1 /*
2 * Copyright (c) 2003, 2023, 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 "precompiled.hpp"
26 #include "classfile/stackMapTable.hpp"
27 #include "classfile/verifier.hpp"
28 #include "memory/resourceArea.hpp"
29 #include "oops/constantPool.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "runtime/handles.inline.hpp"
32
33 StackMapTable::StackMapTable(StackMapReader* reader, StackMapFrame* init_frame,
34 u2 max_locals, u2 max_stack,
35 char* code_data, int code_len, TRAPS) {
36 _code_length = code_len;
37 _frame_count = reader->get_frame_count();
38 if (_frame_count > 0) {
39 _frame_array = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD,
40 StackMapFrame*, _frame_count);
41 StackMapFrame* pre_frame = init_frame;
42 for (int32_t i = 0; i < _frame_count; i++) {
43 StackMapFrame* frame = reader->next(
44 pre_frame, i == 0, max_locals, max_stack,
45 CHECK_VERIFY(pre_frame->verifier()));
46 _frame_array[i] = frame;
47 int offset = frame->offset();
48 if (offset >= code_len || code_data[offset] == 0) {
49 frame->verifier()->verify_error(
50 ErrorContext::bad_stackmap(i, frame),
51 "StackMapTable error: bad offset");
52 return;
53 }
54 pre_frame = frame;
55 }
56 }
57 reader->check_end(CHECK);
58 }
59
60 // This method is only called by method in StackMapTable.
61 int StackMapTable::get_index_from_offset(int32_t offset) const {
62 int i = 0;
63 for (; i < _frame_count; i++) {
64 if (_frame_array[i]->offset() == offset) {
65 return i;
66 }
67 }
68 return i; // frame with offset doesn't exist in the array
69 }
70
71 bool StackMapTable::match_stackmap(
72 StackMapFrame* frame, int32_t target,
73 bool match, bool update, ErrorContext* ctx, TRAPS) const {
74 int index = get_index_from_offset(target);
75 return match_stackmap(frame, target, index, match, update, ctx, THREAD);
76 }
77
78 // Match and/or update current_frame to the frame in stackmap table with
79 // specified offset and frame index. Return true if the two frames match.
80 //
81 // The values of match and update are: _match__update
82 //
83 // checking a branch target: true false
84 // checking an exception handler: true false
85 // linear bytecode verification following an
86 // unconditional branch: false true
87 // linear bytecode verification not following an
88 // unconditional branch: true true
89 bool StackMapTable::match_stackmap(
90 StackMapFrame* frame, int32_t target, int32_t frame_index,
91 bool match, bool update, ErrorContext* ctx, TRAPS) const {
92 if (frame_index < 0 || frame_index >= _frame_count) {
93 *ctx = ErrorContext::missing_stackmap(frame->offset());
94 frame->verifier()->verify_error(
95 *ctx, "Expecting a stackmap frame at branch target %d", target);
96 return false;
97 }
98
99 StackMapFrame *stackmap_frame = _frame_array[frame_index];
100 bool result = true;
101 if (match) {
102 // Has direct control flow from last instruction, need to match the two
103 // frames.
104 result = frame->is_assignable_to(stackmap_frame,
105 ctx, CHECK_VERIFY_(frame->verifier(), result));
106 }
107 if (update) {
108 // Use the frame in stackmap table as current frame
109 int lsize = stackmap_frame->locals_size();
110 int ssize = stackmap_frame->stack_size();
111 if (frame->locals_size() > lsize || frame->stack_size() > ssize) {
112 // Make sure unused type array items are all _bogus_type.
113 frame->reset();
114 }
115 frame->set_locals_size(lsize);
116 frame->copy_locals(stackmap_frame);
117 frame->set_stack_size(ssize);
118 frame->copy_stack(stackmap_frame);
119 frame->set_flags(stackmap_frame->flags());
120 }
121 return result;
122 }
123
124 void StackMapTable::check_jump_target(
125 StackMapFrame* frame, int32_t target, TRAPS) const {
126 ErrorContext ctx;
127 bool match = match_stackmap(
128 frame, target, true, false, &ctx, CHECK_VERIFY(frame->verifier()));
129 if (!match || (target < 0 || target >= _code_length)) {
130 frame->verifier()->verify_error(ctx,
131 "Inconsistent stackmap frames at branch target %d", target);
132 }
133 }
134
135 void StackMapTable::print_on(outputStream* str) const {
136 str->indent().print_cr("StackMapTable: frame_count = %d", _frame_count);
137 str->indent().print_cr("table = { ");
138 {
139 streamIndentor si(str);
140 for (int32_t i = 0; i < _frame_count; ++i) {
141 _frame_array[i]->print_on(str);
142 }
143 }
144 str->print_cr(" }");
145 }
146
147 StackMapReader::StackMapReader(ClassVerifier* v, StackMapStream* stream, char* code_data,
148 int32_t code_len, TRAPS) :
149 _verifier(v), _stream(stream),
150 _code_data(code_data), _code_length(code_len) {
151 methodHandle m = v->method();
152 if (m->has_stackmap_table()) {
153 _cp = constantPoolHandle(THREAD, m->constants());
154 _frame_count = _stream->get_u2(CHECK);
155 } else {
156 // There's no stackmap table present. Frame count and size are 0.
157 _frame_count = 0;
158 }
159 }
160
161 int32_t StackMapReader::chop(
162 VerificationType* locals, int32_t length, int32_t chops) {
163 if (locals == nullptr) return -1;
164 int32_t pos = length - 1;
165 for (int32_t i=0; i<chops; i++) {
166 if (locals[pos].is_category2_2nd()) {
167 pos -= 2;
168 } else {
169 pos --;
170 }
171 if (pos<0 && i<(chops-1)) return -1;
172 }
173 return pos+1;
174 }
175
176 #define CHECK_NT CHECK_(VerificationType::bogus_type())
177
178 VerificationType StackMapReader::parse_verification_type(u1* flags, TRAPS) {
179 u1 tag = _stream->get_u1(CHECK_NT);
180 if (tag < (u1)ITEM_UninitializedThis) {
181 return VerificationType::from_tag(tag);
182 }
183 if (tag == ITEM_Object) {
184 u2 class_index = _stream->get_u2(CHECK_NT);
185 int nconstants = _cp->length();
186 if ((class_index <= 0 || class_index >= nconstants) ||
187 (!_cp->tag_at(class_index).is_klass() &&
188 !_cp->tag_at(class_index).is_unresolved_klass())) {
189 _stream->stackmap_format_error("bad class index", THREAD);
190 return VerificationType::bogus_type();
191 }
192 Symbol* klass_name = _cp->klass_name_at(class_index);
193 return VerificationType::reference_type(klass_name);
194 }
195 if (tag == ITEM_UninitializedThis) {
196 if (flags != nullptr) {
197 *flags |= FLAG_THIS_UNINIT;
198 }
199 return VerificationType::uninitialized_this_type();
200 }
201 if (tag == ITEM_Uninitialized) {
202 u2 offset = _stream->get_u2(CHECK_NT);
203 if (offset >= _code_length ||
204 _code_data[offset] != ClassVerifier::NEW_OFFSET) {
205 _verifier->class_format_error(
206 "StackMapTable format error: bad offset for Uninitialized");
207 return VerificationType::bogus_type();
208 }
209 return VerificationType::uninitialized_type(offset);
210 }
211 _stream->stackmap_format_error("bad verification type", THREAD);
212 return VerificationType::bogus_type();
213 }
214
215 StackMapFrame* StackMapReader::next(
216 StackMapFrame* pre_frame, bool first, u2 max_locals, u2 max_stack, TRAPS) {
217 StackMapFrame* frame;
218 int offset;
219 VerificationType* locals = nullptr;
220 u1 frame_type = _stream->get_u1(CHECK_NULL);
221 if (frame_type < 64) {
222 // same_frame
223 if (first) {
224 offset = frame_type;
225 // Can't share the locals array since that is updated by the verifier.
226 if (pre_frame->locals_size() > 0) {
227 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
228 THREAD, VerificationType, pre_frame->locals_size());
229 }
230 } else {
231 offset = pre_frame->offset() + frame_type + 1;
232 locals = pre_frame->locals();
233 }
234 frame = new StackMapFrame(
235 offset, pre_frame->flags(), pre_frame->locals_size(), 0,
236 max_locals, max_stack, locals, nullptr, _verifier);
237 if (first && locals != nullptr) {
238 frame->copy_locals(pre_frame);
239 }
240 return frame;
241 }
242 if (frame_type < 128) {
243 // same_locals_1_stack_item_frame
244 if (first) {
245 offset = frame_type - 64;
246 // Can't share the locals array since that is updated by the verifier.
247 if (pre_frame->locals_size() > 0) {
248 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
249 THREAD, VerificationType, pre_frame->locals_size());
250 }
251 } else {
252 offset = pre_frame->offset() + frame_type - 63;
253 locals = pre_frame->locals();
254 }
255 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
256 THREAD, VerificationType, 2);
257 u2 stack_size = 1;
258 stack[0] = parse_verification_type(nullptr, CHECK_VERIFY_(_verifier, nullptr));
259 if (stack[0].is_category2()) {
260 stack[1] = stack[0].to_category2_2nd();
261 stack_size = 2;
262 }
263 check_verification_type_array_size(
264 stack_size, max_stack, CHECK_VERIFY_(_verifier, nullptr));
265 frame = new StackMapFrame(
266 offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
267 max_locals, max_stack, locals, stack, _verifier);
268 if (first && locals != nullptr) {
269 frame->copy_locals(pre_frame);
270 }
271 return frame;
272 }
273
274 u2 offset_delta = _stream->get_u2(CHECK_NULL);
275
276 if (frame_type < SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
277 // reserved frame types
278 _stream->stackmap_format_error(
279 "reserved frame type", CHECK_VERIFY_(_verifier, nullptr));
280 }
281
282 if (frame_type == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
283 // same_locals_1_stack_item_frame_extended
284 if (first) {
285 offset = offset_delta;
286 // Can't share the locals array since that is updated by the verifier.
287 if (pre_frame->locals_size() > 0) {
288 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
289 THREAD, VerificationType, pre_frame->locals_size());
290 }
291 } else {
292 offset = pre_frame->offset() + offset_delta + 1;
293 locals = pre_frame->locals();
294 }
295 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
296 THREAD, VerificationType, 2);
297 u2 stack_size = 1;
298 stack[0] = parse_verification_type(nullptr, CHECK_VERIFY_(_verifier, nullptr));
299 if (stack[0].is_category2()) {
300 stack[1] = stack[0].to_category2_2nd();
301 stack_size = 2;
302 }
303 check_verification_type_array_size(
304 stack_size, max_stack, CHECK_VERIFY_(_verifier, nullptr));
305 frame = new StackMapFrame(
306 offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
307 max_locals, max_stack, locals, stack, _verifier);
308 if (first && locals != nullptr) {
309 frame->copy_locals(pre_frame);
310 }
311 return frame;
312 }
313
314 if (frame_type <= SAME_EXTENDED) {
315 // chop_frame or same_frame_extended
316 locals = pre_frame->locals();
317 int length = pre_frame->locals_size();
318 int chops = SAME_EXTENDED - frame_type;
319 int new_length = length;
320 u1 flags = pre_frame->flags();
321 if (chops != 0) {
322 new_length = chop(locals, length, chops);
323 check_verification_type_array_size(
324 new_length, max_locals, CHECK_VERIFY_(_verifier, nullptr));
325 // Recompute flags since uninitializedThis could have been chopped.
326 flags = 0;
327 for (int i=0; i<new_length; i++) {
328 if (locals[i].is_uninitialized_this()) {
329 flags |= FLAG_THIS_UNINIT;
330 break;
331 }
332 }
333 }
334 if (first) {
335 offset = offset_delta;
336 // Can't share the locals array since that is updated by the verifier.
337 if (new_length > 0) {
338 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
339 THREAD, VerificationType, new_length);
340 } else {
341 locals = nullptr;
342 }
343 } else {
344 offset = pre_frame->offset() + offset_delta + 1;
345 }
346 frame = new StackMapFrame(
347 offset, flags, new_length, 0, max_locals, max_stack,
348 locals, nullptr, _verifier);
349 if (first && locals != nullptr) {
350 frame->copy_locals(pre_frame);
351 }
352 return frame;
353 } else if (frame_type < SAME_EXTENDED + 4) {
354 // append_frame
355 int appends = frame_type - SAME_EXTENDED;
356 int real_length = pre_frame->locals_size();
357 int new_length = real_length + appends*2;
358 locals = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, VerificationType, new_length);
359 VerificationType* pre_locals = pre_frame->locals();
360 int i;
361 for (i=0; i<pre_frame->locals_size(); i++) {
362 locals[i] = pre_locals[i];
363 }
364 u1 flags = pre_frame->flags();
365 for (i=0; i<appends; i++) {
366 locals[real_length] = parse_verification_type(&flags, CHECK_NULL);
367 if (locals[real_length].is_category2()) {
368 locals[real_length + 1] = locals[real_length].to_category2_2nd();
369 ++real_length;
370 }
371 ++real_length;
372 }
373 check_verification_type_array_size(
374 real_length, max_locals, CHECK_VERIFY_(_verifier, nullptr));
375 if (first) {
376 offset = offset_delta;
377 } else {
378 offset = pre_frame->offset() + offset_delta + 1;
379 }
380 frame = new StackMapFrame(
381 offset, flags, real_length, 0, max_locals,
382 max_stack, locals, nullptr, _verifier);
383 return frame;
384 }
385 if (frame_type == FULL) {
386 // full_frame
387 u1 flags = 0;
388 u2 locals_size = _stream->get_u2(CHECK_NULL);
389 int real_locals_size = 0;
390 if (locals_size > 0) {
391 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
392 THREAD, VerificationType, locals_size*2);
393 }
394 int i;
395 for (i=0; i<locals_size; i++) {
396 locals[real_locals_size] = parse_verification_type(&flags, CHECK_NULL);
397 if (locals[real_locals_size].is_category2()) {
398 locals[real_locals_size + 1] =
399 locals[real_locals_size].to_category2_2nd();
400 ++real_locals_size;
401 }
402 ++real_locals_size;
403 }
404 check_verification_type_array_size(
405 real_locals_size, max_locals, CHECK_VERIFY_(_verifier, nullptr));
406 u2 stack_size = _stream->get_u2(CHECK_NULL);
407 int real_stack_size = 0;
408 VerificationType* stack = nullptr;
409 if (stack_size > 0) {
410 stack = NEW_RESOURCE_ARRAY_IN_THREAD(
411 THREAD, VerificationType, stack_size*2);
412 }
413 for (i=0; i<stack_size; i++) {
414 stack[real_stack_size] = parse_verification_type(nullptr, CHECK_NULL);
415 if (stack[real_stack_size].is_category2()) {
416 stack[real_stack_size + 1] = stack[real_stack_size].to_category2_2nd();
417 ++real_stack_size;
418 }
419 ++real_stack_size;
420 }
421 check_verification_type_array_size(
422 real_stack_size, max_stack, CHECK_VERIFY_(_verifier, nullptr));
423 if (first) {
424 offset = offset_delta;
425 } else {
426 offset = pre_frame->offset() + offset_delta + 1;
427 }
428 frame = new StackMapFrame(
429 offset, flags, real_locals_size, real_stack_size,
430 max_locals, max_stack, locals, stack, _verifier);
431 return frame;
432 }
433
434 _stream->stackmap_format_error(
435 "reserved frame type", CHECK_VERIFY_(pre_frame->verifier(), nullptr));
436 return nullptr;
437 }