1 /*
   2  * Copyright (c) 1998, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_CLASSFILE_VERIFIER_HPP
  26 #define SHARE_VM_CLASSFILE_VERIFIER_HPP
  27 
  28 #include "classfile/verificationType.hpp"
  29 #include "gc/shared/gcLocker.hpp"
  30 #include "oops/klass.hpp"
  31 #include "oops/method.hpp"
  32 #include "runtime/handles.hpp"
  33 #include "utilities/exceptions.hpp"
  34 #include "utilities/growableArray.hpp"
  35 
  36 // The verifier class
  37 class Verifier : AllStatic {
  38  public:
  39   enum {
  40     STRICTER_ACCESS_CTRL_CHECK_VERSION  = 49,
  41     STACKMAP_ATTRIBUTE_MAJOR_VERSION    = 50,
  42     INVOKEDYNAMIC_MAJOR_VERSION         = 51,
  43     NO_RELAX_ACCESS_CTRL_CHECK_VERSION  = 52
  44   };
  45   typedef enum { ThrowException, NoException } Mode;
  46 
  47   /**
  48    * Verify the bytecodes for a class.  If 'throw_exception' is true
  49    * then the appropriate VerifyError or ClassFormatError will be thrown.
  50    * Otherwise, no exception is thrown and the return indicates the
  51    * error.
  52    */
  53   static void log_end_verification(outputStream* st, const char* klassName, Symbol* exception_name, TRAPS);
  54   static bool verify(instanceKlassHandle klass, Mode mode, bool should_verify_class, TRAPS);
  55 
  56   // Return false if the class is loaded by the bootstrap loader,
  57   // or if defineClass was called requesting skipping verification
  58   // -Xverify:all/none override this value
  59   static bool should_verify_for(oop class_loader, bool should_verify_class);
  60 
  61   // Relax certain access checks to enable some broken 1.1 apps to run on 1.2.
  62   static bool relax_access_for(oop class_loader);
  63 
  64   // Print output for class+resolve
  65   static void trace_class_resolution(Klass* resolve_class, InstanceKlass* verify_class);
  66 
  67  private:
  68   static bool is_eligible_for_verification(instanceKlassHandle klass, bool should_verify_class);
  69   static Symbol* inference_verify(
  70     instanceKlassHandle klass, char* msg, size_t msg_len, TRAPS);
  71 };
  72 
  73 class RawBytecodeStream;
  74 class StackMapFrame;
  75 class StackMapTable;
  76 
  77 // Summary of verifier's memory usage:
  78 // StackMapTable is stack allocated.
  79 // StackMapFrame are resource allocated. There is only one ResourceMark
  80 // for each class verification, which is created at the top level.
  81 // There is one mutable StackMapFrame (current_frame) which is updated
  82 // by abstract bytecode interpretation. frame_in_exception_handler() returns
  83 // a frame that has a mutable one-item stack (ready for pushing the
  84 // catch type exception object). All the other StackMapFrame's
  85 // are immutable (including their locals and stack arrays) after
  86 // their constructions.
  87 // locals/stack arrays in StackMapFrame are resource allocated.
  88 // locals/stack arrays can be shared between StackMapFrame's, except
  89 // the mutable StackMapFrame (current_frame).
  90 
  91 // These macros are used similarly to CHECK macros but also check
  92 // the status of the verifier and return if that has an error.
  93 #define CHECK_VERIFY(verifier) \
  94   CHECK); if ((verifier)->has_error()) return; ((void)0
  95 #define CHECK_VERIFY_(verifier, result) \
  96   CHECK_(result)); if ((verifier)->has_error()) return (result); ((void)0
  97 
  98 class TypeOrigin VALUE_OBJ_CLASS_SPEC {
  99  private:
 100   typedef enum {
 101     CF_LOCALS,  // Comes from the current frame locals
 102     CF_STACK,   // Comes from the current frame expression stack
 103     SM_LOCALS,  // Comes from stackmap locals
 104     SM_STACK,   // Comes from stackmap expression stack
 105     CONST_POOL, // Comes from the constant pool
 106     SIG,        // Comes from method signature
 107     IMPLICIT,   // Comes implicitly from code or context
 108     BAD_INDEX,  // No type, but the index is bad
 109     FRAME_ONLY, // No type, context just contains the frame
 110     NONE
 111   } Origin;
 112 
 113   Origin _origin;
 114   u2 _index;              // local, stack, or constant pool index
 115   StackMapFrame* _frame;  // source frame if CF or SM
 116   VerificationType _type; // The actual type
 117 
 118   TypeOrigin(
 119       Origin origin, u2 index, StackMapFrame* frame, VerificationType type)
 120       : _origin(origin), _index(index), _frame(frame), _type(type) {}
 121 
 122  public:
 123   TypeOrigin() : _origin(NONE), _index(0), _frame(NULL) {}
 124 
 125   static TypeOrigin null();
 126   static TypeOrigin local(u2 index, StackMapFrame* frame);
 127   static TypeOrigin stack(u2 index, StackMapFrame* frame);
 128   static TypeOrigin sm_local(u2 index, StackMapFrame* frame);
 129   static TypeOrigin sm_stack(u2 index, StackMapFrame* frame);
 130   static TypeOrigin cp(u2 index, VerificationType vt);
 131   static TypeOrigin signature(VerificationType vt);
 132   static TypeOrigin bad_index(u2 index);
 133   static TypeOrigin implicit(VerificationType t);
 134   static TypeOrigin frame(StackMapFrame* frame);
 135 
 136   void reset_frame();
 137   void details(outputStream* ss) const;
 138   void print_frame(outputStream* ss) const;
 139   const StackMapFrame* frame() const { return _frame; }
 140   bool is_valid() const { return _origin != NONE; }
 141   u2 index() const { return _index; }
 142 
 143 #ifdef ASSERT
 144   void print_on(outputStream* str) const;
 145 #endif
 146 };
 147 
 148 class ErrorContext VALUE_OBJ_CLASS_SPEC {
 149  private:
 150   typedef enum {
 151     INVALID_BYTECODE,     // There was a problem with the bytecode
 152     WRONG_TYPE,           // Type value was not as expected
 153     FLAGS_MISMATCH,       // Frame flags are not assignable
 154     BAD_CP_INDEX,         // Invalid constant pool index
 155     BAD_LOCAL_INDEX,      // Invalid local index
 156     LOCALS_SIZE_MISMATCH, // Frames have differing local counts
 157     STACK_SIZE_MISMATCH,  // Frames have different stack sizes
 158     STACK_OVERFLOW,       // Attempt to push onto a full expression stack
 159     STACK_UNDERFLOW,      // Attempt to pop and empty expression stack
 160     MISSING_STACKMAP,     // No stackmap for this location and there should be
 161     BAD_STACKMAP,         // Format error in stackmap
 162     NO_FAULT,             // No error
 163     UNKNOWN
 164   } FaultType;
 165 
 166   int _bci;
 167   FaultType _fault;
 168   TypeOrigin _type;
 169   TypeOrigin _expected;
 170 
 171   ErrorContext(int bci, FaultType fault) :
 172       _bci(bci), _fault(fault)  {}
 173   ErrorContext(int bci, FaultType fault, TypeOrigin type) :
 174       _bci(bci), _fault(fault), _type(type)  {}
 175   ErrorContext(int bci, FaultType fault, TypeOrigin type, TypeOrigin exp) :
 176       _bci(bci), _fault(fault), _type(type), _expected(exp)  {}
 177 
 178  public:
 179   ErrorContext() : _bci(-1), _fault(NO_FAULT) {}
 180 
 181   static ErrorContext bad_code(u2 bci) {
 182     return ErrorContext(bci, INVALID_BYTECODE);
 183   }
 184   static ErrorContext bad_type(u2 bci, TypeOrigin type) {
 185     return ErrorContext(bci, WRONG_TYPE, type);
 186   }
 187   static ErrorContext bad_type(u2 bci, TypeOrigin type, TypeOrigin exp) {
 188     return ErrorContext(bci, WRONG_TYPE, type, exp);
 189   }
 190   static ErrorContext bad_flags(u2 bci, StackMapFrame* frame) {
 191     return ErrorContext(bci, FLAGS_MISMATCH, TypeOrigin::frame(frame));
 192   }
 193   static ErrorContext bad_flags(u2 bci, StackMapFrame* cur, StackMapFrame* sm) {
 194     return ErrorContext(bci, FLAGS_MISMATCH,
 195                         TypeOrigin::frame(cur), TypeOrigin::frame(sm));
 196   }
 197   static ErrorContext bad_cp_index(u2 bci, u2 index) {
 198     return ErrorContext(bci, BAD_CP_INDEX, TypeOrigin::bad_index(index));
 199   }
 200   static ErrorContext bad_local_index(u2 bci, u2 index) {
 201     return ErrorContext(bci, BAD_LOCAL_INDEX, TypeOrigin::bad_index(index));
 202   }
 203   static ErrorContext locals_size_mismatch(
 204       u2 bci, StackMapFrame* frame0, StackMapFrame* frame1) {
 205     return ErrorContext(bci, LOCALS_SIZE_MISMATCH,
 206         TypeOrigin::frame(frame0), TypeOrigin::frame(frame1));
 207   }
 208   static ErrorContext stack_size_mismatch(
 209       u2 bci, StackMapFrame* frame0, StackMapFrame* frame1) {
 210     return ErrorContext(bci, STACK_SIZE_MISMATCH,
 211         TypeOrigin::frame(frame0), TypeOrigin::frame(frame1));
 212   }
 213   static ErrorContext stack_overflow(u2 bci, StackMapFrame* frame) {
 214     return ErrorContext(bci, STACK_OVERFLOW, TypeOrigin::frame(frame));
 215   }
 216   static ErrorContext stack_underflow(u2 bci, StackMapFrame* frame) {
 217     return ErrorContext(bci, STACK_UNDERFLOW, TypeOrigin::frame(frame));
 218   }
 219   static ErrorContext missing_stackmap(u2 bci) {
 220     return ErrorContext(bci, MISSING_STACKMAP);
 221   }
 222   static ErrorContext bad_stackmap(int index, StackMapFrame* frame) {
 223     return ErrorContext(0, BAD_STACKMAP, TypeOrigin::frame(frame));
 224   }
 225 
 226   bool is_valid() const { return _fault != NO_FAULT; }
 227   int bci() const { return _bci; }
 228 
 229   void reset_frames() {
 230     _type.reset_frame();
 231     _expected.reset_frame();
 232   }
 233 
 234   void details(outputStream* ss, const Method* method) const;
 235 
 236 #ifdef ASSERT
 237   void print_on(outputStream* str) const {
 238     str->print("error_context(%d, %d,", _bci, _fault);
 239     _type.print_on(str);
 240     str->print(",");
 241     _expected.print_on(str);
 242     str->print(")");
 243   }
 244 #endif
 245 
 246  private:
 247   void location_details(outputStream* ss, const Method* method) const;
 248   void reason_details(outputStream* ss) const;
 249   void frame_details(outputStream* ss) const;
 250   void bytecode_details(outputStream* ss, const Method* method) const;
 251   void handler_details(outputStream* ss, const Method* method) const;
 252   void stackmap_details(outputStream* ss, const Method* method) const;
 253 };
 254 
 255 // A new instance of this class is created for each class being verified
 256 class ClassVerifier : public StackObj {
 257  private:
 258   Thread* _thread;
 259   GrowableArray<Symbol*>* _symbols;  // keep a list of symbols created
 260 
 261   Symbol* _exception_type;
 262   char* _message;
 263 
 264   ErrorContext _error_context;  // contains information about an error
 265 
 266   void verify_method(const methodHandle& method, TRAPS);
 267   char* generate_code_data(const methodHandle& m, u4 code_length, TRAPS);
 268   void verify_exception_handler_table(u4 code_length, char* code_data,
 269                                       int& min, int& max, TRAPS);
 270   void verify_local_variable_table(u4 code_length, char* code_data, TRAPS);
 271 
 272   VerificationType cp_ref_index_to_type(
 273       int index, const constantPoolHandle& cp, TRAPS) {
 274     return cp_index_to_type(cp->klass_ref_index_at(index), cp, THREAD);
 275   }
 276 
 277   bool is_protected_access(
 278     instanceKlassHandle this_class, Klass* target_class,
 279     Symbol* field_name, Symbol* field_sig, bool is_method);
 280 
 281   void verify_cp_index(u2 bci, const constantPoolHandle& cp, int index, TRAPS);
 282   void verify_cp_type(u2 bci, int index, const constantPoolHandle& cp,
 283       unsigned int types, TRAPS);
 284   void verify_cp_class_type(u2 bci, int index, const constantPoolHandle& cp, TRAPS);
 285 
 286   u2 verify_stackmap_table(
 287     u2 stackmap_index, u2 bci, StackMapFrame* current_frame,
 288     StackMapTable* stackmap_table, bool no_control_flow, TRAPS);
 289 
 290   void verify_exception_handler_targets(
 291     u2 bci, bool this_uninit, StackMapFrame* current_frame,
 292     StackMapTable* stackmap_table, TRAPS);
 293 
 294   void verify_ldc(
 295     int opcode, u2 index, StackMapFrame *current_frame,
 296     const constantPoolHandle& cp, u2 bci, TRAPS);
 297 
 298   void verify_switch(
 299     RawBytecodeStream* bcs, u4 code_length, char* code_data,
 300     StackMapFrame* current_frame, StackMapTable* stackmap_table, TRAPS);
 301 
 302   void verify_field_instructions(
 303     RawBytecodeStream* bcs, StackMapFrame* current_frame,
 304     const constantPoolHandle& cp, bool allow_arrays, TRAPS);
 305 
 306   void verify_invoke_init(
 307     RawBytecodeStream* bcs, u2 ref_index, VerificationType ref_class_type,
 308     StackMapFrame* current_frame, u4 code_length, bool in_try_block,
 309     bool* this_uninit, const constantPoolHandle& cp, StackMapTable* stackmap_table,
 310     TRAPS);
 311 
 312   // Used by ends_in_athrow() to push all handlers that contain bci onto the
 313   // handler_stack, if the handler has not already been pushed on the stack.
 314   void push_handlers(ExceptionTable* exhandlers,
 315                      GrowableArray<u4>* handler_list,
 316                      GrowableArray<u4>* handler_stack,
 317                      u4 bci);
 318 
 319   // Returns true if all paths starting with start_bc_offset end in athrow
 320   // bytecode or loop.
 321   bool ends_in_athrow(u4 start_bc_offset);
 322 
 323   void verify_invoke_instructions(
 324     RawBytecodeStream* bcs, u4 code_length, StackMapFrame* current_frame,
 325     bool in_try_block, bool* this_uninit, VerificationType return_type,
 326     const constantPoolHandle& cp, StackMapTable* stackmap_table, TRAPS);
 327 
 328   VerificationType get_newarray_type(u2 index, u2 bci, TRAPS);
 329   void verify_anewarray(u2 bci, u2 index, const constantPoolHandle& cp,
 330       StackMapFrame* current_frame, TRAPS);
 331   void verify_return_value(
 332       VerificationType return_type, VerificationType type, u2 offset,
 333       StackMapFrame* current_frame, TRAPS);
 334 
 335   void verify_iload (u2 index, StackMapFrame* current_frame, TRAPS);
 336   void verify_lload (u2 index, StackMapFrame* current_frame, TRAPS);
 337   void verify_fload (u2 index, StackMapFrame* current_frame, TRAPS);
 338   void verify_dload (u2 index, StackMapFrame* current_frame, TRAPS);
 339   void verify_aload (u2 index, StackMapFrame* current_frame, TRAPS);
 340   void verify_istore(u2 index, StackMapFrame* current_frame, TRAPS);
 341   void verify_lstore(u2 index, StackMapFrame* current_frame, TRAPS);
 342   void verify_fstore(u2 index, StackMapFrame* current_frame, TRAPS);
 343   void verify_dstore(u2 index, StackMapFrame* current_frame, TRAPS);
 344   void verify_astore(u2 index, StackMapFrame* current_frame, TRAPS);
 345   void verify_iinc  (u2 index, StackMapFrame* current_frame, TRAPS);
 346 
 347   bool name_in_supers(Symbol* ref_name, instanceKlassHandle current);
 348 
 349   VerificationType object_type() const;
 350 
 351   instanceKlassHandle _klass;  // the class being verified
 352   methodHandle        _method; // current method being verified
 353   VerificationType    _this_type; // the verification type of the current class
 354 
 355   // Some recursive calls from the verifier to the name resolver
 356   // can cause the current class to be re-verified and rewritten.
 357   // If this happens, the original verification should not continue,
 358   // because constant pool indexes will have changed.
 359   // The rewriter is preceded by the verifier.  If the verifier throws
 360   // an error, rewriting is prevented.  Also, rewriting always precedes
 361   // bytecode execution or compilation.  Thus, is_rewritten implies
 362   // that a class has been verified and prepared for execution.
 363   bool was_recursively_verified() { return _klass->is_rewritten(); }
 364 
 365   bool is_same_or_direct_interface(instanceKlassHandle klass,
 366     VerificationType klass_type, VerificationType ref_class_type);
 367 
 368  public:
 369   enum {
 370     BYTECODE_OFFSET = 1,
 371     NEW_OFFSET = 2
 372   };
 373 
 374   // constructor
 375   ClassVerifier(instanceKlassHandle klass, TRAPS);
 376 
 377   // destructor
 378   ~ClassVerifier();
 379 
 380   Thread* thread()             { return _thread; }
 381   const methodHandle& method() { return _method; }
 382   instanceKlassHandle current_class() const { return _klass; }
 383   VerificationType current_type() const { return _this_type; }
 384 
 385   // Verifies the class.  If a verify or class file format error occurs,
 386   // the '_exception_name' symbols will set to the exception name and
 387   // the message_buffer will be filled in with the exception message.
 388   void verify_class(TRAPS);
 389 
 390   // Return status modes
 391   Symbol* result() const { return _exception_type; }
 392   bool has_error() const { return result() != NULL; }
 393   char* exception_message() {
 394     stringStream ss;
 395     ss.print("%s", _message);
 396     _error_context.details(&ss, _method());
 397     return ss.as_string();
 398   }
 399 
 400   // Called when verify or class format errors are encountered.
 401   // May throw an exception based upon the mode.
 402   void verify_error(ErrorContext ctx, const char* fmt, ...) ATTRIBUTE_PRINTF(3, 4);
 403   void class_format_error(const char* fmt, ...) ATTRIBUTE_PRINTF(2, 3);
 404 
 405   Klass* load_class(Symbol* name, TRAPS);
 406 
 407   int change_sig_to_verificationType(
 408     SignatureStream* sig_type, VerificationType* inference_type, TRAPS);
 409 
 410   VerificationType cp_index_to_type(int index, const constantPoolHandle& cp, TRAPS) {
 411     return VerificationType::reference_type(cp->klass_name_at(index));
 412   }
 413 
 414   // Keep a list of temporary symbols created during verification because
 415   // their reference counts need to be decremented when the verifier object
 416   // goes out of scope.  Since these symbols escape the scope in which they're
 417   // created, we can't use a TempNewSymbol.
 418   Symbol* create_temporary_symbol(const Symbol* s, int begin, int end, TRAPS);
 419   Symbol* create_temporary_symbol(const char *s, int length, TRAPS);
 420 
 421   Symbol* create_temporary_symbol(Symbol* s) {
 422     // This version just updates the reference count and saves the symbol to be
 423     // dereferenced later.
 424     s->increment_refcount();
 425     _symbols->push(s);
 426     return s;
 427   }
 428 
 429   TypeOrigin ref_ctx(const char* str, TRAPS);
 430 
 431 };
 432 
 433 inline int ClassVerifier::change_sig_to_verificationType(
 434     SignatureStream* sig_type, VerificationType* inference_type, TRAPS) {
 435   BasicType bt = sig_type->type();
 436   switch (bt) {
 437     case T_OBJECT:
 438     case T_ARRAY:
 439       {
 440         Symbol* name = sig_type->as_symbol(CHECK_0);
 441         // Create another symbol to save as signature stream unreferences this symbol.
 442         Symbol* name_copy = create_temporary_symbol(name);
 443         assert(name_copy == name, "symbols don't match");
 444         *inference_type =
 445           VerificationType::reference_type(name_copy);
 446         return 1;
 447       }
 448     case T_LONG:
 449       *inference_type = VerificationType::long_type();
 450       *++inference_type = VerificationType::long2_type();
 451       return 2;
 452     case T_DOUBLE:
 453       *inference_type = VerificationType::double_type();
 454       *++inference_type = VerificationType::double2_type();
 455       return 2;
 456     case T_INT:
 457     case T_BOOLEAN:
 458     case T_BYTE:
 459     case T_CHAR:
 460     case T_SHORT:
 461       *inference_type = VerificationType::integer_type();
 462       return 1;
 463     case T_FLOAT:
 464       *inference_type = VerificationType::float_type();
 465       return 1;
 466     default:
 467       ShouldNotReachHere();
 468       return 1;
 469   }
 470 }
 471 
 472 #endif // SHARE_VM_CLASSFILE_VERIFIER_HPP