Mutually exclusive execution using std::atomic? (C11, S7.24.2.1). public boolean isNameEmpty() { return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked } . This will normally lead to an unhandled error, resulting in a segmentation fault. What methods/tools can be used to determine the cause so that you stop the exception from causing the progra. It is useful to have a function with portable interface but platform-dependent implementation: extern bool invalid(const void *); Good question! What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? I added a comment to explain that SIZE_MAX is the limit of size_t. The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. Dereferencing a null pointer is undefined behavior. When and how should I use a ThreadLocal variable? Status: Dormant. 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. Many platforms can support testing for those also. Is it possible to create a concave light? NULL vs Uninitialized pointer - An uninitialized pointer stores an undefined value. 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. So the SIZE_MAX check was unnecessary. This code also violates ERR33-C. Detect and handle standard library errors. return p == NULL || (char *)p < &_etext; Is it suspicious or odd to stand by the gate of a GA airport watching the planes? () The standard will simply copy 0 byteswhich is essentially a no-op. Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, SonarQube - Null Pointer Dereference Issue. This topic was automatically closed 7 days after the last reply. If you try to access any member variables or methods with that variable, you are trying to dereference it. Just because something is a pointer does not mean you should call delete . By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. There are many ways to resolve this. How to tell which packages are held back due to phased updates. When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. Find null smart pointer dereferences with the Clang Static Analyzer 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. Is the God of a monotheism necessarily omnipotent? rev2023.3.3.43278. Null pointers should not be dereferenced. 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 A bug can cause them never to be reassigned. ), 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. I guess you could write a proposal to modify the C Standard, but our coding standard is meant to provide guidance for the existing language. Explain about call by reference with an . 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. Issues Components. Description: This JSR will work to develop standard annotations (such as @NonNull) that can be applied to Java programs to assist tools that detect software defects. ii. > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. 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. Finally, there is the matter of the compliant solution. When B is null, The control reaches inside the main if block only when length of A is 1. [RSPEC-2259] - Jira 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. Interactions/interfaces with C can't use references. "After the incident", I started to be more careful not to trip over things. Software project. In C# and Java, all reference types can point to null. At best, such an exception will cause abrupt program termination. 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). The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. It looks like a logic bug, which can cause a memory leaking. It also uses the unsigned type size_t to pass the length parameter, ensuring that negative values are not passed to func(). What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? In the first compliant example it's useless to do allocation if the essential pointer user_data is NULL. We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. This is indeed an obvious False Positive from the rule. Finally my method is returning a response with value of restTemplate. Please explain: Without this, we wont be able to help you. It does not point to any area of memory. EXP34-C. Do not dereference null pointers - Confluence [squid:S2259] False positive - "Null pointers should not be dereferenced" IMHO, the rule title should be changed to something less general. Is it possible to rotate a window 90 degrees if it has the same length and width? Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? ncdu: What's going on with this second size column? Could I capture, and I would be able to glean much security information from the dump? (from res.getBody().getServiceResult() ). Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. If the project is not compiled, and without sonar.java.binaries whether the white list takes effect? 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. 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. SonarQube null pointers should not be dereferenced on try/catch Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. assert(!invalid(p)); // or whatever, bool invalid(const void *p) { To learn more, see our tips on writing great answers. The only potential null is the return value of list(). Sonar is ok. Null Dereference | OWASP Foundation https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx Do "superinfinite" sets exist? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 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. Pointer is so confusing : Stack with singly linked list in C - Stack 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 subscribe to this RSS feed, copy and paste this URL into your RSS reader. Hi @Michael! Is it possible to create a concave light? 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 the complaint version, I like to make source code checking a little quicker by putting parenthesizes around arguments to |= or &= as. Basically, yes. Not the answer you're looking for? So Bar might not be initialized but then the last line of your example should not be evaluated in this case. 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. 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. , RemoteContext new ExceptionType() RemoteContext , SonarLintJava (), java - sonarLint "Null pointers should not be dereferenced (squid:S2259)"Stack Overflow validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. A NULL pointer can be dereferenced when signatures are being verified on PKCS7 signed or signedAndEnveloped data. 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). This rule applies to all null pointers, regardless of which function returned them. Find centralized, trusted content and collaborate around the technologies you use most. Powered by Discourse, best viewed with JavaScript enabled. Share Improve this answer Follow answered Oct 5, 2017 at 16:27 Is there a single-word adjective for "having exceptionally strong moral principles"? How do I align things in the following tabular environment? 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. Obviously the value of that pointer could have changed since the . Null pointer should not be dereferenced . PS: I also tried the code in android studio which uses Lint and got no warnings. which version of SonarQube are you using? It also adds assertions to document that certain other pointers must not be null. - the incident has nothing to do with me; can I use this this way? context.RaiseException , (/) EXP01-J. Do not use a null in a case where an object is required (/). We cannot understand how there could be a null pointer exception at the reported line. There are many ways to resolve this. If not, this might be a bug. 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. And fwstr > is dereferenced in the following codes. Using Kolmogorov complexity to measure difficulty of problems? It's still illegal. The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). I would also guess that pointers that point to the one-past-the-end of an array are also invalid. 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>. Pointer members in structs are not checked. Thered be huge value in jumping onto the latest version of the ecosystem (notably SonarQube), and benefit from all latest analyzers (e.g. How to avoid dereferencing null pointers in Java - Quora Recovering from a blunder I made while emailing a professor. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? Answered: difference between a void pointer and a | bartleby COMP-PROG-MODULE-5-6-REVIEWER.pdf - Pointers to string 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! Clearly the standard enumerates 1 case of undefined behavior, but makes no special mention of n=0. 0 is a valid value as far as memcpy() is concerned, and malloc() has special language concerning malloc(0). The result of calling such a helper function should be . 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). 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. SonarJava Version 5.9.2 (build 16552). Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. Things go fine now. Some Interesting Facts: 1) void pointers cannot be dereferenced. Automated Detection Null pointer dereferences can happen in path-dependent ways. 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. 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 Optimizers are optimizing based on this latitude and have been for years. This issues is displayed by SonarQube. Thanks for contributing an answer to Stack Overflow! Callable statement giving Null Pointer Exception - Oracle Forums Instead use String.valueOf (object). That interpretation of the standard is not supported universally. isEmpty(Collection collection) Null Pointer Exception In Java - GeeksforGeeks - A computer science 11 Sep, 2006. sonarLint (3.2.) How can we prove that the supernatural or paranormal doesn't exist? Iflengthhas the value1, the addition yields 0, and png_malloc() subsequently returns a null pointer, which is assigned to chunkdata. FindBugs CORRECTNESS - [4] Thanks for contributing an answer to Stack Overflow! Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. When a variable is declared as being a pointer to type void, it is known as a generic pointer. PDF Fourth Coccinelle Workshop { Exercises 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. 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. 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. 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. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. That makes sense. Unfortunately, its actual state also has some limitations, like the one you are hitting here. can have the value zero on a call to that function. Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. For the time being, I would unfortunately recommend to mark as False Positive the issue. Original Java Specification Request (JSR) - Java Community Process Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. That is why I explicitly check for this in my attempted solution. 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. Does Counterspell prevent from any further spells being cast on a given turn? What should you do if somebody passes a null pointer for a parameter SonarQube - Null Pointer Dereference Issue java simonsirak (Simon Sirak) June 14, 2018, 1:18pm 1 Hi! Does it just mean failing to correctly check if a value is null? One could argue that all code examples would be redundant with the first pair. 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. - the incident has nothing to do with me; can I use this this way? rev2023.3.3.43278. Java Specification Participation Agreement version in use: 2.0. The solution that I recommend is not work with null returns or variables on Java, try to avoid it. java Solution 1, it looks like, today's solution tomorrow's problem. What is null pointer exception in android. Connect and share knowledge within a single location that is structured and easy to search. Asking for help, clarification, or responding to other answers. Null Pointer Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Connect and share knowledge within a single location that is structured and easy to search. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. When and how should I use a ThreadLocal variable? Making statements based on opinion; back them up with references or personal experience. The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. Phew, we're agreed here. What does it mean that a reference must refer to an object, not a dereferenced null pointer? You're in a company-managed project. If you preorder a special airline meal (e.g. Provide a self-contained reproducer (zipped project?) That's true. A reference to null should never be dereferenced/accessed. Isn't easier just to check valid range of length? If copying takes place between objects that overlap, the behavior is undefined. The method isNR(minRating) is a helper method that validate among other things, if the object minRating is null. Sonar is ok. Sonar can't determine that the helper method did the null validation. rev2023.3.3.43278. Believing that dereferencing NULL shouldn't crash the system doesn't make it true. So let me be more precise in my wording: I assert that a platform whose memcpy() did anything besides copy zero bytes when given n=0 and valid src and dest pointers was not C-standards-compliant. ROSE does not handle cases where an allocation is assigned to an lvalue that is not a variable (such as a struct member or C++ function call returning a reference), Finds instances where a pointer is checked against NULL and then later dereferenced, Identifies functions that can return a null pointer but are not checked, Identifies code that dereferences a pointer and then checks the pointer against NULL, Can find the instances where NULL is explicitly dereferenced or a pointer is checked againstNULL but then dereferenced anyway. . Asking for help, clarification, or responding to other answers. io.NotSerializableException : java. C# static code analysis: HTTP responses should not be vulnerable to 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. However, memory allocation > functions such as kstrdup() may fail and returns NULL. 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.) Accessing or modifying a null object's field. how to handle Sonarlint java:S2259 (Null pointers should not be rev2023.3.3.43278. Should trycatch go inside or outside a loop? Find centralized, trusted content and collaborate around the technologies you use most. I feel my situation is not as complicated. sonar_etReines-CSDN How do I align things in the following tabular environment? Does a summoned creature play immediately after being summoned by a ready action? Cause we need throw our own Runtime Exception, well-known methods wont help. 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. The null concept refers to the idea that a pointer can hold a special value that is not equal to another pointer. I'd guess null pointers are not valid, even though they point to 0 bytes. An awesome tip to avoid NPE is to return empty strings or empty collections rather than null. In Java, a special null value can be assigned to an object reference. static-code-analysis And the compliant solution guarantees that the pointer will be valid if the code calls memcpy(). 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. SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. A reference to Nothing should never be dereferenced/accessed. 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. The alert is related to the sonar rule : Null pointers should not be dereferenced.