/*

 * Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "classfile/classFileStream.hpp"

#include "classfile/javaClasses.hpp"

#include "classfile/stackMapTable.hpp"

#include "classfile/systemDictionary.hpp"

#include "classfile/verifier.hpp"

#include "classfile/vmSymbols.hpp"

#include "interpreter/bytecodeStream.hpp"

#include "memory/oopFactory.hpp"

#include "memory/resourceArea.hpp"

#include "oops/instanceKlass.hpp"

#include "oops/oop.inline.hpp"

#include "oops/typeArrayOop.hpp"

#include "prims/jvm.h"

#include "runtime/fieldDescriptor.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/interfaceSupport.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/orderAccess.hpp"

#include "runtime/os.hpp"

#ifdef TARGET_ARCH_x86

# include "bytes_x86.hpp"

#endif

#ifdef TARGET_ARCH_sparc

# include "bytes_sparc.hpp"

#endif

#ifdef TARGET_ARCH_zero

# include "bytes_zero.hpp"

#endif

#ifdef TARGET_ARCH_arm

# include "bytes_arm.hpp"

#endif

#ifdef TARGET_ARCH_ppc

# include "bytes_ppc.hpp"

#endif

#define NOFAILOVER_MAJOR_VERSION 51

// Access to external entry for VerifyClassCodes - old byte code verifier

extern "C" {

  typedef jboolean (*verify_byte_codes_fn_t)(JNIEnv *, jclass, char *, jint);

  typedef jboolean (*verify_byte_codes_fn_new_t)(JNIEnv *, jclass, char *, jint, jint);

}

static void* volatile _verify_byte_codes_fn = NULL;

static volatile jint _is_new_verify_byte_codes_fn = (jint) true;

static void* verify_byte_codes_fn() {

  if (_verify_byte_codes_fn == NULL) {

    void *lib_handle = os::native_java_library();

    void *func = os::dll_lookup(lib_handle, "VerifyClassCodesForMajorVersion");

    OrderAccess::release_store_ptr(&_verify_byte_codes_fn, func);

    if (func == NULL) {

      OrderAccess::release_store(&_is_new_verify_byte_codes_fn, false);

      func = os::dll_lookup(lib_handle, "VerifyClassCodes");

      OrderAccess::release_store_ptr(&_verify_byte_codes_fn, func);

    }

  }

  return (void*)_verify_byte_codes_fn;

}

// Methods in Verifier

bool Verifier::should_verify_for(oop class_loader, bool should_verify_class) {

  return (class_loader == NULL || !should_verify_class) ?

    BytecodeVerificationLocal : BytecodeVerificationRemote;

}

bool Verifier::relax_verify_for(oop loader) {

  bool trusted = java_lang_ClassLoader::is_trusted_loader(loader);

  bool need_verify =

    // verifyAll

    (BytecodeVerificationLocal && BytecodeVerificationRemote) ||

    // verifyRemote

    (!BytecodeVerificationLocal && BytecodeVerificationRemote && !trusted);

  return !need_verify;

}

bool Verifier::verify(instanceKlassHandle klass, Verifier::Mode mode, bool should_verify_class, TRAPS) {

  HandleMark hm;

  ResourceMark rm(THREAD);

  Symbol* exception_name = NULL;

  const size_t message_buffer_len = klass->name()->utf8_length() + 1024;

  char* message_buffer = NEW_RESOURCE_ARRAY(char, message_buffer_len);

  const char* klassName = klass->external_name();

  // If the class should be verified, first see if we can use the split

  // verifier.  If not, or if verification fails and FailOverToOldVerifier

  // is set, then call the inference verifier.

  if (is_eligible_for_verification(klass, should_verify_class)) {

    if (TraceClassInitialization) {

      tty->print_cr("Start class verification for: %s", klassName);

    }

    if (UseSplitVerifier &&

        klass->major_version() >= STACKMAP_ATTRIBUTE_MAJOR_VERSION) {

        ClassVerifier split_verifier(

          klass, message_buffer, message_buffer_len, THREAD);

        split_verifier.verify_class(THREAD);

        exception_name = split_verifier.result();

      if (klass->major_version() < NOFAILOVER_MAJOR_VERSION &&

          FailOverToOldVerifier && !HAS_PENDING_EXCEPTION &&

          (exception_name == vmSymbols::java_lang_VerifyError() ||

           exception_name == vmSymbols::java_lang_ClassFormatError())) {

        if (TraceClassInitialization) {

          tty->print_cr(

            "Fail over class verification to old verifier for: %s", klassName);

        }

        exception_name = inference_verify(

          klass, message_buffer, message_buffer_len, THREAD);

      }

    } else {

      exception_name = inference_verify(

          klass, message_buffer, message_buffer_len, THREAD);

    }

    if (TraceClassInitialization) {

      if (HAS_PENDING_EXCEPTION) {

        tty->print("Verification for %s has", klassName);

        tty->print_cr(" exception pending %s ",

          instanceKlass::cast(PENDING_EXCEPTION->klass())->external_name());

      } else if (exception_name != NULL) {

        tty->print_cr("Verification for %s failed", klassName);

      }

      tty->print_cr("End class verification for: %s", klassName);

    }

  }

  if (HAS_PENDING_EXCEPTION) {

    return false; // use the existing exception

  } else if (exception_name == NULL) {

    return true; // verifcation succeeded

  } else { // VerifyError or ClassFormatError to be created and thrown

    ResourceMark rm(THREAD);

    instanceKlassHandle kls =

      SystemDictionary::resolve_or_fail(exception_name, true, CHECK_false);

    while (!kls.is_null()) {

      if (kls == klass) {

        // If the class being verified is the exception we're creating

        // or one of it's superclasses, we're in trouble and are going

        // to infinitely recurse when we try to initialize the exception.

        // So bail out here by throwing the preallocated VM error.

        THROW_OOP_(Universe::virtual_machine_error_instance(), false);

      }

      kls = kls->super();

    }

    message_buffer[message_buffer_len - 1] = '\0'; // just to be sure

    THROW_MSG_(exception_name, message_buffer, false);

  }

}

bool Verifier::is_eligible_for_verification(instanceKlassHandle klass, bool should_verify_class) {

  Symbol* name = klass->name();

  klassOop refl_magic_klass = SystemDictionary::reflect_MagicAccessorImpl_klass();

  return (should_verify_for(klass->class_loader(), should_verify_class) &&

    // return if the class is a bootstrapping class

    // or defineClass specified not to verify by default (flags override passed arg)

    // We need to skip the following four for bootstraping

    name != vmSymbols::java_lang_Object() &&

    name != vmSymbols::java_lang_Class() &&

    name != vmSymbols::java_lang_String() &&

    name != vmSymbols::java_lang_Throwable() &&

    // Can not verify the bytecodes for shared classes because they have

    // already been rewritten to contain constant pool cache indices,

    // which the verifier can't understand.

    // Shared classes shouldn't have stackmaps either.

    !klass()->is_shared() &&

    // As of the fix for 4486457 we disable verification for all of the

    // dynamically-generated bytecodes associated with the 1.4

    // reflection implementation, not just those associated with

    // sun/reflect/SerializationConstructorAccessor.

    // NOTE: this is called too early in the bootstrapping process to be

    // guarded by Universe::is_gte_jdk14x_version()/UseNewReflection.

    (refl_magic_klass == NULL ||

     !klass->is_subtype_of(refl_magic_klass) ||

     VerifyReflectionBytecodes)

  );

}

Symbol* Verifier::inference_verify(

    instanceKlassHandle klass, char* message, size_t message_len, TRAPS) {

  JavaThread* thread = (JavaThread*)THREAD;

  JNIEnv *env = thread->jni_environment();

  void* verify_func = verify_byte_codes_fn();

  if (verify_func == NULL) {

    jio_snprintf(message, message_len, "Could not link verifier");

    return vmSymbols::java_lang_VerifyError();

  }

  ResourceMark rm(THREAD);

  if (ClassVerifier::_verify_verbose) {

    tty->print_cr("Verifying class %s with old format", klass->external_name());

  }

  jclass cls = (jclass) JNIHandles::make_local(env, klass->java_mirror());

  jint result;

  {

    HandleMark hm(thread);

    ThreadToNativeFromVM ttn(thread);

    // ThreadToNativeFromVM takes care of changing thread_state, so safepoint

    // code knows that we have left the VM

    if (_is_new_verify_byte_codes_fn) {

      verify_byte_codes_fn_new_t func =

        CAST_TO_FN_PTR(verify_byte_codes_fn_new_t, verify_func);

      result = (*func)(env, cls, message, (int)message_len,

          klass->major_version());

    } else {

      verify_byte_codes_fn_t func =

        CAST_TO_FN_PTR(verify_byte_codes_fn_t, verify_func);

      result = (*func)(env, cls, message, (int)message_len);

    }

  }

  JNIHandles::destroy_local(cls);

  // These numbers are chosen so that VerifyClassCodes interface doesn't need

  // to be changed (still return jboolean (unsigned char)), and result is

  // 1 when verification is passed.

  if (result == 0) {

    return vmSymbols::java_lang_VerifyError();

  } else if (result == 1) {

    return NULL; // verified.

  } else if (result == 2) {

    THROW_MSG_(vmSymbols::java_lang_OutOfMemoryError(), message, NULL);

  } else if (result == 3) {

    return vmSymbols::java_lang_ClassFormatError();

  } else {

    ShouldNotReachHere();

    return NULL;

  }

}

// Methods in ClassVerifier

bool ClassVerifier::_verify_verbose = false;

ClassVerifier::ClassVerifier(

    instanceKlassHandle klass, char* msg, size_t msg_len, TRAPS)

    : _thread(THREAD), _exception_type(NULL), _message(msg),

      _message_buffer_len(msg_len), _klass(klass) {

  _this_type = VerificationType::reference_type(klass->name());

  // Create list to hold symbols in reference area.

  _symbols = new GrowableArray<Symbol*>(100, 0, NULL);

}

ClassVerifier::~ClassVerifier() {

  // Decrement the reference count for any symbols created.

  for (int i = 0; i < _symbols->length(); i++) {

    Symbol* s = _symbols->at(i);

    s->decrement_refcount();

  }

}

VerificationType ClassVerifier::object_type() const {

  return VerificationType::reference_type(vmSymbols::java_lang_Object());

}

void ClassVerifier::verify_class(TRAPS) {

  if (_verify_verbose) {

    tty->print_cr("Verifying class %s with new format",

      _klass->external_name());

  }

  objArrayHandle methods(THREAD, _klass->methods());

  int num_methods = methods->length();

  for (int index = 0; index < num_methods; index++) {

    // Check for recursive re-verification before each method.

    if (was_recursively_verified())  return;

    methodOop m = (methodOop)methods->obj_at(index);

    if (m->is_native() || m->is_abstract()) {

      // If m is native or abstract, skip it.  It is checked in class file

      // parser that methods do not override a final method.

      continue;

    }

    verify_method(methodHandle(THREAD, m), CHECK_VERIFY(this));

  }

  if (_verify_verbose || TraceClassInitialization) {

    if (was_recursively_verified())

      tty->print_cr("Recursive verification detected for: %s",

          _klass->external_name());

  }

}

void ClassVerifier::verify_method(methodHandle m, TRAPS) {

  _method = m;   // initialize _method

  if (_verify_verbose) {

    tty->print_cr("Verifying method %s", m->name_and_sig_as_C_string());

  }

  const char* bad_type_msg = "Bad type on operand stack in %s";

  int32_t max_stack = m->max_stack();

  int32_t max_locals = m->max_locals();

  constantPoolHandle cp(THREAD, m->constants());

  if (!SignatureVerifier::is_valid_method_signature(m->signature())) {

    class_format_error("Invalid method signature");

    return;

  }

  // Initial stack map frame: offset is 0, stack is initially empty.

  StackMapFrame current_frame(max_locals, max_stack, this);

  // Set initial locals

  VerificationType return_type = current_frame.set_locals_from_arg(

    m, current_type(), CHECK_VERIFY(this));

  int32_t stackmap_index = 0; // index to the stackmap array

  u4 code_length = m->code_size();

  // Scan the bytecode and map each instruction's start offset to a number.

  char* code_data = generate_code_data(m, code_length, CHECK_VERIFY(this));

  int ex_min = code_length;

  int ex_max = -1;

  // Look through each item on the exception table. Each of the fields must refer

  // to a legal instruction.

  verify_exception_handler_table(

    code_length, code_data, ex_min, ex_max, CHECK_VERIFY(this));

  // Look through each entry on the local variable table and make sure

  // its range of code array offsets is valid. (4169817)

  if (m->has_localvariable_table()) {

    verify_local_variable_table(code_length, code_data, CHECK_VERIFY(this));

  }

  typeArrayHandle stackmap_data(THREAD, m->stackmap_data());

  StackMapStream stream(stackmap_data);

  StackMapReader reader(this, &stream, code_data, code_length, THREAD);

  StackMapTable stackmap_table(&reader, &current_frame, max_locals, max_stack,

                               code_data, code_length, CHECK_VERIFY(this));

  if (_verify_verbose) {

    stackmap_table.print();

  }

  RawBytecodeStream bcs(m);

  // Scan the byte code linearly from the start to the end

  bool no_control_flow = false; // Set to true when there is no direct control

                                // flow from current instruction to the next

                                // instruction in sequence

  Bytecodes::Code opcode;

  while (!bcs.is_last_bytecode()) {

    // Check for recursive re-verification before each bytecode.

    if (was_recursively_verified())  return;

    opcode = bcs.raw_next();

    u2 bci = bcs.bci();

    // Set current frame's offset to bci

    current_frame.set_offset(bci);

    // Make sure every offset in stackmap table point to the beginning to

    // an instruction. Match current_frame to stackmap_table entry with

    // the same offset if exists.

    stackmap_index = verify_stackmap_table(

      stackmap_index, bci, &current_frame, &stackmap_table,

      no_control_flow, CHECK_VERIFY(this));

    bool this_uninit = false;  // Set to true when invokespecial <init> initialized 'this'

    // Merge with the next instruction

    {

      u2 index;

      int target;

      VerificationType type, type2;

      VerificationType atype;

#ifndef PRODUCT

      if (_verify_verbose) {

        current_frame.print();

        tty->print_cr("offset = %d,  opcode = %s", bci, Bytecodes::name(opcode));

      }

#endif

      // Make sure wide instruction is in correct format

      if (bcs.is_wide()) {

        if (opcode != Bytecodes::_iinc   && opcode != Bytecodes::_iload  &&

            opcode != Bytecodes::_aload  && opcode != Bytecodes::_lload  &&

            opcode != Bytecodes::_istore && opcode != Bytecodes::_astore &&

            opcode != Bytecodes::_lstore && opcode != Bytecodes::_fload  &&

            opcode != Bytecodes::_dload  && opcode != Bytecodes::_fstore &&

            opcode != Bytecodes::_dstore) {

          verify_error(bci, "Bad wide instruction");

          return;

        }

      }

      switch (opcode) {

        case Bytecodes::_nop :

          no_control_flow = false; break;

        case Bytecodes::_aconst_null :

          current_frame.push_stack(

            VerificationType::null_type(), CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_iconst_m1 :

        case Bytecodes::_iconst_0 :

        case Bytecodes::_iconst_1 :

        case Bytecodes::_iconst_2 :

        case Bytecodes::_iconst_3 :

        case Bytecodes::_iconst_4 :

        case Bytecodes::_iconst_5 :

          current_frame.push_stack(

            VerificationType::integer_type(), CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_lconst_0 :

        case Bytecodes::_lconst_1 :

          current_frame.push_stack_2(

            VerificationType::long_type(),

            VerificationType::long2_type(), CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_fconst_0 :

        case Bytecodes::_fconst_1 :

        case Bytecodes::_fconst_2 :

          current_frame.push_stack(

            VerificationType::float_type(), CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_dconst_0 :

        case Bytecodes::_dconst_1 :

          current_frame.push_stack_2(

            VerificationType::double_type(),

            VerificationType::double2_type(), CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_sipush :

        case Bytecodes::_bipush :

          current_frame.push_stack(

            VerificationType::integer_type(), CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_ldc :

          verify_ldc(

            opcode, bcs.get_index_u1(), &current_frame,

            cp, bci, CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_ldc_w :

        case Bytecodes::_ldc2_w :

          verify_ldc(

            opcode, bcs.get_index_u2(), &current_frame,

            cp, bci, CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_iload :

          verify_iload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_iload_0 :

        case Bytecodes::_iload_1 :

        case Bytecodes::_iload_2 :

        case Bytecodes::_iload_3 :

          index = opcode - Bytecodes::_iload_0;

          verify_iload(index, &current_frame, CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_lload :

          verify_lload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_lload_0 :

        case Bytecodes::_lload_1 :

        case Bytecodes::_lload_2 :

        case Bytecodes::_lload_3 :

          index = opcode - Bytecodes::_lload_0;

          verify_lload(index, &current_frame, CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_fload :

          verify_fload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_fload_0 :

        case Bytecodes::_fload_1 :

        case Bytecodes::_fload_2 :

        case Bytecodes::_fload_3 :

          index = opcode - Bytecodes::_fload_0;

          verify_fload(index, &current_frame, CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_dload :

          verify_dload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));

          no_control_flow = false; break;

        case Bytecodes::_dload_0 :

        case Bytecodes::_dload_1 :

        case Bytecodes::_dload_2 :

        case Bytecodes::_dload_3 :

          index = opcode - Bytecodes::_dload_0;

          verify_dload(index, &current_frame, CHECK_VERIFY(this));

          no_control_flow = false; break;