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 }
131 return result;
132 }
133
134 void StackMapTable::check_jump_target(
135 StackMapFrame* frame, int32_t target, TRAPS) const {
136 ErrorContext ctx;
137 bool match = match_stackmap(
138 frame, target, true, false, &ctx, CHECK_VERIFY(frame->verifier()));
139 if (!match || (target < 0 || target >= _code_length)) {
140 frame->verifier()->verify_error(ctx,
141 "Inconsistent stackmap frames at branch target %d", target);
142 }
143 }
144
145 void StackMapTable::print_on(outputStream* str) const {
146 str->indent().print_cr("StackMapTable: frame_count = %d", _frame_count);
147 str->indent().print_cr("table = { ");
148 {
149 streamIndentor si(str);
150 for (int32_t i = 0; i < _frame_count; ++i) {
151 _frame_array->at(i)->print_on(str);
152 }
153 }
154 str->print_cr(" }");
155 }
156
157 StackMapReader::StackMapReader(ClassVerifier* v, StackMapStream* stream,
158 char* code_data, int32_t code_len,
159 StackMapFrame* init_frame,
160 u2 max_locals, u2 max_stack, TRAPS) :
161 _verifier(v), _stream(stream), _code_data(code_data),
162 _code_length(code_len), _parsed_frame_count(0),
163 _prev_frame(init_frame), _max_locals(max_locals),
164 _max_stack(max_stack), _first(true) {
165 methodHandle m = v->method();
166 if (m->has_stackmap_table()) {
167 _cp = constantPoolHandle(THREAD, m->constants());
168 _frame_count = _stream->get_u2(CHECK);
169 } else {
170 // There's no stackmap table present. Frame count and size are 0.
171 _frame_count = 0;
172 }
173 }
174
175 int32_t StackMapReader::chop(
176 VerificationType* locals, int32_t length, int32_t chops) {
177 if (locals == nullptr) return -1;
178 int32_t pos = length - 1;
179 for (int32_t i=0; i<chops; i++) {
180 if (locals[pos].is_category2_2nd()) {
181 pos -= 2;
182 } else {
183 pos --;
184 }
185 if (pos<0 && i<(chops-1)) return -1;
186 }
187 return pos+1;
188 }
189
190 #define CHECK_NT CHECK_(VerificationType::bogus_type())
191
192 VerificationType StackMapReader::parse_verification_type(u1* flags, TRAPS) {
193 u1 tag = _stream->get_u1(CHECK_NT);
194 if (tag < (u1)ITEM_UninitializedThis) {
195 return VerificationType::from_tag(tag);
196 }
197 if (tag == ITEM_Object) {
198 u2 class_index = _stream->get_u2(CHECK_NT);
199 int nconstants = _cp->length();
200 if ((class_index <= 0 || class_index >= nconstants) ||
201 (!_cp->tag_at(class_index).is_klass() &&
202 !_cp->tag_at(class_index).is_unresolved_klass())) {
203 _stream->stackmap_format_error("bad class index", THREAD);
204 return VerificationType::bogus_type();
205 }
206 return VerificationType::reference_type(_cp->klass_name_at(class_index));
207 }
208 if (tag == ITEM_UninitializedThis) {
209 if (flags != nullptr) {
210 *flags |= FLAG_THIS_UNINIT;
211 }
212 return VerificationType::uninitialized_this_type();
213 }
214 if (tag == ITEM_Uninitialized) {
215 u2 offset = _stream->get_u2(CHECK_NT);
216 if (offset >= _code_length ||
217 _code_data[offset] != ClassVerifier::NEW_OFFSET) {
218 _verifier->class_format_error(
219 "StackMapTable format error: bad offset for Uninitialized");
220 return VerificationType::bogus_type();
221 }
222 return VerificationType::uninitialized_type(offset);
223 }
224 _stream->stackmap_format_error("bad verification type", THREAD);
225 return VerificationType::bogus_type();
226 }
227
228 StackMapFrame* StackMapReader::next(TRAPS) {
229 _parsed_frame_count++;
230 check_size(CHECK_NULL);
231 StackMapFrame* frame = next_helper(CHECK_VERIFY_(_verifier, nullptr));
232 if (frame != nullptr) {
233 check_offset(frame);
234 if (frame->verifier()->has_error()) {
235 return nullptr;
236 }
237 _prev_frame = frame;
238 }
239 return frame;
240 }
241
242 StackMapFrame* StackMapReader::next_helper(TRAPS) {
243 StackMapFrame* frame;
244 int offset;
245 VerificationType* locals = nullptr;
246 u1 frame_type = _stream->get_u1(CHECK_NULL);
247 if (frame_type < 64) {
248 // same_frame
249 if (_first) {
250 offset = frame_type;
251 // Can't share the locals array since that is updated by the verifier.
252 if (_prev_frame->locals_size() > 0) {
253 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
254 THREAD, VerificationType, _prev_frame->locals_size());
255 }
256 } else {
257 offset = _prev_frame->offset() + frame_type + 1;
258 locals = _prev_frame->locals();
259 }
260 frame = new StackMapFrame(
261 offset, _prev_frame->flags(), _prev_frame->locals_size(), 0,
262 _max_locals, _max_stack, locals, nullptr, _verifier);
263 if (_first && locals != nullptr) {
264 frame->copy_locals(_prev_frame);
265 }
266 _first = false;
267 return frame;
268 }
269 if (frame_type < 128) {
270 // same_locals_1_stack_item_frame
271 if (_first) {
272 offset = frame_type - 64;
273 // Can't share the locals array since that is updated by the verifier.
274 if (_prev_frame->locals_size() > 0) {
275 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
276 THREAD, VerificationType, _prev_frame->locals_size());
277 }
278 } else {
279 offset = _prev_frame->offset() + frame_type - 63;
280 locals = _prev_frame->locals();
281 }
282 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
283 THREAD, VerificationType, 2);
284 u2 stack_size = 1;
285 stack[0] = parse_verification_type(nullptr, CHECK_VERIFY_(_verifier, nullptr));
286 if (stack[0].is_category2()) {
287 stack[1] = stack[0].to_category2_2nd();
288 stack_size = 2;
289 }
290 check_verification_type_array_size(
291 stack_size, _max_stack, CHECK_VERIFY_(_verifier, nullptr));
292 frame = new StackMapFrame(
293 offset, _prev_frame->flags(), _prev_frame->locals_size(), stack_size,
294 _max_locals, _max_stack, locals, stack, _verifier);
295 if (_first && locals != nullptr) {
296 frame->copy_locals(_prev_frame);
297 }
298 _first = false;
299 return frame;
300 }
301
302 u2 offset_delta = _stream->get_u2(CHECK_NULL);
303
304 if (frame_type < SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
305 // reserved frame types
306 _stream->stackmap_format_error(
307 "reserved frame type", CHECK_VERIFY_(_verifier, nullptr));
308 }
309
310 if (frame_type == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
311 // same_locals_1_stack_item_frame_extended
312 if (_first) {
313 offset = offset_delta;
314 // Can't share the locals array since that is updated by the verifier.
315 if (_prev_frame->locals_size() > 0) {
316 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
317 THREAD, VerificationType, _prev_frame->locals_size());
318 }
319 } else {
320 offset = _prev_frame->offset() + offset_delta + 1;
321 locals = _prev_frame->locals();
322 }
323 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
324 THREAD, VerificationType, 2);
325 u2 stack_size = 1;
326 stack[0] = parse_verification_type(nullptr, CHECK_VERIFY_(_verifier, nullptr));
327 if (stack[0].is_category2()) {
328 stack[1] = stack[0].to_category2_2nd();
329 stack_size = 2;
330 }
331 check_verification_type_array_size(
332 stack_size, _max_stack, CHECK_VERIFY_(_verifier, nullptr));
333 frame = new StackMapFrame(
334 offset, _prev_frame->flags(), _prev_frame->locals_size(), stack_size,
335 _max_locals, _max_stack, locals, stack, _verifier);
336 if (_first && locals != nullptr) {
337 frame->copy_locals(_prev_frame);
338 }
339 _first = false;
340 return frame;
341 }
342
343 if (frame_type <= SAME_EXTENDED) {
344 // chop_frame or same_frame_extended
345 locals = _prev_frame->locals();
346 int length = _prev_frame->locals_size();
347 int chops = SAME_EXTENDED - frame_type;
348 int new_length = length;
349 u1 flags = _prev_frame->flags();
350 if (chops != 0) {
351 new_length = chop(locals, length, chops);
352 check_verification_type_array_size(
353 new_length, _max_locals, CHECK_VERIFY_(_verifier, nullptr));
354 // Recompute flags since uninitializedThis could have been chopped.
355 flags = 0;
356 for (int i=0; i<new_length; i++) {
357 if (locals[i].is_uninitialized_this()) {
358 flags |= FLAG_THIS_UNINIT;
359 break;
360 }
361 }
362 }
363 if (_first) {
364 offset = offset_delta;
365 // Can't share the locals array since that is updated by the verifier.
366 if (new_length > 0) {
367 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
368 THREAD, VerificationType, new_length);
369 } else {
370 locals = nullptr;
371 }
372 } else {
373 offset = _prev_frame->offset() + offset_delta + 1;
374 }
375 frame = new StackMapFrame(
376 offset, flags, new_length, 0, _max_locals, _max_stack,
377 locals, nullptr, _verifier);
378 if (_first && locals != nullptr) {
379 frame->copy_locals(_prev_frame);
380 }
381 _first = false;
382 return frame;
383 } else if (frame_type < SAME_EXTENDED + 4) {
384 // append_frame
385 int appends = frame_type - SAME_EXTENDED;
386 int real_length = _prev_frame->locals_size();
387 int new_length = real_length + appends*2;
388 locals = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, VerificationType, new_length);
389 VerificationType* pre_locals = _prev_frame->locals();
390 for (int i = 0; i < _prev_frame->locals_size(); i++) {
391 locals[i] = pre_locals[i];
392 }
393 u1 flags = _prev_frame->flags();
394 for (int i = 0; i < appends; i++) {
395 locals[real_length] = parse_verification_type(&flags, CHECK_NULL);
396 if (locals[real_length].is_category2()) {
397 locals[real_length + 1] = locals[real_length].to_category2_2nd();
398 ++real_length;
399 }
400 ++real_length;
401 }
402 check_verification_type_array_size(
403 real_length, _max_locals, CHECK_VERIFY_(_verifier, nullptr));
404 if (_first) {
405 offset = offset_delta;
406 } else {
407 offset = _prev_frame->offset() + offset_delta + 1;
408 }
409 frame = new StackMapFrame(
410 offset, flags, real_length, 0, _max_locals,
411 _max_stack, locals, nullptr, _verifier);
412 _first = false;
413 return frame;
414 }
415 if (frame_type == FULL) {
416 // full_frame
417 u1 flags = 0;
418 u2 locals_size = _stream->get_u2(CHECK_NULL);
419 int real_locals_size = 0;
420 if (locals_size > 0) {
421 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
422 THREAD, VerificationType, locals_size*2);
423 }
424 for (int i = 0; i < locals_size; i++) {
425 locals[real_locals_size] = parse_verification_type(&flags, CHECK_NULL);
426 if (locals[real_locals_size].is_category2()) {
427 locals[real_locals_size + 1] =
428 locals[real_locals_size].to_category2_2nd();
429 ++real_locals_size;
430 }
431 ++real_locals_size;
432 }
433 check_verification_type_array_size(
434 real_locals_size, _max_locals, CHECK_VERIFY_(_verifier, nullptr));
435 u2 stack_size = _stream->get_u2(CHECK_NULL);
436 int real_stack_size = 0;
437 VerificationType* stack = nullptr;
438 if (stack_size > 0) {
439 stack = NEW_RESOURCE_ARRAY_IN_THREAD(
440 THREAD, VerificationType, stack_size*2);
441 }
442 for (int i = 0; i < stack_size; i++) {
443 stack[real_stack_size] = parse_verification_type(nullptr, CHECK_NULL);
444 if (stack[real_stack_size].is_category2()) {
445 stack[real_stack_size + 1] = stack[real_stack_size].to_category2_2nd();
446 ++real_stack_size;
447 }
448 ++real_stack_size;
449 }
450 check_verification_type_array_size(
451 real_stack_size, _max_stack, CHECK_VERIFY_(_verifier, nullptr));
452 if (_first) {
453 offset = offset_delta;
454 } else {
455 offset = _prev_frame->offset() + offset_delta + 1;
456 }
457 frame = new StackMapFrame(
458 offset, flags, real_locals_size, real_stack_size,
459 _max_locals, _max_stack, locals, stack, _verifier);
460 _first = false;
461 return frame;
462 }
463
464 _stream->stackmap_format_error(
465 "reserved frame type", CHECK_VERIFY_(_prev_frame->verifier(), nullptr));
466 return nullptr;
467 }
--- EOF ---