Author: thebeing
Date: Fri Jun 17 11:04:04 2016
New Revision: 39872
URL: http://svn.gna.org/viewcvs/gnustep?rev=39872&view=rev
Log:
Implement resource limits for regular expression evaluation. Tweaked
to roughly match the Cocoa behaviour, but can be changed through
the GSRegularExpressionWorkLimit user default.
Modified:
libs/base/trunk/ChangeLog
libs/base/trunk/Headers/Foundation/NSRegularExpression.h
libs/base/trunk/Source/NSRegularExpression.m
libs/base/trunk/Tests/base/NSRegularExpression/basic.m
Modified: libs/base/trunk/ChangeLog
URL:
http://svn.gna.org/viewcvs/gnustep/libs/base/trunk/ChangeLog?rev=39872&r1=39871&r2=39872&view=diff
==============================================================================
--- libs/base/trunk/ChangeLog (original)
+++ libs/base/trunk/ChangeLog Fri Jun 17 11:04:04 2016
@@ -1,3 +1,13 @@
+2016-06-17 Niels Grewe <[email protected]>
+
+ * Headers/Foundation/NSRegularExpression.h
+ * Source/NSRegularExpression.m
+ * Tests/base/NSRegularExpression/basic.m:
+
+ Implement resource limits for regular expression evaluation. Tweaked
+ to roughly match the Cocoa behaviour, but can be changed through
+ the GSRegularExpressionWorkLimit user default.
+
2016-06-17 Niels Grewe <[email protected]>
* Source/NSRegularExpression.m: Implement -isEqual: and -hash
Modified: libs/base/trunk/Headers/Foundation/NSRegularExpression.h
URL:
http://svn.gna.org/viewcvs/gnustep/libs/base/trunk/Headers/Foundation/NSRegularExpression.h?rev=39872&r1=39871&r2=39872&view=diff
==============================================================================
--- libs/base/trunk/Headers/Foundation/NSRegularExpression.h (original)
+++ libs/base/trunk/Headers/Foundation/NSRegularExpression.h Fri Jun 17
11:04:04 2016
@@ -1,18 +1,19 @@
+
/* Definition of class NSRegularExpression
Copyright (C) 2011 Free Software Foundation, Inc.
-
+
This file is part of the GNUstep Library.
-
+
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
-
+
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
-
+
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
@@ -72,7 +73,19 @@
#ifndef GSREGEXTYPE
# define GSREGEXTYPE void
#endif
-
+/**
+ * NSRegularExpression is used to inspect and manipulate strings using regular
+ * expressions. The interface is thread safe: The same NSRegularExpression
+ * object may be used to concurrently perform matching on multiple threads.
+ *
+ * To guard against regular expressions with extremely poor performance, the
+ * underlying matcher will abort after a certain number of steps. This is
+ * controlled using the GSRegularExpressionWorkLimit user default. The value of
+ * this default key represents the number of steps executed by the match
engine,
+ * so it is only indirectly correlated with the time taken to execute the
+ * pattern, but it usually in the order of milliseconds. The preset 1500,
+ * setting value to 0 disables the work limit.
+ */
@interface NSRegularExpression : NSObject <NSCoding, NSCopying>
{
#if GS_EXPOSE(NSRegularExpression)
@@ -153,4 +166,3 @@
#endif /* GS_API_MACOSX */
#endif /* _NSRegualrExpression_h_GNUSTEP_BASE_INCLUDE */
-
Modified: libs/base/trunk/Source/NSRegularExpression.m
URL:
http://svn.gna.org/viewcvs/gnustep/libs/base/trunk/Source/NSRegularExpression.m?rev=39872&r1=39871&r2=39872&view=diff
==============================================================================
--- libs/base/trunk/Source/NSRegularExpression.m (original)
+++ libs/base/trunk/Source/NSRegularExpression.m Fri Jun 17 11:04:04 2016
@@ -46,6 +46,8 @@
#import "Foundation/NSTextCheckingResult.h"
#import "Foundation/NSArray.h"
#import "Foundation/NSCoder.h"
+#import "Foundation/NSUserDefaults.h"
+#import "Foundation/NSNotification.h"
/**
@@ -293,6 +295,48 @@
return stop;
}
+
+#define DEFAULT_WORK_LIMIT 1500
+/**
+ * The work limit specifies the number of iterations the matcher will do before
+ * aborting an operation. This ensures that degenerate pattern/input
+ * combinations don't send the application into what for all intents and
+ * purposes seems like an infinite loop.
+ */
+static int32_t _workLimit = DEFAULT_WORK_LIMIT;
+
++ (void) _defaultsChanged: (NSNotification*)n
+{
+ NSUserDefaults *defs = [NSUserDefaults standardUserDefaults];
+ id value = [defs objectForKey: @"GSRegularExpressionWorkLimit"];
+ int32_t newLimit = DEFAULT_WORK_LIMIT;
+ if ([value respondsToSelector: @selector(intValue)])
+ {
+ int32_t v = [value intValue];
+ if (v >= 0)
+ {
+ newLimit = v;
+ }
+ }
+ _workLimit = newLimit;
+}
+
++ (void) initialize
+{
+ if (self == [NSRegularExpression class])
+ {
+ [[NSNotificationCenter defaultCenter]
+ addObserver: self
+ selector: @selector(_defaultsChanged:)
+ name: NSUserDefaultsDidChangeNotification
+ object: nil];
+ [self _defaultsChanged: nil];
+ }
+}
+
+
+
+
/**
* Sets up a libicu regex object for use. Note: the documentation states that
* NSRegularExpression must be thread safe. To accomplish this, we store a
@@ -328,6 +372,7 @@
{
uregex_useTransparentBounds(r, TRUE, &s);
}
+ uregex_setTimeLimit(r, _workLimit, &s);
if (U_FAILURE(s))
{
uregex_close(r);
@@ -363,6 +408,7 @@
{
uregex_useTransparentBounds(r, TRUE, &s);
}
+ uregex_setTimeLimit(r, _workLimit, &s);
if (U_FAILURE(s))
{
uregex_close(r);
Modified: libs/base/trunk/Tests/base/NSRegularExpression/basic.m
URL:
http://svn.gna.org/viewcvs/gnustep/libs/base/trunk/Tests/base/NSRegularExpression/basic.m?rev=39872&r1=39871&r2=39872&view=diff
==============================================================================
--- libs/base/trunk/Tests/base/NSRegularExpression/basic.m (original)
+++ libs/base/trunk/Tests/base/NSRegularExpression/basic.m Fri Jun 17
11:04:04 2016
@@ -1,22 +1,102 @@
+
#import "ObjectTesting.h"
#import <Foundation/NSAutoreleasePool.h>
#import <Foundation/NSRegularExpression.h>
+#import <Foundation/NSDate.h>
+#import <Foundation/NSDictionary.h>
+#import <Foundation/NSUserDefaults.h>
+#import <Foundation/NSRunLoop.h>
+#import <Foundation/NSThread.h>
+#import <Foundation/NSValue.h>
+
+@interface DegeneratePatternTest : NSObject
+{
+ NSRegularExpression *expression;
+ NSString* input;
+}
+@end
+
+@implementation DegeneratePatternTest
+
+- (instancetype) init
+{
+ if (nil == (self = [super init]))
+ {
+ return nil;
+ }
+ expression =
+ [[NSRegularExpression alloc] initWithPattern:
@"^(([a-z])+.)+[A-Z]([a-z])+$"
+ options: 0
+ error: NULL];
+ ASSIGN(input,
@"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa!");
+ return self;
+}
+
+- (void) runTest: (id)obj
+{
+ NSAutoreleasePool *pool = [NSAutoreleasePool new];
+ [expression matchesInString: input
+ options: 0
+ range: NSMakeRange(0, [input length])];
+ DESTROY(pool);
+}
+
+- (void) dealloc
+{
+ DESTROY(expression);
+ DESTROY(input);
+ [super dealloc];
+}
+@end
+
int main()
{
NSAutoreleasePool *arp = [NSAutoreleasePool new];
+# ifdef GNUSTEP
+ // Ensure that a deterministic limit is set up for this process
+ NSUserDefaults *dflts = [NSUserDefaults standardUserDefaults];
+ NSDictionary *domain = [NSDictionary dictionaryWithObjectsAndKeys:
+ [NSNumber numberWithInt: 1500], @"GSRegularExpressionWorkLimit", nil];
+ [dflts setVolatileDomain: domain
+ forName: @"GSTestDomain"];
+# endif
id testObj = [[NSRegularExpression alloc] initWithPattern: @"^a"
options: 0
error: NULL];
test_NSObject(@"NSRegularExpression",
- [NSArray arrayWithObject:
+ [NSArray arrayWithObject:
[[NSRegularExpression alloc] initWithPattern: @"^a"
options: 0
error: NULL]]);
test_NSCopying(@"NSRegularExpression",@"NSRegularExpression",
[NSArray arrayWithObject:testObj],NO,NO);
-
+
+
+ /* To test whether we correctly bail out of processing degenerate patterns,
+ * we spin up a new thread and evaluate an expression there. The expectation
+ * is that the thread should terminate within a few seconds.
+ *
+ * NOTE: Since we cannot terminate the thread in case of a failure, this
+ * test should be run last.
+ */
+ DegeneratePatternTest *test = [DegeneratePatternTest new];
+ NSThread *thread = [[NSThread alloc] initWithTarget: test
+ selector: @selector(runTest:)
+ object: nil];
+ [thread start];
+ [thread setName: @"PatternTestRunner"];
+ NSDate *started = [NSDate date];
+ NSRunLoop *rl = [NSRunLoop currentRunLoop];
+ /* We spin the runloop for a bit while we wait for the other thread to bail
+ * out */
+ while ([thread isExecuting] && abs([started timeIntervalSinceNow] < 10.0f))
+ {
+ [rl runMode: NSDefaultRunLoopMode
+ beforeDate: [NSDate dateWithTimeIntervalSinceNow: 0.01]];
+ }
+ PASS(NO == [thread isExecuting], "Faulty regular expression terminated");
[arp release]; arp = nil;
return 0;
}
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