kt

@@ -0,0 +1,5 @@
+package app.revanced.patches.music.misc.spoof
+
+import app.revanced.patches.shared.misc.spoof.userAgentClientSpoofPatch
+
+val userAgentClientSpoofPatch = userAgentClientSpoofPatch("com.google.android.apps.youtube.music")

patches/src/main/kotlin/app/revanced/patches/shared/misc/spoof/UserAgentClientSpoofPatch.kt

@@ -0,0 +1,81 @@
+package app.revanced.patches.shared.misc.spoof
+
+import app.revanced.patcher.extensions.InstructionExtensions.getInstruction
+import app.revanced.patcher.extensions.InstructionExtensions.replaceInstruction
+import app.revanced.patches.all.misc.transformation.IMethodCall
+import app.revanced.patches.all.misc.transformation.filterMapInstruction35c
+import app.revanced.patches.all.misc.transformation.transformInstructionsPatch
+import app.revanced.util.getReference
+import app.revanced.util.indexOfFirstInstruction
+import com.android.tools.smali.dexlib2.Opcode
+import com.android.tools.smali.dexlib2.iface.instruction.OneRegisterInstruction
+import com.android.tools.smali.dexlib2.iface.reference.MethodReference
+import com.android.tools.smali.dexlib2.iface.reference.StringReference
+
+private const val USER_AGENT_STRING_BUILDER_APPEND_METHOD_REFERENCE =
+    "Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;"
+
+fun userAgentClientSpoofPatch(originalPackageName: String) = transformInstructionsPatch(
+    filterMap = { classDef, _, instruction, instructionIndex ->
+        filterMapInstruction35c<MethodCall>(
+            "Lapp/revanced/extension",
+            classDef,
+            instruction,
+            instructionIndex,
+        )
+    },
+    transform = transform@{ mutableMethod, entry ->
+        val (_, _, instructionIndex) = entry
+
+        // Replace the result of context.getPackageName(), if it is used in a user agent string.
+        mutableMethod.apply {
+            // After context.getPackageName() the result is moved to a register.
+            val targetRegister = (
+                getInstruction(instructionIndex + 1)
+                    as? OneRegisterInstruction ?: return@transform
+                ).registerA
+
+            // IndexOutOfBoundsException is technically possible here,
+            // but no such occurrences are present in the app.
+            val referee = getInstruction(instructionIndex + 2).getReference<MethodReference>()?.toString()
+
+            // Only replace string builder usage.
+            if (referee != USER_AGENT_STRING_BUILDER_APPEND_METHOD_REFERENCE) {
+                return@transform
+            }
+
+            // Do not change the package name in methods that use resources, or for methods that use GmsCore.
+            // Changing these package names will result in playback limitations,
+            // particularly Android VR background audio only playback.
+            val resourceOrGmsStringInstructionIndex = indexOfFirstInstruction {
+                val reference = getReference<StringReference>()
+                opcode == Opcode.CONST_STRING &&
+                    (reference?.string == "android.resource://" || reference?.string == "gcore_")
+            }
+            if (resourceOrGmsStringInstructionIndex >= 0) {
+                return@transform
+            }
+
+            // Overwrite the result of context.getPackageName() with the original package name.
+            replaceInstruction(
+                instructionIndex + 1,
+                "const-string v$targetRegister, \"$originalPackageName\"",
+            )
+        }
+    },
+)
+
+@Suppress("unused")
+private enum class MethodCall(
+    override val definedClassName: String,
+    override val methodName: String,
+    override val methodParams: Array<String>,
+    override val returnType: String,
+) : IMethodCall {
+    GetPackageName(
+        "Landroid/content/Context;",
+        "getPackageName",
+        emptyArray(),
+        "Ljava/lang/String;",
+    ),
+}