Possible fix: Assign a valid address to the pointer in all branches of the conditional statement.. Pointer can point to dynamically allocated memory. 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. sonarlint, sonarLint (3.2.) . Java Specification Participation Agreement version in use: 2.0. ", 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". Passing ownership of something also requires pointers. I suggest that this topic needs to include calloc() and realloc() Refer to Linux man pages online for more enlightenment about malloc(), and friends. The standard will simply copy 0 byteswhich is essentially a no-op. 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. What is a serialVersionUID and why should I use it? Reports. res.getBody() == null || res.getBody().getServiceResult() == null). It looks like a logic bug, which can cause a memory leaking. Can you please start a new thread and be more explicit about the issue you are observing. Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. This solution also ensures that theuser_data pointer is not null. All rights are expressly reserved. Im very new to sonar, is there a way to add methods to the whitelist? My question is; is my solution incorrect? As for today, the SE engine is able to explore non-overridable methods (static, for instance), when declared in the same file being analyzed. (C11, S7.24.2.1). which version of SonarQube are you using? java > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. Thanks for contributing an answer to Stack Overflow! Additionally, if input_str is a null pointer, the call to strlen() dereferences a null pointer, also resulting in undefined behavior. context.RaiseException . util.regex.Matcher, java - Swing .getParent() . 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. Is there a proper earth ground point in this switch box? ability to run any cleanup processes. We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. Why does Mister Mxyzptlk need to have a weakness in the comics? 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. It does not point to any area of memory. It is still a pointer though, to use it you just have to cast it to another kind of pointer first. The solution that I recommend is not work with null returns or variables on Java, try to avoid it. 3.7. Using Kolmogorov complexity to measure difficulty of problems? To learn more, see our tips on writing great answers. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 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. What methods/tools can be used to determine the cause so that you stop the exception from causing the progra. SonarJava Version 5.9.2 (build 16552). void *pointerVariableName = NULL; Since they are very general in nature, they are also known as generic pointers. You can use Optional instead. extern char _etext; The null concept refers to the idea that a pointer can hold a special value that is not equal to another pointer. What does "Could not find or load main class" mean? 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. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 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. it could allow an attacker to bypass security measures. When you have a variable of non-primitive type, it is a reference to an object. By explicitly teaching the C++ standard class behaviors we can make the Analyzer to find more bugs related to modern C++ code. Making statements based on opinion; back them up with references or personal experience. Status: Dormant. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? Many platforms can support testing for those also. Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. When a variable is declared as being a pointer to type void, it is known as a generic pointer. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. How do you ensure that a red herring doesn't violate Chekhov's gun? C# static code analysis: Null pointers should not be dereferenced Products In-IDE IDE extension that lets you fix coding issues before they exist! Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. NULL vs Uninitialized pointer - An uninitialized pointer stores an undefined value. 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). Some Interesting Facts: 1) void pointers cannot be dereferenced. Is there a single-word adjective for "having exceptionally strong moral principles"? How can we prove that the supernatural or paranormal doesn't exist? 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! Thered be huge value in jumping onto the latest version of the ecosystem (notably SonarQube), and benefit from all latest analyzers (e.g. Aaron:I suspect we are talking past each other. 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. What is a NullPointerException, and how do I fix it?,What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? Trying to understand how to get this basic Fourier Series. The article easily misleads the reader into believeing that ensuring pointer validity boils down to checking for pointer being not equal to NULL. 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). rev2023.3.3.43278. Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. Consider the following scenario: you are asked to create a Java class MetaDisplay that contains a static void printTable(String r) method. A reference to null should never be dereferenced/accessed. 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. Making statements based on opinion; back them up with references or personal experience. NullPointerException is a RuntimeException. 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. However, memory allocation > functions such as kstrdup() may fail and returns NULL. To be precise, once length is changed to a size_t and cannot take negative values, it cannot have an invalid value. 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 How can we let this pass? So Bar might not be initialized but then the last line of your example should not be evaluated in this case. 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.) , NPE : null-, . Unlike reference types, pointer types are not tracked by the default garbage . Null pointer should not be dereferenced . The issue arises when dereferenced pointers are used. All rights are expressly reserved. 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. (In contrast, the case of passing 0 bytes to malloc is addressed in C11.) 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. What is null pointer exception in android. null(java.lang.NullPointerException) . Dereferencing a null pointer results in undefined behavior. I reordered that code example to do all the checks before allocations. 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. And if there is no pointer_default declaration, then the default default is ref. Then we hit memcpy with length 0. That makes sense. In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. 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. Making statements based on opinion; back them up with references or personal experience. ), Does not guess that return values from malloc(), strchr(), etc., can be NULL (The return value from malloc() is NULL only if there is OOMo and the dev might not care to handle that. 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. io.NotSerializableException : java. Which version of SonarJava plugin do you have? Basically, yes. https://stackoverflow.com/questions/47534436/, https://stackoverflow.com/questions/47534436/, java - Jenkins groovy : Error: java. Trying to understand how to get this basic Fourier Series. This noncompliant code example is derived from a real-world example taken from a vulnerable version of the libpng library as deployed on a popular ARM-based cell phone [Jack 2007]. (/). This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. 1 Null pointers should not be dereferenced @CheckForNull String getName(){.} Doing so will cause a NullReferenceException to be thrown. Fixed by #1156 Contributor 94cb5f8 boris-unckel on Jul 28, 2021 9e62550 boris-unckel mentioned this issue on Jul 28, 2021 Closes #1155 - Null pointers should not be dereferenced #1156 Merged specifies the length of the array for a function. Identify where the allocation occurs. Thanks for contributing an answer to Stack Overflow! 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. What sort of strategies would a medieval military use against a fantasy giant? It is useful to have a function with portable interface but platform-dependent implementation: extern bool invalid(const void *); And the semantics, as I said, are different. LANG.MEM.NPDLANG.STRUCT.NTADLANG.STRUCT.UPD, Null pointer dereferenceNull test after dereferenceUnchecked parameter dereference, Can detect violations of this rule. 2008-2023 SonarSource S.A., Switzerland. I feel my situation is not as complicated. 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. If malloc() fails, it returns a null pointer that is assigned to c_str. minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). Avoid Returning null from Methods. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? This compliant solution ensures that the pointer returned by png_malloc() is not null. This sounds indeed like a bug in the flow when an exception is raised. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 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. JCP version in use: 2.6. 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. Can I tell police to wait and call a lawyer when served with a search warrant?
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