Carnegie Mellon University Connect and share knowledge within a single location that is structured and easy to search. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. All rights are expressly reserved. Believing that dereferencing NULL shouldn't crash the system doesn't make it true. Calls to extension methods are not reported because they can still operate on null values. 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. There can be a null pointer type for each pointer type, such as a pointer to a character or a pointer to an integer, although this is . Good question! When you have a variable of non-primitive type, it is a reference to an object. What is the point of Thrower's Bandolier? PS: I also tried the code in android studio which uses Lint and got no warnings. Doing so will at best cause abrupt program termination, without the 1. Introduction - Understanding and Using C Pointers [Book] Callable statement giving Null Pointer Exception - Oracle Forums Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, SonarQube - Null Pointer Dereference Issue. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to bypass security measures. 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. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. Not the answer you're looking for? If you try to access any member variables or methods with that variable, you are trying to dereference it. Clearly the standard enumerates 1 case of undefined behavior, but makes no special mention of n=0. PS: I also tried the code in android studio which uses Lint and got no warnings. 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. Ticket opened : Thanks a lot for the minimalized reproducer ! Dereferencing a null pointer can lead to a denial of service. Finally, there is the matter of the compliant solution. IDE extension that lets you fix coding issues before they exist! In some situations, however, dereferencing a null pointer can lead to the execution of arbitrary code [Jack 2007,van Sprundel 2006]. Your code needs to do something about the possible NullPointerException when some exception is caught, because in this scenario the responseDto will be null. Null pointers should not be dereferenced (#42) Issues - GitLab A nonnegative return value represents the number of bytes successfully read (the return value is a "signed size" type, usually the native integer type for the target platform). Consider the following scenario: you are asked to create a Java class MetaDisplay that contains a static void printTable(String r) method. This engine is validating execution paths and checking for non-null values or null-check along the way, exploring all the possibilities. Pointer members in structs are not checked. The chunkdata pointer is later used as a destination argument in a call to memcpy(), resulting in user-defined data overwriting memory starting at address 0. My question is; is my solution incorrect? Thanks for contributing an answer to Stack Overflow! Not the answer you're looking for? After that, you call res.getBody() again. This sounds indeed like a bug in the flow when an exception is raised. I'd guess WG14 has considered these questions, but I haven't until now :). In layman's terms, a null pointer is a pointer to an address in the memory space that does not have a meaningful value and cannot be referenced by the calling program, for whatever reason. {"serverDuration": 214, "requestCorrelationId": "084acdc104f21c51"}, EXP34-C. Do not dereference null pointers, Clever Attack Exploits Fully-Patched Linux Kernel, ERR33-C. Detect and handle standard library errors, one compliant and one non-compliant example, CERT Oracle Secure Coding Standard for Java, EXP01-J. Null Pointer So, this code should address the Sonar problem: You can also eliminate the null check using Optional>, like: Even I don't recommend this, you can just check the null responseDto without any use of Optional: Thanks for contributing an answer to Stack Overflow! which would allow us to systematically observe what you are having. sonar_etReines-CSDN We. (In contrast, the case of passing 0 bytes to malloc is addressed in C11.) FindBugs CORRECTNESS - It's a modular system with the . The null pointer check for writing or dereferencing should be a compiler flag or library setting. 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). What is generic pointer? The correct idiom is to only allocate storage if the pointer is currently NULL. validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. Things go fine now. raiseException() return, Sonar This compliant solution ensures that both input_str andthe pointer returned by malloc() are not null: This noncompliant code example is from a version of drivers/net/tun.c and affects Linux kernel 2.6.30 [Goodin 2009]: The sk pointer is initialized to tun->sk before checking if tun is a null pointer. The result of calling such a helper function should be . Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. The user_data pointer could be invalid in other ways, such as pointing to freed memory. There are many ways to resolve this. Null pointer should not be dereferenced . We resolved it by adding our tools path in the white list, and repackaging it. Does it just mean failing to correctly check if a value is null? sonarlint complains that This is indeed an obvious False Positive from the rule. 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" What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? Can you please start a new thread and be more explicit about the issue you are observing. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Null pointers should not be dereferenced. Can I tell police to wait and call a lawyer when served with a search warrant? Extended Description NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions. rev2023.3.3.43278. Void pointers cannot be dereferenced as any other pointer. Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. Because null pointer dereferencing is UB, the if (!tun) check can be elided entirely by the optimizer (since the tun->sk implies that tun must be non-null). S2259: Null pointers should not be dereferenced - Sonar Community [JAVA] 3.9 - FP for S2259 Null pointers should not be dereferenced Sonar detects that res.getBody() can be null when you do the check res.getBody()==null. C# static code analysis: Null pointers should not be dereferenced Products In-IDE IDE extension that lets you fix coding issues before they exist! 1 Answer Sorted by: 1 Your code is ok. 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. Note that it doesn't know how to check for non-heap, non-stack. JCP version in use: 2.6. Depending on whether the pointer is valid (i.e. Isn't easier just to check valid range of length? SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. Obviously the value of that pointer could have changed since the . 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. [SONARJAVA-2808] - Jira - SonarSource Is it suspicious or odd to stand by the gate of a GA airport watching the planes? Much like dereferencing a dangling (or wild) pointer leads to undefined behavior, dereferencing a null pointer also leads to undefined behavior. In case the hash algorithm used for the signature is known to the OpenSSL library but the implementation of the hash algorithm is not available the digest initialization will fail. Fix S2583/S2589 FP: On null check if instance is used in try block - GitHub I added an assertion to that compliant code example. In my experience, there are reasons to check for a NULL pointer other than dereferencing it. This latter use of pointers is a combined boolean/satellite: the pointer being non-null indicates "I have this sister object", and it provides that object. We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. Sonar is ok. I suppose we can check that that is not null, but we cannot check that it is valid (in any portable way). 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. // <------- 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. ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . All rights are expressly reserved. 1 Null pointers should not be dereferenced @CheckForNull String getName(){.} 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.. 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. Write a semantic patch to nd cases where the result of calling kmalloc is dereferenced with no previous NULL pointer test. How to get rid of NullPointerException - freeCodeCamp.org the Java one). Why void pointer cannot be dereferenced? Explained by Sharing Culture Sonar false-positive on rule: Null pointers should not be dereferenced Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. . The solution that I recommend is not work with null returns or variables on Java, try to avoid it. Does Counterspell prevent from any further spells being cast on a given turn? Why does Mister Mxyzptlk need to have a weakness in the comics? By 'valid pointers' I mean that both src and dest pointers are not null and they both point to non-overlapping arrays containing at least n bytes each. If you preorder a special airline meal (e.g. specifies the length of the array for a function. null(java.lang.NullPointerException) . 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. S2259: Null pointers should not be dereferenced java tsubasa (Jiaoyang Ma) January 11, 2019, 6:57am 1 versions used (SonarQube, Scanner, language analyzer) SonarQube Version 6.7.2 (build 37468) SonarJava Version 5.9.2 (build 16552) minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). Is there a single-word adjective for "having exceptionally strong moral principles"? can have the value zero on a call to that function. I think that checking for user_data being NULL would be an improvement to the CS so long as there is an explicit mention that user_data being NULL is invalid even if length == 0. Asking for help, clarification, or responding to other answers. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 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, This error was found in the following code: else if (foo.list().length > 0) { }, I attempted to resolve this by rewriting as: else if (null != foo.list() && foo.list().length > 0) { }, foo is an instance of the File class in Java, and is directly instantiated through new File(). Phew, we're agreed here. This rule applies to all null pointers, regardless of which function returned them. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? . Not the answer you're looking for? 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 Software project. IMHO, the rule title should be changed to something less general. The article easily misleads the reader into believeing that ensuring pointer validity boils down to checking for pointer being not equal to NULL. In this noncompliant code example, input_str is copied into dynamically allocated memory referenced by c_str. Answered: difference between a void pointer and a | bartleby That is why I explicitly check for this in my attempted solution. Removing the check "exception != null" raises S2259 "Null pointers should not be dereferenced" on "throw exception". That noncompliant code example (it's currently the 3rd) came from the Linux kernel, whose source is publicly available. At https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx Aaron:I suspect we are talking past each other. Pittsburgh, PA 15213-2612 Likewise, pointers to freed memory are not valid. res.getBody() == null || res.getBody().getServiceResult() == null). Trying to understand how to get this basic Fourier Series. Null pointers should not be dereferenced #1155 - GitHub 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. Haiku is a free and open-source operating system for PC designed to be binary compatible with the BeOS operating system and embodying the basic ideas of BeOS. Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. 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. The approximation of the try catch flow is such that we consider an exception can be thrown just after the curly brace of the try. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. To create a custom null validation method declare an attribute with name ValidatedNotNullAttribute and mark the parameter that is It is still a pointer though, to use it you just have to cast it to another kind of pointer first. Pointer is so confusing : Stack with singly linked list in C - Stack Styling contours by colour and by line thickness in QGIS. What is a serialVersionUID and why should I use it? I say "theoretical" because I have not successfully produced strings of this length in testing. When B is null, The control reaches inside the main if block only when length of A is 1. isEmpty(Collection collection) NullPointerException is a RuntimeException. This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. We can get a reference to point to null in the following ways: "uninitialized" reference type variables variables which are initialized with nulls and are assigned their real value afterward. What are the effects of exceptions on performance in Java? The idea is not to guarantee validity, but to catch a substantial number of problems that could occur. (in the meantime, in case of any other false-positive suspicion, make sure to check those latest versions as bunch of improvements are regularly released). If copying takes place between objects that overlap, the behavior is undefined. Java Specification Participation Agreement version in use: 2.0. Handling Java NullPointerException and Best Practices - HowToDoInJava So Bar might not be initialized but then the last line of your example should not be evaluated in this case. When exploring such methods, the engine then deduces behaviors regarding null-checking (among other things). Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? Cause we need throw our own Runtime Exception, well-known methods wont help. When and how should I use a ThreadLocal variable? Made code more compliant with other rules. NULL POINTERS SHOULD NOT BE DEREFERENCED - jobhuntley.com Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, It is a false positive, but it might be a good idea not to do the, Sonar false-positive on rule: Null pointers should not be dereferenced, How Intuit democratizes AI development across teams through reusability. 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. C# static code analysis: HTTP responses should not be vulnerable to But the problem also exists in the compliant version, so I'm not so sure that it's really compliant. 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. This code also violates ERR33-C. Detect and handle standard library errors. - the incident has nothing to do with me; can I use this this way? Thus we should check > this kstrdup() operation. Now (sonarqube java analyzer version 4.3.0.7717) it's supported and works fine. 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. Is it possible to create a concave light? To learn more, see our tips on writing great answers. (/). U1 merged - It is a great text book for learning about linux devices. Why are physically impossible and logically impossible concepts considered separate in terms of probability? [RSPEC-2259] - Jira 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 NULL pointer can be dereferenced when signatures are being verified on PKCS7 signed or signedAndEnveloped data. [squid:S2259] False positive - "Null pointers should not be dereferenced" Additionally, if input_str is a null pointer, the call to strlen() dereferences a null pointer, also resulting in undefined behavior. In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. This is indeed a false positive because, at time of writing, the sonarqube java analyzer (version 4.2.1 at time of writing) does not support cross procedural analysis and so it is not able to determine that indeed, for the condition to be true, the value of minRating has to be non null. Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. I would also guess that pointers that point to the one-past-the-end of an array are also invalid. 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). Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. isEmpty(Map map) Fixed by #1156 Contributor 94cb5f8 boris-unckel on Jul 28, 2021 9e62550 boris-unckel mentioned this issue on Jul 28, 2021 Closes #1155 - Null pointers should not be dereferenced #1156 Merged Dereferencing > this null pointer may cause the kernel go wrong. Is a PhD visitor considered as a visiting scholar? Then we hit memcpy with length 0. java - sonarLint "Null pointers should not be Discover SonarLint SaaS Setup is effortless and analysis is automatic for most languages Discover SonarCloud Self-Hosted Fast, accurate analysis; enterprise scalability Discover SonarQube Secrets ABAP If you say [in] or [out] without a modifier, then the modifier defaults to the pointer_default for the enclosing class. int changed to size_t and if size_t parameter's is zero, allocate one word. 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 (?,?,?,?,?,?,?,? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Not the answer you're looking for? On many platforms, dereferencing a null pointer results in abnormal program termination, but this is not required by the standard. Why pointers are not used in python? Explained by Sharing Culture It's even called out explicitly in C17 7.24.1p2: Where an argument declared as size_t n specifies the length of the array for a function, n can have the value zero on a call to that function. Thanks for contributing an answer to Stack Overflow! 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.

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