/*

 * Copyright (c) 1998, 2017, 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

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 */

#ifndef SHARE_VM_CLASSFILE_VERIFIER_HPP

#define SHARE_VM_CLASSFILE_VERIFIER_HPP

#include "classfile/verificationType.hpp"

#include "gc/shared/gcLocker.hpp"

#include "oops/klass.hpp"

#include "oops/method.hpp"

#include "runtime/handles.hpp"

#include "utilities/exceptions.hpp"

#include "utilities/growableArray.hpp"

// The verifier class

class Verifier : AllStatic {

 public:

  enum {

    STRICTER_ACCESS_CTRL_CHECK_VERSION  = 49,

    STACKMAP_ATTRIBUTE_MAJOR_VERSION    = 50,

    INVOKEDYNAMIC_MAJOR_VERSION         = 51,

  };

  typedef enum { ThrowException, NoException } Mode;

  /**

   * Verify the bytecodes for a class.  If 'throw_exception' is true

   * then the appropriate VerifyError or ClassFormatError will be thrown.

   * Otherwise, no exception is thrown and the return indicates the

   * error.

   */

  static void log_end_verification(outputStream* st, const char* klassName, Symbol* exception_name, TRAPS);

  static bool verify(InstanceKlass* klass, Mode mode, bool should_verify_class, TRAPS);

  // Return false if the class is loaded by the bootstrap loader,

  // or if defineClass was called requesting skipping verification

  // -Xverify:all/none override this value

  static bool should_verify_for(oop class_loader, bool should_verify_class);

  // Relax certain access checks to enable some broken 1.1 apps to run on 1.2.

  static bool relax_access_for(oop class_loader);

  // Print output for class+resolve

  static void trace_class_resolution(Klass* resolve_class, InstanceKlass* verify_class);

 private:

  static bool is_eligible_for_verification(InstanceKlass* klass, bool should_verify_class);

  static Symbol* inference_verify(

    InstanceKlass* klass, char* msg, size_t msg_len, TRAPS);

};

class RawBytecodeStream;

class StackMapFrame;

class StackMapTable;

// Summary of verifier's memory usage:

// StackMapTable is stack allocated.

// StackMapFrame are resource allocated. There is only one ResourceMark

// for each class verification, which is created at the top level.

// There is one mutable StackMapFrame (current_frame) which is updated

// by abstract bytecode interpretation. frame_in_exception_handler() returns

// a frame that has a mutable one-item stack (ready for pushing the

// catch type exception object). All the other StackMapFrame's

// are immutable (including their locals and stack arrays) after

// their constructions.

// locals/stack arrays in StackMapFrame are resource allocated.

// locals/stack arrays can be shared between StackMapFrame's, except

// the mutable StackMapFrame (current_frame).

// These macros are used similarly to CHECK macros but also check

// the status of the verifier and return if that has an error.

#define CHECK_VERIFY(verifier) \

  CHECK); if ((verifier)->has_error()) return; ((void)0

#define CHECK_VERIFY_(verifier, result) \

  CHECK_(result)); if ((verifier)->has_error()) return (result); ((void)0

class TypeOrigin VALUE_OBJ_CLASS_SPEC {

 private:

  typedef enum {

    CF_LOCALS,  // Comes from the current frame locals

    CF_STACK,   // Comes from the current frame expression stack

    SM_LOCALS,  // Comes from stackmap locals

    SM_STACK,   // Comes from stackmap expression stack

    CONST_POOL, // Comes from the constant pool

    SIG,        // Comes from method signature

    IMPLICIT,   // Comes implicitly from code or context

    BAD_INDEX,  // No type, but the index is bad

    FRAME_ONLY, // No type, context just contains the frame

    NONE

  } Origin;

  Origin _origin;

  u2 _index;              // local, stack, or constant pool index

  StackMapFrame* _frame;  // source frame if CF or SM

  VerificationType _type; // The actual type

  TypeOrigin(

      Origin origin, u2 index, StackMapFrame* frame, VerificationType type)

      : _origin(origin), _index(index), _frame(frame), _type(type) {}

 public:

  TypeOrigin() : _origin(NONE), _index(0), _frame(NULL) {}

  static TypeOrigin null();

  static TypeOrigin local(u2 index, StackMapFrame* frame);

  static TypeOrigin stack(u2 index, StackMapFrame* frame);

  static TypeOrigin sm_local(u2 index, StackMapFrame* frame);

  static TypeOrigin sm_stack(u2 index, StackMapFrame* frame);

  static TypeOrigin cp(u2 index, VerificationType vt);

  static TypeOrigin signature(VerificationType vt);

  static TypeOrigin bad_index(u2 index);

  static TypeOrigin implicit(VerificationType t);

  static TypeOrigin frame(StackMapFrame* frame);

  void reset_frame();

  void details(outputStream* ss) const;

  void print_frame(outputStream* ss) const;

  const StackMapFrame* frame() const { return _frame; }

  bool is_valid() const { return _origin != NONE; }

  u2 index() const { return _index; }

#ifdef ASSERT

  void print_on(outputStream* str) const;

#endif

};

class ErrorContext VALUE_OBJ_CLASS_SPEC {

 private:

  typedef enum {

    INVALID_BYTECODE,     // There was a problem with the bytecode

    WRONG_TYPE,           // Type value was not as expected

    FLAGS_MISMATCH,       // Frame flags are not assignable

    BAD_CP_INDEX,         // Invalid constant pool index

    BAD_LOCAL_INDEX,      // Invalid local index

    LOCALS_SIZE_MISMATCH, // Frames have differing local counts

    STACK_SIZE_MISMATCH,  // Frames have different stack sizes

    STACK_OVERFLOW,       // Attempt to push onto a full expression stack

    STACK_UNDERFLOW,      // Attempt to pop and empty expression stack

    MISSING_STACKMAP,     // No stackmap for this location and there should be

    BAD_STACKMAP,         // Format error in stackmap

    NO_FAULT,             // No error

    UNKNOWN

  } FaultType;

  int _bci;

  FaultType _fault;

  TypeOrigin _type;

  TypeOrigin _expected;

  ErrorContext(int bci, FaultType fault) :

      _bci(bci), _fault(fault)  {}

  ErrorContext(int bci, FaultType fault, TypeOrigin type) :

      _bci(bci), _fault(fault), _type(type)  {}

  ErrorContext(int bci, FaultType fault, TypeOrigin type, TypeOrigin exp) :

      _bci(bci), _fault(fault), _type(type), _expected(exp)  {}

 public:

  ErrorContext() : _bci(-1), _fault(NO_FAULT) {}

  static ErrorContext bad_code(u2 bci) {

    return ErrorContext(bci, INVALID_BYTECODE);

  }

  static ErrorContext bad_type(u2 bci, TypeOrigin type) {

    return ErrorContext(bci, WRONG_TYPE, type);

  }

  static ErrorContext bad_type(u2 bci, TypeOrigin type, TypeOrigin exp) {

    return ErrorContext(bci, WRONG_TYPE, type, exp);

  }

  static ErrorContext bad_flags(u2 bci, StackMapFrame* frame) {

    return ErrorContext(bci, FLAGS_MISMATCH, TypeOrigin::frame(frame));

  }

  static ErrorContext bad_flags(u2 bci, StackMapFrame* cur, StackMapFrame* sm) {

    return ErrorContext(bci, FLAGS_MISMATCH,

                        TypeOrigin::frame(cur), TypeOrigin::frame(sm));

  }

  static ErrorContext bad_cp_index(u2 bci, u2 index) {

    return ErrorContext(bci, BAD_CP_INDEX, TypeOrigin::bad_index(index));

  }

  static ErrorContext bad_local_index(u2 bci, u2 index) {

    return ErrorContext(bci, BAD_LOCAL_INDEX, TypeOrigin::bad_index(index));

  }

  static ErrorContext locals_size_mismatch(

      u2 bci, StackMapFrame* frame0, StackMapFrame* frame1) {

    return ErrorContext(bci, LOCALS_SIZE_MISMATCH,

        TypeOrigin::frame(frame0), TypeOrigin::frame(frame1));

  }

  static ErrorContext stack_size_mismatch(

      u2 bci, StackMapFrame* frame0, StackMapFrame* frame1) {

    return ErrorContext(bci, STACK_SIZE_MISMATCH,

        TypeOrigin::frame(frame0), TypeOrigin::frame(frame1));

  }

  static ErrorContext stack_overflow(u2 bci, StackMapFrame* frame) {

    return ErrorContext(bci, STACK_OVERFLOW, TypeOrigin::frame(frame));

  }

  static ErrorContext stack_underflow(u2 bci, StackMapFrame* frame) {

    return ErrorContext(bci, STACK_UNDERFLOW, TypeOrigin::frame(frame));

  }

  static ErrorContext missing_stackmap(u2 bci) {

    return ErrorContext(bci, MISSING_STACKMAP);

  }

  static ErrorContext bad_stackmap(int index, StackMapFrame* frame) {

    return ErrorContext(0, BAD_STACKMAP, TypeOrigin::frame(frame));

  }

  bool is_valid() const { return _fault != NO_FAULT; }

  int bci() const { return _bci; }

  void reset_frames() {

    _type.reset_frame();

    _expected.reset_frame();

  }

  void details(outputStream* ss, const Method* method) const;

#ifdef ASSERT

  void print_on(outputStream* str) const {

    str->print("error_context(%d, %d,", _bci, _fault);

    _type.print_on(str);

    str->print(",");

    _expected.print_on(str);

    str->print(")");

  }

#endif

 private:

  void location_details(outputStream* ss, const Method* method) const;

  void reason_details(outputStream* ss) const;

  void frame_details(outputStream* ss) const;

  void bytecode_details(outputStream* ss, const Method* method) const;

  void handler_details(outputStream* ss, const Method* method) const;

  void stackmap_details(outputStream* ss, const Method* method) const;

};

// A new instance of this class is created for each class being verified

class ClassVerifier : public StackObj {

 private:

  Thread* _thread;

  GrowableArray<Symbol*>* _symbols;  // keep a list of symbols created

  Symbol* _exception_type;

  char* _message;

  ErrorContext _error_context;  // contains information about an error

  void verify_method(const methodHandle& method, TRAPS);

  char* generate_code_data(const methodHandle& m, u4 code_length, TRAPS);

  void verify_exception_handler_table(u4 code_length, char* code_data,

                                      int& min, int& max, TRAPS);

  void verify_local_variable_table(u4 code_length, char* code_data, TRAPS);

  VerificationType cp_ref_index_to_type(

      int index, const constantPoolHandle& cp, TRAPS) {

    return cp_index_to_type(cp->klass_ref_index_at(index), cp, THREAD);

  }

  bool is_protected_access(

    InstanceKlass* this_class, Klass* target_class,

    Symbol* field_name, Symbol* field_sig, bool is_method);

  void verify_cp_index(u2 bci, const constantPoolHandle& cp, int index, TRAPS);

  void verify_cp_type(u2 bci, int index, const constantPoolHandle& cp,

      unsigned int types, TRAPS);

  void verify_cp_class_type(u2 bci, int index, const constantPoolHandle& cp, TRAPS);

  u2 verify_stackmap_table(

    u2 stackmap_index, u2 bci, StackMapFrame* current_frame,

    StackMapTable* stackmap_table, bool no_control_flow, TRAPS);

  void verify_exception_handler_targets(

    u2 bci, bool this_uninit, StackMapFrame* current_frame,

    StackMapTable* stackmap_table, TRAPS);

  void verify_ldc(

    int opcode, u2 index, StackMapFrame *current_frame,

    const constantPoolHandle& cp, u2 bci, TRAPS);

  void verify_switch(

    RawBytecodeStream* bcs, u4 code_length, char* code_data,

    StackMapFrame* current_frame, StackMapTable* stackmap_table, TRAPS);

  void verify_field_instructions(

    RawBytecodeStream* bcs, StackMapFrame* current_frame,

    const constantPoolHandle& cp, bool allow_arrays, TRAPS);

  void verify_invoke_init(

    RawBytecodeStream* bcs, u2 ref_index, VerificationType ref_class_type,

    StackMapFrame* current_frame, u4 code_length, bool in_try_block,

    bool* this_uninit, const constantPoolHandle& cp, StackMapTable* stackmap_table,

    TRAPS);

  // Used by ends_in_athrow() to push all handlers that contain bci onto the

  // handler_stack, if the handler has not already been pushed on the stack.

  void push_handlers(ExceptionTable* exhandlers,

                     GrowableArray<u4>* handler_list,

                     GrowableArray<u4>* handler_stack,

                     u4 bci);

  // Returns true if all paths starting with start_bc_offset end in athrow

  // bytecode or loop.

  bool ends_in_athrow(u4 start_bc_offset);

  void verify_invoke_instructions(

    RawBytecodeStream* bcs, u4 code_length, StackMapFrame* current_frame,

    bool in_try_block, bool* this_uninit, VerificationType return_type,

    const constantPoolHandle& cp, StackMapTable* stackmap_table, TRAPS);

  VerificationType get_newarray_type(u2 index, u2 bci, TRAPS);

  void verify_anewarray(u2 bci, u2 index, const constantPoolHandle& cp,

      StackMapFrame* current_frame, TRAPS);

  void verify_return_value(

      VerificationType return_type, VerificationType type, u2 offset,

      StackMapFrame* current_frame, TRAPS);

  void verify_iload (u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_lload (u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_fload (u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_dload (u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_aload (u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_istore(u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_lstore(u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_fstore(u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_dstore(u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_astore(u2 index, StackMapFrame* current_frame, TRAPS);

  void verify_iinc  (u2 index, StackMapFrame* current_frame, TRAPS);

  bool name_in_supers(Symbol* ref_name, InstanceKlass* current);

  VerificationType object_type() const;

  InstanceKlass*      _klass;  // the class being verified

  methodHandle        _method; // current method being verified

  VerificationType    _this_type; // the verification type of the current class

  // Some recursive calls from the verifier to the name resolver

  // can cause the current class to be re-verified and rewritten.

  // If this happens, the original verification should not continue,

  // because constant pool indexes will have changed.

  // The rewriter is preceded by the verifier.  If the verifier throws

  // an error, rewriting is prevented.  Also, rewriting always precedes

  // bytecode execution or compilation.  Thus, is_rewritten implies

  // that a class has been verified and prepared for execution.

  bool was_recursively_verified() { return _klass->is_rewritten(); }

  bool is_same_or_direct_interface(InstanceKlass* klass,

    VerificationType klass_type, VerificationType ref_class_type);

 public:

  enum {

    BYTECODE_OFFSET = 1,

    NEW_OFFSET = 2

  };

  // constructor

  ClassVerifier(InstanceKlass* klass, TRAPS);

  // destructor

  ~ClassVerifier();

  Thread* thread()             { return _thread; }

  const methodHandle& method() { return _method; }

  InstanceKlass* current_class() const { return _klass; }

  VerificationType current_type() const { return _this_type; }

  // Verifies the class.  If a verify or class file format error occurs,

  // the '_exception_name' symbols will set to the exception name and

  // the message_buffer will be filled in with the exception message.

  void verify_class(TRAPS);

  // Return status modes

  Symbol* result() const { return _exception_type; }

  bool has_error() const { return result() != NULL; }

  char* exception_message() {

    stringStream ss;

    ss.print("%s", _message);

    _error_context.details(&ss, _method());

    return ss.as_string();

  }

  // Called when verify or class format errors are encountered.

  // May throw an exception based upon the mode.

  void verify_error(ErrorContext ctx, const char* fmt, ...) ATTRIBUTE_PRINTF(3, 4);

  void class_format_error(const char* fmt, ...) ATTRIBUTE_PRINTF(2, 3);

  Klass* load_class(Symbol* name, TRAPS);

  int change_sig_to_verificationType(

    SignatureStream* sig_type, VerificationType* inference_type, TRAPS);

  VerificationType cp_index_to_type(int index, const constantPoolHandle& cp, TRAPS) {

    return VerificationType::reference_type(cp->klass_name_at(index));

  }

  // Keep a list of temporary symbols created during verification because

  // their reference counts need to be decremented when the verifier object

  // goes out of scope.  Since these symbols escape the scope in which they're

  // created, we can't use a TempNewSymbol.

  Symbol* create_temporary_symbol(const Symbol* s, int begin, int end, TRAPS);

  Symbol* create_temporary_symbol(const char *s, int length, TRAPS);

  Symbol* create_temporary_symbol(Symbol* s) {

    // This version just updates the reference count and saves the symbol to be

    // dereferenced later.

    s->increment_refcount();

    _symbols->push(s);

    return s;

  }

  TypeOrigin ref_ctx(const char* str, TRAPS);

};

inline int ClassVerifier::change_sig_to_verificationType(

    SignatureStream* sig_type, VerificationType* inference_type, TRAPS) {

  BasicType bt = sig_type->type();

  switch (bt) {

    case T_OBJECT:

    case T_ARRAY:

      {

        Symbol* name = sig_type->as_symbol(CHECK_0);

        // Create another symbol to save as signature stream unreferences this symbol.

        Symbol* name_copy = create_temporary_symbol(name);

        assert(name_copy == name, "symbols don't match");

        *inference_type =

          VerificationType::reference_type(name_copy);

        return 1;

      }

    case T_LONG:

      *inference_type = VerificationType::long_type();

      *++inference_type = VerificationType::long2_type();

      return 2;

    case T_DOUBLE:

      *inference_type = VerificationType::double_type();

      *++inference_type = VerificationType::double2_type();

      return 2;

    case T_INT:

    case T_BOOLEAN:

    case T_BYTE:

    case T_CHAR:

    case T_SHORT:

      *inference_type = VerificationType::integer_type();

      return 1;

    case T_FLOAT:

      *inference_type = VerificationType::float_type();

      return 1;

    default:

      ShouldNotReachHere();

      return 1;

  }

}

#endif // SHARE_VM_CLASSFILE_VERIFIER_HPP