1 /*
2 * Copyright (c) 2003, 2025, 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 #include "classfile/stackMapTable.hpp"
26 #include "classfile/verifier.hpp"
27 #include "memory/resourceArea.hpp"
28 #include "oops/constantPool.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "runtime/handles.inline.hpp"
31
32 StackMapTable::StackMapTable(StackMapReader* reader, TRAPS) {
33 _code_length = reader->code_length();
34 _frame_count = reader->get_frame_count();
35 if (_frame_count > 0) {
36 _frame_array = new GrowableArray<StackMapFrame*>(_frame_count);
37 while (!reader->at_end()) {
38 StackMapFrame* frame = reader->next(CHECK_VERIFY(reader->prev_frame()->verifier()));
39 if (frame != nullptr) {
40 _frame_array->push(frame);
41 }
42 }
43 reader->check_end(CHECK);
44 // Correct frame count based on how many actual frames are generated
45 _frame_count = _frame_array->length();
46 }
47 }
48
49 void StackMapReader::check_offset(StackMapFrame* frame) {
50 int offset = frame->offset();
51 if (offset >= _code_length || _code_data[offset] == 0) {
52 _verifier->verify_error(ErrorContext::bad_stackmap(0, frame),
53 "StackMapTable error: bad offset");
54 }
55 }
56
57 void StackMapReader::check_size(TRAPS) {
58 if (_frame_count < _parsed_frame_count) {
59 StackMapStream::stackmap_format_error("wrong attribute size", THREAD);
60 }
61 }
62
63 void StackMapReader::check_end(TRAPS) {
64 assert(_stream->at_end(), "must be");
65 if (_frame_count != _parsed_frame_count) {
66 StackMapStream::stackmap_format_error("wrong attribute size", THREAD);
67 }
68 }
69
70 // This method is only called by method in StackMapTable.
71 int StackMapTable::get_index_from_offset(int32_t offset) const {
72 int i = 0;
73 for (; i < _frame_count; i++) {
74 if (_frame_array->at(i)->offset() == offset) {
75 return i;
76 }
77 }
78 return i; // frame with offset doesn't exist in the array
79 }
80
81 bool StackMapTable::match_stackmap(
82 StackMapFrame* frame, int32_t target,
83 bool match, bool update, ErrorContext* ctx, TRAPS) const {
84 int index = get_index_from_offset(target);
85 return match_stackmap(frame, target, index, match, update, ctx, THREAD);
86 }
87
88 // Match and/or update current_frame to the frame in stackmap table with
89 // specified offset and frame index. Return true if the two frames match.
90 //
91 // The values of match and update are: _match__update
92 //
93 // checking a branch target: true false
94 // checking an exception handler: true false
95 // linear bytecode verification following an
96 // unconditional branch: false true
97 // linear bytecode verification not following an
98 // unconditional branch: true true
99 bool StackMapTable::match_stackmap(
100 StackMapFrame* frame, int32_t target, int32_t frame_index,
101 bool match, bool update, ErrorContext* ctx, TRAPS) const {
102 if (frame_index < 0 || frame_index >= _frame_count) {
103 *ctx = ErrorContext::missing_stackmap(frame->offset());
104 frame->verifier()->verify_error(
105 *ctx, "Expecting a stackmap frame at branch target %d", target);
106 return false;
107 }
108
109 StackMapFrame* stackmap_frame = _frame_array->at(frame_index);
110 bool result = true;
111 if (match) {
112 // Has direct control flow from last instruction, need to match the two
113 // frames.
114 result = frame->is_assignable_to(stackmap_frame,
115 ctx, CHECK_VERIFY_(frame->verifier(), result));
116 }
117 if (update) {
118 // Use the frame in stackmap table as current frame
119 int lsize = stackmap_frame->locals_size();
120 int ssize = stackmap_frame->stack_size();
121 if (frame->locals_size() > lsize || frame->stack_size() > ssize) {
122 // Make sure unused type array items are all _bogus_type.
123 frame->reset();
124 }
125 frame->set_locals_size(lsize);
126 frame->copy_locals(stackmap_frame);
127 frame->set_stack_size(ssize);
128 frame->copy_stack(stackmap_frame);
129 frame->set_flags(stackmap_frame->flags());
130 frame->set_assert_unset_fields(stackmap_frame->assert_unset_fields());
131 }
132 return result;
133 }
134
135 void StackMapTable::check_jump_target(
136 StackMapFrame* frame, int32_t target, TRAPS) const {
137 ErrorContext ctx;
138 bool match = match_stackmap(
139 frame, target, true, false, &ctx, CHECK_VERIFY(frame->verifier()));
140 if (!match || (target < 0 || target >= _code_length)) {
141 frame->verifier()->verify_error(ctx,
142 "Inconsistent stackmap frames at branch target %d", target);
143 }
144 }
145
146 void StackMapTable::print_on(outputStream* str) const {
147 str->indent().print_cr("StackMapTable: frame_count = %d", _frame_count);
148 str->indent().print_cr("table = { ");
149 {
150 streamIndentor si(str);
151 for (int32_t i = 0; i < _frame_count; ++i) {
152 _frame_array->at(i)->print_on(str);
153 }
154 }
155 str->print_cr(" }");
156 }
157
158 StackMapReader::StackMapReader(ClassVerifier* v, StackMapStream* stream,
159 char* code_data, int32_t code_len,
160 StackMapFrame* init_frame,
161 u2 max_locals, u2 max_stack,
162 StackMapFrame::AssertUnsetFieldTable* initial_strict_fields, TRAPS) :
163 _verifier(v), _stream(stream), _code_data(code_data),
164 _code_length(code_len), _parsed_frame_count(0),
165 _prev_frame(init_frame), _max_locals(max_locals),
166 _max_stack(max_stack), _assert_unset_fields_buffer(initial_strict_fields),
167 _first(true) {
168 methodHandle m = v->method();
169 if (m->has_stackmap_table()) {
170 _cp = constantPoolHandle(THREAD, m->constants());
171 _frame_count = _stream->get_u2(CHECK);
172 } else {
173 // There's no stackmap table present. Frame count and size are 0.
174 _frame_count = 0;
175 }
176 }
177
178 int32_t StackMapReader::chop(
179 VerificationType* locals, int32_t length, int32_t chops) {
180 if (locals == nullptr) return -1;
181 int32_t pos = length - 1;
182 for (int32_t i=0; i<chops; i++) {
183 if (locals[pos].is_category2_2nd()) {
184 pos -= 2;
185 } else {
186 pos --;
187 }
188 if (pos<0 && i<(chops-1)) return -1;
189 }
190 return pos+1;
191 }
192
193 #define CHECK_NT CHECK_(VerificationType::bogus_type())
194
195 VerificationType StackMapReader::parse_verification_type(u1* flags, TRAPS) {
196 u1 tag = _stream->get_u1(CHECK_NT);
197 if (tag < (u1)ITEM_UninitializedThis) {
198 return VerificationType::from_tag(tag);
199 }
200 if (tag == ITEM_Object) {
201 u2 class_index = _stream->get_u2(CHECK_NT);
202 int nconstants = _cp->length();
203 if ((class_index <= 0 || class_index >= nconstants) ||
204 (!_cp->tag_at(class_index).is_klass() &&
205 !_cp->tag_at(class_index).is_unresolved_klass())) {
206 _stream->stackmap_format_error("bad class index", THREAD);
207 return VerificationType::bogus_type();
208 }
209 Symbol* klass_name = _cp->klass_name_at(class_index);
210 return VerificationType::reference_type(klass_name);
211 }
212 if (tag == ITEM_UninitializedThis) {
213 if (flags != nullptr) {
214 *flags |= FLAG_THIS_UNINIT;
215 }
216 return VerificationType::uninitialized_this_type();
217 }
218 if (tag == ITEM_Uninitialized) {
219 u2 offset = _stream->get_u2(CHECK_NT);
220 if (offset >= _code_length ||
221 _code_data[offset] != ClassVerifier::NEW_OFFSET) {
222 _verifier->class_format_error(
223 "StackMapTable format error: bad offset for Uninitialized");
224 return VerificationType::bogus_type();
225 }
226 return VerificationType::uninitialized_type(offset);
227 }
228 _stream->stackmap_format_error("bad verification type", THREAD);
229 return VerificationType::bogus_type();
230 }
231
232 StackMapFrame* StackMapReader::next(TRAPS) {
233 _parsed_frame_count++;
234 check_size(CHECK_NULL);
235 StackMapFrame* frame = next_helper(CHECK_VERIFY_(_verifier, nullptr));
236 if (frame != nullptr) {
237 check_offset(frame);
238 if (frame->verifier()->has_error()) {
239 return nullptr;
240 }
241 _prev_frame = frame;
242 }
243 return frame;
244 }
245
246 StackMapFrame* StackMapReader::next_helper(TRAPS) {
247 StackMapFrame* frame;
248 int offset;
249 VerificationType* locals = nullptr;
250 u1 frame_type = _stream->get_u1(CHECK_NULL);
251 if (frame_type == EARLY_LARVAL) {
252 u2 num_unset_fields = _stream->get_u2(CHECK_NULL);
253 StackMapFrame::AssertUnsetFieldTable* new_fields = new StackMapFrame::AssertUnsetFieldTable();
254
255 for (u2 i = 0; i < num_unset_fields; i++) {
256 u2 index = _stream->get_u2(CHECK_NULL);
257 Symbol* name = _cp->symbol_at(_cp->name_ref_index_at(index));
258 Symbol* sig = _cp->symbol_at(_cp->signature_ref_index_at(index));
259 NameAndSig tmp(name, sig);
260
261 if (!_prev_frame->assert_unset_fields()->contains(tmp)) {
262 ResourceMark rm(THREAD);
263 log_info(verification)("Field %s%s is not found among initial strict instance fields", name->as_C_string(), sig->as_C_string());
264 StackMapFrame::print_strict_fields(_prev_frame->assert_unset_fields());
265 _prev_frame->verifier()->verify_error(
266 ErrorContext::bad_strict_fields(_prev_frame->offset(), _prev_frame),
267 "Strict fields not a subset of initial strict instance fields: %s:%s", name->as_C_string(), sig->as_C_string());
268 } else {
269 new_fields->put(tmp, false);
270 }
271 }
272
273 // Only modify strict instance fields the frame has uninitialized this
274 if (_prev_frame->flag_this_uninit()) {
275 _assert_unset_fields_buffer = _prev_frame->merge_unset_fields(new_fields);
276 } else if (new_fields->number_of_entries() > 0) {
277 _prev_frame->verifier()->verify_error(
278 ErrorContext::bad_strict_fields(_prev_frame->offset(), _prev_frame),
279 "Cannot have uninitialized strict fields after class initialization");
280 }
281
282 // Continue reading frame data
283 if (at_end()) {
284 _prev_frame->verifier()->verify_error(
285 ErrorContext::bad_strict_fields(_prev_frame->offset(), _prev_frame),
286 "Early larval frame must be followed by a base frame");
287 }
288
289 frame_type = _stream->get_u1(CHECK_NULL);
290 if (frame_type == EARLY_LARVAL) {
291 _prev_frame->verifier()->verify_error(
292 ErrorContext::bad_strict_fields(_prev_frame->offset(), _prev_frame),
293 "Early larval frame must be followed by a base frame");
294 }
295 }
296
297 if (frame_type < 64) {
298 // same_frame
299 if (_first) {
300 offset = frame_type;
301 // Can't share the locals array since that is updated by the verifier.
302 if (_prev_frame->locals_size() > 0) {
303 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
304 THREAD, VerificationType, _prev_frame->locals_size());
305 }
306 } else {
307 offset = _prev_frame->offset() + frame_type + 1;
308 locals = _prev_frame->locals();
309 }
310 frame = new StackMapFrame(
311 offset, _prev_frame->flags(), _prev_frame->locals_size(), 0,
312 _max_locals, _max_stack, locals, nullptr,
313 _assert_unset_fields_buffer, _verifier);
314 if (_first && locals != nullptr) {
315 frame->copy_locals(_prev_frame);
316 }
317 _first = false;
318 return frame;
319 }
320 if (frame_type < 128) {
321 // same_locals_1_stack_item_frame
322 if (_first) {
323 offset = frame_type - 64;
324 // Can't share the locals array since that is updated by the verifier.
325 if (_prev_frame->locals_size() > 0) {
326 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
327 THREAD, VerificationType, _prev_frame->locals_size());
328 }
329 } else {
330 offset = _prev_frame->offset() + frame_type - 63;
331 locals = _prev_frame->locals();
332 }
333 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
334 THREAD, VerificationType, 2);
335 u2 stack_size = 1;
336 stack[0] = parse_verification_type(nullptr, CHECK_VERIFY_(_verifier, nullptr));
337 if (stack[0].is_category2()) {
338 stack[1] = stack[0].to_category2_2nd();
339 stack_size = 2;
340 }
341 check_verification_type_array_size(
342 stack_size, _max_stack, CHECK_VERIFY_(_verifier, nullptr));
343 frame = new StackMapFrame(
344 offset, _prev_frame->flags(), _prev_frame->locals_size(), stack_size,
345 _max_locals, _max_stack, locals, stack,
346 _assert_unset_fields_buffer, _verifier);
347 if (_first && locals != nullptr) {
348 frame->copy_locals(_prev_frame);
349 }
350 _first = false;
351 return frame;
352 }
353
354 u2 offset_delta = _stream->get_u2(CHECK_NULL);
355
356 if (frame_type < EARLY_LARVAL) {
357 // reserved frame types
358 _stream->stackmap_format_error(
359 "reserved frame type", CHECK_VERIFY_(_verifier, nullptr));
360 }
361
362 if (frame_type == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
363 // same_locals_1_stack_item_frame_extended
364 if (_first) {
365 offset = offset_delta;
366 // Can't share the locals array since that is updated by the verifier.
367 if (_prev_frame->locals_size() > 0) {
368 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
369 THREAD, VerificationType, _prev_frame->locals_size());
370 }
371 } else {
372 offset = _prev_frame->offset() + offset_delta + 1;
373 locals = _prev_frame->locals();
374 }
375 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
376 THREAD, VerificationType, 2);
377 u2 stack_size = 1;
378 stack[0] = parse_verification_type(nullptr, CHECK_VERIFY_(_verifier, nullptr));
379 if (stack[0].is_category2()) {
380 stack[1] = stack[0].to_category2_2nd();
381 stack_size = 2;
382 }
383 check_verification_type_array_size(
384 stack_size, _max_stack, CHECK_VERIFY_(_verifier, nullptr));
385 frame = new StackMapFrame(
386 offset, _prev_frame->flags(), _prev_frame->locals_size(), stack_size,
387 _max_locals, _max_stack, locals, stack,
388 _assert_unset_fields_buffer, _verifier);
389 if (_first && locals != nullptr) {
390 frame->copy_locals(_prev_frame);
391 }
392 _first = false;
393 return frame;
394 }
395
396 if (frame_type <= SAME_EXTENDED) {
397 // chop_frame or same_frame_extended
398 locals = _prev_frame->locals();
399 int length = _prev_frame->locals_size();
400 int chops = SAME_EXTENDED - frame_type;
401 int new_length = length;
402 u1 flags = _prev_frame->flags();
403 if (chops != 0) {
404 new_length = chop(locals, length, chops);
405 check_verification_type_array_size(
406 new_length, _max_locals, CHECK_VERIFY_(_verifier, nullptr));
407 // Recompute flags since uninitializedThis could have been chopped.
408 flags = 0;
409 for (int i=0; i<new_length; i++) {
410 if (locals[i].is_uninitialized_this()) {
411 flags |= FLAG_THIS_UNINIT;
412 break;
413 }
414 }
415 }
416 if (_first) {
417 offset = offset_delta;
418 // Can't share the locals array since that is updated by the verifier.
419 if (new_length > 0) {
420 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
421 THREAD, VerificationType, new_length);
422 } else {
423 locals = nullptr;
424 }
425 } else {
426 offset = _prev_frame->offset() + offset_delta + 1;
427 }
428 frame = new StackMapFrame(
429 offset, flags, new_length, 0, _max_locals, _max_stack,
430 locals, nullptr,
431 _assert_unset_fields_buffer, _verifier);
432 if (_first && locals != nullptr) {
433 frame->copy_locals(_prev_frame);
434 }
435 _first = false;
436 return frame;
437 } else if (frame_type < SAME_EXTENDED + 4) {
438 // append_frame
439 int appends = frame_type - SAME_EXTENDED;
440 int real_length = _prev_frame->locals_size();
441 int new_length = real_length + appends*2;
442 locals = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, VerificationType, new_length);
443 VerificationType* pre_locals = _prev_frame->locals();
444 for (int i = 0; i < _prev_frame->locals_size(); i++) {
445 locals[i] = pre_locals[i];
446 }
447 u1 flags = _prev_frame->flags();
448 for (int i = 0; i < appends; i++) {
449 locals[real_length] = parse_verification_type(&flags, CHECK_NULL);
450 if (locals[real_length].is_category2()) {
451 locals[real_length + 1] = locals[real_length].to_category2_2nd();
452 ++real_length;
453 }
454 ++real_length;
455 }
456 check_verification_type_array_size(
457 real_length, _max_locals, CHECK_VERIFY_(_verifier, nullptr));
458 if (_first) {
459 offset = offset_delta;
460 } else {
461 offset = _prev_frame->offset() + offset_delta + 1;
462 }
463 frame = new StackMapFrame(
464 offset, flags, real_length, 0, _max_locals,
465 _max_stack, locals, nullptr,
466 _assert_unset_fields_buffer, _verifier);
467 _first = false;
468 return frame;
469 }
470 if (frame_type == FULL) {
471 // full_frame
472 u1 flags = 0;
473 u2 locals_size = _stream->get_u2(CHECK_NULL);
474 int real_locals_size = 0;
475 if (locals_size > 0) {
476 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
477 THREAD, VerificationType, locals_size*2);
478 }
479 for (int i = 0; i < locals_size; i++) {
480 locals[real_locals_size] = parse_verification_type(&flags, CHECK_NULL);
481 if (locals[real_locals_size].is_category2()) {
482 locals[real_locals_size + 1] =
483 locals[real_locals_size].to_category2_2nd();
484 ++real_locals_size;
485 }
486 ++real_locals_size;
487 }
488 check_verification_type_array_size(
489 real_locals_size, _max_locals, CHECK_VERIFY_(_verifier, nullptr));
490 u2 stack_size = _stream->get_u2(CHECK_NULL);
491 int real_stack_size = 0;
492 VerificationType* stack = nullptr;
493 if (stack_size > 0) {
494 stack = NEW_RESOURCE_ARRAY_IN_THREAD(
495 THREAD, VerificationType, stack_size*2);
496 }
497 for (int i = 0; i < stack_size; i++) {
498 stack[real_stack_size] = parse_verification_type(nullptr, CHECK_NULL);
499 if (stack[real_stack_size].is_category2()) {
500 stack[real_stack_size + 1] = stack[real_stack_size].to_category2_2nd();
501 ++real_stack_size;
502 }
503 ++real_stack_size;
504 }
505 check_verification_type_array_size(
506 real_stack_size, _max_stack, CHECK_VERIFY_(_verifier, nullptr));
507 if (_first) {
508 offset = offset_delta;
509 } else {
510 offset = _prev_frame->offset() + offset_delta + 1;
511 }
512 frame = new StackMapFrame(
513 offset, flags, real_locals_size, real_stack_size,
514 _max_locals, _max_stack, locals, stack,
515 _assert_unset_fields_buffer, _verifier);
516 _first = false;
517 return frame;
518 }
519
520 _stream->stackmap_format_error(
521 "reserved frame type", CHECK_VERIFY_(_prev_frame->verifier(), nullptr));
522 return nullptr;
523 }