null pointers should not be dereferenced
This compliant solution ensures that the pointer returned by png_malloc() is not null. There is a missing check for the return value from . If not, this might be a bug. sonarlint complains that And fwstr > is dereferenced in the following codes. The fact that you can't pass a null (no object) with a reference parameter can be a reason to use a pointer instead. 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). . 5.2 Part 2 Sometimes a helper function is de ned to perform the memory allocation. A pointer is simply a variable that contains a memory address. Not the answer you're looking for? minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). Is it possible to create a concave light? But when length of A is 1, the control never reaches the else block. But no where in that particular idiom would a NULL pointer necessarily be deferenced. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? () Write a semantic patch to nd cases where the result of calling kmalloc is dereferenced with no previous NULL pointer test. 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. Find centralized, trusted content and collaborate around the technologies you use most. Clearly the standard enumerates 1 case of undefined behavior, but makes no special mention of n=0. My main problem is because I'm doing a restTemplate.exchange with try-catch and declaring a variable with null value before the clause try and then using it inside the try. Doing so will at best cause abrupt program termination, without the If the project is not compiled, and without sonar.java.binaries whether the white list takes effect? At worst, it could expose debugging information that would be useful to an attacker, or specifies the length of the array for a function. Im currently using SonarQube version 5.6.6. better way to handle this is to store the result of method invocation in a variable. There are other problems with this code, as is noted in the rule. 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). Mutually exclusive execution using std::atomic? Hi Andreas, Thanks for the feedback. How do I align things in the following tabular environment? This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. If you preorder a special airline meal (e.g. When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. SonarLint: A "NullPointerException" could be thrown; "getBody()" can return null. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 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. How do you ensure that a red herring doesn't violate Chekhov's gun? io.NotSerializableException : java. 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. Answered: difference between a void pointer and a | bartleby 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?) Void pointers cannot be dereferenced as any other pointer. 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.) [PATCH 1/3] usb: ucsi: Fix NULL pointer deref in ucsi_connector_change() In the code, we check the not nullity with java.util.Objects.nonNull(). If you write [ref], then a null pointer is not allowed, but if you write [unique], then a null pointer is permitted. Cause we need throw our own Runtime Exception, well-known methods wont help. You can use Optional instead. How to avoid dereferencing null pointers in Java - Quora Whoops, you're right. 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. A reference to null should never be dereferenced/accessed. That noncompliant code example (it's currently the 3rd) came from the Linux kernel, whose source is publicly available. That is only true if possibleNumbers contains no element.. BTW: none of these warnings are shown by . But when length of A is 1, the control never reaches the else block. New replies are no longer allowed. That interpretation of the standard is not supported universally. The result of calling such a helper function should be . 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. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. attacker to bypass security measures. 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 really appreciate your help. 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. , . But passing 0 to memcpy() is not one of them. What is null pointer exception in android. Using Kolmogorov complexity to measure difficulty of problems? (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). 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. Pointers in C Explained - They're Not as Difficult - freeCodeCamp.org You're in a company-managed project. 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). As for copy vs pointer/reference - it depends. // <------- 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. Just a few words about the rule now. When B is null, The control reaches inside the main if block only when length of A is 1. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? Finally my method is returning a response with value of restTemplate. 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 . 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. Phew, we're agreed here. I've changed it to say null pointer instead of invalid pointer. 4. At "After the incident", I started to be more careful not to trip over things. For the time being, I would unfortunately recommend to mark as False Positive the issue. Automated Detection Null pointer dereferences can happen in path-dependent ways. 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. C# static code analysis: HTTP responses should not be vulnerable to Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. 2008-2023 SonarSource S.A., Switzerland. https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx null(java.lang.NullPointerException) . Null Dereference | OWASP Foundation Possible fix: Assign a valid address to the pointer in all branches of the conditional statement.. Pointer can point to dynamically allocated memory. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to . Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. What sort of strategies would a medieval military use against a fantasy giant? the Java one). Basically, yes. How can we prove that the supernatural or paranormal doesn't exist? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. (I think you cover that in a different rule.) If you call connect() function, it better do the connection, but failing simply because some ptr is NULL is not good behaviour -- failures should . Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. ", Eclipse - Sonar S2629 possible false positive with new String, SonarQube null pointers should not be dereferenced on try/catch, getTextContent() through "Null pointers should not be dereferenced". > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. 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. 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. 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" What are the effects of exceptions on performance in Java? 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. }. EXP34-C is a common consequence of ignoring function return values, but it is a distinct error, and can occur in other scenarios too. 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. All rights are expressly reserved. In some situations, however, dereferencing a null pointer can lead to the execution of arbitrary code [Jack 2007,van Sprundel 2006]. Ticket opened : Thanks a lot for the minimalized reproducer ! FindBugs CORRECTNESS - 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. squid:S2259 : A "NullPointerException" could be thrown; "dc" is Note that it doesn't know how to check for non-heap, non-stack. There is no guarantee that subsequent invocations are returning the same value, thats why issue is raised. Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. Is there a proper earth ground point in this switch box? Because null pointer dereferencing is undefined behavior, the compiler (GCC in this case) can optimize away the if (!tun) check because it is performed after tun->sk is accessed, implying that tun is non-null. Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. When should pointers be checked for NULL in C? How to deal with "java.lang.OutOfMemoryError: Java heap space" error? Is the God of a monotheism necessarily omnipotent? Software project. This is a matter of style, and also following code walkthrough. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? Now, you can find the list of whitelisted methods here. The correct idiom is to only allocate storage if the pointer is currently NULL. 9.7 Null pointers - Learn C++ - LearnCpp.com Recovering from a blunder I made while emailing a professor. Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. Carnegie Mellon University
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isEmpty(Collection collection) Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. It could be non-null the first time but not the second time, sonar does not know this. Why do academics stay as adjuncts for years rather than move around? 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. When length is zero, it is probably unusable condition for this function. - the incident has nothing to do with me; can I use this this way? NULL POINTERS SHOULD NOT BE DEREFERENCED - jobhuntley.com How to use Slater Type Orbitals as a basis functions in matrix method correctly? The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. I believe in this case, either expression would work. The 4gig boundary will probably be important too with unsigned int in LP64, but since size_t will be 64-bit, there will have to be some truncation that compilers will be able to warn on. How to fix int cannot be dereferenced? Explained by Sharing Culture very old code or C code being worked into c++ may have functions that expect the user to delete the data. In the first compliant example it's useless to do allocation if the essential pointer user_data is NULL. util.regex.Matcher, java - Swing .getParent() . How can this new ban on drag possibly be considered constitutional? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, how to handle Sonarlint java:S2259 (Null pointers should not be dereferenced), How Intuit democratizes AI development across teams through reusability. CWE - CWE-476: NULL Pointer Dereference (4.10) - Mitre Corporation @Tibor SonarQube version 5.6.6, IntelliJ SonarLint plugin 3.0.0.2041, Sonar: Null pointers should not be dereferenced, How Intuit democratizes AI development across teams through reusability. And the semantics, as I said, are different. Aaron:I suspect we are talking past each other. Correct; a null pointer is not a valid pointer for the C library functions. In the simplest case, this function just returns the result of calling kmalloc. [SONARJAVA-2808] - Jira - SonarSource If you try to access any member variables or methods with that variable, you are trying to dereference it. Do "superinfinite" sets exist? 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). can have the value zero on a call to that function. C static code analysis: Null pointers should not be dereferenced 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. extern char _etext; ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . The standard will simply copy 0 byteswhich is essentially a no-op. sonar-java. At worst, it could expose debugging information that would be useful to an attacker or it could allow an Find null smart pointer dereferences with the Clang Static Analyzer But even with this, the concerned object it tagged as a possible NullPointerException problem. Asking for help, clarification, or responding to other answers. 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. Obviously the value of that pointer could have changed since the . PDF Fourth Coccinelle Workshop { Exercises This issues is displayed by SonarQube. 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. That is why I explicitly check for this in my attempted solution. False fault 'Null pointers should not be dereferenced' using Optional Goal We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. 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. Accessing or modifying a null object's field. How can we let this pass? PS: I also tried the code in android studio which uses Lint and got no warnings. Alternate Terms Relationships Provide a self-contained reproducer (zipped project?) Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. )}"); SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. Is there a solution to add special characters from software and how to do it, Acidity of alcohols and basicity of amines. Issues Components. Unlike reference types, pointer types are not tracked by the default garbage . We cannot understand how there could be a null pointer exception at the reported line. Im very new to sonar, is there a way to add methods to the whitelist? I already tried to put ResponseEntity
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null pointers should not be dereferenced