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// Copyright 2021 Code Intelligence GmbH
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.code_intelligence.jazzer.agent
import com.code_intelligence.jazzer.instrumentor.ClassInstrumentor
import com.code_intelligence.jazzer.instrumentor.CoverageRecorder
import com.code_intelligence.jazzer.instrumentor.Hook
import com.code_intelligence.jazzer.instrumentor.InstrumentationType
import com.code_intelligence.jazzer.utils.ClassNameGlobber
import java.lang.instrument.ClassFileTransformer
import java.lang.instrument.Instrumentation
import java.nio.file.Path
import java.security.ProtectionDomain
import kotlin.math.roundToInt
import kotlin.system.exitProcess
import kotlin.time.measureTimedValue
class RuntimeInstrumentor(
private val instrumentation: Instrumentation,
private val classesToFullyInstrument: ClassNameGlobber,
private val classesToHookInstrument: ClassNameGlobber,
private val instrumentationTypes: Set<InstrumentationType>,
private val includedHooks: List<Hook>,
private val customHooks: List<Hook>,
// Dedicated name globber for additional classes to hook stated in hook annotations is needed due to
// existing include and exclude pattern of classesToHookInstrument. All classes are included in hook
// instrumentation except the ones from default excludes, like JDK and Kotlin classes. But additional
// classes to hook, based on annotations, are allowed to reference normally ignored ones, like JDK
// and Kotlin internals.
// FIXME: Adding an additional class to hook will apply _all_ hooks to it and not only the one it's
// defined in. At some point we might want to track the list of classes per custom hook rather than globally.
private val additionalClassesToHookInstrument: ClassNameGlobber,
private val coverageIdSynchronizer: CoverageIdStrategy,
private val dumpClassesDir: Path?,
) : ClassFileTransformer {
@OptIn(kotlin.time.ExperimentalTime::class)
override fun transform(
loader: ClassLoader?,
internalClassName: String,
classBeingRedefined: Class<*>?,
protectionDomain: ProtectionDomain?,
classfileBuffer: ByteArray,
): ByteArray? {
return try {
// Bail out early if we would instrument ourselves. This prevents ClassCircularityErrors as we might need to
// load additional Jazzer classes until we reach the full exclusion logic.
if (internalClassName.startsWith("com/code_intelligence/jazzer/"))
return null
transformInternal(internalClassName, classfileBuffer)
} catch (t: Throwable) {
// Throwables raised from transform are silently dropped, making it extremely hard to detect instrumentation
// failures. The docs advise to use a top-level try-catch.
// https://docs.oracle.com/javase/9/docs/api/java/lang/instrument/ClassFileTransformer.html
t.printStackTrace()
throw t
}.also { instrumentedByteCode ->
// Only dump classes that were instrumented.
if (instrumentedByteCode != null && dumpClassesDir != null) {
dumpToClassFile(internalClassName, instrumentedByteCode)
dumpToClassFile(internalClassName, classfileBuffer, basenameSuffix = ".original")
}
}
}
private fun dumpToClassFile(internalClassName: String, bytecode: ByteArray, basenameSuffix: String = "") {
val relativePath = "$internalClassName$basenameSuffix.class"
val absolutePath = dumpClassesDir!!.resolve(relativePath)
val dumpFile = absolutePath.toFile()
dumpFile.parentFile.mkdirs()
dumpFile.writeBytes(bytecode)
}
override fun transform(
module: Module?,
loader: ClassLoader?,
internalClassName: String,
classBeingRedefined: Class<*>?,
protectionDomain: ProtectionDomain?,
classfileBuffer: ByteArray
): ByteArray? {
return try {
if (module != null && !module.canRead(RuntimeInstrumentor::class.java.module)) {
// Make all other modules read our (unnamed) module, which allows them to access the classes needed by the
// instrumentations, e.g. CoverageMap. If a module can't be modified, it should not be instrumented as the
// injected bytecode might throw NoClassDefFoundError.
// https://mail.openjdk.java.net/pipermail/jigsaw-dev/2021-May/014663.html
if (!instrumentation.isModifiableModule(module)) {
val prettyClassName = internalClassName.replace('/', '.')
println("WARN: Failed to instrument $prettyClassName in unmodifiable module ${module.name}, skipping")
return null
}
instrumentation.redefineModule(
module,
/* extraReads */ setOf(RuntimeInstrumentor::class.java.module),
emptyMap(),
emptyMap(),
emptySet(),
emptyMap()
)
}
transform(loader, internalClassName, classBeingRedefined, protectionDomain, classfileBuffer)
} catch (t: Throwable) {
// Throwables raised from transform are silently dropped, making it extremely hard to detect instrumentation
// failures. The docs advise to use a top-level try-catch.
// https://docs.oracle.com/javase/9/docs/api/java/lang/instrument/ClassFileTransformer.html
t.printStackTrace()
throw t
}
}
@OptIn(kotlin.time.ExperimentalTime::class)
fun transformInternal(internalClassName: String, classfileBuffer: ByteArray): ByteArray? {
val fullInstrumentation = when {
classesToFullyInstrument.includes(internalClassName) -> true
classesToHookInstrument.includes(internalClassName) -> false
additionalClassesToHookInstrument.includes(internalClassName) -> false
else -> return null
}
val prettyClassName = internalClassName.replace('/', '.')
val (instrumentedBytecode, duration) = measureTimedValue {
try {
instrument(internalClassName, classfileBuffer, fullInstrumentation)
} catch (e: CoverageIdException) {
System.err.println("ERROR: Coverage IDs are out of sync")
e.printStackTrace()
exitProcess(1)
} catch (e: Exception) {
println("WARN: Failed to instrument $prettyClassName, skipping")
e.printStackTrace()
return null
}
}
val durationInMs = duration.inWholeMilliseconds
val sizeIncrease = ((100.0 * (instrumentedBytecode.size - classfileBuffer.size)) / classfileBuffer.size).roundToInt()
if (fullInstrumentation) {
println("INFO: Instrumented $prettyClassName (took $durationInMs ms, size +$sizeIncrease%)")
} else {
println("INFO: Instrumented $prettyClassName with custom hooks only (took $durationInMs ms, size +$sizeIncrease%)")
}
return instrumentedBytecode
}
private fun instrument(internalClassName: String, bytecode: ByteArray, fullInstrumentation: Boolean): ByteArray {
return ClassInstrumentor(bytecode).run {
if (fullInstrumentation) {
// Hook instrumentation must be performed after data flow tracing as the injected
// bytecode would trigger the GEP callbacks for byte[]. Coverage instrumentation
// must be performed after hook instrumentation as the injected bytecode would
// trigger the GEP callbacks for ByteBuffer.
traceDataFlow(instrumentationTypes)
hooks(includedHooks + customHooks)
coverageIdSynchronizer.withIdForClass(internalClassName) { firstId ->
coverage(firstId).also { actualNumEdgeIds ->
CoverageRecorder.recordInstrumentedClass(
internalClassName,
bytecode,
firstId,
actualNumEdgeIds
)
}
}
} else {
hooks(customHooks)
}
instrumentedBytecode
}
}
}
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