The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). Sonar is ok. When exploring such methods, the engine then deduces behaviors regarding null-checking (among other things). The alert is related to the sonar rule : Null pointers should not be dereferenced. This issues is displayed by SonarQube. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? LANG.MEM.NPDLANG.STRUCT.NTADLANG.STRUCT.UPD, Null pointer dereferenceNull test after dereferenceUnchecked parameter dereference, Can detect violations of this rule. Null pointers should not be dereferenced (#42) Issues - GitLab Two null pointers will always be equal to each other. At best, such an exception will cause abrupt program termination. java Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. Appropriate typecasting is necessary. Optimizers are optimizing based on this latitude and have been for years. This will normally lead to an unhandled error, resulting in a segmentation fault. Off by one error: It is the third example. Removing the check "exception != null" raises S2259 "Null pointers should not be dereferenced" on "throw exception". sonarqube Fix S2583/S2589 FP: On null check if instance is used in try block - GitHub In order to fix this, just do the following: BodyType body=res.getBody (); if (body == null || body.getServiceResult () == null) { return; } You can then even reuse body after that. Thanks, David! 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. EXP34-C. Do not dereference null pointers - Confluence Is null check needed before calling instanceof? Is a PhD visitor considered as a visiting scholar? We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. Recovering from a blunder I made while emailing a professor. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? Is it possible to create a concave light? Good question! At best, such an exception will cause abrupt program termination. Some Interesting Facts: 1) void pointers cannot be dereferenced. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. 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. 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. Which version of SonarJava plugin do you have? There is no legitimate reason to dereference a null pointer unless you on a rare system that maps page zero (or you intend your program to crash). // <------- 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. So no checking of the length is necessary (besides preventing integer overflow, which the compliant solution does). Your assertion is not backed by the wording in the standard, nor by common implementer understanding. NullPointerException is a RuntimeException. Now (sonarqube java analyzer version 4.3.0.7717) it's supported and works fine. C# static code analysis: Null pointers should not be dereferenced How can we let this pass? squid:S2259 : A "NullPointerException" could be thrown; "dc" is Doing so will cause a NullPointerException to be thrown. . C static code analysis: Null pointers should not be dereferenced C static code analysis Unique rules to find Bugs, Vulnerabilities, Security Hotspots, and Code Smells in your C code All rules 311 Vulnerability 13 Bug 74 Security Hotspot 18 Code Smell 206 Quick Fix 14 Tags "memset" should not be used to delete sensitive data Vulnerability If you preorder a special airline meal (e.g. Review and Fix Illegally Dereferenced Pointer Checks 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). We. I believe in this case, either expression would work. Why void pointer cannot be dereferenced? Explained by Sharing Culture Unfortunately the problem is much more complex, and generally unsolvable within standard C. Consider the following example: There's no way f can check whether x points into valid memory or not. 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. 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. . rev2023.3.3.43278. MSBuild SonarQube Runner Resharper Plugin receives skipping info errors File not in sonarqube, SonarQube jenkins plugin returns "Server returned HTTP response code: -1, message: 'null' for URL: https://api.github.com/user", SonarQube: Ignore issues in blocks not working with regex, sonarLint complains "Null pointers should not be dereferenced (squid:S2259)" despite that possibility being handled, Java: (false?) versions used (SonarQube, Scanner, language analyzer) IDE extension that lets you fix coding issues before they exist! Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. I suggest that this topic needs to include calloc() and realloc() Refer to Linux man pages online for more enlightenment about malloc(), and friends. NULL vs Void Pointer - Null pointer is a value, while void pointer is a type. How to get rid of NullPointerException - freeCodeCamp.org Linear regulator thermal information missing in datasheet, Identify those arcade games from a 1983 Brazilian music video. Solution 1, it looks like, today's solution tomorrow's problem. At this point we define size as strlen(input_str) + 1. PDF Fourth Coccinelle Workshop { Exercises If you try to access any member variables or methods with that variable, you are trying to dereference it. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. The fact that you can't pass a null (no object) with a reference parameter can be a reason to use a pointer instead. assert(!invalid(p)); // or whatever, bool invalid(const void *p) { null(java.lang.NullPointerException) . This solution also ensures that theuser_data pointer is not null. What is a serialVersionUID and why should I use it? C static code analysis: Null pointers should not be dereferenced Your code needs to do something about the possible NullPointerException when some exception is caught, because in this scenario the responseDto will be null. 4. It also uses the unsigned type size_t to pass the length parameter, ensuring that negative values are not passed to func(). After that, you call res.getBody() again. At You're in a company-managed project. 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. Thanks for contributing an answer to Stack Overflow! Do not dereference null pointers Created by Jeffrey Gennari, last modified by Jill Britton on Jan 18, 2023 Dereferencing a null pointer is undefined behavior. ncdu: What's going on with this second size column? attacker to bypass security measures. On many platforms, dereferencing a null pointer results in abnormal program termination, but this is not required by the standard. The null concept refers to the idea that a pointer can hold a special value that is not equal to another pointer. 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. sonarLint (3.2.) Batch split images vertically in half, sequentially numbering the output files, Recovering from a blunder I made while emailing a professor. If that variable hasn't had a reference assigned, it's a null reference, which (for internal/historical reasons) is referred to as a null pointer. Write a semantic patch to nd cases where the result of calling kmalloc is dereferenced with no previous NULL pointer test. Isn't easier just to check valid range of length? I think "res.getBody() == null" checks null first so it should go to return line, not reach to next if condition. How to deal with "java.lang.OutOfMemoryError: Java heap space" error? Why do academics stay as adjuncts for years rather than move around? Thanks for contributing an answer to Stack Overflow! All content is copyright protected. What should you do if somebody passes a null pointer for a parameter In C/C++ speak, 'dereferencing' simply means getting the object that a pointer . The purpose of a NULL pointer is not to cause a processor exception when it is dereferenced (although that is nice to have for debugging.) Likewise, pointers to freed memory are not valid. Are there tables of wastage rates for different fruit and veg? name result . Seems the analizer don't recognice the logic with the funcional object Optional. Pittsburgh, PA 15213-2612 Why does the second compliant example permit using possibly-null pointers? Possible fix: Assign a valid address to the pointer in all branches of the conditional statement.. Pointer can point to dynamically allocated memory. 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. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Calls to extension methods are not reported because they can still operate on null values. Is it possible to create a concave light? "After the incident", I started to be more careful not to trip over things. New replies are no longer allowed. This is indeed an obvious False Positive from the rule. strongSwan - strongSwan Vulnerability (CVE-2023-26463) I've changed it to say null pointer instead of invalid pointer. Much like dereferencing a dangling (or wild) pointer leads to undefined behavior, dereferencing a null pointer also leads to undefined behavior. - the incident has nothing to do with me; can I use this this way? Hi @Michael! Whats the grammar of "For those whose stories they are"? How to use java.net.URLConnection to fire and handle HTTP requests, Why should Java 8's Optional not be used in arguments, sonarLint complains "Null pointers should not be dereferenced (squid:S2259)" despite that possibility being handled. Small typo nit: "such as if i t pointed to freed memory" meant to say "if it" instead (removing whitespace). (from res.getBody().getServiceResult() ). But passing 0 to memcpy() is not one of them. Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. Phew, we're agreed here. Making statements based on opinion; back them up with references or personal experience. SonarJava Version 5.9.2 (build 16552). The article easily misleads the reader into believeing that ensuring pointer validity boils down to checking for pointer being not equal to NULL. 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. Check whether a String is not Null and not Empty. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to . I am a student implementing stack with singly linked list using C, following a book called Fundamentals of Data Structures in C.. A null pointer in this position causes the read system call to fail with -EINVAL ("Invalid argument"). Null pointers should not be dereferenced. How to tell which packages are held back due to phased updates. Coverity Prevent cannot discover all violations of this rule, so further verification is necessary, Detects when NULL is dereferenced (Array of pointers is not checked. Carnegie Mellon University 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 . Best to cite C11 s7.24.2.1 here: The memcpy function copies n characters from the object pointed to by s2 into the object pointed to by s1. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, Sonar false-positive on rule: Null pointers should not be dereferenced, Null Pointer Dereference issue not detected when the pointer is returned by another function. I have checked on multiple . 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. () References, C++ FAQ I reordered that code example to do all the checks before allocations. Hello. Why are physically impossible and logically impossible concepts considered separate in terms of probability? To learn more, see our tips on writing great answers. Find null smart pointer dereferences with the Clang Static Analyzer The null pointer check for writing or dereferencing should be a compiler flag or library setting. We have a false positive with the " Null pointers should not be dereferenced -squid:S2259" rule : We have a "NullPointerException" false positive for which we do not know how to solve it. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Is there a solution to add special characters from software and how to do it, Acidity of alcohols and basicity of amines. 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. This is a matter of style, and also following code walkthrough. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. Mutually exclusive execution using std::atomic? I don't need to do this validation again. This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. "After the incident", I started to be more careful not to trip over things. Instead use String.valueOf (object). Pointer is so confusing : Stack with singly linked list in C - Stack Made code more compliant with other rules. There are other problems with this code, as is noted in the rule. sometimes FP occurs. Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. The return value from strchr() is often NULL, but the dev might know that a specific strchr() function call will not return NULL. which version of SonarQube are you using? When length is zero, it is probably unusable condition for this function. Thanks for contributing an answer to Stack Overflow! Search for vulnerabilities resulting from the violation of this rule on the CERT website. (I think you cover that in a different rule.) What is a NullPointerException, and how do I fix it? You're in a company-managed project. How can this new ban on drag possibly be considered constitutional? Automated Detection Null pointer dereferences can happen in path-dependent ways. Issues Components. Null pointer - Wikipedia 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 However there is no portable way to verify that the pointer is valid, other than checking for null. 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. That's true. That noncompliant code example (it's currently the 3rd) came from the Linux kernel, whose source is publicly available. 11 Sep, 2006. When I added the not null validation as sonar suggest. vegan) just to try it, does this inconvenience the caterers and staff? It means this is illegal: T* p = nullptr; T& r = *p; // illegal NOTE: Please do not email us saying the above works on your particular version of your particular compiler. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, SonarQube null pointers should not be dereferenced on try/catch, How Intuit democratizes AI development across teams through reusability. Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, S2259: Null pointers should not be dereferenced, find the list of whitelisted methods here, Rule java:S2259: False-positive NullPointerException bug logged when variable is null-checked by an imported method, What is the issue you are observing, in details, What version of SonarSource products you are using, as well as the version of SonarJava. Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. The correct idiom is to only allocate storage if the pointer is currently NULL. We might set a pointer to null even if we are not freeing a object, simply to dissociate one object from another: tty_driver->tty = NULL; /* detach low level driver from the tty device */ There are many ways to resolve this. This likely means that youre on an ancient version of the Java analyzer. Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, SonarQube - Null Pointer Dereference Issue. 1. Introduction - Understanding and Using C Pointers [Book] Its purpose is to serve as a special value for a pointer that could indicate a special condition in your program. io.NotSerializableException : java. In the code, we check the not nullity with java.util.Objects.nonNull(). Making statements based on opinion; back them up with references or personal experience. What does it mean that a reference must refer to an object, not a dereferenced null pointer? Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Reports. ii. A common memory-leak idiom, is reallocating storage and assigning its address to a pointer that already points to allocated storage. Unfortunately, its actual state also has some limitations, like the one you are hitting here. Here is our source code: Sign in to download full-size image Handling Java NullPointerException and Best Practices - HowToDoInJava Share Improve this answer Follow answered Oct 5, 2017 at 16:27 A non-null but invalid pointer passed to memcpy() can indeed cause undefined behavior, but that is not the issue in the noncompliant codethe pointer will either be valid or null. What is null pointer exception in android. A NULL pointer can be dereferenced when signatures are being verified on PKCS7 signed or signedAndEnveloped data. 0 is certainly within the 'domain of the function' (a phrase defined by mathematics but not by C11), as copying 0 bytes is well-understood (although silly). sonar-java. static-code-analysis Im very new to sonar, is there a way to add methods to the whitelist? [JAVA] 3.9 - FP for S2259 Null pointers should not be dereferenced So you can declare a string t and then add characters to the string with a plus sign : t += 'a'; The code you are having issue with is just moving the pointer to the next character which the foreach is already doing. Description The program can potentially dereference a null pointer, thereby raising a NullPointerException. To learn more, see our tips on writing great answers. Passing ownership of something also requires pointers. 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. context.RaiseException , (/) Void pointers cannot be dereferenced as any other pointer. What is pointed to should only be deleted if it was created with new. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? I suppose there is a question of "Is a pointer that points to 0 bytes valid?" public boolean isNameEmpty() { return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked } . Null Dereference | OWASP Foundation Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. java - sonarLint "Null pointers should not be . Find centralized, trusted content and collaborate around the technologies you use most. raiseException() return, Sonar very old code or C code being worked into c++ may have functions that expect the user to delete the data. Dereferencing > this null pointer may cause the kernel go wrong. 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. 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. COMP-PROG-MODULE-5-6-REVIEWER.pdf - Pointers to string SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. 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. Just a few words about the rule now. 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. [RSPEC-2259] - Jira Dereferencing a null pointer can lead to a denial of service. Software Engineering Institute To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, how to handle Sonarlint java:S2259 (Null pointers should not be dereferenced), How Intuit democratizes AI development across teams through reusability. Then we hit memcpy with length 0. How to use Slater Type Orbitals as a basis functions in matrix method correctly? }. This engine is validating execution paths and checking for non-null values or null-check along the way, exploring all the possibilities. For the time being, I would unfortunately recommend to mark as False Positive the issue. VB.NET static code analysis: Null pointers should not be dereferenced Powered by Discourse, best viewed with JavaScript enabled. Why pointers are not used in python? Explained by Sharing Culture Null Pointer Exception In Java - GeeksforGeeks - A computer science Is the God of a monotheism necessarily omnipotent? U1 merged - It is a great text book for learning about linux devices. Identify where the allocation occurs. These can be: Invoking a method from a null object. What does "Could not find or load main class" mean? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide.