Aaron:I suspect we are talking past each other. I added an assertion to that compliant code example. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? At best, such an exception will cause abrupt program termination. Using platform-specific means (e.g. Agreed. 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>. () 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. 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. My question is; is my solution incorrect? So Bar might not be initialized but then the last line of your example should not be evaluated in this case. Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? (C11, S7.24.2.1). As for today, the SE engine is able to explore non-overridable methods (static, for instance), when declared in the same file being analyzed. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. If copying takes place between objects that overlap, the behavior is undefined. The null pointer check for writing or dereferencing should be a compiler flag or library setting. that we haven't considered here: I'd guess null pointers are not valid, even though they point to 0 bytes. 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 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). At best, such an exception will cause abrupt program termination. Pointer members in structs are not checked. That's true. But when length of A is 1, the control never reaches the else block. Automated Detection Null pointer dereferences can happen in path-dependent ways. What is generic pointer? SonarJava. 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. 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. If you say [in] or [out] without a modifier, then the modifier defaults to the pointer_default for the enclosing class. ucsi->connector gets dereferenced by both ucsi_connector_change() and ucsi_resume(), both check for ucsi->connector being NULL in case ucsi_init() has not finished yet; or in case ucsi_init() has failed. Passing a null pointer tomemcpy() would produce undefined behavior, even if the number of bytes to copy were 0. Styling contours by colour and by line thickness in QGIS. You need to benchmark. Instead use String.valueOf (object). A common memory-leak idiom, is reallocating storage and assigning its address to a pointer that already points to allocated storage. Accessing or modifying a null object's field. 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. One could argue that all code examples would be redundant with the first pair. I suppose there is a question of "Is a pointer that points to 0 bytes valid?" String *x, y; X is a pointer to a string, Y is a string & = address of variable/ operator || referencing operator * = value of address || dereferencing operator Pointers = stores memory address as its variables NULL pointer = a constant with a value of zero defined || assigned to null Void pointer = a pointer that is not associated with any data types New operator = denotes a request for . Asking for help, clarification, or responding to other answers. ii. In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. 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 (?,?,?,?,?,?,?,? specifies the length of the array for a function. What is a NullPointerException, and how do I fix it?,What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? Why do academics stay as adjuncts for years rather than move around? You're in a company-managed project. But even with this, the concerned object it tagged as a possible NullPointerException problem. Just a few words about the rule now. @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. 0 is a valid value as far as memcpy() is concerned, and malloc() has special language concerning malloc(0). Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, SonarQube - Null Pointer Dereference Issue. Issues Components. Is a PhD visitor considered as a visiting scholar? In some situations, however, dereferencing a null pointer can lead to the execution of arbitrary code [Jack 2007,van Sprundel 2006]. Sonar detects that res.getBody() can be null when you do the check res.getBody()==null. "After the incident", I started to be more careful not to trip over things. How to use Slater Type Orbitals as a basis functions in matrix method correctly? , RemoteContext new ExceptionType() RemoteContext , SonarLintJava (), java - sonarLint "Null pointers should not be dereferenced (squid:S2259)"Stack Overflow 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 B is null, The control reaches inside the main if block only when length of A is 1. C# static code analysis: Null pointers should not be dereferenced Products In-IDE IDE extension that lets you fix coding issues before they exist! All content is copyright protected. And if there is no pointer_default declaration, then the default default is ref. Thanks for contributing an answer to Stack Overflow! Batch split images vertically in half, sequentially numbering the output files, Recovering from a blunder I made while emailing a professor. Null pointers should not be dereferenced. Do not dereference null pointers Created by Jeffrey Gennari, last modified by Jill Britton on Jan 18, 2023 Dereferencing a null pointer is undefined behavior. And the semantics, as I said, are different. But passing 0 to memcpy() is not one of them. Is there a solution to add special characters from software and how to do it, Acidity of alcohols and basicity of amines. SonarLint: A "NullPointerException" could be thrown; "getBody()" can return null. Now (sonarqube java analyzer version 4.3.0.7717) it's supported and works fine. What methods/tools can be used to determine the cause so that you stop the exception from causing the progra. The result of calling such a helper function should be . Which @NotNull Java annotation should I use? The fact that you can't pass a null (no object) with a reference parameter can be a reason to use a pointer instead. On many platforms, dereferencing a null pointer results in abnormal program termination, but this is not required by the standard. 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. Asking for help, clarification, or responding to other answers. 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. Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. And fwstr > is dereferenced in the following codes. It also uses the unsigned type size_t to pass the length parameter, ensuring that negative values are not passed to func(). Batch split images vertically in half, sequentially numbering the output files, Difficulties with estimation of epsilon-delta limit proof, Minimising the environmental effects of my dyson brain. Recovering from a blunder I made while emailing a professor. sonarlint complains that Unfortunately, its actual state also has some limitations, like the one you are hitting here. LANG.MEM.NPDLANG.STRUCT.NTADLANG.STRUCT.UPD, Null pointer dereferenceNull test after dereferenceUnchecked parameter dereference, Can detect violations of this rule. 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. How do I align things in the following tabular environment? Write a semantic patch to nd cases where the result of calling kmalloc is dereferenced with no previous NULL pointer test. 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. Avoid Returning null from Methods. That makes sense. Using Kolmogorov complexity to measure difficulty of problems? NullPointerException is thrown when program attempts to use an object reference that has the null value. Issues Components. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? 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. JCP version in use: 2.6. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. 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. Not the answer you're looking for? 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. 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. But what exactly does it mean to "dereference a null pointer"? (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). sometimes FP occurs. This engine is validating execution paths and checking for non-null values or null-check along the way, exploring all the possibilities. The only potential null is the return value of list(). In C# and Java, all reference types can point to null. We cannot understand how there could be a null pointer exception at the reported line. 11 Sep, 2006. . Not the answer you're looking for? I'd guess null pointers are not valid, even though they point to 0 bytes. Isn't easier just to check valid range of length? , NPE : null-, . 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. Hello. 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. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. That is only true if possibleNumbers contains no element.. BTW: none of these warnings are shown by . Whats the grammar of "For those whose stories they are"? Likewise, pointers to freed memory are not valid. Then we hit memcpy with length 0. To learn more, see our tips on writing great answers. Iflengthhas the value1, the addition yields 0, and png_malloc() subsequently returns a null pointer, which is assigned to chunkdata. There is a missing check for the return value from . validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. Find centralized, trusted content and collaborate around the technologies you use most. New replies are no longer allowed. I would also guess that pointers that point to the one-past-the-end of an array are also invalid. I suggest that this topic needs to include calloc() and realloc() Refer to Linux man pages online for more enlightenment about malloc(), and friends. Thanks for contributing an answer to Stack Overflow! The indicated severity is for this more severe case; on platforms where it is not possible to exploit a null pointer dereference to execute arbitrary code, the actual severity is low. After that, you call res.getBody() again. This issues is displayed by SonarQube. I feel my situation is not as complicated. A pointer is simply a variable that contains a memory address. 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. Is there a single-word adjective for "having exceptionally strong moral principles"? Dereferencing > this null pointer may cause the kernel go wrong. Can you please start a new thread and be more explicit about the issue you are observing. In C, dereferencing a null pointer is undefined behavior. It's a modular system with the . 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.