If copying takes place between objects that overlap, the behavior is undefined. can have the value zero on a call to that function. 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. (In contrast, the case of passing 0 bytes to malloc is addressed in C11.) Accessing or modifying a null object's field. New replies are no longer allowed. http://blog.llvm.org/2011/05/what-every-c-programmer-should-know_14.html. 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. PS: I also tried the code in android studio which uses Lint and got no warnings. Dereferencing a null pointer can lead to a denial of service. I reordered that code example to do all the checks before allocations. But no where in that particular idiom would a NULL pointer necessarily be deferenced. Minimising the environmental effects of my dyson brain. Trying to understand how to get this basic Fourier Series. This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Hi @Michael! . . Pittsburgh, PA 15213-2612
SonarQube Version 6.7.2 (build 37468) How can this new ban on drag possibly be considered constitutional? Note that it doesn't know how to check for non-heap, non-stack. I doubt that "length" of zero is a valid parameter, and although there no copy, but we see memory allocation. That interpretation of the standard is not supported universally. void *pointerVariableName = NULL; Since they are very general in nature, they are also known as generic pointers. SonarJava Version 5.9.2 (build 16552). 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 When a variable is declared as being a pointer to type void, it is known as a generic pointer. C# static code analysis: HTTP responses should not be vulnerable to Please direct comments on this JSR to the Spec Lead (s) Team. We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. 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. Thanks, David! 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). Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Why is there a voltage on my HDMI and coaxial cables? Replacing broken pins/legs on a DIP IC package, Bulk update symbol size units from mm to map units in rule-based symbology, How do you get out of a corner when plotting yourself into a corner. Sonar is ok. How can we prove that the supernatural or paranormal doesn't exist? 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. Dereferencing a null pointer is undefined behavior. The correct idiom is to only allocate storage if the pointer is currently NULL. Find centralized, trusted content and collaborate around the technologies you use most. Does Counterspell prevent from any further spells being cast on a given turn? You're in a company-managed project. 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. , . assigning to dereferenced struct pointers I have checked on multiple . 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. 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. Not the answer you're looking for? static-code-analysis Connect and share knowledge within a single location that is structured and easy to search. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? LANG.MEM.NPDLANG.STRUCT.NTADLANG.STRUCT.UPD, Null pointer dereferenceNull test after dereferenceUnchecked parameter dereference, Can detect violations of this rule. IDE extension that lets you fix coding issues before they exist! Sonar false-positive on rule: Null pointers should not be dereferenced rev2023.3.3.43278. We resolved it by adding our tools path in the white list, and repackaging it. 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! Original Java Specification Request (JSR) - Java Community Process Is there a proper earth ground point in this switch box? Rule squid:S2259 is based on a Symbolic Execution (SE) engine. 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. The same problem we will have with "Add at least one assertion to this test case." The final NCCE is actually more insidious than it seems at first. Why are physically impossible and logically impossible concepts considered separate in terms of probability? Additionally, if input_str is a null pointer, the call to strlen() dereferences a null pointer, also resulting in undefined behavior. 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. Is the God of a monotheism necessarily omnipotent? IMHO, the rule title should be changed to something less general. Im very new to sonar, is there a way to add methods to the whitelist? I would also guess that pointers that point to the one-past-the-end of an array are also invalid. raiseException() return, Sonar Null pointer should not be dereferenced . Finally, there is the matter of the compliant solution. rev2023.3.3.43278. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. Then we hit memcpy with length 0. Is it possible to rotate a window 90 degrees if it has the same length and width? Sonar is ok. Sonar can't determine that the helper method did the null validation. 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. Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. )}"); Sonar detects that res.getBody() can be null when you do the check res.getBody()==null. Analysis of Haiku Operating System (BeOS Family) by PVS-Studio. Part 1 That is, sets equivalent to a proper subset via an all-structure-preserving bijection. 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. > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. 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(). This is a matter of style, and also following code walkthrough. ability to run any cleanup processes. 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. 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. 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. Using Kolmogorov complexity to measure difficulty of problems? Null Pointers - Keil forum - Support forums - Arm Community Dereferencing a null pointer results in undefined behavior. This compliant solution eliminates the null pointer deference by initializing sk to tun->sk following the null pointer check. Since you cannot have a variable of type void, the pointer will not point to any data and therefore cannot be dereferenced. 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 */ 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. Void pointers cannot be dereferenced as any other pointer. it could allow an attacker to bypass security measures. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? It could be non-null the first time but not the second time, sonar does not know this. I'd guess null pointers are not valid, even though they point to 0 bytes. 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. 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.