Java Specification Participation Agreement version in use: 2.0. Do "superinfinite" sets exist? 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 Can you please start a new thread and be more explicit about the issue you are observing. After that, you call res.getBody() again. 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 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. Now, you can find the list of whitelisted methods here. Finally my method is returning a response with value of restTemplate. Identify where the allocation occurs. Some Interesting Facts: 1) void pointers cannot be dereferenced. Null Dereference | OWASP Foundation An awesome tip to avoid NPE is to return empty strings or empty collections rather than null. res.getBody() == null || res.getBody().getServiceResult() == null). Pointer is so confusing : Stack with singly linked list in C - Stack 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. Trying to understand how to get this basic Fourier Series. We seem to have a false positive for "Null pointers should not be dereferenced" - squid:S2259. 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. Original Java Specification Request (JSR) - Java Community Process Is the God of a monotheism necessarily omnipotent? I added a comment to explain that SIZE_MAX is the limit of size_t. (I think you cover that in a different rule.) So Bar might not be initialized but then the last line of your example should not be evaluated in this case. I have checked on multiple . When B is null, The control reaches inside the main if block only when length of A is 1. Issues Components. Consider the following scenario: you are asked to create a Java class MetaDisplay that contains a static void printTable(String r) method. "After the incident", I started to be more careful not to trip over things. Search for vulnerabilities resulting from the violation of this rule on the CERT website. These can be: Invoking a method from a null object. I could've fixed this by changing else to else if (B != null && B.length == 1), but doing so rewards me with warning "condition(B != null && B.length == 1) is always true". How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. 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. There are many ways to resolve this. That is, sets equivalent to a proper subset via an all-structure-preserving bijection. 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. please explain null pointer dereference [Solved] (Java in General forum IDE extension that lets you fix coding issues before they exist! What is a serialVersionUID and why should I use it? Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. A bug can cause them never to be reassigned. Solution 1, it looks like, today's solution tomorrow's problem. Is there a single-word adjective for "having exceptionally strong moral principles"? Pointer Arithmetic in c - Unit - 4 1. Define pointer. Explain about the It does not point to any area of memory. that we haven't considered here: I'd guess null pointers are not valid, even though they point to 0 bytes. On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. Share Improve this answer Follow answered Oct 5, 2017 at 16:27 5.2 Part 2 Sometimes a helper function is de ned to perform the memory allocation. 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). 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. As a result, this noncompliant code example is vulnerable to a null pointer dereference exploit, because null pointer dereferencing can be permitted on several platforms, for example, by using mmap(2) with the MAP_FIXED flag on Linux and Mac OS X, or by using the shmat() POSIX function with the SHM_RND flag [Liu 2009]. . You're in a company-managed project. How to tell which packages are held back due to phased updates. Provide a self-contained reproducer (zipped project?) The return value from strchr() is often NULL, but the dev might know that a specific strchr() function call will not return NULL. We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. [SONARJAVA-2808] - Jira - SonarSource At this point we define size as strlen(input_str) + 1. SonarQube - Null Pointer Dereference Issue - Sonar Community assigning to dereferenced struct pointers I am a student implementing stack with singly linked list using C, following a book called Fundamentals of Data Structures in C.. This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. Check whether a String is not Null and not Empty. If the project is not compiled, and without sonar.java.binaries whether the white list takes effect? Optimizers are optimizing based on this latitude and have been for years. Finally, there is the matter of the compliant solution. Fix S2583/S2589 FP: On null check if instance is used in try block - GitHub If that variable hasn't had a reference assigned, it's a null reference, which (for internal/historical reasons) is referred to as a null pointer. Such long getter chains can also be replaced with Optional + map + ifPresent lambda style. the Java one). By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. The chunkdata pointer is later used as a destination argument in a call to memcpy(), resulting in user-defined data overwriting memory starting at address 0. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? My question is; is my solution incorrect? It's a modular system with the . The result of calling such a helper function should be . When I added the not null validation as sonar suggest. name result . Is null check needed before calling instanceof? What are the effects of exceptions on performance in Java? java Asking for help, clarification, or responding to other answers. Which version of SonarJava plugin do you have? Null pointers should not be dereferenced (#42) Issues - GitLab null(java.lang.NullPointerException) . LANG.MEM.NPDLANG.STRUCT.NTADLANG.STRUCT.UPD, Null pointer dereferenceNull test after dereferenceUnchecked parameter dereference, Can detect violations of this rule. It is generally accepted that zeroing a pointer is a good way to mark it as invalid and dereferencing an invalid pointer is a bug. C# static code analysis: Null pointers should not be dereferenced Products In-IDE IDE extension that lets you fix coding issues before they exist! NullPointerException is thrown when program attempts to use an object reference that has the null value. We cannot understand how there could be a null pointer exception at the reported line. I suppose there is a question of "Is a pointer that points to 0 bytes valid?" 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. That noncompliant code example (it's currently the 3rd) came from the Linux kernel, whose source is publicly available. 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. 4500 Fifth Avenue
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 methods/tools can be used to determine the cause so that you stop the exception from causing the progra. IMHO, the rule title should be changed to something less general. How to avoid dereferencing null pointers in Java - Quora 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 . Hi Andreas, Thanks for the feedback. Is there a single-word adjective for "having exceptionally strong moral principles"? Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, S2259: Null pointers should not be dereferenced, find the list of whitelisted methods here, Rule java:S2259: False-positive NullPointerException bug logged when variable is null-checked by an imported method, What is the issue you are observing, in details, What version of SonarSource products you are using, as well as the version of SonarJava. Not the answer you're looking for? What is a NullPointerException, and how do I fix it?,What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? The issue arises when dereferenced pointers are used. The standard will simply copy 0 byteswhich is essentially a no-op. Null pointers should not be dereferenced #1155 - GitHub [squid:S2259] False positive - "Null pointers should not be dereferenced" False fault 'Null pointers should not be dereferenced' using Optional That is only true if possibleNumbers contains no element.. BTW: none of these warnings are shown by . Doing so will cause a NullReferenceException to be thrown. So Bar might not be initialized but then the last line of your example should not be evaluated in this case. What is a NullPointerException, and how do I fix it? What does it mean that a reference must refer to an object, not a dereferenced null pointer? Calls to extension methods are not reported because they can still operate on null values. Passing ownership of something also requires pointers. Using Kolmogorov complexity to measure difficulty of problems? Linear regulator thermal information missing in datasheet, Identify those arcade games from a 1983 Brazilian music video. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. In the complaint version, I like to make source code checking a little quicker by putting parenthesizes around arguments to |= or &= as. Please explain: Without this, we wont be able to help you. It is still a pointer though, to use it you just have to cast it to another kind of pointer first. Is there a solution to add special characters from software and how to do it, Acidity of alcohols and basicity of amines. in above code, Many platforms can support testing for those also. The only potential null is the return value of list(). It also uses the unsigned type size_t to pass the length parameter, ensuring that negative values are not passed to func(). Not the answer you're looking for? )}"); CWE - CWE-476: NULL Pointer Dereference (4.10) - Mitre Corporation And the semantics, as I said, are different. At worst, it could expose debugging information that would be useful to an attacker or it could allow an What should you do if somebody passes a null pointer for a parameter Unfortunately the problem is much more complex, and generally unsolvable within standard C. Consider the following example: There's no way f can check whether x points into valid memory or not. 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 this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. assert(!invalid(p)); // or whatever, bool invalid(const void *p) { 9.7 Null pointers - Learn C++ - LearnCpp.com C# static code analysis: Null pointers should not be dereferenced Find centralized, trusted content and collaborate around the technologies you use most. Whoops, you're right. What is null pointer exception in android. Appropriate typecasting is necessary. // <------- 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. When exploring such methods, the engine then deduces behaviors regarding null-checking (among other things). Explain about call by reference with an . If malloc() fails, it returns a null pointer that is assigned to c_str. The same problem we will have with "Add at least one assertion to this test case." Likewise, pointers to freed memory are not valid. sometimes FP occurs. Pointers in C Explained - They're Not as Difficult - freeCodeCamp.org 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. which version of SonarQube are you using? Mutually exclusive execution using std::atomic? I'd guess null pointers are not valid, even though they point to 0 bytes. Since you cannot have a variable of type void, the pointer will not point to any data and therefore cannot be dereferenced. Sonar violation: Null pointers should not be dereferenced #7459 - GitHub To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. I believe in this case, either expression would work. Is there a proper earth ground point in this switch box? specifies the length of the array for a function. @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. The article easily misleads the reader into believeing that ensuring pointer validity boils down to checking for pointer being not equal to NULL. At worst, it could expose debugging information that would be useful to an attacker, or In multithreaded programs, null pointer dereferences can violate cache coherency policies and can cause resource leaks. Is it possible to create a concave light? 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). When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. Is it possible to rotate a window 90 degrees if it has the same length and width? 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. Thanks for contributing an answer to Stack Overflow! What sort of strategies would a medieval military use against a fantasy giant? So no checking of the length is necessary (besides preventing integer overflow, which the compliant solution does). Can I tell police to wait and call a lawyer when served with a search warrant? rev2023.3.3.43278. This issues is displayed by SonarQube. 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. Ticket opened : Thanks a lot for the minimalized reproducer ! ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . Basically, yes. 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. If you preorder a special airline meal (e.g. This latter use of pointers is a combined boolean/satellite: the pointer being non-null indicates "I have this sister object", and it provides that object. Hi @Michael! When you have a variable of non-primitive type, it is a reference to an object. 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. (from res.getBody().getServiceResult() ). 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 VB.NET static code analysis: Null pointers should not be dereferenced . rev2023.3.3.43278. context.RaiseException . > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. Believing that dereferencing NULL shouldn't crash the system doesn't make it true. https://stackoverflow.com/questions/47534436/, https://stackoverflow.com/questions/47534436/, java - Jenkins groovy : Error: java. 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. Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. Using platform-specific means (e.g. sonarlint complains that Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? sonar_etReines-CSDN So, this code should address the Sonar problem: You can also eliminate the null check using Optional
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null pointers should not be dereferenced