Now (sonarqube java analyzer version 4.3.0.7717) it's supported and works fine. 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. When should pointers be checked for NULL in C? Why does Mister Mxyzptlk need to have a weakness in the comics? 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. A reference to null should never be dereferenced/accessed. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? While the engine is in practice already able to explore code from other files if needed (relying solely on bytecode), we restrain this approach to a limited set of well-known methods from standard libraries, for which we know that behaviors are correctly produced. How to get rid of NullPointerException - freeCodeCamp.org Is it possible to create a concave light? Now, you can find the list of whitelisted methods here. Finally my method is returning a response with value of restTemplate. - the incident has nothing to do with me; can I use this this 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. Thanks for your relpy. Recovering from a blunder I made while emailing a professor. SonarQube - Null Pointer Dereference Issue - Sonar Community 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. 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. We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. Obviously the value of that pointer could have changed since the . We. Trying to understand how to get this basic Fourier Series. Null Pointer The result of calling such a helper function should be . . Sonar violation: Null pointers should not be dereferenced #7459 - GitHub sonarLint (3.2.) "After the incident", I started to be more careful not to trip over things. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? So we have to check all the arguments before performing any actions. 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. False-positives are pointed out in other SO posts (1 & 2), where nulls are involved across functions and procedures. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. C# static code analysis: Null pointers should not be dereferenced which would allow us to systematically observe what you are having. 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. Is the God of a monotheism necessarily omnipotent? References, C++ FAQ Im very new to sonar, is there a way to add methods to the whitelist? The libpng library implements its own wrapper to malloc() that returns a null pointer on error or on being passed a 0-byte-length argument. Mutually exclusive execution using std::atomic? Is there a proper earth ground point in this switch box? Trying to understand how to get this basic Fourier Series. 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. But the problem also exists in the compliant version, so I'm not so sure that it's really compliant. https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. - the incident has nothing to do with me; can I use this this way? When I added the not null validation as sonar suggest. 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. 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 */ When and how should I use a ThreadLocal variable? At worst, it could expose debugging information that would be useful to an attacker or it could allow an We really appreciate your help. This topic was automatically closed 7 days after the last reply. With their flexibility, void pointers also bring some constraints. But when length of A is 1, the control never reaches the else block. How to avoid dereferencing null pointers in Java - Quora 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. void *pointerVariableName = NULL; Since they are very general in nature, they are also known as generic pointers. What is null pointer exception in android Smartadm.ru Styling contours by colour and by line thickness in QGIS. strongSwan - strongSwan Vulnerability (CVE-2023-26463) And fwstr > is dereferenced in the following codes. Making statements based on opinion; back them up with references or personal experience. Find centralized, trusted content and collaborate around the technologies you use most. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? sonar_etReines-CSDN Asking for help, clarification, or responding to other answers. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Much like dereferencing a dangling (or wild) pointer leads to undefined behavior, dereferencing a null pointer also leads to undefined behavior. It could be non-null the first time but not the second time, sonar does not know this. When exploring such methods, the engine then deduces behaviors regarding null-checking (among other things). 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 This solution also ensures that theuser_data pointer is not null. How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. 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. VB.NET static code analysis: Null pointers should not be dereferenced [PATCH v2] vsprintf: Do not have bprintf dereference pointers Thank you for clarifying your assertion until I understood it properly. which version of SonarQube are you using? I'd guess WG14 has considered these questions, but I haven't until now :). Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. It also adds assertions to document that certain other pointers must not be null. Sonar is ok. This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. So the SIZE_MAX check was unnecessary. 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 When B is null, The control reaches inside the main if block only when length of A is 1. Note that it doesn't know how to check for non-heap, non-stack. Software project. assigning to dereferenced struct pointers uninitialized reference-type class members. sonarqube If you preorder a special airline meal (e.g. 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. My below code where I'm calling a stored procedure is giving a null pointer exception. I already tried to put ResponseEntity responseDto inside my try clause assigning and returning the respective value but its mandatory to return something out the try/catch. This issues is displayed by SonarQube. The null pointer check for writing or dereferencing should be a compiler flag or library setting. In the meantime, Im locking this thread. Possible fix: Assign a valid address to the pointer in all branches of the conditional statement.. Pointer can point to dynamically allocated memory. Not the answer you're looking for? res.getBody() == null || res.getBody().getServiceResult() == null). Connect and share knowledge within a single location that is structured and easy to search. 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>. , . But no where in that particular idiom would a NULL pointer necessarily be deferenced. If malloc() fails, it returns a null pointer that is assigned to c_str. At best, such an exception will cause abrupt program termination. SonarJava Version 5.9.2 (build 16552). Doing so will cause a NullReferenceException to be thrown. But passing 0 to memcpy() is not one of them. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. This noncompliant code example is derived from a real-world example taken from a vulnerable version of the libpng library as deployed on a popular ARM-based cell phone [Jack 2007]. Why are physically impossible and logically impossible concepts considered separate in terms of probability? [SONARJAVA-2808] - Jira - SonarSource Correct; a null pointer is not a valid pointer for the C library functions. 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. What is generic pointer? Is there a proper earth ground point in this switch box? A reference to null should never be dereferenced/accessed. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Dereferencing a null pointer results in undefined behavior. What sort of strategies would a medieval military use against a fantasy giant? 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. 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. SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. Things go fine now. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How do you ensure that a red herring doesn't violate Chekhov's gun? [RSPEC-2259] - Jira 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" 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. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? What does "Could not find or load main class" mean? Identify where the allocation occurs. Dereferencing a null pointer is undefined behavior. An awesome tip to avoid NPE is to return empty strings or empty collections rather than null. Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. When you have a variable of non-primitive type, it is a reference to an object. Doing so will cause a NullReferenceException to be thrown. The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. Explain about call by reference with an . A pointer is simply a variable that contains a memory address. In C# and Java, all reference types can point to null. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? Issues Components. Software Engineering Institute How can we prove that the supernatural or paranormal doesn't exist? Trying to understand how to get this basic Fourier Series. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. There is a missing check for the return value from . Rule squid:S2259 is based on a Symbolic Execution (SE) engine. 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. Can I tell police to wait and call a lawyer when served with a search warrant? how to handle Sonarlint java:S2259 (Null pointers should not be This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. Dereferencing a null pointer can lead to a denial of service. I think "res.getBody() == null" checks null first so it should go to return line, not reach to next if condition. Does a summoned creature play immediately after being summoned by a ready action? Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. 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). , NPE : null-, . For example the following program doesn't compile. Callable statement giving Null Pointer Exception - Oracle Forums How to convert the address of a dereferenced pointer from C to C# ncdu: What's going on with this second size column? Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Recovering from a blunder I made while emailing a professor. Find centralized, trusted content and collaborate around the technologies you use most. Then the reading of the buffer via bstr_printf() will then look at the pointer to process the final output. We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. Avoid Returning null from Methods. That is only true if possibleNumbers contains no element.. BTW: none of these warnings are shown by . 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 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. Thanks for contributing an answer to Stack Overflow! > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Fix S2583/S2589 FP: On null check if instance is used in try block - GitHub can have the value zero on a call to that function. Find null smart pointer dereferences with the Clang Static Analyzer Phew, we're agreed here. 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. 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. Do not use a null in a case where an object is required, https://gcc.gnu.org/gcc-4.9/porting_to.html, Prior to 2018-01-12: CERT: Unspecified Relationship, Pointer Casting and Pointer Type Changes [HFC], Dereferencing an out-of-domain pointer [nullref], Section 5.2.18, "Null-Pointer Dereference", Dereferencing null pointers that were not returned by a function. Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. the Java one). There are many ways to resolve this. The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. Some Interesting Facts: 1) void pointers cannot be dereferenced. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? Is null check needed before calling instanceof? Null pointer should not be dereferenced . Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. Sonar is ok. Sonar can't determine that the helper method did the null validation. it could allow an attacker to bypass security measures. It is still a pointer though, to use it you just have to cast it to another kind of pointer first. 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. that we haven't considered here: I'd guess null pointers are not valid, even though they point to 0 bytes. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. 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. However, memory allocation > functions such as kstrdup() may fail and returns NULL. Why pointers are not used in python? Explained by Sharing Culture Could I capture, and I would be able to glean much security information from the dump? The final NCCE is actually more insidious than it seems at first. 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?) The solution that I recommend is not work with null returns or variables on Java, try to avoid it. This engine is validating execution paths and checking for non-null values or null-check along the way, exploring all the possibilities. 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 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. I feel my situation is not as complicated. [PATCH 1/3] usb: ucsi: Fix NULL pointer deref in ucsi_connector_change() I would also guess that pointers that point to the one-past-the-end of an array are also invalid. A reference to Nothing should never be dereferenced/accessed. That is why I explicitly check for this in my attempted solution. minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). The article easily misleads the reader into believeing that ensuring pointer validity boils down to checking for pointer being not equal to NULL. It's still illegal. Share Improve this answer Follow answered Oct 5, 2017 at 16:27 It's a modular system with the . positive S2637 in SonarQube 6.7.1 LTS, SonarQube for MSBuild not reporting quality issues, getTextContent() through "Null pointers should not be dereferenced". 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! 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. There are other problems with this code, as is noted in the rule. I suppose there is a question of "Is a pointer that points to 0 bytes valid?" NULL POINTERS SHOULD NOT BE DEREFERENCED - jobhuntley.com sonarlint, sonarLint (3.2.) Asking for help, clarification, or responding to other answers. The issue is: memcpy() and friends do not explicitly state that a null pointer is a valid pointer value, even if the number of bytes to copy is 0. Asking for help, clarification, or responding to other answers. 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. versions used (SonarQube, Scanner, language analyzer) Can I tell police to wait and call a lawyer when served with a search warrant? The standard will simply copy 0 byteswhich is essentially a no-op. Hi Andreas, Thanks for the feedback. Solution 1, it looks like, today's solution tomorrow's problem. The same problem we will have with "Add at least one assertion to this test case." This compliant solution ensures that the pointer returned by png_malloc() is not null. You can use Optional instead. 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). If you write [ref], then a null pointer is not allowed, but if you write [unique], then a null pointer is permitted. Reports. Using platform-specific means (e.g. Instead use String.valueOf (object). 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. best, such an exception will cause abrupt program termination. How do I align things in the following tabular environment? 3.Null pointers should not be derefer enced/accessed. Answered: difference between a void pointer and a | bartleby Null Dereference | OWASP Foundation Null pointers should not be dereferenced. ncdu: What's going on with this second size column? specifies the length of the array for a function. The return value from strchr() is often NULL, but the dev might know that a specific strchr() function call will not return NULL. io.NotSerializableException : java. 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. Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. What does it mean that a reference must refer to an object, not a dereferenced null pointer? null(java.lang.NullPointerException) . 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. 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. I have checked on multiple . SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. Find centralized, trusted content and collaborate around the technologies you use most. I have a sonar alert on this call minRating.getRatgCaam(). The expected result here is solve the issue with sonarqube. These can be: Invoking a method from a null object. 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). [JAVA] 3.9 - FP for S2259 Null pointers should not be dereferenced