1 /*
  2  * Copyright (c) 1998, 2021, 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.
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 23  */
 24 
 25 #ifndef SHARE_CLASSFILE_VERIFIER_HPP
 26 #define SHARE_CLASSFILE_VERIFIER_HPP
 27 
 28 #include "classfile/verificationType.hpp"
 29 #include "oops/klass.hpp"
 30 #include "oops/method.hpp"
 31 #include "runtime/handles.hpp"
 32 #include "utilities/exceptions.hpp"
 33 #include "utilities/growableArray.hpp"
 34 #include "utilities/resourceHash.hpp"
 35 
 36 // The verifier class
 37 class Verifier : AllStatic {
 38  public:
 39   enum {
 40     STACKMAP_ATTRIBUTE_MAJOR_VERSION    = 50,
 41     INVOKEDYNAMIC_MAJOR_VERSION         = 51,
 42     NO_RELAX_ACCESS_CTRL_CHECK_VERSION  = 52,
 43     DYNAMICCONSTANT_MAJOR_VERSION       = 55
 44   };
 45 
 46   // Verify the bytecodes for a class.
 47   static bool verify(InstanceKlass* klass, bool should_verify_class, TRAPS);
 48 
 49   static void log_end_verification(outputStream* st, const char* klassName, Symbol* exception_name,
 50                                     oop pending_exception);
 51 
 52   // Return false if the class is loaded by the bootstrap loader,
 53   // or if defineClass was called requesting skipping verification
 54   // -Xverify:all overrides this value
 55   static bool should_verify_for(oop class_loader, bool should_verify_class);
 56 
 57   // Relax certain access checks to enable some broken 1.1 apps to run on 1.2.
 58   static bool relax_access_for(oop class_loader);
 59 
 60   // Print output for class+resolve
 61   static void trace_class_resolution(Klass* resolve_class, InstanceKlass* verify_class);
 62 
 63  private:
 64   static bool is_eligible_for_verification(InstanceKlass* klass, bool should_verify_class);
 65   static Symbol* inference_verify(
 66     InstanceKlass* klass, char* msg, size_t msg_len, TRAPS);
 67 };
 68 
 69 class RawBytecodeStream;
 70 class StackMapFrame;
 71 class StackMapTable;
 72 
 73 // Summary of verifier's memory usage:
 74 // StackMapTable is stack allocated.
 75 // StackMapFrame are resource allocated. There is only one ResourceMark
 76 // for each class verification, which is created at the top level.
 77 // There is one mutable StackMapFrame (current_frame) which is updated
 78 // by abstract bytecode interpretation. frame_in_exception_handler() returns
 79 // a frame that has a mutable one-item stack (ready for pushing the
 80 // catch type exception object). All the other StackMapFrame's
 81 // are immutable (including their locals and stack arrays) after
 82 // their constructions.
 83 // locals/stack arrays in StackMapFrame are resource allocated.
 84 // locals/stack arrays can be shared between StackMapFrame's, except
 85 // the mutable StackMapFrame (current_frame).
 86 
 87 // These macros are used similarly to CHECK macros but also check
 88 // the status of the verifier and return if that has an error.
 89 #define CHECK_VERIFY(verifier) \
 90   CHECK); if ((verifier)->has_error()) return; ((void)0
 91 #define CHECK_VERIFY_(verifier, result) \
 92   CHECK_(result)); if ((verifier)->has_error()) return (result); ((void)0
 93 
 94 class TypeOrigin {
 95  private:
 96   typedef enum {
 97     CF_LOCALS,  // Comes from the current frame locals
 98     CF_STACK,   // Comes from the current frame expression stack
 99     SM_LOCALS,  // Comes from stackmap locals
100     SM_STACK,   // Comes from stackmap expression stack
101     CONST_POOL, // Comes from the constant pool
102     SIG,        // Comes from method signature
103     IMPLICIT,   // Comes implicitly from code or context
104     BAD_INDEX,  // No type, but the index is bad
105     FRAME_ONLY, // No type, context just contains the frame
106     NONE
107   } Origin;
108 
109   Origin _origin;
110   u2 _index;              // local, stack, or constant pool index
111   StackMapFrame* _frame;  // source frame if CF or SM
112   VerificationType _type; // The actual type
113 
114   TypeOrigin(
115       Origin origin, u2 index, StackMapFrame* frame, VerificationType type)
116       : _origin(origin), _index(index), _frame(frame), _type(type) {}
117 
118  public:
119   TypeOrigin() : _origin(NONE), _index(0), _frame(NULL) {}
120 
121   static TypeOrigin null();
122   static TypeOrigin local(u2 index, StackMapFrame* frame);
123   static TypeOrigin stack(u2 index, StackMapFrame* frame);
124   static TypeOrigin sm_local(u2 index, StackMapFrame* frame);
125   static TypeOrigin sm_stack(u2 index, StackMapFrame* frame);
126   static TypeOrigin cp(u2 index, VerificationType vt);
127   static TypeOrigin signature(VerificationType vt);
128   static TypeOrigin bad_index(u2 index);
129   static TypeOrigin implicit(VerificationType t);
130   static TypeOrigin frame(StackMapFrame* frame);
131 
132   void reset_frame();
133   void details(outputStream* ss) const;
134   void print_frame(outputStream* ss) const;
135   const StackMapFrame* frame() const { return _frame; }
136   bool is_valid() const { return _origin != NONE; }
137   u2 index() const { return _index; }
138 
139 #ifdef ASSERT
140   void print_on(outputStream* str) const;
141 #endif
142 };
143 
144 class ErrorContext {
145  private:
146   typedef enum {
147     INVALID_BYTECODE,     // There was a problem with the bytecode
148     WRONG_TYPE,           // Type value was not as expected
149     FLAGS_MISMATCH,       // Frame flags are not assignable
150     BAD_CP_INDEX,         // Invalid constant pool index
151     BAD_LOCAL_INDEX,      // Invalid local index
152     LOCALS_SIZE_MISMATCH, // Frames have differing local counts
153     STACK_SIZE_MISMATCH,  // Frames have different stack sizes
154     STACK_OVERFLOW,       // Attempt to push onto a full expression stack
155     STACK_UNDERFLOW,      // Attempt to pop and empty expression stack
156     MISSING_STACKMAP,     // No stackmap for this location and there should be
157     BAD_STACKMAP,         // Format error in stackmap
158     NO_FAULT,             // No error
159     UNKNOWN
160   } FaultType;
161 
162   int _bci;
163   FaultType _fault;
164   TypeOrigin _type;
165   TypeOrigin _expected;
166 
167   ErrorContext(int bci, FaultType fault) :
168       _bci(bci), _fault(fault)  {}
169   ErrorContext(int bci, FaultType fault, TypeOrigin type) :
170       _bci(bci), _fault(fault), _type(type)  {}
171   ErrorContext(int bci, FaultType fault, TypeOrigin type, TypeOrigin exp) :
172       _bci(bci), _fault(fault), _type(type), _expected(exp)  {}
173 
174  public:
175   ErrorContext() : _bci(-1), _fault(NO_FAULT) {}
176 
177   static ErrorContext bad_code(u2 bci) {
178     return ErrorContext(bci, INVALID_BYTECODE);
179   }
180   static ErrorContext bad_type(u2 bci, TypeOrigin type) {
181     return ErrorContext(bci, WRONG_TYPE, type);
182   }
183   static ErrorContext bad_type(u2 bci, TypeOrigin type, TypeOrigin exp) {
184     return ErrorContext(bci, WRONG_TYPE, type, exp);
185   }
186   static ErrorContext bad_flags(u2 bci, StackMapFrame* frame) {
187     return ErrorContext(bci, FLAGS_MISMATCH, TypeOrigin::frame(frame));
188   }
189   static ErrorContext bad_flags(u2 bci, StackMapFrame* cur, StackMapFrame* sm) {
190     return ErrorContext(bci, FLAGS_MISMATCH,
191                         TypeOrigin::frame(cur), TypeOrigin::frame(sm));
192   }
193   static ErrorContext bad_cp_index(u2 bci, u2 index) {
194     return ErrorContext(bci, BAD_CP_INDEX, TypeOrigin::bad_index(index));
195   }
196   static ErrorContext bad_local_index(u2 bci, u2 index) {
197     return ErrorContext(bci, BAD_LOCAL_INDEX, TypeOrigin::bad_index(index));
198   }
199   static ErrorContext locals_size_mismatch(
200       u2 bci, StackMapFrame* frame0, StackMapFrame* frame1) {
201     return ErrorContext(bci, LOCALS_SIZE_MISMATCH,
202         TypeOrigin::frame(frame0), TypeOrigin::frame(frame1));
203   }
204   static ErrorContext stack_size_mismatch(
205       u2 bci, StackMapFrame* frame0, StackMapFrame* frame1) {
206     return ErrorContext(bci, STACK_SIZE_MISMATCH,
207         TypeOrigin::frame(frame0), TypeOrigin::frame(frame1));
208   }
209   static ErrorContext stack_overflow(u2 bci, StackMapFrame* frame) {
210     return ErrorContext(bci, STACK_OVERFLOW, TypeOrigin::frame(frame));
211   }
212   static ErrorContext stack_underflow(u2 bci, StackMapFrame* frame) {
213     return ErrorContext(bci, STACK_UNDERFLOW, TypeOrigin::frame(frame));
214   }
215   static ErrorContext missing_stackmap(u2 bci) {
216     return ErrorContext(bci, MISSING_STACKMAP);
217   }
218   static ErrorContext bad_stackmap(int index, StackMapFrame* frame) {
219     return ErrorContext(0, BAD_STACKMAP, TypeOrigin::frame(frame));
220   }
221 
222   bool is_valid() const { return _fault != NO_FAULT; }
223   int bci() const { return _bci; }
224 
225   void reset_frames() {
226     _type.reset_frame();
227     _expected.reset_frame();
228   }
229 
230   void details(outputStream* ss, const Method* method) const;
231 
232 #ifdef ASSERT
233   void print_on(outputStream* str) const {
234     str->print("error_context(%d, %d,", _bci, _fault);
235     _type.print_on(str);
236     str->print(",");
237     _expected.print_on(str);
238     str->print(")");
239   }
240 #endif
241 
242  private:
243   void location_details(outputStream* ss, const Method* method) const;
244   void reason_details(outputStream* ss) const;
245   void frame_details(outputStream* ss) const;
246   void bytecode_details(outputStream* ss, const Method* method) const;
247   void handler_details(outputStream* ss, const Method* method) const;
248   void stackmap_details(outputStream* ss, const Method* method) const;
249 };
250 
251 class sig_as_verification_types : public ResourceObj {
252  private:
253   int _num_args;  // Number of arguments, not including return type.
254   GrowableArray<VerificationType>* _sig_verif_types;
255 
256  public:
257 
258   sig_as_verification_types(GrowableArray<VerificationType>* sig_verif_types) :
259     _num_args(0), _sig_verif_types(sig_verif_types) {
260   }
261 
262   int num_args() const { return _num_args; }
263   void set_num_args(int num_args) { _num_args = num_args; }
264 
265   GrowableArray<VerificationType>* sig_verif_types() { return _sig_verif_types; }
266   void set_sig_verif_types(GrowableArray<VerificationType>* sig_verif_types) {
267     _sig_verif_types = sig_verif_types;
268   }
269 
270 };
271 
272 // This hashtable is indexed by the Utf8 constant pool indexes pointed to
273 // by constant pool (Interface)Method_refs' NameAndType signature entries.
274 typedef ResourceHashtable<int, sig_as_verification_types*, 1007>
275                           method_signatures_table_type;
276 
277 // A new instance of this class is created for each class being verified
278 class ClassVerifier : public StackObj {
279  private:
280   Thread* _thread;
281 
282   Symbol* _previous_symbol;          // cache of the previously looked up symbol
283   GrowableArray<Symbol*>* _symbols;  // keep a list of symbols created
284 
285   Symbol* _exception_type;
286   char* _message;
287 
288   method_signatures_table_type* _method_signatures_table;
289 
290   ErrorContext _error_context;  // contains information about an error
291 
292   void verify_method(const methodHandle& method, TRAPS);
293   char* generate_code_data(const methodHandle& m, u4 code_length, TRAPS);
294   void verify_exception_handler_table(u4 code_length, char* code_data,
295                                       int& min, int& max, TRAPS);
296   void verify_local_variable_table(u4 code_length, char* code_data, TRAPS);
297 
298   VerificationType cp_ref_index_to_type(
299       int index, const constantPoolHandle& cp, TRAPS) {
300     return cp_index_to_type(cp->klass_ref_index_at(index), cp, THREAD);
301   }
302 
303   bool is_protected_access(
304     InstanceKlass* this_class, Klass* target_class,
305     Symbol* field_name, Symbol* field_sig, bool is_method);
306 
307   void verify_cp_index(u2 bci, const constantPoolHandle& cp, int index, TRAPS);
308   void verify_cp_type(u2 bci, int index, const constantPoolHandle& cp,
309       unsigned int types, TRAPS);
310   void verify_cp_class_type(u2 bci, int index, const constantPoolHandle& cp, TRAPS);
311 
312   u2 verify_stackmap_table(
313     u2 stackmap_index, u2 bci, StackMapFrame* current_frame,
314     StackMapTable* stackmap_table, bool no_control_flow, TRAPS);
315 
316   void verify_exception_handler_targets(
317     u2 bci, bool this_uninit, StackMapFrame* current_frame,
318     StackMapTable* stackmap_table, TRAPS);
319 
320   void verify_ldc(
321     int opcode, u2 index, StackMapFrame *current_frame,
322     const constantPoolHandle& cp, u2 bci, TRAPS);
323 
324   void verify_switch(
325     RawBytecodeStream* bcs, u4 code_length, char* code_data,
326     StackMapFrame* current_frame, StackMapTable* stackmap_table, TRAPS);
327 
328   void verify_field_instructions(
329     RawBytecodeStream* bcs, StackMapFrame* current_frame,
330     const constantPoolHandle& cp, bool allow_arrays, TRAPS);
331 
332   void verify_invoke_init(
333     RawBytecodeStream* bcs, u2 ref_index, VerificationType ref_class_type,
334     StackMapFrame* current_frame, u4 code_length, bool in_try_block,
335     bool* this_uninit, const constantPoolHandle& cp, StackMapTable* stackmap_table,
336     TRAPS);
337 
338   // Used by ends_in_athrow() to push all handlers that contain bci onto the
339   // handler_stack, if the handler has not already been pushed on the stack.
340   void push_handlers(ExceptionTable* exhandlers,
341                      GrowableArray<u4>* handler_list,
342                      GrowableArray<u4>* handler_stack,
343                      u4 bci);
344 
345   // Returns true if all paths starting with start_bc_offset end in athrow
346   // bytecode or loop.
347   bool ends_in_athrow(u4 start_bc_offset);
348 
349   void verify_invoke_instructions(
350     RawBytecodeStream* bcs, u4 code_length, StackMapFrame* current_frame,
351     bool in_try_block, bool* this_uninit, VerificationType return_type,
352     const constantPoolHandle& cp, StackMapTable* stackmap_table, TRAPS);
353 
354   VerificationType get_newarray_type(u2 index, u2 bci, TRAPS);
355   void verify_anewarray(u2 bci, u2 index, const constantPoolHandle& cp,
356       StackMapFrame* current_frame, TRAPS);
357   void verify_return_value(
358       VerificationType return_type, VerificationType type, u2 offset,
359       StackMapFrame* current_frame, TRAPS);
360 
361   void verify_iload (u2 index, StackMapFrame* current_frame, TRAPS);
362   void verify_lload (u2 index, StackMapFrame* current_frame, TRAPS);
363   void verify_fload (u2 index, StackMapFrame* current_frame, TRAPS);
364   void verify_dload (u2 index, StackMapFrame* current_frame, TRAPS);
365   void verify_aload (u2 index, StackMapFrame* current_frame, TRAPS);
366   void verify_istore(u2 index, StackMapFrame* current_frame, TRAPS);
367   void verify_lstore(u2 index, StackMapFrame* current_frame, TRAPS);
368   void verify_fstore(u2 index, StackMapFrame* current_frame, TRAPS);
369   void verify_dstore(u2 index, StackMapFrame* current_frame, TRAPS);
370   void verify_astore(u2 index, StackMapFrame* current_frame, TRAPS);
371   void verify_iinc  (u2 index, StackMapFrame* current_frame, TRAPS);
372 
373   bool name_in_supers(Symbol* ref_name, InstanceKlass* current);
374 
375   VerificationType object_type() const;
376 
377   InstanceKlass*      _klass;  // the class being verified
378   methodHandle        _method; // current method being verified
379   VerificationType    _this_type; // the verification type of the current class
380 
381   // Some recursive calls from the verifier to the name resolver
382   // can cause the current class to be re-verified and rewritten.
383   // If this happens, the original verification should not continue,
384   // because constant pool indexes will have changed.
385   // The rewriter is preceded by the verifier.  If the verifier throws
386   // an error, rewriting is prevented.  Also, rewriting always precedes
387   // bytecode execution or compilation.  Thus, is_rewritten implies
388   // that a class has been verified and prepared for execution.
389   bool was_recursively_verified() { return _klass->is_rewritten(); }
390 
391   bool is_same_or_direct_interface(InstanceKlass* klass,
392     VerificationType klass_type, VerificationType ref_class_type);
393 
394  public:
395   enum {
396     BYTECODE_OFFSET = 1,
397     NEW_OFFSET = 2
398   };
399 
400   // constructor
401   ClassVerifier(JavaThread* current, InstanceKlass* klass);
402 
403   // destructor
404   ~ClassVerifier();
405 
406   Thread* thread()             { return _thread; }
407   const methodHandle& method() { return _method; }
408   InstanceKlass* current_class() const { return _klass; }
409   VerificationType current_type() const { return _this_type; }
410 
411   // Verifies the class.  If a verify or class file format error occurs,
412   // the '_exception_name' symbols will set to the exception name and
413   // the message_buffer will be filled in with the exception message.
414   void verify_class(TRAPS);
415 
416   // Translates method signature entries into verificationTypes and saves them
417   // in the growable array.
418   void translate_signature(Symbol* const method_sig, sig_as_verification_types* sig_verif_types);
419 
420   // Initializes a sig_as_verification_types entry and puts it in the hash table.
421   void create_method_sig_entry(sig_as_verification_types* sig_verif_types, int sig_index);
422 
423   // Return status modes
424   Symbol* result() const { return _exception_type; }
425   bool has_error() const { return result() != NULL; }
426   char* exception_message() {
427     stringStream ss;
428     ss.print("%s", _message);
429     _error_context.details(&ss, _method());
430     return ss.as_string();
431   }
432 
433   // Called when verify or class format errors are encountered.
434   // May throw an exception based upon the mode.
435   void verify_error(ErrorContext ctx, const char* fmt, ...) ATTRIBUTE_PRINTF(3, 4);
436   void class_format_error(const char* fmt, ...) ATTRIBUTE_PRINTF(2, 3);
437 
438   Klass* load_class(Symbol* name, TRAPS);
439 
440   method_signatures_table_type* method_signatures_table() const {
441     return _method_signatures_table;
442   }
443 
444   void set_method_signatures_table(method_signatures_table_type* method_signatures_table) {
445     _method_signatures_table = method_signatures_table;
446   }
447 
448   int change_sig_to_verificationType(
449     SignatureStream* sig_type, VerificationType* inference_type);
450 
451   VerificationType cp_index_to_type(int index, const constantPoolHandle& cp, TRAPS) {
452     return VerificationType::reference_type(cp->klass_name_at(index));
453   }
454 
455   // Keep a list of temporary symbols created during verification because
456   // their reference counts need to be decremented when the verifier object
457   // goes out of scope.  Since these symbols escape the scope in which they're
458   // created, we can't use a TempNewSymbol.
459   Symbol* create_temporary_symbol(const char *s, int length);
460   Symbol* create_temporary_symbol(Symbol* s) {
461     if (s == _previous_symbol) {
462       return s;
463     }
464     if (!s->is_permanent()) {
465       s->increment_refcount();
466       if (_symbols == NULL) {
467         _symbols = new GrowableArray<Symbol*>(50, 0, NULL);
468       }
469       _symbols->push(s);
470     }
471     _previous_symbol = s;
472     return s;
473   }
474 
475   TypeOrigin ref_ctx(const char* str);
476 
477 };
478 
479 inline int ClassVerifier::change_sig_to_verificationType(
480     SignatureStream* sig_type, VerificationType* inference_type) {
481   BasicType bt = sig_type->type();
482   switch (bt) {
483     case T_OBJECT:
484     case T_ARRAY:
485       {
486         Symbol* name = sig_type->as_symbol();
487         // Create another symbol to save as signature stream unreferences this symbol.
488         Symbol* name_copy = create_temporary_symbol(name);
489         assert(name_copy == name, "symbols don't match");
490         *inference_type =
491           VerificationType::reference_type(name_copy);
492         return 1;
493       }
494     case T_LONG:
495       *inference_type = VerificationType::long_type();
496       *++inference_type = VerificationType::long2_type();
497       return 2;
498     case T_DOUBLE:
499       *inference_type = VerificationType::double_type();
500       *++inference_type = VerificationType::double2_type();
501       return 2;
502     case T_INT:
503     case T_BOOLEAN:
504     case T_BYTE:
505     case T_CHAR:
506     case T_SHORT:
507       *inference_type = VerificationType::integer_type();
508       return 1;
509     case T_FLOAT:
510       *inference_type = VerificationType::float_type();
511       return 1;
512     default:
513       ShouldNotReachHere();
514       return 1;
515   }
516 }
517 
518 #endif // SHARE_CLASSFILE_VERIFIER_HPP