Null pointers should not be dereferenced. What is pointed to should only be deleted if it was created with new. (In contrast, the case of passing 0 bytes to malloc is addressed in C11.) When B is null, The control reaches inside the main if block only when length of A is 1. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Making statements based on opinion; back them up with references or personal experience. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? Appropriate typecasting is necessary. Off by one error: It is the third example. Agreed. Goal It's still illegal. In the meantime, Im locking this thread. 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. Sonar is ok. Doing so will cause a NullReferenceException to be thrown. The expected result here is solve the issue with sonarqube. Software project. 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?) NullPointerException is a RuntimeException. Now (sonarqube java analyzer version 4.3.0.7717) it's supported and works fine. Is it possible to rotate a window 90 degrees if it has the same length and width? Depending on whether the pointer is valid (i.e. I reordered that code example to do all the checks before allocations. that we haven't considered here: I'd guess null pointers are not valid, even though they point to 0 bytes. 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 )}"); Essentially, this code and the previous dereference disagree as to whether this value is allowed to be null. rev2023.3.3.43278. 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. Using platform-specific means (e.g. In multithreaded programs, null pointer dereferences can violate cache coherency policies and can cause resource leaks. isEmpty(Collection collection) Thanks for the feedback. 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. Unfortunately, its actual state also has some limitations, like the one you are hitting here. 3.7. Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . Cause we need throw our own Runtime Exception, well-known methods wont help. Thanks, David! When and how should I use a ThreadLocal variable? When a variable is declared as being a pointer to type void, it is known as a generic pointer. extern char _etext; Alternate Terms Relationships What is a NullPointerException, and how do I fix it?,What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? 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. 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. Using Kolmogorov complexity to measure difficulty of problems? Aaron:I suspect we are talking past each other. Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. The solution that I recommend is not work with null returns or variables on Java, try to avoid it. But when length of A is 1, the control never reaches the else block. Much like dereferencing a dangling (or wild) pointer leads to undefined behavior, dereferencing a null pointer also leads to undefined behavior. Can I tell police to wait and call a lawyer when served with a search warrant? Why is there a voltage on my HDMI and coaxial cables? raiseException() return, Sonar https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx Styling contours by colour and by line thickness in QGIS. It could be non-null the first time but not the second time, sonar does not know this. How can we prove that the supernatural or paranormal doesn't exist? If you preorder a special airline meal (e.g. It is still a pointer though, to use it you just have to cast it to another kind of pointer first. (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). How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. SIZE_MAX is the largest possible value that a size_t could take, so it is not possible to have anything larger than SIZE_MAX. Consider the following scenario: you are asked to create a Java class MetaDisplay that contains a static void printTable(String r) method. There are many ways to resolve this. 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. For the time being, I would unfortunately recommend to mark as False Positive the issue. Issues Components. And fwstr > is dereferenced in the following codes. Pointer members in structs are not checked. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? Good question! It's a modular system with the . 4500 Fifth Avenue Status: Dormant. it could allow an attacker to bypass security measures. 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 Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, It is a false positive, but it might be a good idea not to do the, Sonar false-positive on rule: Null pointers should not be dereferenced, How Intuit democratizes AI development across teams through reusability. ii. Null pointer should not be dereferenced . I feel my situation is not as complicated. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? We. // <------- 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. Trying to understand how to get this basic Fourier Series. At worst, it could expose debugging information that would be useful to an attacker, or Is there a proper earth ground point in this switch box? A reference to null should never be dereferenced/accessed. Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. ability to run any cleanup processes. At attacker to bypass security measures. 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). Solution 1, it looks like, today's solution tomorrow's problem. How do you ensure that a red herring doesn't violate Chekhov's gun? Two null pointers will always be equal to each other. As for copy vs pointer/reference - it depends. . I am a student implementing stack with singly linked list using C, following a book called Fundamentals of Data Structures in C.. which version of SonarQube are you using? All rights are expressly reserved. Just because something is a pointer does not mean you should call delete . Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. In the simplest case, this function just returns the result of calling kmalloc. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? If malloc() fails, it returns a null pointer that is assigned to c_str. How can this new ban on drag possibly be considered constitutional? How do you ensure that a red herring doesn't violate Chekhov's gun? I think "res.getBody() == null" checks null first so it should go to return line, not reach to next if condition. Not the answer you're looking for? There can be a null pointer type for each pointer type, such as a pointer to a character or a pointer to an integer, although this is . When I added the not null validation as sonar suggest. Trying to understand how to get this basic Fourier Series. Should trycatch go inside or outside a loop? It's even called out explicitly in C17 7.24.1p2: Where an argument declared as size_t n specifies the length of the array for a function, n can have the value zero on a call to that function. I say "theoretical" because I have not successfully produced strings of this length in testing. Finally my method is returning a response with value of restTemplate. Does a summoned creature play immediately after being summoned by a ready action? Are there tables of wastage rates for different fruit and veg? Phew, we're agreed here. 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. What is a serialVersionUID and why should I use it? Note that it doesn't know how to check for non-heap, non-stack. positive S2637 in SonarQube 6.7.1 LTS, SonarQube for MSBuild not reporting quality issues, getTextContent() through "Null pointers should not be dereferenced". validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. 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. Do "superinfinite" sets exist? 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. 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. 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. 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. . Is null check needed before calling instanceof? Doing so will cause a NullReferenceException to be thrown. (I think you cover that in a different rule.) 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. The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. Connect and share knowledge within a single location that is structured and easy to search. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? 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. 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. Software project. Trying to understand how to get this basic Fourier Series. To learn more, see our tips on writing great answers. 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. So no checking of the length is necessary (besides preventing integer overflow, which the compliant solution does). Explain about call by reference with an . Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? This sounds indeed like a bug in the flow when an exception is raised. In order to fix this, just do the following: If you are absolutely sure that res.getBody() stays null and is also not modified by another thread, you could also use a //NOSONAR comment in order to suppress the warning. Is there a single-word adjective for "having exceptionally strong moral principles"? Trying to understand how to get this basic Fourier Series. By explicitly teaching the C++ standard class behaviors we can make the Analyzer to find more bugs related to modern C++ code. Linear regulator thermal information missing in datasheet, Identify those arcade games from a 1983 Brazilian music video. 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. 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). We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. 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?) Iflengthhas the value1, the addition yields 0, and png_malloc() subsequently returns a null pointer, which is assigned to chunkdata. io.NotSerializableException : java. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Why does the second compliant example permit using possibly-null pointers? Connect and share knowledge within a single location that is structured and easy to search. Please explain: Without this, we wont be able to help you. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. HTTP request redirections should not be open to forging attacks Deserialization should not be vulnerable to injection attacks Endpoints should not be vulnerable to reflected cross-site scripting (XSS) attacks "CoSetProxyBlanket" and "CoInitializeSecurity" should not be used Database queries should not be vulnerable to injection attacks It also uses the unsigned type size_t to pass the length parameter, ensuring that negative values are not passed to func(). rev2023.3.3.43278. Interactions/interfaces with C can't use references. You're in a company-managed project. The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. . This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. Connect and share knowledge within a single location that is structured and easy to search. Can I tell police to wait and call a lawyer when served with a search warrant? If you try to access any member variables or methods with that variable, you are trying to dereference it. This code also violates ERR33-C. Detect and handle standard library errors. The test was added to catch the possibly theoretical situation where the length of input_str was somehow the maximum size for size_t, and adding one to this size in the malloc expression (to allocated space for the trailing null byte) results in an integer overflow. https://stackoverflow.com/questions/47534436/, https://stackoverflow.com/questions/47534436/, java - Jenkins groovy : Error: java. In the code, we check the not nullity with java.util.Objects.nonNull(). . (from res.getBody().getServiceResult() ). At best, such an exception will cause abrupt program termination. 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? At this point we define size as strlen(input_str) + 1. 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. Carnegie Mellon University Whats the grammar of "For those whose stories they are"? 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. Many platforms can support testing for those also. Find centralized, trusted content and collaborate around the technologies you use most. 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 (?,?,?,?,?,?,?,? 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. How do I align things in the following tabular environment? Why do academics stay as adjuncts for years rather than move around? 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. Since you cannot have a variable of type void, the pointer will not point to any data and therefore cannot be dereferenced. 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. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). Making statements based on opinion; back them up with references or personal experience. A pointer to null (the 0 memory address) should never be dereferenced/accessed. 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. Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. IDE extension that lets you fix coding issues before they exist! Thanks for your relpy. This compliant solution ensures that both input_str andthe pointer returned by malloc() are not null: This noncompliant code example is from a version of drivers/net/tun.c and affects Linux kernel 2.6.30 [Goodin 2009]: The sk pointer is initialized to tun->sk before checking if tun is a null pointer. rev2023.3.3.43278. Believing that dereferencing NULL shouldn't crash the system doesn't make it true. 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(). 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). Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. Not the answer you're looking for? 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. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? void *pointerVariableName = NULL; Since they are very general in nature, they are also known as generic pointers. The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. How can we let this pass? , NPE : null-, . Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. Optimizers are optimizing based on this latitude and have been for years. Does Java have support for multiline strings? That's true.
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