This sounds indeed like a bug in the flow when an exception is raised. It could be non-null the first time but not the second time, sonar does not know this. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? Find centralized, trusted content and collaborate around the technologies you use most. rev2023.3.3.43278. Can I tell police to wait and call a lawyer when served with a search warrant? Why do academics stay as adjuncts for years rather than move around? Is it possible to rotate a window 90 degrees if it has the same length and width? The article easily misleads the reader into believeing that ensuring pointer validity boils down to checking for pointer being not equal to NULL. To learn more, see our tips on writing great answers. (/). How to tell which packages are held back due to phased updates. Trying to understand how to get this basic Fourier Series. Is there a proper earth ground point in this switch box? Is there a single-word adjective for "having exceptionally strong moral principles"? And fwstr > is dereferenced in the following codes. How do you ensure that a red herring doesn't violate Chekhov's gun? Unless explicitly stated otherwise in the description of a particular function in this subclause, pointer arguments on such a call shall still have valid values, as described in 7.1.4. SonarQube null pointers should not be dereferenced on try/catch How do you ensure that a red herring doesn't violate Chekhov's gun? Please direct comments on this JSR to the Spec Lead (s) Team. sonar-java. Which version of SonarJava plugin do you have? Do "superinfinite" sets exist? This sounds indeed like a bug in the flow when an exception is raised. How can this new ban on drag possibly be considered constitutional? to non-modifiable storage when the corresponding parameter is not const-qualified) or a type (after default argument promotion) not expected by a function with a variable number of arguments, the behavior is undefined. Your code needs to do something about the possible NullPointerException when some exception is caught, because in this scenario the responseDto will be null. Removing the check "exception != null" raises S2259 "Null pointers should not be dereferenced" on "throw exception". Trying to understand how to get this basic Fourier Series. int changed to size_t and if size_t parameter's is zero, allocate one word. Null pointer should not be dereferenced , SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. 412-268-5800, If an argument to a function has an invalid value (such as a value outside the domain of the function, or a pointer outside the address space of the program, or a null pointer, or a pointer. Is the God of a monotheism necessarily omnipotent? ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . (I think you cover that in a different rule.) To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Doing so will cause a NullReferenceException to be thrown. C# static code analysis: Null pointers should not be dereferenced can have the value zero on a call to that function. - the incident has nothing to do with me; can I use this this way? To be precise, once length is changed to a size_t and cannot take negative values, it cannot have an invalid value. CWE-476: NULL Pointer Dereference: A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. parsing /proc/self/maps under linux) one might find out whether the pointer points into mapped memory, but this is still not a guarantee of validity because it is very coarse-grained see again the above example. 1 Answer Sorted by: 2 Your code needs to do something about the possible NullPointerException when some exception is caught, because in this scenario the responseDto will be null. Depending on whether the pointer is valid (i.e. Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. On such a call, a function that locates a character finds no occurrence, a function that compares two character sequences returns zero, and a function that copies characters copies zero characters. Revert Update S2259: "Null pointer dereference" CFG should ignore expressions in Debug.Assert #397 Introduce means to not raise "Expression always true/false" on values that were checked with Debug.Assert. In my experience, there are reasons to check for a NULL pointer other than dereferencing it. The only potential null is the return value of list(). If not, this might be a bug. Made code more compliant with other rules. Share Improve this answer Follow answered Oct 5, 2017 at 16:27 A bug can cause them never to be reassigned. How can we let this pass? public boolean isNameEmpty() { return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked } . Null Pointer Exception In Java - GeeksforGeeks - A computer science isEmpty(Map map) It's a modular system with the . The solution that I recommend is not work with null returns or variables on Java, try to avoid it. How to fix int cannot be dereferenced? Explained by Sharing Culture What is the point of Thrower's Bandolier? If copying takes place between objects that overlap, the behavior is undefined. Handling Java NullPointerException and Best Practices - HowToDoInJava A null pointer stores a defined value, but one that is defined by the environment to not be a valid address for any member or object. Things go fine now. ", Eclipse - Sonar S2629 possible false positive with new String, SonarQube null pointers should not be dereferenced on try/catch, getTextContent() through "Null pointers should not be dereferenced". Likewise, pointers to freed memory are not valid. Yeah, I suspect once it's possible to allocate 2+gigs contiguously in amainstream install of a modern OS, we'll see a frenzy of new vulnerabilities come out. vegan) just to try it, does this inconvenience the caterers and staff? On many platforms, dereferencing a null pointer results in abnormal program termination, but this is not required by the standard. Calls to extension methods are not reported because they can still operate on null values. All content is copyright protected. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. At best, such an exception will cause abrupt program termination. VB.NET static code analysis: Null pointers should not be dereferenced IMHO, the rule title should be changed to something less general. PS: I also tried the code in android studio which uses Lint and got no warnings. assert(!invalid(p)); // or whatever, bool invalid(const void *p) { Styling contours by colour and by line thickness in QGIS. points to memory allocated to the process) and what exactly was allocated there after the public key was freed, this may cause a segmentation fault or even execute code, which could again cause a segmentation fault, but might potentially be under the attacker's control. Why does Mister Mxyzptlk need to have a weakness in the comics? When length is zero, it is probably unusable condition for this function. In Java, a special null value can be assigned to an object reference. Asking for help, clarification, or responding to other answers. A pointer to null (the 0 memory address) should never be dereferenced/accessed. Phew, we're agreed here. Whats the grammar of "For those whose stories they are"? How to deal with "java.lang.OutOfMemoryError: Java heap space" error? Is there a proper earth ground point in this switch box? . Not the answer you're looking for? ucsi->connector gets dereferenced by both ucsi_connector_change() and ucsi_resume(), both check for ucsi->connector being NULL in case ucsi_init() has not finished yet; or in case ucsi_init() has failed. A value is checked here to see whether it is null, but this value can't be null because it was previously dereferenced and if it were null a null pointer exception would have occurred at the earlier dereference. The Clang Static Analyzer already has a checker to find the null pointer dereference in code, however it is not sufficient for higher abstractions such as C++ smart pointers or optionals. The correct idiom is to only allocate storage if the pointer is currently NULL. But when length of A is 1, the control never reaches the else block. The expected result here is solve the issue with sonarqube. Optimizers are optimizing based on this latitude and have been for years. Hi @Michael! Null pointers should not be dereferenced (#42) Issues - GitLab I would therefore assert that a platform whose memcpy() did anything besides a no-op when given n=0 and valid source/destination pointers was not C-standards-compliant. Asking for help, clarification, or responding to other answers. Doing so will at best cause abrupt program termination, without the SonarQube null pointers should not be dereferenced on try/catch, Sonarcube :Null pointers should not be dereferenced, How do you get out of a corner when plotting yourself into a corner. Iflengthhas the value1, the addition yields 0, and png_malloc() subsequently returns a null pointer, which is assigned to chunkdata. positive S2637 in SonarQube 6.7.1 LTS, SonarQube for MSBuild not reporting quality issues, getTextContent() through "Null pointers should not be dereferenced". sonarqube This compliant solution ensures that the pointer returned by png_malloc() is not null. Why pointers are not used in python? Explained by Sharing Culture So the first execution of ValidateNumber inside the foreach works fine and valid is set to true.The second execution throws the exception and exception is set in the catch-Block.. And the compliant solution guarantees that the pointer will be valid if the code calls memcpy(). context.RaiseException . http://blog.llvm.org/2011/05/what-every-c-programmer-should-know_14.html. Believing that dereferencing NULL shouldn't crash the system doesn't make it true. But when length of A is 1, the control never reaches the else block. return p == NULL || (char *)p < &_etext; This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. In the meantime, Im locking this thread. I think "res.getBody() == null" checks null first so it should go to return line, not reach to next if condition. I believe that dereferencing NULL should not crash the system, should not allow a write to a NULL pointer area, but should always set errno, If I am a hacker, could I trap a null failure that would force a memory dump. Dereferencing a null pointer is undefined behavior, typically abnormal program termination. S2259: Null pointers should not be dereferenced - Sonar Community CWE - CWE-476: NULL Pointer Dereference (4.10) - Mitre Corporation Aaron:I suspect we are talking past each other. Null pointer should not be dereferenced . Unlike reference types, pointer types are not tracked by the default garbage . When you have a variable of non-primitive type, it is a reference to an object. Answered: difference between a void pointer and a | bartleby When should pointers be checked for NULL in C? Using platform-specific means (e.g. New replies are no longer allowed. NULL POINTERS SHOULD NOT BE DEREFERENCED - jobhuntley.com Does a summoned creature play immediately after being summoned by a ready action? In order to fix this, just do the following: If you are absolutely sure that res.getBody() stays null and is also not modified by another thread, you could also use a //NOSONAR comment in order to suppress the warning. The fact that you can't pass a null (no object) with a reference parameter can be a reason to use a pointer instead. SonarLint IntelliJ 4.0.0.2916 Java Rule 'Null pointers should not be dereferenced' I'm getting this fault in the next code when obj can't be null in any scenario. Software Engineering Institute That interpretation of the standard is not supported universally. Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. Since SIZE_MAX represents the largest possible object, the largest possible string would then be SIZE_MAX-1 characters long (excluding '\0'). Recovering from a blunder I made while emailing a professor. Review and Fix Illegally Dereferenced Pointer Checks If the project is not compiled, and without sonar.java.binaries whether the white list takes effect? The n=0 is a mildly interesting edge case: Clearly a pointer that points to at least one valid byte could be used as the src or dest pointer to a call to memcpy(, 0). To create a custom null validation method declare an attribute with name ValidatedNotNullAttribute and mark the parameter that is On the command prompt, the same arguments work and the record is added in db but not when I call the stored procedure from inside java program CallableStatement insertStat = db_conn.prepareCall (" {call InsertCourses (?,?,?,?,?,?,?,? Please explain: Without this, we wont be able to help you. 5.2 Part 2 Sometimes a helper function is de ned to perform the memory allocation. The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. Finally, there is the matter of the compliant solution. Write a semantic patch to nd cases where the result of calling kmalloc is dereferenced with no previous NULL pointer test. The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to . Is the God of a monotheism necessarily omnipotent? Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Sonar: Null pointers should not be dereferenced, Why should Java 8's Optional not be used in arguments, Sonar alert : "private" methods that don't access instance data should be "static", sonarLint complains "Null pointers should not be dereferenced (squid:S2259)" despite that possibility being handled, Java: (false?) We cannot understand how there could be a null pointer exception at the reported line. But even with this, the concerned object it tagged as a possible NullPointerException problem. In some situations, however, dereferencing a null pointer can lead to the execution of arbitrary code [Jack 2007,van Sprundel 2006]. . C static code analysis: Null pointers should not be dereferenced An awesome tip to avoid NPE is to return empty strings or empty collections rather than null. When and how should I use a ThreadLocal variable? Null Pointers - Keil forum - Support forums - Arm Community Sonar violation: Null pointers should not be dereferenced #7459 - GitHub A pointer is simply a variable that contains a memory address. Appropriate typecasting is necessary. Provide a self-contained reproducer (zipped project?) Null - which version of SonarQube are you using? The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. positive S2637 in SonarQube 6.7.1 LTS, Sonar false positive, "change condition so that it does not always evaluate to true. Seems the analizer don't recognice the logic with the funcional object Optional. It does not point to any area of memory. Thanks for contributing an answer to Stack Overflow! java - sonarLint "Null pointers should not be Note that it doesn't know how to check for non-heap, non-stack. Void pointers cannot be dereferenced as any other pointer. I was fixing some issues gathered by SonarQube when I stumbled upon the following issue: "SonarQube violation: Possible null pointer dereference in ___ due to return value of called method" When and how should I use a ThreadLocal variable? You're in a company-managed project. [SONARJAVA-2808] - Jira - SonarSource It also reinforces the notion to the reader that any time you see arithmetic in an allocation expression, you need to think about corner-cases. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Finally my method is returning a response with value of restTemplate. [squid:S2259] False positive - "Null pointers should not be dereferenced" See C17 7.1.4p1, which says, in part: Each of the following statements applies unless explicitly stated otherwise in the detailed descriptions that follow: If an argument to a function has an invalid value (such as a value outside the domain of the function, or a pointer outside the address space of the program, or a null pointer, or a pointerto non-modifiable storage when the corresponding parameter is not const-qualified) or a type (after default argument promotion) not expected by a function with a variable number of arguments, the behavior is undefined. In particular, ROSE ensures that any pointer returned by malloc(), calloc(), or realloc() is first checked for NULL before being used (otherwise, it is free()-ed). Thanks for contributing an answer to Stack Overflow! You do not have permission to delete messages in this group, Either email addresses are anonymous for this group or you need the view member email addresses permission to view the original message. Reports. I reordered that code example to do all the checks before allocations. The above check can't hurt, as I guess you could have a system with a 32-bit size_t that had a ton of memory and had some crazy banking/selector scheme with pointers. You can compare a pointer with NULL to test for the special condition. With their flexibility, void pointers also bring some constraints. Is null check needed before calling instanceof? But the problem also exists in the compliant version, so I'm not so sure that it's really compliant. HTTP request redirections should not be open to forging attacks Deserialization should not be vulnerable to injection attacks Endpoints should not be vulnerable to reflected cross-site scripting (XSS) attacks "CoSetProxyBlanket" and "CoInitializeSecurity" should not be used Database queries should not be vulnerable to injection attacks Pointer Arithmetic in c - Unit - 4 1. Define pointer. Explain about the Here is our source code: Sign in to download full-size image Dereferencing a null pointer is undefined behavior. What is generic pointer? Does Java have support for multiline strings? See the "Null pointer checks may be optimized away more aggressively" section inhttps://gcc.gnu.org/gcc-4.9/porting_to.htmlas an example with one common implementation. But no where in that particular idiom would a NULL pointer necessarily be deferenced. How to get rid of NullPointerException - freeCodeCamp.org This is a matter of style, and also following code walkthrough. Identify where the allocation occurs. Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, SonarQube - Null Pointer Dereference Issue. specifies the length of the array for a function. LANG.MEM.NPDLANG.STRUCT.NTADLANG.STRUCT.UPD, Null pointer dereferenceNull test after dereferenceUnchecked parameter dereference, Can detect violations of this rule. Extended Description NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions. So we have to check all the arguments before performing any actions. Pointers in C Explained - They're Not as Difficult - freeCodeCamp.org In the case of the ARM and XScale architectures, the 0x0 address is mapped in memory and serves as the exception vector table; consequently, dereferencing 0x0 did not cause an abnormal program termination. U1 merged - It is a great text book for learning about linux devices. Cause we need throw our own Runtime Exception, well-known methods wont help. Can you please start a new thread and be more explicit about the issue you are observing. Sonar detects that res.getBody() can be null when you do the check res.getBody()==null. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Find centralized, trusted content and collaborate around the technologies you use most. One could argue that all code examples would be redundant with the first pair. String *x, y; X is a pointer to a string, Y is a string & = address of variable/ operator || referencing operator * = value of address || dereferencing operator Pointers = stores memory address as its variables NULL pointer = a constant with a value of zero defined || assigned to null Void pointer = a pointer that is not associated with any data types New operator = denotes a request for . I added an assertion to that compliant code example. I say "theoretical" because I have not successfully produced strings of this length in testing. Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. Now (sonarqube java analyzer version 4.3.0.7717) it's supported and works fine. The method isNR (minRating) is a helper method that validate among other things, if the object minRating is null public boolean isNR (AgencyRating rating) { return rating == null || isNR (rating.getRatgCaam ()); } When I added the not null validation as sonar suggest. Does it just mean failing to correctly check if a value is null? Your assertion is not backed by the wording in the standard, nor by common implementer understanding. raiseException() return, Sonar Using Kolmogorov complexity to measure difficulty of problems? I could've fixed this by changing else to else if (B != null && B.length == 1), but doing so rewards me with warning "condition(B != null && B.length == 1) is always true". , RemoteContext new ExceptionType() RemoteContext , SonarLintJava (), java - sonarLint "Null pointers should not be dereferenced (squid:S2259)"Stack Overflow name result . I have a sonar alert on this call minRating.getRatgCaam(). Does Counterspell prevent from any further spells being cast on a given turn? Much like dereferencing a dangling (or wild) pointer leads to undefined behavior, dereferencing a null pointer also leads to undefined behavior. // <------- reported violation: NullPointerException might be thrown as 'bar' is nullable here, https://jira.sonarsource.com/browse/SONARJAVA-1490, https://groups.google.com/d/msgid/sonarqube/4752a999-246e-42c2-bbdc-8a44a5564ce9%40googlegroups.com. The standard will simply copy 0 byteswhich is essentially a no-op. Pittsburgh, PA 15213-2612 Batch split images vertically in half, sequentially numbering the output files, Difficulties with estimation of epsilon-delta limit proof, Minimising the environmental effects of my dyson brain. All rights are expressly reserved. Because a null pointer does not point to a meaningful object, an attempt to dereference(i.e., access the data stored at that memory location) a null pointer usually (but not always) causes a run-time error or immediate program crash. Possible fix: Assign a valid address to the pointer in all branches of the conditional statement.. Pointer can point to dynamically allocated memory. Good question! Because null pointer dereferencing is undefined behavior, the compiler (GCC in this case) can optimize away the if (!tun) check because it is performed after tun->sk is accessed, implying that tun is non-null. Not the answer you're looking for? My question is; is my solution incorrect? References, C++ FAQ Why does the second compliant example permit using possibly-null pointers? At worst, it could expose debugging information that would be useful to an attacker or it could allow an However, memory allocation > functions such as kstrdup() may fail and returns NULL. In the code, we check the not nullity with java.util.Objects.nonNull(). Thanks for your relpy. Is there a single-word adjective for "having exceptionally strong moral principles"? By explicitly teaching the C++ standard class behaviors we can make the Analyzer to find more bugs related to modern C++ code. The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. ability to run any cleanup processes. (C11, S7.24.2.1). Alternate Terms Relationships () How can I check before my flight that the cloud separation requirements in VFR flight rules are met? As for today, the SE engine is able to explore non-overridable methods (static, for instance), when declared in the same file being analyzed. 4500 Fifth Avenue Replacing broken pins/legs on a DIP IC package, Bulk update symbol size units from mm to map units in rule-based symbology, How do you get out of a corner when plotting yourself into a corner. To learn more, see our tips on writing great answers. The value 0 for the number of bytes to copy is not what causes the UB, it's the null pointer value which triggers it. the Java one). What does "Could not find or load main class" mean? The 4gig boundary will probably be important too with unsigned int in LP64, but since size_t will be 64-bit, there will have to be some truncation that compilers will be able to warn on. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. util.regex.Matcher, java - Swing .getParent() . For example the following program doesn't compile. At best, such an exception will cause abrupt program termination. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence?