Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Consider the following scenario: you are asked to create a Java class MetaDisplay that contains a static void printTable(String r) method. , RemoteContext new ExceptionType() RemoteContext , SonarLintJava (), java - sonarLint "Null pointers should not be dereferenced (squid:S2259)"Stack Overflow How to get rid of NullPointerException - freeCodeCamp.org IDE extension that lets you fix coding issues before they exist! 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). If the project is not compiled, and without sonar.java.binaries whether the white list takes effect? When I added the not null validation as sonar suggest. 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. 2008-2023 SonarSource S.A., Switzerland. Is it possible to create a concave light? Thanks, David! Is there a single-word adjective for "having exceptionally strong moral principles"? Phew, we're agreed here. This topic was automatically closed 7 days after the last reply. That is, sets equivalent to a proper subset via an all-structure-preserving bijection. rev2023.3.3.43278. ), NPD.CHECK.CALL.MIGHTNPD.CHECK.CALL.MUSTNPD.CHECK.MIGHTNPD.CHECK.MUSTNPD.CONST.CALLNPD.CONST.DEREFNPD.FUNC.CALL.MIGHTNPD.FUNC.CALL.MUSTNPD.FUNC.MIGHTNPD.FUNC.MUSTNPD.GEN.CALL.MIGHTNPD.GEN.CALL.MUSTNPD.GEN.MIGHTNPD.GEN.MUSTRNPD.CALLRNPD.DEREF, 45 D, 123 D, 128 D, 129 D, 130 D, 131 D, 652 S, Checks for use of null pointers (rule partially covered). 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. We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. Dereferencing a null pointer is undefined behavior, typically abnormal program termination. It could be non-null the first time but not the second time, sonar does not know this. void *pointerVariableName = NULL; Since they are very general in nature, they are also known as generic pointers. int changed to size_t and if size_t parameter's is zero, allocate one word. it could allow an attacker to bypass security measures. In the code, we check the not nullity with java.util.Objects.nonNull(). To learn more, see our tips on writing great answers. Then we hit memcpy with length 0. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. positive S2637 in SonarQube 6.7.1 LTS, Sonar false positive, "change condition so that it does not always evaluate to true. This is a matter of style, and also following code walkthrough. There are many ways to resolve this. It's a modular system with the . 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. Reports. As a result, this noncompliant code example is vulnerable to a null pointer dereference exploit, because null pointer dereferencing can be permitted on several platforms, for example, by using mmap(2) with the MAP_FIXED flag on Linux and Mac OS X, or by using the shmat() POSIX function with the SHM_RND flag [Liu 2009]. Many platforms can support testing for those also. These can be: Invoking a method from a null object. Null pointer - Wikipedia 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.. 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. The correct idiom is to only allocate storage if the pointer is currently NULL. Sonar violation: Null pointers should not be dereferenced #7459 - GitHub Trying to understand how to get this basic Fourier Series. See "Clever Attack Exploits Fully-Patched Linux Kernel" [Goodin 2009] for an example of a code execution exploit that resulted from a null pointer dereference. That's true. 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.) We. You're in a company-managed project. C static code analysis: Null pointers should not be dereferenced [PATCH v2] vsprintf: Do not have bprintf dereference pointers Optimizers are optimizing based on this latitude and have been for years. And the compliant solution guarantees that the pointer will be valid if the code calls memcpy(). minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). Iflengthhas the value1, the addition yields 0, and png_malloc() subsequently returns a null pointer, which is assigned to chunkdata. Using platform-specific means (e.g. squid:S2259 : A "NullPointerException" could be thrown; "dc" is So we have to check all the arguments before performing any actions. Interactions/interfaces with C can't use references. Making statements based on opinion; back them up with references or personal experience. We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. Just a few words about the rule now. The null concept refers to the idea that a pointer can hold a special value that is not equal to another pointer. Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. Im currently using SonarQube version 5.6.6. better way to handle this is to store the result of method invocation in a variable. Avoid Returning null from Methods. Carnegie Mellon University Agreed. public boolean isNameEmpty() { return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked } . Is there a proper earth ground point in this switch box? Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. [JAVA] 3.9 - FP for S2259 Null pointers should not be dereferenced raiseException() return, Sonar Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx If the pointer is not NULL, see if the assignment occurs only in a branch of a conditional statement.Investigate when that branch does not execute. (In contrast, the case of passing 0 bytes to malloc is addressed in C11.) Should trycatch go inside or outside a loop? 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. 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. uninitialized reference-type class members. Powered by Discourse, best viewed with JavaScript enabled. The standard will simply copy 0 byteswhich is essentially a no-op. Doing so will cause a NullReferenceException to be thrown. For the time being, I would unfortunately recommend to mark as False Positive the issue. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 9.7 Null pointers - Learn C++ - LearnCpp.com The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. When a variable is declared as being a pointer to type void, it is known as a generic pointer. EXP01-J. Do not use a null in a case where an object is required the Java one). By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. The only potential null is the return value of list(). 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. Alternate Terms Relationships in above code, By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Whats the grammar of "For those whose stories they are"? 3.7. 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(). The expected result here is solve the issue with sonarqube. Trying to understand how to get this basic Fourier Series. Clearly the standard enumerates 1 case of undefined behavior, but makes no special mention of n=0. [PATCH 1/3] usb: ucsi: Fix NULL pointer deref in ucsi_connector_change() I'd guess null pointers are not valid, even though they point to 0 bytes. When B is null, The control reaches inside the main if block only when length of A is 1. NullPointerException is a RuntimeException. What is null pointer exception in android Smartadm.ru SonarQube - Null Pointer Dereference Issue java simonsirak (Simon Sirak) June 14, 2018, 1:18pm 1 Hi! SonarQube Version 6.7.2 (build 37468) Original Java Specification Request (JSR) - Java Community Process I suppose there is a question of "Is a pointer that points to 0 bytes valid?" Your assertion is not backed by the wording in the standard, nor by common implementer understanding. 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. But what exactly does it mean to "dereference a null pointer"? In the meantime, Im locking this thread. This sounds indeed like a bug in the flow when an exception is raised. This sounds indeed like a bug in the flow when an exception is raised. Is a PhD visitor considered as a visiting scholar? Description The program can potentially dereference a null pointer, thereby raising a NullPointerException. Calls to extension methods are not reported because they can still operate on null values. 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. rev2023.3.3.43278. The problem is, I hope this code's result to be <5,3> and <9,6> BUT the console only shows me <5,3> and <9,3>. So the SIZE_MAX check was unnecessary. ), Does not guess that return values from malloc(), strchr(), etc., can be NULL (The return value from malloc() is NULL only if there is OOMo and the dev might not care to handle that. When I scan with sonar-lint in idea, it seams white list is useful, but when use sonar-scanner, always FP, org.springframework.util.CollectionUtils#isEmpty So no checking of the length is necessary (besides preventing integer overflow, which the compliant solution does). Essentially, this code and the previous dereference disagree as to whether this value is allowed to be null. 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 "After the incident", I started to be more careful not to trip over things. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? The solution that I recommend is not work with null returns or variables on Java, try to avoid it. sonarLint (3.2.) Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. My question is; is my solution incorrect? A pointer is simply a variable that contains a memory address. Here is our source code: Sign in to download full-size image If not, this might be a bug. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. null(java.lang.NullPointerException) . False fault 'Null pointers should not be dereferenced' using Optional 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. (from res.getBody().getServiceResult() ). Connect and share knowledge within a single location that is structured and easy to search. vegan) just to try it, does this inconvenience the caterers and staff? However there is no portable way to verify that the pointer is valid, other than checking for null. How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. Thanks for contributing an answer to Stack Overflow! Reference vs dereference pointers in arguments C++/C To learn more, see our tips on writing great answers. What is generic pointer? Sonar is ok. Sonar can't determine that the helper method did the null validation. Dereferencing > this null pointer may cause the kernel go wrong. The method isNR(minRating) is a helper method that validate among other things, if the object minRating is null. What is null pointer exception in android. Analysis of Haiku Operating System (BeOS Family) by PVS-Studio. Part 1 "After the incident", I started to be more careful not to trip over things. This solution also ensures that theuser_data pointer is not null. Why pointers are not used in python? Explained by Sharing Culture Cause we need throw our own Runtime Exception, well-known methods wont help. Hi @Michael! How can we prove that the supernatural or paranormal doesn't exist? SonarQube null pointers should not be dereferenced on try/catch 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. Isn't easier just to check valid range of length? (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). Do "superinfinite" sets exist? Is there a solution to add special characters from software and how to do it, Acidity of alcohols and basicity of amines. We can not disable any rule, sonar do validation in "Sonar way" (actual name of profile :) ), so we will need to mark them "Wont fix" each time it appear again in new code. Check whether a String is not Null and not Empty. Likewise, pointers to freed memory are not valid. 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 (?,?,?,?,?,?,?,? Null Dereference | OWASP Foundation 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. I have checked on multiple . Doing so will cause a NullReferenceException to be thrown. How to deal with "java.lang.OutOfMemoryError: Java heap space" error? FindBugs CORRECTNESS - The idea is not to guarantee validity, but to catch a substantial number of problems that could occur. It's still illegal. All content is copyright protected. 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. But the problem also exists in the compliant version, so I'm not so sure that it's really compliant. What does it mean that a reference must refer to an object, not a dereferenced null pointer? Just because something is a pointer does not mean you should call delete . Now (sonarqube java analyzer version 4.3.0.7717) it's supported and works fine. specifies the length of the array for a function. But no where in that particular idiom would a NULL pointer necessarily be deferenced. That makes sense. How can we let this pass? (/). Since you cannot have a variable of type void, the pointer will not point to any data and therefore cannot be dereferenced. 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. In the first compliant example it's useless to do allocation if the essential pointer user_data is NULL. res.getBody() == null || res.getBody().getServiceResult() == null). 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. Sonar: Null pointers should not be dereferenced - Stack Overflow Void pointers cannot be dereferenced as any other pointer. Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. Thanks for contributing an answer to Stack Overflow! Null Pointer Null pointer should not be dereferenced , Pointers in C Explained - They're Not as Difficult - freeCodeCamp.org Null Pointer Exception In Java - GeeksforGeeks - A computer science I feel my situation is not as complicated. Batch split images vertically in half, sequentially numbering the output files, Recovering from a blunder I made while emailing a professor. best, such an exception will cause abrupt program termination. Rule squid:S2259 is based on a Symbolic Execution (SE) engine. positive S2637 in SonarQube 6.7.1 LTS, SonarQube for MSBuild not reporting quality issues, getTextContent() through "Null pointers should not be dereferenced".
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