1 /*
2 * Copyright (c) 2003, 2018, 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/fieldType.hpp"
32 #include "runtime/handles.inline.hpp"
33
34 StackMapTable::StackMapTable(StackMapReader* reader, StackMapFrame* init_frame,
35 u2 max_locals, u2 max_stack,
36 char* code_data, int code_len, TRAPS) {
37 _code_length = code_len;
38 _frame_count = reader->get_frame_count();
39 if (_frame_count > 0) {
40 _frame_array = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD,
41 StackMapFrame*, _frame_count);
42 StackMapFrame* pre_frame = init_frame;
43 for (int32_t i = 0; i < _frame_count; i++) {
44 StackMapFrame* frame = reader->next(
45 pre_frame, i == 0, max_locals, max_stack,
46 CHECK_VERIFY(pre_frame->verifier()));
47 _frame_array[i] = frame;
48 int offset = frame->offset();
49 if (offset >= code_len || code_data[offset] == 0) {
50 frame->verifier()->verify_error(
51 ErrorContext::bad_stackmap(i, frame),
52 "StackMapTable error: bad offset");
53 return;
54 }
55 pre_frame = frame;
56 }
57 }
58 reader->check_end(CHECK);
59 }
60
61 // This method is only called by method in StackMapTable.
62 int StackMapTable::get_index_from_offset(int32_t offset) const {
63 int i = 0;
64 for (; i < _frame_count; i++) {
65 if (_frame_array[i]->offset() == offset) {
66 return i;
67 }
68 }
69 return i; // frame with offset doesn't exist in the array
70 }
71
72 bool StackMapTable::match_stackmap(
73 StackMapFrame* frame, int32_t target,
74 bool match, bool update, ErrorContext* ctx, TRAPS) const {
75 int index = get_index_from_offset(target);
76 return match_stackmap(frame, target, index, match, update, ctx, THREAD);
77 }
78
79 // Match and/or update current_frame to the frame in stackmap table with
80 // specified offset and frame index. Return true if the two frames match.
81 //
82 // The values of match and update are: _match__update
83 //
84 // checking a branch target: true false
85 // checking an exception handler: true false
86 // linear bytecode verification following an
87 // unconditional branch: false true
88 // linear bytecode verification not following an
89 // unconditional branch: true true
90 bool StackMapTable::match_stackmap(
91 StackMapFrame* frame, int32_t target, int32_t frame_index,
92 bool match, bool update, ErrorContext* ctx, TRAPS) const {
93 if (frame_index < 0 || frame_index >= _frame_count) {
94 *ctx = ErrorContext::missing_stackmap(frame->offset());
95 frame->verifier()->verify_error(
96 *ctx, "Expecting a stackmap frame at branch target %d", target);
97 return false;
98 }
99
100 StackMapFrame *stackmap_frame = _frame_array[frame_index];
101 bool result = true;
102 if (match) {
103 // Has direct control flow from last instruction, need to match the two
104 // frames.
105 result = frame->is_assignable_to(stackmap_frame,
106 ctx, CHECK_VERIFY_(frame->verifier(), result));
107 }
108 if (update) {
109 // Use the frame in stackmap table as current frame
110 int lsize = stackmap_frame->locals_size();
111 int ssize = stackmap_frame->stack_size();
112 if (frame->locals_size() > lsize || frame->stack_size() > ssize) {
113 // Make sure unused type array items are all _bogus_type.
114 frame->reset();
115 }
116 frame->set_locals_size(lsize);
117 frame->copy_locals(stackmap_frame);
118 frame->set_stack_size(ssize);
119 frame->copy_stack(stackmap_frame);
120 frame->set_flags(stackmap_frame->flags());
121 }
122 return result;
123 }
124
125 void StackMapTable::check_jump_target(
126 StackMapFrame* frame, int32_t target, TRAPS) const {
127 ErrorContext ctx;
128 bool match = match_stackmap(
129 frame, target, true, false, &ctx, CHECK_VERIFY(frame->verifier()));
130 if (!match || (target < 0 || target >= _code_length)) {
131 frame->verifier()->verify_error(ctx,
132 "Inconsistent stackmap frames at branch target %d", target);
133 }
134 }
135
136 void StackMapTable::print_on(outputStream* str) const {
137 str->indent().print_cr("StackMapTable: frame_count = %d", _frame_count);
138 str->indent().print_cr("table = { ");
139 {
140 streamIndentor si(str);
141 for (int32_t i = 0; i < _frame_count; ++i) {
142 _frame_array[i]->print_on(str);
143 }
144 }
145 str->print_cr(" }");
146 }
147
148 StackMapReader::StackMapReader(ClassVerifier* v, StackMapStream* stream, char* code_data,
149 int32_t code_len, TRAPS) :
150 _verifier(v), _stream(stream),
151 _code_data(code_data), _code_length(code_len) {
152 methodHandle m = v->method();
153 if (m->has_stackmap_table()) {
154 _cp = constantPoolHandle(THREAD, m->constants());
155 _frame_count = _stream->get_u2(CHECK);
156 } else {
157 // There's no stackmap table present. Frame count and size are 0.
158 _frame_count = 0;
159 }
160 }
161
162 int32_t StackMapReader::chop(
163 VerificationType* locals, int32_t length, int32_t chops) {
164 if (locals == NULL) return -1;
165 int32_t pos = length - 1;
166 for (int32_t i=0; i<chops; i++) {
167 if (locals[pos].is_category2_2nd()) {
168 pos -= 2;
169 } else {
170 pos --;
171 }
172 if (pos<0 && i<(chops-1)) return -1;
173 }
174 return pos+1;
175 }
176
177 VerificationType StackMapReader::parse_verification_type(u1* flags, TRAPS) {
178 u1 tag = _stream->get_u1(THREAD);
179 if (tag < (u1)ITEM_UninitializedThis) {
180 return VerificationType::from_tag(tag);
181 }
182 if (tag == ITEM_Object) {
183 u2 class_index = _stream->get_u2(THREAD);
184 int nconstants = _cp->length();
185 if ((class_index <= 0 || class_index >= nconstants) ||
186 (!_cp->tag_at(class_index).is_klass() &&
187 !_cp->tag_at(class_index).is_unresolved_klass())) {
188 _stream->stackmap_format_error("bad class index", THREAD);
189 return VerificationType::bogus_type();
190 }
191 Symbol* klass_name = _cp->klass_name_at(class_index);
192 if (klass_name->is_Q_signature()) {
193 Symbol* fund_name = klass_name->fundamental_name(THREAD);
194 if (fund_name == NULL) {
195 _stream->stackmap_format_error("TBD something bad happened", THREAD);
196 return VerificationType::bogus_type();
197 }
198 return VerificationType::valuetype_type(fund_name);
199 } else {
200 return VerificationType::reference_type(klass_name);
201 }
202 }
203 if (tag == ITEM_UninitializedThis) {
204 if (flags != NULL) {
205 *flags |= FLAG_THIS_UNINIT;
206 }
207 return VerificationType::uninitialized_this_type();
208 }
209 if (tag == ITEM_Uninitialized) {
210 u2 offset = _stream->get_u2(THREAD);
211 if (offset >= _code_length ||
212 _code_data[offset] != ClassVerifier::NEW_OFFSET) {
213 _verifier->class_format_error(
214 "StackMapTable format error: bad offset for Uninitialized");
215 return VerificationType::bogus_type();
216 }
217 return VerificationType::uninitialized_type(offset);
218 }
219 _stream->stackmap_format_error("bad verification type", THREAD);
220 return VerificationType::bogus_type();
221 }
222
223 StackMapFrame* StackMapReader::next(
224 StackMapFrame* pre_frame, bool first, u2 max_locals, u2 max_stack, TRAPS) {
225 StackMapFrame* frame;
226 int offset;
227 VerificationType* locals = NULL;
228 u1 frame_type = _stream->get_u1(THREAD);
229 if (frame_type < 64) {
230 // same_frame
231 if (first) {
232 offset = frame_type;
233 // Can't share the locals array since that is updated by the verifier.
234 if (pre_frame->locals_size() > 0) {
235 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
236 THREAD, VerificationType, pre_frame->locals_size());
237 }
238 } else {
239 offset = pre_frame->offset() + frame_type + 1;
240 locals = pre_frame->locals();
241 }
242 frame = new StackMapFrame(
243 offset, pre_frame->flags(), pre_frame->locals_size(), 0,
244 max_locals, max_stack, locals, NULL, _verifier);
245 if (first && locals != NULL) {
246 frame->copy_locals(pre_frame);
247 }
248 return frame;
249 }
250 if (frame_type < 128) {
251 // same_locals_1_stack_item_frame
252 if (first) {
253 offset = frame_type - 64;
254 // Can't share the locals array since that is updated by the verifier.
255 if (pre_frame->locals_size() > 0) {
256 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
257 THREAD, VerificationType, pre_frame->locals_size());
258 }
259 } else {
260 offset = pre_frame->offset() + frame_type - 63;
261 locals = pre_frame->locals();
262 }
263 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
264 THREAD, VerificationType, 2);
265 u2 stack_size = 1;
266 stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
267 if (stack[0].is_category2()) {
268 stack[1] = stack[0].to_category2_2nd();
269 stack_size = 2;
270 }
271 check_verification_type_array_size(
272 stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
273 frame = new StackMapFrame(
274 offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
275 max_locals, max_stack, locals, stack, _verifier);
276 if (first && locals != NULL) {
277 frame->copy_locals(pre_frame);
278 }
279 return frame;
280 }
281
282 u2 offset_delta = _stream->get_u2(THREAD);
283
284 if (frame_type < SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
285 // reserved frame types
286 _stream->stackmap_format_error(
287 "reserved frame type", CHECK_VERIFY_(_verifier, NULL));
288 }
289
290 if (frame_type == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
291 // same_locals_1_stack_item_frame_extended
292 if (first) {
293 offset = offset_delta;
294 // Can't share the locals array since that is updated by the verifier.
295 if (pre_frame->locals_size() > 0) {
296 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
297 THREAD, VerificationType, pre_frame->locals_size());
298 }
299 } else {
300 offset = pre_frame->offset() + offset_delta + 1;
301 locals = pre_frame->locals();
302 }
303 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
304 THREAD, VerificationType, 2);
305 u2 stack_size = 1;
306 stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
307 if (stack[0].is_category2()) {
308 stack[1] = stack[0].to_category2_2nd();
309 stack_size = 2;
310 }
311 check_verification_type_array_size(
312 stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
313 frame = new StackMapFrame(
314 offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
315 max_locals, max_stack, locals, stack, _verifier);
316 if (first && locals != NULL) {
317 frame->copy_locals(pre_frame);
318 }
319 return frame;
320 }
321
322 if (frame_type <= SAME_EXTENDED) {
323 // chop_frame or same_frame_extended
324 locals = pre_frame->locals();
325 int length = pre_frame->locals_size();
326 int chops = SAME_EXTENDED - frame_type;
327 int new_length = length;
328 u1 flags = pre_frame->flags();
329 if (chops != 0) {
330 new_length = chop(locals, length, chops);
331 check_verification_type_array_size(
332 new_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
333 // Recompute flags since uninitializedThis could have been chopped.
334 flags = 0;
335 for (int i=0; i<new_length; i++) {
336 if (locals[i].is_uninitialized_this()) {
337 flags |= FLAG_THIS_UNINIT;
338 break;
339 }
340 }
341 }
342 if (first) {
343 offset = offset_delta;
344 // Can't share the locals array since that is updated by the verifier.
345 if (new_length > 0) {
346 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
347 THREAD, VerificationType, new_length);
348 } else {
349 locals = NULL;
350 }
351 } else {
352 offset = pre_frame->offset() + offset_delta + 1;
353 }
354 frame = new StackMapFrame(
355 offset, flags, new_length, 0, max_locals, max_stack,
356 locals, NULL, _verifier);
357 if (first && locals != NULL) {
358 frame->copy_locals(pre_frame);
359 }
360 return frame;
361 } else if (frame_type < SAME_EXTENDED + 4) {
362 // append_frame
363 int appends = frame_type - SAME_EXTENDED;
364 int real_length = pre_frame->locals_size();
365 int new_length = real_length + appends*2;
366 locals = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, VerificationType, new_length);
367 VerificationType* pre_locals = pre_frame->locals();
368 int i;
369 for (i=0; i<pre_frame->locals_size(); i++) {
370 locals[i] = pre_locals[i];
371 }
372 u1 flags = pre_frame->flags();
373 for (i=0; i<appends; i++) {
374 locals[real_length] = parse_verification_type(&flags, THREAD);
375 if (locals[real_length].is_category2()) {
376 locals[real_length + 1] = locals[real_length].to_category2_2nd();
377 ++real_length;
378 }
379 ++real_length;
380 }
381 check_verification_type_array_size(
382 real_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
383 if (first) {
384 offset = offset_delta;
385 } else {
386 offset = pre_frame->offset() + offset_delta + 1;
387 }
388 frame = new StackMapFrame(
389 offset, flags, real_length, 0, max_locals,
390 max_stack, locals, NULL, _verifier);
391 return frame;
392 }
393 if (frame_type == FULL) {
394 // full_frame
395 u1 flags = 0;
396 u2 locals_size = _stream->get_u2(THREAD);
397 int real_locals_size = 0;
398 if (locals_size > 0) {
399 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
400 THREAD, VerificationType, locals_size*2);
401 }
402 int i;
403 for (i=0; i<locals_size; i++) {
404 locals[real_locals_size] = parse_verification_type(&flags, THREAD);
405 if (locals[real_locals_size].is_category2()) {
406 locals[real_locals_size + 1] =
407 locals[real_locals_size].to_category2_2nd();
408 ++real_locals_size;
409 }
410 ++real_locals_size;
411 }
412 check_verification_type_array_size(
413 real_locals_size, max_locals, CHECK_VERIFY_(_verifier, NULL));
414 u2 stack_size = _stream->get_u2(THREAD);
415 int real_stack_size = 0;
416 VerificationType* stack = NULL;
417 if (stack_size > 0) {
418 stack = NEW_RESOURCE_ARRAY_IN_THREAD(
419 THREAD, VerificationType, stack_size*2);
420 }
421 for (i=0; i<stack_size; i++) {
422 stack[real_stack_size] = parse_verification_type(NULL, THREAD);
423 if (stack[real_stack_size].is_category2()) {
424 stack[real_stack_size + 1] = stack[real_stack_size].to_category2_2nd();
425 ++real_stack_size;
426 }
427 ++real_stack_size;
428 }
429 check_verification_type_array_size(
430 real_stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
431 if (first) {
432 offset = offset_delta;
433 } else {
434 offset = pre_frame->offset() + offset_delta + 1;
435 }
436 frame = new StackMapFrame(
437 offset, flags, real_locals_size, real_stack_size,
438 max_locals, max_stack, locals, stack, _verifier);
439 return frame;
440 }
441
442 _stream->stackmap_format_error(
443 "reserved frame type", CHECK_VERIFY_(pre_frame->verifier(), NULL));
444 return NULL;
445 }