1 /*
2 * Copyright (c) 2016, 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.io;
27
28 import java.security.AccessController;
29 import java.security.PrivilegedAction;
30 import java.security.Security;
31 import java.util.ArrayList;
32 import java.util.List;
33 import java.util.Objects;
34 import java.util.Optional;
35 import java.util.function.Function;
36
37
38 /**
39 * Filter classes, array lengths, and graph metrics during deserialization.
40 * If set on an {@link ObjectInputStream}, the {@link #checkInput checkInput(FilterInfo)}
41 * method is called to validate classes, the length of each array,
42 * the number of objects being read from the stream, the depth of the graph,
43 * and the total number of bytes read from the stream.
44 * <p>
45 * A filter can be set via {@link ObjectInputStream#setObjectInputFilter setObjectInputFilter}
46 * for an individual ObjectInputStream.
47 * A filter can be set via {@link Config#setSerialFilter(ObjectInputFilter) Config.setSerialFilter}
48 * to affect every {@code ObjectInputStream} that does not otherwise set a filter.
49 * <p>
50 * A filter determines whether the arguments are {@link Status#ALLOWED ALLOWED}
51 * or {@link Status#REJECTED REJECTED} and should return the appropriate status.
52 * If the filter cannot determine the status it should return
53 * {@link Status#UNDECIDED UNDECIDED}.
54 * Filters should be designed for the specific use case and expected types.
55 * A filter designed for a particular use may be passed a class that is outside
56 * of the scope of the filter. If the purpose of the filter is to black-list classes
57 * then it can reject a candidate class that matches and report UNDECIDED for others.
58 * A filter may be called with class equals {@code null}, {@code arrayLength} equal -1,
59 * the depth, number of references, and stream size and return a status
60 * that reflects only one or only some of the values.
61 * This allows a filter to specific about the choice it is reporting and
62 * to use other filters without forcing either allowed or rejected status.
63 *
64 * <p>
65 * Typically, a custom filter should check if a process-wide filter
66 * is configured and defer to it if so. For example,
67 * <pre>{@code
68 * ObjectInputFilter.Status checkInput(FilterInfo info) {
69 * ObjectInputFilter serialFilter = ObjectInputFilter.Config.getSerialFilter();
70 * if (serialFilter != null) {
71 * ObjectInputFilter.Status status = serialFilter.checkInput(info);
72 * if (status != ObjectInputFilter.Status.UNDECIDED) {
73 * // The process-wide filter overrides this filter
74 * return status;
75 * }
76 * }
77 * if (info.serialClass() != null &&
78 * Remote.class.isAssignableFrom(info.serialClass())) {
79 * return Status.REJECTED; // Do not allow Remote objects
80 * }
81 * return Status.UNDECIDED;
82 * }
83 *}</pre>
84 * <p>
85 * Unless otherwise noted, passing a {@code null} argument to a
86 * method in this interface and its nested classes will cause a
87 * {@link NullPointerException} to be thrown.
88 *
89 * @see ObjectInputStream#setObjectInputFilter(ObjectInputFilter)
90 * @since 9
91 */
92 @FunctionalInterface
93 public interface ObjectInputFilter {
94
95 /**
96 * Check the class, array length, number of object references, depth,
97 * stream size, and other available filtering information.
98 * Implementations of this method check the contents of the object graph being created
99 * during deserialization. The filter returns {@link Status#ALLOWED Status.ALLOWED},
100 * {@link Status#REJECTED Status.REJECTED}, or {@link Status#UNDECIDED Status.UNDECIDED}.
101 *
102 * @param filterInfo provides information about the current object being deserialized,
103 * if any, and the status of the {@link ObjectInputStream}
104 * @return {@link Status#ALLOWED Status.ALLOWED} if accepted,
105 * {@link Status#REJECTED Status.REJECTED} if rejected,
106 * {@link Status#UNDECIDED Status.UNDECIDED} if undecided.
107 * @since 9
108 */
109 Status checkInput(FilterInfo filterInfo);
110
111 /**
112 * FilterInfo provides access to information about the current object
113 * being deserialized and the status of the {@link ObjectInputStream}.
114 * @since 9
115 */
116 interface FilterInfo {
117 /**
118 * The class of an object being deserialized.
119 * For arrays, it is the array type.
120 * For example, the array class name of a 2 dimensional array of strings is
121 * "{@code [[Ljava.lang.String;}".
122 * To check the array's element type, iteratively use
123 * {@link Class#getComponentType() Class.getComponentType} while the result
124 * is an array and then check the class.
125 * The {@code serialClass is null} in the case where a new object is not being
126 * created and to give the filter a chance to check the depth, number of
127 * references to existing objects, and the stream size.
128 *
129 * @return class of an object being deserialized; may be null
130 */
131 Class<?> serialClass();
132
133 /**
134 * The number of array elements when deserializing an array of the class.
135 *
136 * @return the non-negative number of array elements when deserializing
137 * an array of the class, otherwise -1
138 */
139 long arrayLength();
140
141 /**
142 * The current depth.
143 * The depth starts at {@code 1} and increases for each nested object and
144 * decrements when each nested object returns.
145 *
146 * @return the current depth
147 */
148 long depth();
149
150 /**
151 * The current number of object references.
152 *
153 * @return the non-negative current number of object references
154 */
155 long references();
156
157 /**
158 * The current number of bytes consumed.
159 * @implSpec {@code streamBytes} is implementation specific
160 * and may not be directly related to the object in the stream
161 * that caused the callback.
162 *
163 * @return the non-negative current number of bytes consumed
164 */
165 long streamBytes();
166 }
167
168 /**
169 * The status of a check on the class, array length, number of references,
170 * depth, and stream size.
171 *
172 * @since 9
173 */
174 enum Status {
175 /**
176 * The status is undecided, not allowed and not rejected.
177 */
178 UNDECIDED,
179 /**
180 * The status is allowed.
181 */
182 ALLOWED,
183 /**
184 * The status is rejected.
185 */
186 REJECTED;
187 }
188
189 /**
190 * A utility class to set and get the process-wide filter or create a filter
191 * from a pattern string. If a process-wide filter is set, it will be
192 * used for each {@link ObjectInputStream} that does not set its own filter.
193 * <p>
194 * When setting the filter, it should be stateless and idempotent,
195 * reporting the same result when passed the same arguments.
196 * <p>
197 * The filter is configured during the initialization of the {@code ObjectInputFilter.Config}
198 * class. For example, by calling {@link #getSerialFilter() Config.getSerialFilter}.
199 * If the system property {@code jdk.serialFilter} is defined, it is used
200 * to configure the filter.
201 * If the system property is not defined, and the {@link java.security.Security}
202 * property {@code jdk.serialFilter} is defined then it is used to configure the filter.
203 * Otherwise, the filter is not configured during initialization.
204 * The syntax for each property is the same as for the
205 * {@link #createFilter(String) createFilter} method.
206 * If a filter is not configured, it can be set with
207 * {@link #setSerialFilter(ObjectInputFilter) Config.setSerialFilter}.
208 *
209 * @since 9
210 */
211 final class Config {
212 /* No instances. */
213 private Config() {}
214
215 /**
216 * Lock object for process-wide filter.
217 */
218 private final static Object serialFilterLock = new Object();
219
220 /**
221 * Debug: Logger
222 */
223 private final static System.Logger configLog;
224
225 /**
226 * Logger for debugging.
227 */
228 static void filterLog(System.Logger.Level level, String msg, Object... args) {
229 if (configLog != null) {
230 configLog.log(level, msg, args);
231 }
232 }
233
234 /**
235 * The name for the process-wide deserialization filter.
236 * Used as a system property and a java.security.Security property.
237 */
238 private final static String SERIAL_FILTER_PROPNAME = "jdk.serialFilter";
239
240 /**
241 * The process-wide filter; may be null.
242 * Lookup the filter in java.security.Security or
243 * the system property.
244 */
245 private final static ObjectInputFilter configuredFilter;
246
247 static {
248 configuredFilter = AccessController
249 .doPrivileged((PrivilegedAction<ObjectInputFilter>) () -> {
250 String props = System.getProperty(SERIAL_FILTER_PROPNAME);
251 if (props == null) {
252 props = Security.getProperty(SERIAL_FILTER_PROPNAME);
253 }
254 if (props != null) {
255 System.Logger log =
256 System.getLogger("java.io.serialization");
257 log.log(System.Logger.Level.INFO,
258 "Creating serialization filter from {0}", props);
259 try {
260 return createFilter(props);
261 } catch (RuntimeException re) {
262 log.log(System.Logger.Level.ERROR,
263 "Error configuring filter: {0}", re);
264 }
265 }
266 return null;
267 });
268 configLog = (configuredFilter != null) ? System.getLogger("java.io.serialization") : null;
269 }
270
271 /**
272 * Current configured filter.
273 */
274 private static ObjectInputFilter serialFilter = configuredFilter;
275
276 /**
277 * Returns the process-wide serialization filter or {@code null} if not configured.
278 *
279 * @return the process-wide serialization filter or {@code null} if not configured
280 */
281 public static ObjectInputFilter getSerialFilter() {
282 synchronized (serialFilterLock) {
283 return serialFilter;
284 }
285 }
286
287 /**
288 * Set the process-wide filter if it has not already been configured or set.
289 *
290 * @param filter the serialization filter to set as the process-wide filter; not null
291 * @throws SecurityException if there is security manager and the
292 * {@code SerializablePermission("serialFilter")} is not granted
293 * @throws IllegalStateException if the filter has already been set {@code non-null}
294 */
295 public static void setSerialFilter(ObjectInputFilter filter) {
296 Objects.requireNonNull(filter, "filter");
297 SecurityManager sm = System.getSecurityManager();
298 if (sm != null) {
299 sm.checkPermission(ObjectStreamConstants.SERIAL_FILTER_PERMISSION);
300 }
301 synchronized (serialFilterLock) {
302 if (serialFilter != null) {
303 throw new IllegalStateException("Serial filter can only be set once");
304 }
305 serialFilter = filter;
306 }
307 }
308
309 /**
310 * Returns an ObjectInputFilter from a string of patterns.
311 * <p>
312 * Patterns are separated by ";" (semicolon). Whitespace is significant and
313 * is considered part of the pattern.
314 * If a pattern includes an equals assignment, "{@code =}" it sets a limit.
315 * If a limit appears more than once the last value is used.
316 * <ul>
317 * <li>maxdepth={@code value} - the maximum depth of a graph</li>
318 * <li>maxrefs={@code value} - the maximum number of internal references</li>
319 * <li>maxbytes={@code value} - the maximum number of bytes in the input stream</li>
320 * <li>maxarray={@code value} - the maximum array length allowed</li>
321 * </ul>
322 * <p>
323 * Other patterns match or reject class or package name
324 * as returned from {@link Class#getName() Class.getName()} and
325 * if an optional module name is present
326 * {@link java.lang.reflect.Module#getName() class.getModule().getName()}.
327 * Note that for arrays the element type is used in the pattern,
328 * not the array type.
329 * <ul>
330 * <li>If the pattern starts with "!", the class is rejected if the remaining pattern is matched;
331 * otherwise the class is allowed if the pattern matches.
332 * <li>If the pattern contains "/", the non-empty prefix up to the "/" is the module name;
333 * if the module name matches the module name of the class then
334 * the remaining pattern is matched with the class name.
335 * If there is no "/", the module name is not compared.
336 * <li>If the pattern ends with ".**" it matches any class in the package and all subpackages.
337 * <li>If the pattern ends with ".*" it matches any class in the package.
338 * <li>If the pattern ends with "*", it matches any class with the pattern as a prefix.
339 * <li>If the pattern is equal to the class name, it matches.
340 * <li>Otherwise, the pattern is not matched.
341 * </ul>
342 * <p>
343 * The resulting filter performs the limit checks and then
344 * tries to match the class, if any. If any of the limits are exceeded,
345 * the filter returns {@link Status#REJECTED Status.REJECTED}.
346 * If the class is an array type, the class to be matched is the element type.
347 * Arrays of any number of dimensions are treated the same as the element type.
348 * For example, a pattern of "{@code !example.Foo}",
349 * rejects creation of any instance or array of {@code example.Foo}.
350 * The first pattern that matches, working from left to right, determines
351 * the {@link Status#ALLOWED Status.ALLOWED}
352 * or {@link Status#REJECTED Status.REJECTED} result.
353 * If the limits are not exceeded and no pattern matches the class,
354 * the result is {@link Status#UNDECIDED Status.UNDECIDED}.
355 *
356 * @param pattern the pattern string to parse; not null
357 * @return a filter to check a class being deserialized;
358 * {@code null} if no patterns
359 * @throws IllegalArgumentException if the pattern string is illegal or
360 * malformed and cannot be parsed.
361 * In particular, if any of the following is true:
362 * <ul>
363 * <li> if a limit is missing the name or the name is not one of
364 * "maxdepth", "maxrefs", "maxbytes", or "maxarray"
365 * <li> if the value of the limit can not be parsed by
366 * {@link Long#parseLong Long.parseLong} or is negative
367 * <li> if the pattern contains "/" and the module name is missing
368 * or the remaining pattern is empty
369 * <li> if the package is missing for ".*" and ".**"
370 * </ul>
371 */
372 public static ObjectInputFilter createFilter(String pattern) {
373 Objects.requireNonNull(pattern, "pattern");
374 return Global.createFilter(pattern);
375 }
376
377 /**
378 * Implementation of ObjectInputFilter that performs the checks of
379 * the process-wide serialization filter. If configured, it will be
380 * used for all ObjectInputStreams that do not set their own filters.
381 *
382 */
383 final static class Global implements ObjectInputFilter {
384 /**
385 * The pattern used to create the filter.
386 */
387 private final String pattern;
388 /**
389 * The list of class filters.
390 */
391 private final List<Function<Class<?>, Status>> filters;
392 /**
393 * Maximum allowed bytes in the stream.
394 */
395 private long maxStreamBytes;
396 /**
397 * Maximum depth of the graph allowed.
398 */
399 private long maxDepth;
400 /**
401 * Maximum number of references in a graph.
402 */
403 private long maxReferences;
404 /**
405 * Maximum length of any array.
406 */
407 private long maxArrayLength;
408
409 /**
410 * Returns an ObjectInputFilter from a string of patterns.
411 *
412 * @param pattern the pattern string to parse
413 * @return a filter to check a class being deserialized;
414 * {@code null} if no patterns
415 * @throws IllegalArgumentException if the parameter is malformed
416 * if the pattern is missing the name, the long value
417 * is not a number or is negative.
418 */
419 static ObjectInputFilter createFilter(String pattern) {
420 try {
421 return new Global(pattern);
422 } catch (UnsupportedOperationException uoe) {
423 // no non-empty patterns
424 return null;
425 }
426 }
427
428 /**
429 * Construct a new filter from the pattern String.
430 *
431 * @param pattern a pattern string of filters
432 * @throws IllegalArgumentException if the pattern is malformed
433 * @throws UnsupportedOperationException if there are no non-empty patterns
434 */
435 private Global(String pattern) {
436 boolean hasLimits = false;
437 this.pattern = pattern;
438
439 maxArrayLength = Long.MAX_VALUE; // Default values are unlimited
440 maxDepth = Long.MAX_VALUE;
441 maxReferences = Long.MAX_VALUE;
442 maxStreamBytes = Long.MAX_VALUE;
443
444 String[] patterns = pattern.split(";");
445 filters = new ArrayList<>(patterns.length);
446 for (int i = 0; i < patterns.length; i++) {
447 String p = patterns[i];
448 int nameLen = p.length();
449 if (nameLen == 0) {
450 continue;
451 }
452 if (parseLimit(p)) {
453 // If the pattern contained a limit setting, i.e. type=value
454 hasLimits = true;
455 continue;
456 }
457 boolean negate = p.charAt(0) == '!';
458 int poffset = negate ? 1 : 0;
459
460 // isolate module name, if any
461 int slash = p.indexOf('/', poffset);
462 if (slash == poffset) {
463 throw new IllegalArgumentException("module name is missing in: \"" + pattern + "\"");
464 }
465 final String moduleName = (slash >= 0) ? p.substring(poffset, slash) : null;
466 poffset = (slash >= 0) ? slash + 1 : poffset;
467
468 final Function<Class<?>, Status> patternFilter;
469 if (p.endsWith("*")) {
470 // Wildcard cases
471 if (p.endsWith(".*")) {
472 // Pattern is a package name with a wildcard
473 final String pkg = p.substring(poffset, nameLen - 1);
474 if (pkg.length() < 2) {
475 throw new IllegalArgumentException("package missing in: \"" + pattern + "\"");
476 }
477 if (negate) {
478 // A Function that fails if the class starts with the pattern, otherwise don't care
479 patternFilter = c -> matchesPackage(c, pkg) ? Status.REJECTED : Status.UNDECIDED;
480 } else {
481 // A Function that succeeds if the class starts with the pattern, otherwise don't care
482 patternFilter = c -> matchesPackage(c, pkg) ? Status.ALLOWED : Status.UNDECIDED;
483 }
484 } else if (p.endsWith(".**")) {
485 // Pattern is a package prefix with a double wildcard
486 final String pkgs = p.substring(poffset, nameLen - 2);
487 if (pkgs.length() < 2) {
488 throw new IllegalArgumentException("package missing in: \"" + pattern + "\"");
489 }
490 if (negate) {
491 // A Function that fails if the class starts with the pattern, otherwise don't care
492 patternFilter = c -> c.getName().startsWith(pkgs) ? Status.REJECTED : Status.UNDECIDED;
493 } else {
494 // A Function that succeeds if the class starts with the pattern, otherwise don't care
495 patternFilter = c -> c.getName().startsWith(pkgs) ? Status.ALLOWED : Status.UNDECIDED;
496 }
497 } else {
498 // Pattern is a classname (possibly empty) with a trailing wildcard
499 final String className = p.substring(poffset, nameLen - 1);
500 if (negate) {
501 // A Function that fails if the class starts with the pattern, otherwise don't care
502 patternFilter = c -> c.getName().startsWith(className) ? Status.REJECTED : Status.UNDECIDED;
503 } else {
504 // A Function that succeeds if the class starts with the pattern, otherwise don't care
505 patternFilter = c -> c.getName().startsWith(className) ? Status.ALLOWED : Status.UNDECIDED;
506 }
507 }
508 } else {
509 final String name = p.substring(poffset);
510 if (name.isEmpty()) {
511 throw new IllegalArgumentException("class or package missing in: \"" + pattern + "\"");
512 }
513 // Pattern is a class name
514 if (negate) {
515 // A Function that fails if the class equals the pattern, otherwise don't care
516 patternFilter = c -> c.getName().equals(name) ? Status.REJECTED : Status.UNDECIDED;
517 } else {
518 // A Function that succeeds if the class equals the pattern, otherwise don't care
519 patternFilter = c -> c.getName().equals(name) ? Status.ALLOWED : Status.UNDECIDED;
520 }
521 }
522 // If there is a moduleName, combine the module name check with the package/class check
523 if (moduleName == null) {
524 filters.add(patternFilter);
525 } else {
526 filters.add(c -> moduleName.equals(c.getModule().getName()) ? patternFilter.apply(c) : Status.UNDECIDED);
527 }
528 }
529 if (filters.isEmpty() && !hasLimits) {
530 throw new UnsupportedOperationException("no non-empty patterns");
531 }
532 }
533
534 /**
535 * Parse out a limit for one of maxarray, maxdepth, maxbytes, maxreferences.
536 *
537 * @param pattern a string with a type name, '=' and a value
538 * @return {@code true} if a limit was parsed, else {@code false}
539 * @throws IllegalArgumentException if the pattern is missing
540 * the name, the Long value is not a number or is negative.
541 */
542 private boolean parseLimit(String pattern) {
543 int eqNdx = pattern.indexOf('=');
544 if (eqNdx < 0) {
545 // not a limit pattern
546 return false;
547 }
548 String valueString = pattern.substring(eqNdx + 1);
549 if (pattern.startsWith("maxdepth=")) {
550 maxDepth = parseValue(valueString);
551 } else if (pattern.startsWith("maxarray=")) {
552 maxArrayLength = parseValue(valueString);
553 } else if (pattern.startsWith("maxrefs=")) {
554 maxReferences = parseValue(valueString);
555 } else if (pattern.startsWith("maxbytes=")) {
556 maxStreamBytes = parseValue(valueString);
557 } else {
558 throw new IllegalArgumentException("unknown limit: " + pattern.substring(0, eqNdx));
559 }
560 return true;
561 }
562
563 /**
564 * Parse the value of a limit and check that it is non-negative.
565 * @param string inputstring
566 * @return the parsed value
567 * @throws IllegalArgumentException if parsing the value fails or the value is negative
568 */
569 private static long parseValue(String string) throws IllegalArgumentException {
570 // Parse a Long from after the '=' to the end
571 long value = Long.parseLong(string);
572 if (value < 0) {
573 throw new IllegalArgumentException("negative limit: " + string);
574 }
575 return value;
576 }
577
578 /**
579 * {@inheritDoc}
580 */
581 @Override
582 public Status checkInput(FilterInfo filterInfo) {
583 if (filterInfo.references() < 0
584 || filterInfo.depth() < 0
585 || filterInfo.streamBytes() < 0
586 || filterInfo.references() > maxReferences
587 || filterInfo.depth() > maxDepth
588 || filterInfo.streamBytes() > maxStreamBytes) {
589 return Status.REJECTED;
590 }
591
592 Class<?> clazz = filterInfo.serialClass();
593 if (clazz != null) {
594 if (clazz.isArray()) {
595 if (filterInfo.arrayLength() >= 0 && filterInfo.arrayLength() > maxArrayLength) {
596 // array length is too big
597 return Status.REJECTED;
598 }
599 do {
600 // Arrays are decided based on the component type
601 clazz = clazz.getComponentType();
602 } while (clazz.isArray());
603 }
604
605 if (clazz.isPrimitive()) {
606 // Primitive types are undecided; let someone else decide
607 return Status.UNDECIDED;
608 } else {
609 // Find any filter that allowed or rejected the class
610 final Class<?> cl = clazz;
611 Optional<Status> status = filters.stream()
612 .map(f -> f.apply(cl))
613 .filter(p -> p != Status.UNDECIDED)
614 .findFirst();
615 return status.orElse(Status.UNDECIDED);
616 }
617 }
618 return Status.UNDECIDED;
619 }
620
621 /**
622 * Returns {@code true} if the class is in the package.
623 *
624 * @param c a class
625 * @param pkg a package name (including the trailing ".")
626 * @return {@code true} if the class is in the package,
627 * otherwise {@code false}
628 */
629 private static boolean matchesPackage(Class<?> c, String pkg) {
630 String n = c.getName();
631 return n.startsWith(pkg) && n.lastIndexOf('.') == pkg.length() - 1;
632 }
633
634 /**
635 * Returns the pattern used to create this filter.
636 * @return the pattern used to create this filter
637 */
638 @Override
639 public String toString() {
640 return pattern;
641 }
642 }
643 }
644 }