IDE extension that lets you fix coding issues before they exist! ", 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". 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. 0 is a valid value as far as memcpy() is concerned, and malloc() has special language concerning malloc(0). This compliant solution eliminates the null pointer deference by initializing sk to tun->sk following the null pointer check. On many platforms, dereferencing a null pointer results in abnormal program termination, but this is not required by the standard. Note that it doesn't know how to check for non-heap, non-stack. Null Pointer rev2023.3.3.43278. very old code or C code being worked into c++ may have functions that expect the user to delete the data. Not the answer you're looking for? Not the answer you're looking for? Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. raiseException() return, Sonar Why is there a voltage on my HDMI and coaxial cables? I added an assertion to that compliant code example. Your code needs to do something about the possible NullPointerException when some exception is caught, because in this scenario the responseDto will be null. If you try to access any member variables or methods with that variable, you are trying to dereference it. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. LANG.MEM.NPDLANG.STRUCT.NTADLANG.STRUCT.UPD, Null pointer dereferenceNull test after dereferenceUnchecked parameter dereference, Can detect violations of this rule. [RSPEC-2259] - Jira 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. 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). Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. Accessing or modifying a null object's field. 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. Pointer is so confusing : Stack with singly linked list in C - Stack 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. Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. Java Specification Participation Agreement version in use: 2.0. minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). 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. Shouldn't the function check all pointers before dereferencing them or passing them to another function? That interpretation of the standard is not supported universally. We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. 3.Null pointers should not be derefer enced/accessed. SonarJava. 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. The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). Then the reading of the buffer via bstr_printf() will then look at the pointer to process the final output. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. 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. I reordered that code example to do all the checks before allocations. 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. To be precise, once length is changed to a size_t and cannot take negative values, it cannot have an invalid value. Aaron:I suspect we are talking past each other. Doing so will cause a NullReferenceException to be thrown. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. Coverity Prevent cannot discover all violations of this rule, so further verification is necessary, Detects when NULL is dereferenced (Array of pointers is not checked. 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. Null - How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. Pointers in C Explained - They're Not as Difficult - freeCodeCamp.org What is null pointer exception in android. This code also violates ERR33-C. Detect and handle standard library errors. that we haven't considered here: I'd guess null pointers are not valid, even though they point to 0 bytes. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? Im currently using SonarQube version 5.6.6. better way to handle this is to store the result of method invocation in a variable. Does it just mean failing to correctly check if a value is null? Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. The correct idiom is to only allocate storage if the pointer is currently NULL. 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. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. This compliant solution ensures that the pointer returned by png_malloc() is not null. The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. S2259: Null pointers should not be dereferenced java tsubasa (Jiaoyang Ma) January 11, 2019, 6:57am 1 versions used (SonarQube, Scanner, language analyzer) SonarQube Version 6.7.2 (build 37468) SonarJava Version 5.9.2 (build 16552) minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). One could argue that all code examples would be redundant with the first pair. But no where in that particular idiom would a NULL pointer necessarily be deferenced. How to tell which packages are held back due to phased updates. res.getBody() == null || res.getBody().getServiceResult() == null). 4500 Fifth Avenue Write a semantic patch to nd cases where the result of calling kmalloc is dereferenced with no previous NULL pointer test. When B is null, The control reaches inside the main if block only when length of A is 1. Now, you can find the list of whitelisted methods here. The null pointer check for writing or dereferencing should be a compiler flag or library setting. Unfortunately, its actual state also has some limitations, like the one you are hitting here. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. If you preorder a special airline meal (e.g. 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. [PATCH] drm_edid-load: Fix a missing-check bug in drivers/gpu/drm/drm 1. Introduction - Understanding and Using C Pointers [Book] I've changed it to say null pointer instead of invalid pointer. Find centralized, trusted content and collaborate around the technologies you use most. I doubt that "length" of zero is a valid parameter, and although there no copy, but we see memory allocation. Trying to understand how to get this basic Fourier Series. 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. At worst, it could expose debugging information that would be useful to an attacker or it could allow an Share Improve this answer Follow answered Oct 5, 2017 at 16:27 Is there a proper earth ground point in this switch box? Instead use String.valueOf (object). If the project is not compiled, and without sonar.java.binaries whether the white list takes effect? isEmpty(Collection collection) This likely means that youre on an ancient version of the Java analyzer. Whats the grammar of "For those whose stories they are"? When and how should I use a ThreadLocal variable? C# static code analysis: Null pointers should not be dereferenced 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. An awesome tip to avoid NPE is to return empty strings or empty collections rather than null. Optimizers are optimizing based on this latitude and have been for years. A bug can cause them never to be reassigned. In multithreaded programs, null pointer dereferences can violate cache coherency policies and can cause resource leaks. Powered by Discourse, best viewed with JavaScript enabled. This rule applies to all null pointers, regardless of which function returned them. 9.7 Null pointers - Learn C++ - LearnCpp.com 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. Fix S2583/S2589 FP: On null check if instance is used in try block - GitHub This topic was automatically closed 7 days after the last reply. https://stackoverflow.com/questions/47534436/, https://stackoverflow.com/questions/47534436/, java - Jenkins groovy : Error: java. Is it possible to rotate a window 90 degrees if it has the same length and width? Why are physically impossible and logically impossible concepts considered separate in terms of probability? return p == NULL || (char *)p < &_etext; I feel my situation is not as complicated. 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. Status: Dormant. ncdu: What's going on with this second size column? SonarQube null pointers should not be dereferenced on try/catch best, such an exception will cause abrupt program termination. Doing so will cause a NullReferenceException to be thrown. () Essentially, this code and the previous dereference disagree as to whether this value is allowed to be null. We can get a reference to point to null in the following ways: "uninitialized" reference type variables variables which are initialized with nulls and are assigned their real value afterward. Trying to understand how to get this basic Fourier Series. Its purpose is to serve as a special value for a pointer that could indicate a special condition in your program.