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. In the meantime, Im locking this thread. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. The idea is not to guarantee validity, but to catch a substantial number of problems that could occur. Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. 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). Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, SonarQube null pointers should not be dereferenced on try/catch, How Intuit democratizes AI development across teams through reusability. This code also violates ERR33-C. Detect and handle standard library errors. 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. In C# and Java, all reference types can point to null. strongSwan - strongSwan Vulnerability (CVE-2023-26463) What methods/tools can be used to determine the cause so that you stop the exception from causing the progra. By explicitly teaching the C++ standard class behaviors we can make the Analyzer to find more bugs related to modern C++ code. When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. Reports. Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. Basically, yes. Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. 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.) How can we let this pass? This is a feature that we are currently heavily working on to be able to switch off such kind of false positives. Why void pointer cannot be dereferenced? Explained by Sharing Culture Analysis of Haiku Operating System (BeOS Family) by PVS-Studio. Part 1 I already tried to put ResponseEntity responseDto inside my try clause assigning and returning the respective value but its mandatory to return something out the try/catch. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Shouldn't the function check all pointers before dereferencing them or passing them to another function? [PATCH v2] vsprintf: Do not have bprintf dereference pointers What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? NULL POINTERS SHOULD NOT BE DEREFERENCED - jobhuntley.com Reports. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. COMP-PROG-MODULE-5-6-REVIEWER.pdf - Pointers to string ncdu: What's going on with this second size column? Connect and share knowledge within a single location that is structured and easy to search. Null pointers should not be dereferenced. The null pointer check for writing or dereferencing should be a compiler flag or library setting. ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . It also reinforces the notion to the reader that any time you see arithmetic in an allocation expression, you need to think about corner-cases. 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. Issues Components. This will normally lead to an unhandled error, resulting in a segmentation fault. On many platforms, dereferencing a null pointer results in abnormal program termination, but this is not required by the standard. Whats the grammar of "For those whose stories they are"? Doing so will at best cause abrupt program termination, without the There is a missing check for the return value from . The alert is related to the sonar rule : Null pointers should not be dereferenced. context.RaiseException . which version of SonarQube are you using? Dereferencing a null pointer is undefined behavior. In the simplest case, this function just returns the result of calling kmalloc. Rule squid:S2259 is based on a Symbolic Execution (SE) engine. When a variable is declared as being a pointer to type void, it is known as a generic pointer. best, such an exception will cause abrupt program termination. 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. Put a new ResponseEntity is wrong because I won't know what will be the answer for the status of http. 9.7 Null pointers - Learn C++ - LearnCpp.com VB.NET static code analysis: Null pointers should not be dereferenced Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. I added a comment to explain that SIZE_MAX is the limit of size_t. Why do academics stay as adjuncts for years rather than move around? Null pointer should not be dereferenced . JCP version in use: 2.6. How to use Slater Type Orbitals as a basis functions in matrix method correctly? versions used (SonarQube, Scanner, language analyzer) 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. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. that we haven't considered here: I'd guess null pointers are not valid, even though they point to 0 bytes. What are the effects of exceptions on performance in Java? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. All rights are expressly reserved. return p == NULL || (char *)p < &_etext; , . Unlike reference types, pointer types are not tracked by the default garbage . Made code more compliant with other rules. Good question! Just because something is a pointer does not mean you should call delete . Automated Detection Null pointer dereferences can happen in path-dependent ways. Revert Update S2259: "Null pointer dereference" CFG should ignore expressions in Debug.Assert #397 Introduce means to not raise "Expression always true/false" on values that were checked with Debug.Assert. That is why I explicitly check for this in my attempted solution. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. the Java one). Hi @Michael! ), NPD.CHECK.CALL.MIGHTNPD.CHECK.CALL.MUSTNPD.CHECK.MIGHTNPD.CHECK.MUSTNPD.CONST.CALLNPD.CONST.DEREFNPD.FUNC.CALL.MIGHTNPD.FUNC.CALL.MUSTNPD.FUNC.MIGHTNPD.FUNC.MUSTNPD.GEN.CALL.MIGHTNPD.GEN.CALL.MUSTNPD.GEN.MIGHTNPD.GEN.MUSTRNPD.CALLRNPD.DEREF, 45 D, 123 D, 128 D, 129 D, 130 D, 131 D, 652 S, Checks for use of null pointers (rule partially covered). The expected result here is solve the issue with sonarqube. Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. 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?) The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. Find centralized, trusted content and collaborate around the technologies you use most. Using Kolmogorov complexity to measure difficulty of problems? Making statements based on opinion; back them up with references or personal experience. Is there a proper earth ground point in this switch box? Doing so will cause a NullPointerException to be thrown. Not the answer you're looking for? Is there a single-word adjective for "having exceptionally strong moral principles"? When B is null, The control reaches inside the main if block only when length of A is 1. 0 is a valid value as far as memcpy() is concerned, and malloc() has special language concerning malloc(0). Does it just mean failing to correctly check if a value is null? We cannot understand how there could be a null pointer exception at the reported line. (from res.getBody().getServiceResult() ). java How to tell which packages are held back due to phased updates. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? 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. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 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. When B is null, The control reaches inside the main if block only when length of A is 1. http://blog.llvm.org/2011/05/what-every-c-programmer-should-know_14.html. I suggest that this topic needs to include calloc() and realloc() Refer to Linux man pages online for more enlightenment about malloc(), and friends. sonarqube How to deal with "java.lang.OutOfMemoryError: Java heap space" error? What should you do if somebody passes a null pointer for a parameter Status: Dormant. When and how should I use a ThreadLocal variable? Recovering from a blunder I made while emailing a professor. I've changed it to say null pointer instead of invalid pointer. What is pointed to should only be deleted if it was created with new. Phew, we're agreed here. I doubt that "length" of zero is a valid parameter, and although there no copy, but we see memory allocation. NullPointerException is a RuntimeException. Description: This JSR will work to develop standard annotations (such as @NonNull) that can be applied to Java programs to assist tools that detect software defects. 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. Minimising the environmental effects of my dyson brain. Not the answer you're looking for? assert(!invalid(p)); // or whatever, bool invalid(const void *p) { MSBuild SonarQube Runner Resharper Plugin receives skipping info errors File not in sonarqube, SonarQube jenkins plugin returns "Server returned HTTP response code: -1, message: 'null' for URL: https://api.github.com/user", SonarQube: Ignore issues in blocks not working with regex, sonarLint complains "Null pointers should not be dereferenced (squid:S2259)" despite that possibility being handled, Java: (false?) Thanks for your relpy. Consider the following scenario: you are asked to create a Java class MetaDisplay that contains a static void printTable(String r) method. 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. A reference to null should never be dereferenced/accessed. But passing 0 to memcpy() is not one of them. You can use Optional instead. We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. Doing so will cause a NullReferenceException to be thrown. What does "Could not find or load main class" mean? NullPointerException is thrown when program attempts to use an object reference that has the null value. sonar_etReines-CSDN NULL vs Void Pointer - Null pointer is a value, while void pointer is a type. Passing ownership of something also requires pointers. I reordered that code example to do all the checks before allocations. rev2023.3.3.43278. As for today, the SE engine is able to explore non-overridable methods (static, for instance), when declared in the same file being analyzed. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. 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, This error was found in the following code: else if (foo.list().length > 0) { }, I attempted to resolve this by rewriting as: else if (null != foo.list() && foo.list().length > 0) { }, foo is an instance of the File class in Java, and is directly instantiated through new File(). 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. - the incident has nothing to do with me; can I use this this way? Thus we should check > this kstrdup() operation. This code also violates ERR33-C. Detect and handle standard library errors. 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 (?,?,?,?,?,?,?,? Trying to understand how to get this basic Fourier Series. We really appreciate your help. 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. IMHO, the rule title should be changed to something less general. 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 . I think "res.getBody() == null" checks null first so it should go to return line, not reach to next if condition. S2259: Null pointers should not be dereferenced - Sonar Community 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. SONAR, SONARSOURCE, SONARLINT, SONARQUBE and SONARCLOUD are trademarks of SonarSource S.A. All other trademarks and copyrights are the property of their respective owners. You're in a company-managed project. So the SIZE_MAX check was unnecessary. 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. 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. 1. Introduction - Understanding and Using C Pointers [Book] ii. This cross-file approach analysis can be quite resource-consuming, and we are not ready to openly enable the feature. There are many ways to resolve this. In C/C++ speak, 'dereferencing' simply means getting the object that a pointer . Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Finally my method is returning a response with value of restTemplate. 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. If you write [ref], then a null pointer is not allowed, but if you write [unique], then a null pointer is permitted. Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. squid:S2259 : A "NullPointerException" could be thrown; "dc" is So no checking of the length is necessary (besides preventing integer overflow, which the compliant solution does). PS: I also tried the code in android studio which uses Lint and got no warnings. 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 Passing a null pointer tomemcpy() would produce undefined behavior, even if the number of bytes to copy were 0. 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. Essentially, this code and the previous dereference disagree as to whether this value is allowed to be null. This is indeed an obvious False Positive from the rule. EXP34-C. Do not dereference null pointers - Confluence Null Pointer Exception In Java - GeeksforGeeks - A computer science To subscribe to this RSS feed, copy and paste this URL into your RSS reader. This compliant solution ensures that the pointer returned by png_malloc() is not null. Finally, there is the matter of the compliant solution. In some situations, however, dereferencing a null pointer can lead to the execution of arbitrary code [Jack 2007,van Sprundel 2006]. // <------- 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. This is a matter of style, and also following code walkthrough. Discover SonarLint SaaS Setup is effortless and analysis is automatic for most languages Discover SonarCloud Self-Hosted Fast, accurate analysis; enterprise scalability Discover SonarQube Secrets ABAP A pointer is simply a variable that contains a memory address. Explain about call by reference with an . in above code, In the code, we check the not nullity with java.util.Objects.nonNull(). Is it possible to create a concave light? So let me be more precise in my wording: I assert that a platform whose memcpy() did anything besides copy zero bytes when given n=0 and valid src and dest pointers was not C-standards-compliant. How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. It is still a pointer though, to use it you just have to cast it to another kind of pointer first. assigning to dereferenced struct pointers 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" But when length of A is 1, the control never reaches the else block. 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). But even with this, the concerned object it tagged as a possible NullPointerException problem. To be precise, once length is changed to a size_t and cannot take negative values, it cannot have an invalid value. Hi Andreas, Thanks for the feedback. Why does the second compliant example permit using possibly-null pointers? Powered by Discourse, best viewed with JavaScript enabled. A bug can cause them never to be reassigned. Java Specification Participation Agreement version in use: 2.0. In this noncompliant code example, input_str is copied into dynamically allocated memory referenced by c_str. 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. SonarQube Version 6.7.2 (build 37468) In the case of the ARM and XScale architectures, the 0x0 address is mapped in memory and serves as the exception vector table; consequently, dereferencing 0x0 did not cause an abnormal program termination. 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. There is no guarantee that subsequent invocations are returning the same value, thats why issue is raised. How to fix int cannot be dereferenced? Explained by Sharing Culture 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. C# static code analysis: Null pointers should not be dereferenced Im very new to sonar, is there a way to add methods to the whitelist? static-code-analysis Depending on whether the pointer is valid (i.e. It could be non-null the first time but not the second time, sonar does not know this. 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 . 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. Can you please start a new thread and be more explicit about the issue you are observing.

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