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, int bci, int offset, TRAPS) const {
137 ErrorContext ctx;
138 // Jump targets must be within the method and the method size is limited. See JVMS 4.11
139 int min_offset = -1 * max_method_code_size;
140 if (offset < min_offset || offset > max_method_code_size) {
141 frame->verifier()->verify_error(ErrorContext::bad_stackmap(bci, frame),
142 "Illegal target of jump or branch (bci %d + offset %d)", bci, offset);
143 return;
144 }
145 int target = bci + offset;
146 bool match = match_stackmap(
147 frame, target, true, false, &ctx, CHECK_VERIFY(frame->verifier()));
148 if (!match || (target < 0 || target >= _code_length)) {
149 frame->verifier()->verify_error(ctx,
150 "Inconsistent stackmap frames at branch target %d", target);
151 }
152 }
153
154 void StackMapTable::print_on(outputStream* str) const {
155 str->print_cr("StackMapTable: frame_count = %d", _frame_count);
156 str->print_cr("table = {");
157 {
158 StreamIndentor si(str, 2);
159 for (int32_t i = 0; i < _frame_count; ++i) {
160 _frame_array->at(i)->print_on(str);
161 }
162 }
163 str->print_cr(" }");
164 }
165
166 StackMapReader::StackMapReader(ClassVerifier* v, StackMapStream* stream,
167 char* code_data, int32_t code_len,
168 StackMapFrame* init_frame,
169 u2 max_locals, u2 max_stack,
170 StackMapFrame::AssertUnsetFieldTable* initial_strict_fields, TRAPS) :
171 _verifier(v), _stream(stream), _code_data(code_data),
172 _code_length(code_len), _parsed_frame_count(0),
173 _prev_frame(init_frame), _max_locals(max_locals),
174 _max_stack(max_stack), _assert_unset_fields_buffer(initial_strict_fields),
175 _first(true) {
176 methodHandle m = v->method();
177 if (m->has_stackmap_table()) {
178 _cp = constantPoolHandle(THREAD, m->constants());
179 _frame_count = _stream->get_u2(CHECK);
180 } else {
181 // There's no stackmap table present. Frame count and size are 0.
182 _frame_count = 0;
183 }
184 }
185
186 int32_t StackMapReader::chop(
187 VerificationType* locals, int32_t length, int32_t chops) {
188 if (locals == nullptr) return -1;
189 int32_t pos = length - 1;
190 for (int32_t i=0; i<chops; i++) {
191 if (locals[pos].is_category2_2nd()) {
192 pos -= 2;
193 } else {
194 pos --;
195 }
196 if (pos<0 && i<(chops-1)) return -1;
197 }
198 return pos+1;
199 }
200
201 #define CHECK_NT CHECK_(VerificationType::bogus_type())
202
203 VerificationType StackMapReader::parse_verification_type(u1* flags, TRAPS) {
204 u1 tag = _stream->get_u1(CHECK_NT);
205 if (tag < (u1)ITEM_UninitializedThis) {
206 return VerificationType::from_tag(tag);
207 }
208 if (tag == ITEM_Object) {
209 u2 class_index = _stream->get_u2(CHECK_NT);
210 int nconstants = _cp->length();
211 if ((class_index <= 0 || class_index >= nconstants) ||
212 (!_cp->tag_at(class_index).is_klass() &&
213 !_cp->tag_at(class_index).is_unresolved_klass())) {
214 _stream->stackmap_format_error("bad class index", THREAD);
215 return VerificationType::bogus_type();
216 }
217 Symbol* klass_name = _cp->klass_name_at(class_index);
218 return VerificationType::reference_type(klass_name);
219 }
220 if (tag == ITEM_UninitializedThis) {
221 if (flags != nullptr) {
222 *flags |= FLAG_THIS_UNINIT;
223 }
224 return VerificationType::uninitialized_this_type();
225 }
226 if (tag == ITEM_Uninitialized) {
227 u2 offset = _stream->get_u2(CHECK_NT);
228 if (offset >= _code_length ||
229 _code_data[offset] != ClassVerifier::NEW_OFFSET) {
230 _verifier->class_format_error(
231 "StackMapTable format error: bad offset for Uninitialized");
232 return VerificationType::bogus_type();
233 }
234 return VerificationType::uninitialized_type(offset);
235 }
236 _stream->stackmap_format_error("bad verification type", THREAD);
237 return VerificationType::bogus_type();
238 }
239
240 StackMapFrame* StackMapReader::next(TRAPS) {
241 _parsed_frame_count++;
242 check_size(CHECK_NULL);
243 StackMapFrame* frame = next_helper(CHECK_VERIFY_(_verifier, nullptr));
244 if (frame != nullptr) {
245 check_offset(frame);
246 if (frame->verifier()->has_error()) {
247 return nullptr;
248 }
249 _prev_frame = frame;
250 }
251 return frame;
252 }
253
254 StackMapFrame* StackMapReader::next_helper(TRAPS) {
255 StackMapFrame* frame;
256 int offset;
257 VerificationType* locals = nullptr;
258 u1 frame_type = _stream->get_u1(CHECK_NULL);
259 if (frame_type == EARLY_LARVAL) {
260 u2 num_unset_fields = _stream->get_u2(CHECK_NULL);
261 StackMapFrame::AssertUnsetFieldTable* new_fields = new StackMapFrame::AssertUnsetFieldTable();
262
263 for (u2 i = 0; i < num_unset_fields; i++) {
264 u2 index = _stream->get_u2(CHECK_NULL);
265
266 if (!_cp->is_within_bounds(index) || !_cp->tag_at(index).is_name_and_type()) {
267 _prev_frame->verifier()->verify_error(
268 ErrorContext::bad_strict_fields(_prev_frame->offset(), _prev_frame),
269 "Invalid constant pool index in early larval frame: %d", index);
270 return nullptr;
271 }
272
273 Symbol* name = _cp->symbol_at(_cp->name_ref_index_at(index));
274 Symbol* sig = _cp->symbol_at(_cp->signature_ref_index_at(index));
275 NameAndSig tmp(name, sig);
276
277 if (!_prev_frame->assert_unset_fields()->contains(tmp)) {
278 log_info(verification)("NameAndType %s%s(CP index: %d) is not found among initial strict instance fields", name->as_C_string(), sig->as_C_string(), index);
279 StackMapFrame::print_strict_fields(_prev_frame->assert_unset_fields());
280 _prev_frame->verifier()->verify_error(
281 ErrorContext::bad_strict_fields(_prev_frame->offset(), _prev_frame),
282 "Strict fields not a subset of initial strict instance fields: %s:%s", name->as_C_string(), sig->as_C_string());
283 return nullptr;
284 } else {
285 new_fields->put(tmp, false);
286 }
287 }
288
289 // Only modify strict instance fields the frame has uninitialized this
290 if (_prev_frame->flag_this_uninit()) {
291 _assert_unset_fields_buffer = _prev_frame->merge_unset_fields(new_fields);
292 } else if (new_fields->number_of_entries() > 0) {
293 _prev_frame->verifier()->verify_error(
294 ErrorContext::bad_strict_fields(_prev_frame->offset(), _prev_frame),
295 "Cannot have uninitialized strict fields after class initialization");
296 return nullptr;
297 }
298
299 // Continue reading frame data
300 if (at_end()) {
301 _prev_frame->verifier()->verify_error(
302 ErrorContext::bad_strict_fields(_prev_frame->offset(), _prev_frame),
303 "Early larval frame must be followed by a base frame");
304 return nullptr;
305 }
306
307 frame_type = _stream->get_u1(CHECK_NULL);
308 if (frame_type == EARLY_LARVAL) {
309 _prev_frame->verifier()->verify_error(
310 ErrorContext::bad_strict_fields(_prev_frame->offset(), _prev_frame),
311 "Early larval frame must be followed by a base frame");
312 return nullptr;
313 }
314 }
315
316 if (frame_type <= SAME_FRAME_END) {
317 // same_frame
318 if (_first) {
319 offset = frame_type;
320 // Can't share the locals array since that is updated by the verifier.
321 if (_prev_frame->locals_size() > 0) {
322 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
323 THREAD, VerificationType, _prev_frame->locals_size());
324 }
325 } else {
326 offset = _prev_frame->offset() + frame_type + 1;
327 locals = _prev_frame->locals();
328 }
329 frame = new StackMapFrame(
330 offset, _prev_frame->flags(), _prev_frame->locals_size(), 0,
331 _max_locals, _max_stack, locals, nullptr,
332 _assert_unset_fields_buffer, _verifier);
333 if (_first && locals != nullptr) {
334 frame->copy_locals(_prev_frame);
335 }
336 _first = false;
337 return frame;
338 }
339 if (frame_type <= SAME_LOCALS_1_STACK_ITEM_FRAME_END) {
340 // same_locals_1_stack_item_frame
341 if (_first) {
342 offset = frame_type - SAME_LOCALS_1_STACK_ITEM_FRAME_START;
343 // Can't share the locals array since that is updated by the verifier.
344 if (_prev_frame->locals_size() > 0) {
345 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
346 THREAD, VerificationType, _prev_frame->locals_size());
347 }
348 } else {
349 offset = _prev_frame->offset() + frame_type - (SAME_LOCALS_1_STACK_ITEM_FRAME_START - 1);
350 locals = _prev_frame->locals();
351 }
352 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
353 THREAD, VerificationType, 2);
354 u2 stack_size = 1;
355 stack[0] = parse_verification_type(nullptr, CHECK_VERIFY_(_verifier, nullptr));
356 if (stack[0].is_category2()) {
357 stack[1] = stack[0].to_category2_2nd();
358 stack_size = 2;
359 }
360 check_verification_type_array_size(
361 stack_size, _max_stack, CHECK_VERIFY_(_verifier, nullptr));
362 frame = new StackMapFrame(
363 offset, _prev_frame->flags(), _prev_frame->locals_size(), stack_size,
364 _max_locals, _max_stack, locals, stack,
365 _assert_unset_fields_buffer, _verifier);
366 if (_first && locals != nullptr) {
367 frame->copy_locals(_prev_frame);
368 }
369 _first = false;
370 return frame;
371 }
372
373 u2 offset_delta = _stream->get_u2(CHECK_NULL);
374
375 if (frame_type < EARLY_LARVAL) {
376 // reserved frame types
377 _stream->stackmap_format_error(
378 "reserved frame type", CHECK_VERIFY_(_verifier, nullptr));
379 }
380
381 if (frame_type == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
382 // same_locals_1_stack_item_frame_extended
383 if (_first) {
384 offset = offset_delta;
385 // Can't share the locals array since that is updated by the verifier.
386 if (_prev_frame->locals_size() > 0) {
387 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
388 THREAD, VerificationType, _prev_frame->locals_size());
389 }
390 } else {
391 offset = _prev_frame->offset() + offset_delta + 1;
392 locals = _prev_frame->locals();
393 }
394 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
395 THREAD, VerificationType, 2);
396 u2 stack_size = 1;
397 stack[0] = parse_verification_type(nullptr, CHECK_VERIFY_(_verifier, nullptr));
398 if (stack[0].is_category2()) {
399 stack[1] = stack[0].to_category2_2nd();
400 stack_size = 2;
401 }
402 check_verification_type_array_size(
403 stack_size, _max_stack, CHECK_VERIFY_(_verifier, nullptr));
404 frame = new StackMapFrame(
405 offset, _prev_frame->flags(), _prev_frame->locals_size(), stack_size,
406 _max_locals, _max_stack, locals, stack,
407 _assert_unset_fields_buffer, _verifier);
408 if (_first && locals != nullptr) {
409 frame->copy_locals(_prev_frame);
410 }
411 _first = false;
412 return frame;
413 }
414
415 if (frame_type <= SAME_FRAME_EXTENDED) {
416 // chop_frame or same_frame_extended
417 locals = _prev_frame->locals();
418 int length = _prev_frame->locals_size();
419 int chops = SAME_FRAME_EXTENDED - frame_type;
420 int new_length = length;
421 u1 flags = _prev_frame->flags();
422 assert(chops == 0 || (frame_type >= CHOP_FRAME_START && frame_type <= CHOP_FRAME_END), "should be");
423 if (chops != 0) {
424 new_length = chop(locals, length, chops);
425 check_verification_type_array_size(
426 new_length, _max_locals, CHECK_VERIFY_(_verifier, nullptr));
427 // Recompute flags since uninitializedThis could have been chopped.
428 flags = 0;
429 for (int i=0; i<new_length; i++) {
430 if (locals[i].is_uninitialized_this()) {
431 flags |= FLAG_THIS_UNINIT;
432 break;
433 }
434 }
435 }
436 if (_first) {
437 offset = offset_delta;
438 // Can't share the locals array since that is updated by the verifier.
439 if (new_length > 0) {
440 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
441 THREAD, VerificationType, new_length);
442 } else {
443 locals = nullptr;
444 }
445 } else {
446 offset = _prev_frame->offset() + offset_delta + 1;
447 }
448 frame = new StackMapFrame(
449 offset, flags, new_length, 0, _max_locals, _max_stack,
450 locals, nullptr,
451 _assert_unset_fields_buffer, _verifier);
452 if (_first && locals != nullptr) {
453 frame->copy_locals(_prev_frame);
454 }
455 _first = false;
456 return frame;
457 } else if (frame_type <= APPEND_FRAME_END) {
458 // append_frame
459 assert(frame_type >= APPEND_FRAME_START && frame_type <= APPEND_FRAME_END, "should be");
460 int appends = frame_type - APPEND_FRAME_START + 1;
461 int real_length = _prev_frame->locals_size();
462 int new_length = real_length + appends*2;
463 locals = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, VerificationType, new_length);
464 VerificationType* pre_locals = _prev_frame->locals();
465 for (int i = 0; i < _prev_frame->locals_size(); i++) {
466 locals[i] = pre_locals[i];
467 }
468 u1 flags = _prev_frame->flags();
469 for (int i = 0; i < appends; i++) {
470 locals[real_length] = parse_verification_type(&flags, CHECK_NULL);
471 if (locals[real_length].is_category2()) {
472 locals[real_length + 1] = locals[real_length].to_category2_2nd();
473 ++real_length;
474 }
475 ++real_length;
476 }
477 check_verification_type_array_size(
478 real_length, _max_locals, CHECK_VERIFY_(_verifier, nullptr));
479 if (_first) {
480 offset = offset_delta;
481 } else {
482 offset = _prev_frame->offset() + offset_delta + 1;
483 }
484 frame = new StackMapFrame(
485 offset, flags, real_length, 0, _max_locals,
486 _max_stack, locals, nullptr,
487 _assert_unset_fields_buffer, _verifier);
488 _first = false;
489 return frame;
490 }
491 if (frame_type == FULL_FRAME) {
492 // full_frame
493 u1 flags = 0;
494 u2 locals_size = _stream->get_u2(CHECK_NULL);
495 int real_locals_size = 0;
496 if (locals_size > 0) {
497 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
498 THREAD, VerificationType, locals_size*2);
499 }
500 for (int i = 0; i < locals_size; i++) {
501 locals[real_locals_size] = parse_verification_type(&flags, CHECK_NULL);
502 if (locals[real_locals_size].is_category2()) {
503 locals[real_locals_size + 1] =
504 locals[real_locals_size].to_category2_2nd();
505 ++real_locals_size;
506 }
507 ++real_locals_size;
508 }
509 check_verification_type_array_size(
510 real_locals_size, _max_locals, CHECK_VERIFY_(_verifier, nullptr));
511 u2 stack_size = _stream->get_u2(CHECK_NULL);
512 int real_stack_size = 0;
513 VerificationType* stack = nullptr;
514 if (stack_size > 0) {
515 stack = NEW_RESOURCE_ARRAY_IN_THREAD(
516 THREAD, VerificationType, stack_size*2);
517 }
518 for (int i = 0; i < stack_size; i++) {
519 stack[real_stack_size] = parse_verification_type(nullptr, CHECK_NULL);
520 if (stack[real_stack_size].is_category2()) {
521 stack[real_stack_size + 1] = stack[real_stack_size].to_category2_2nd();
522 ++real_stack_size;
523 }
524 ++real_stack_size;
525 }
526 check_verification_type_array_size(
527 real_stack_size, _max_stack, CHECK_VERIFY_(_verifier, nullptr));
528 if (_first) {
529 offset = offset_delta;
530 } else {
531 offset = _prev_frame->offset() + offset_delta + 1;
532 }
533 frame = new StackMapFrame(
534 offset, flags, real_locals_size, real_stack_size,
535 _max_locals, _max_stack, locals, stack,
536 _assert_unset_fields_buffer, _verifier);
537 _first = false;
538 return frame;
539 }
540
541 _stream->stackmap_format_error(
542 "reserved frame type", CHECK_VERIFY_(_prev_frame->verifier(), nullptr));
543 return nullptr;
544 }