Which ensures that the chunkdata pointer is valid, but makes no such check to the user_data pointer. It looks like a logic bug, which can cause a memory leaking. positive S2637 in SonarQube 6.7.1 LTS, SonarQube for MSBuild not reporting quality issues, getTextContent() through "Null pointers should not be dereferenced". What is a serialVersionUID and why should I use it? My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? 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). )}"); The 2nd NCCE/CS pair seems redundant with the first NCCE/CS pair. specifies the length of the array for a function. 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 Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. Passing a null pointer tomemcpy() would produce undefined behavior, even if the number of bytes to copy were 0. 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>. Not the answer you're looking for? EXP01-J. Do not use a null in a case where an object is required Consider the following scenario: you are asked to create a Java class MetaDisplay that contains a static void printTable(String r) method. What is pointed to should only be deleted if it was created with new. 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. I added a comment to explain that SIZE_MAX is the limit of size_t. C# static code analysis: Null pointers should not be dereferenced Products In-IDE IDE extension that lets you fix coding issues before they exist! I have a sonar alert on this call minRating.getRatgCaam(). Sonar is ok. Recovering from a blunder I made while emailing a professor. So the first execution of ValidateNumber inside the foreach works fine and valid is set to true.The second execution throws the exception and exception is set in the catch-Block.. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. . Original Java Specification Request (JSR) - Java Community Process Callable statement giving Null Pointer Exception - Oracle Forums https://stackoverflow.com/questions/47534436/, https://stackoverflow.com/questions/47534436/, java - Jenkins groovy : Error: java. Finally, there is the matter of the compliant solution. Pittsburgh, PA 15213-2612 In my experience, there are reasons to check for a NULL pointer other than dereferencing it. - the incident has nothing to do with me; can I use this this way? 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. Alternate Terms Relationships Carnegie Mellon University The problem is that something like %*pbl which reads a bitmask, will save the pointer to the bitmask in the buffer. can have the value zero on a call to that function. For example the following program doesn't compile. Note that it doesn't know how to check for non-heap, non-stack. [PATCH 1/3] usb: ucsi: Fix NULL pointer deref in ucsi_connector_change() It also adds assertions to document that certain other pointers must not be null. Null Pointer Explain about call by reference with an . 1. Introduction - Understanding and Using C Pointers [Book] Null Dereference | OWASP Foundation ii. I suppose there is a question of "Is a pointer that points to 0 bytes valid?" Trying to understand how to get this basic Fourier Series. We might set a pointer to null even if we are not freeing a object, simply to dissociate one object from another: tty_driver->tty = NULL; /* detach low level driver from the tty device */ On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. , . The correct idiom is to only allocate storage if the pointer is currently NULL. Batch split images vertically in half, sequentially numbering the output files, Recovering from a blunder I made while emailing a professor. [squid:S2259] False positive - "Null pointers should not be dereferenced" But the problem also exists in the compliant version, so I'm not so sure that it's really compliant. Clearly the standard enumerates 1 case of undefined behavior, but makes no special mention of n=0. 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. Off by one error: It is the third example. Which version of SonarJava plugin do you have? ", 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". 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. On many platforms, dereferencing a null pointer results in abnormal program termination, but this is not required by the standard. To learn more, see our tips on writing great answers. In C, dereferencing a null pointer is undefined behavior. 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. 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. Find centralized, trusted content and collaborate around the technologies you use most. The null pointer check for writing or dereferencing should be a compiler flag or library setting. These can be: Invoking a method from a null object. sonarLint (3.2.) But no where in that particular idiom would a NULL pointer necessarily be deferenced. 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. Find centralized, trusted content and collaborate around the technologies you use most. How can we let this pass? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Null pointer - Wikipedia When should pointers be checked for NULL in C? null(java.lang.NullPointerException) . The method isNR (minRating) is a helper method that validate among other things, if the object minRating is null public boolean isNR (AgencyRating rating) { return rating == null || isNR (rating.getRatgCaam ()); } When I added the not null validation as sonar suggest. 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. All content is copyright protected. The expected result here is solve the issue with sonarqube. Can I tell police to wait and call a lawyer when served with a search warrant? 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. Thanks for contributing an answer to Stack Overflow! What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? The article easily misleads the reader into believeing that ensuring pointer validity boils down to checking for pointer being not equal to NULL. 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. 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]. how to handle Sonarlint java:S2259 (Null pointers should not be It also uses the unsigned type size_t to pass the length parameter, ensuring that negative values are not passed to func(). This will normally lead to an unhandled error, resulting in a segmentation fault. Sonar detects that res.getBody() can be null when you do the check res.getBody()==null. How to avoid dereferencing null pointers in Java - Quora To learn more, see our tips on writing great answers. The value 0 for the number of bytes to copy is not what causes the UB, it's the null pointer value which triggers it. What is generic pointer? Basically, yes. > Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to > the caller site. name result . SonarQube - Null Pointer Dereference Issue java simonsirak (Simon Sirak) June 14, 2018, 1:18pm 1 Hi! Your assertion is not backed by the wording in the standard, nor by common implementer understanding. . 11 Sep, 2006. My below code where I'm calling a stored procedure is giving a null pointer exception. When B is null, The control reaches inside the main if block only when length of A is 1. The alert is related to the sonar rule : Null pointers should not be dereferenced. Removing the check "exception != null" raises S2259 "Null pointers should not be dereferenced" on "throw exception". It's still illegal. Cause we need throw our own Runtime Exception, well-known methods wont help. Powered by Discourse, best viewed with JavaScript enabled. You can use Optional instead. Possible fix: Assign a valid address to the pointer in all branches of the conditional statement.. Pointer can point to dynamically allocated memory. When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. Connect and share knowledge within a single location that is structured and easy to search. ), 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. I suppose we can check that that is not null, but we cannot check that it is valid (in any portable way). There are many ways to resolve this. 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. Powered by Discourse, best viewed with JavaScript enabled. Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. Ticket opened : Thanks a lot for the minimalized reproducer ! Null pointer should not be dereferenced . When length is zero, it is probably unusable condition for this function. 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 Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? Is the God of a monotheism necessarily omnipotent? The same problem we will have with "Add at least one assertion to this test case." Replacing broken pins/legs on a DIP IC package, Bulk update symbol size units from mm to map units in rule-based symbology, How do you get out of a corner when plotting yourself into a corner. Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. 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. How to fix int cannot be dereferenced? Explained by Sharing Culture I believe in this case, either expression would work. However there is no portable way to verify that the pointer is valid, other than checking for null. java This compliant solution ensures that both input_str andthe pointer returned by malloc() are not null: This noncompliant code example is from a version of drivers/net/tun.c and affects Linux kernel 2.6.30 [Goodin 2009]: The sk pointer is initialized to tun->sk before checking if tun is a null pointer. How to deal with "java.lang.OutOfMemoryError: Java heap space" error? 0 is certainly within the 'domain of the function' (a phrase defined by mathematics but not by C11), as copying 0 bytes is well-understood (although silly). Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. This solution also ensures that theuser_data pointer is not null. When B is null, The control reaches inside the main if block only when length of A is 1. When and how should I use a ThreadLocal variable? Linear regulator thermal information missing in datasheet, Identify those arcade games from a 1983 Brazilian music video. which version of SonarQube are you using? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Please explain: Without this, we wont be able to help you. There are other problems with this code, as is noted in the rule. Find centralized, trusted content and collaborate around the technologies you use most. So the SIZE_MAX check was unnecessary. The result of calling such a helper function should be . In some situations, however, dereferencing a null pointer can lead to the execution of arbitrary code [Jack 2007,van Sprundel 2006]. sonar-java. Do "superinfinite" sets exist? In multithreaded programs, null pointer dereferences can violate cache coherency policies and can cause resource leaks. There are many ways to resolve this. An awesome tip to avoid NPE is to return empty strings or empty collections rather than null. And the semantics, as I said, are different. You need to benchmark. Why is there a voltage on my HDMI and coaxial cables? We cannot understand how there could be a null pointer exception at the reported line. In C# and Java, all reference types can point to null. Does a summoned creature play immediately after being summoned by a ready action? The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. vegan) just to try it, does this inconvenience the caterers and staff? After that, you call res.getBody() again. context.RaiseException . If you try to access any member variables or methods with that variable, you are trying to dereference it. Obviously the value of that pointer could have changed since the . When I added the not null validation as sonar suggest. VB.NET static code analysis: Null pointers should not be dereferenced If you say [in] or [out] without a modifier, then the modifier defaults to the pointer_default for the enclosing class. static-code-analysis You're in a company-managed project. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? PS: I also tried the code in android studio which uses Lint and got no warnings. util.regex.Matcher, java - Swing .getParent() . Instead use String.valueOf (object). 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. LANG.MEM.NPDLANG.STRUCT.NTADLANG.STRUCT.UPD, Null pointer dereferenceNull test after dereferenceUnchecked parameter dereference, Can detect violations of this rule. Answered: difference between a void pointer and a | bartleby 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. {"serverDuration": 214, "requestCorrelationId": "084acdc104f21c51"}, EXP34-C. Do not dereference null pointers, Clever Attack Exploits Fully-Patched Linux Kernel, ERR33-C. Detect and handle standard library errors, one compliant and one non-compliant example, CERT Oracle Secure Coding Standard for Java, EXP01-J. Im very new to sonar, is there a way to add methods to the whitelist? Extended Description NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions. If the pointer is not NULL, see if the assignment occurs only in a branch of a conditional statement.Investigate when that branch does not execute. ssize_t (*aio_read)(struct kiocb *, char __user *, size_t . 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. Status: Dormant. I feel my situation is not as complicated. This rule applies to all null pointers, regardless of which function returned them. Agreed. Pointer is so confusing : Stack with singly linked list in C - Stack Why pointers are not used in python? Explained by Sharing Culture Interactions/interfaces with C can't use references. The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). 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). 0 is a valid value as far as memcpy() is concerned, and malloc() has special language concerning malloc(0). Sonar is ok. Sonar can't determine that the helper method did the null validation. minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). It means this is illegal: T* p = nullptr; T& r = *p; // illegal NOTE: Please do not email us saying the above works on your particular version of your particular compiler. It is useful to have a function with portable interface but platform-dependent implementation: extern bool invalid(const void *); Is a PhD visitor considered as a visiting scholar? (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). Is there a proper earth ground point in this switch box? At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to . At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to bypass security measures. "After the incident", I started to be more careful not to trip over things. Null pointers should not be dereferenced. To be precise, once length is changed to a size_t and cannot take negative values, it cannot have an invalid value. This compliant solution ensures that the pointer returned by png_malloc() is not null. I reordered that code example to do all the checks before allocations. Find centralized, trusted content and collaborate around the technologies you use most. At worst, it could expose debugging information that would be useful to an attacker or it could allow an Provide a self-contained reproducer (zipped project?) [PATCH v2] vsprintf: Do not have bprintf dereference pointers Many platforms can support testing for those also. I suggest that this topic needs to include calloc() and realloc() Refer to Linux man pages online for more enlightenment about malloc(), and friends. 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. 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. sonarqube False-positives are pointed out in other SO posts (1 & 2), where nulls are involved across functions and procedures. which would allow us to systematically observe what you are having. Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. How can we prove that the supernatural or paranormal doesn't exist? Using Kolmogorov complexity to measure difficulty of problems? Correct; a null pointer is not a valid pointer for the C library functions. How to use Slater Type Orbitals as a basis functions in matrix method correctly? How to get rid of NullPointerException - freeCodeCamp.org Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. How do I align things in the following tabular environment? NullPointerException is thrown when program attempts to use an object reference that has the null value. That is only true if possibleNumbers contains no element.. BTW: none of these warnings are shown by . What does "Could not find or load main class" mean? Null pointers should not be dereferenced (#42) Issues - GitLab Making statements based on opinion; back them up with references or personal experience. Small typo nit: "such as if i t pointed to freed memory" meant to say "if it" instead (removing whitespace). [SONARJAVA-2808] - Jira - SonarSource NULL POINTERS SHOULD NOT BE DEREFERENCED - jobhuntley.com @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. Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. That interpretation of the standard is not supported universally. That is, sets equivalent to a proper subset via an all-structure-preserving bijection. To learn more, see our tips on writing great answers. Aaron:I suspect we are talking past each other. very old code or C code being worked into c++ may have functions that expect the user to delete the data. [JAVA] 3.9 - FP for S2259 Null pointers should not be dereferenced How to use java.net.URLConnection to fire and handle HTTP requests, Why should Java 8's Optional not be used in arguments, sonarLint complains "Null pointers should not be dereferenced (squid:S2259)" despite that possibility being handled. This topic was automatically closed 7 days after the last reply. Styling contours by colour and by line thickness in QGIS. All content is copyright protected. Some Interesting Facts: 1) void pointers cannot be dereferenced. Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Is it possible to rotate a window 90 degrees if it has the same length and width? Currently I'm working with SonarQube solving issues but I'm facing a trouble to how handle null pointers that shouldn't be dereferenced. Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. The fact that you can't pass a null (no object) with a reference parameter can be a reason to use a pointer instead. And the compliant solution guarantees that the pointer will be valid if the code calls memcpy(). uninitialized reference-type class members. 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. Why does Mister Mxyzptlk need to have a weakness in the comics? sonarlint complains that 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" Seems the analizer don't recognice the logic with the funcional object Optional. sonarlint, sonarLint (3.2.) Dereferencing > this null pointer may cause the kernel go wrong. There is no guarantee that subsequent invocations are returning the same value, thats why issue is raised. rev2023.3.3.43278. I doubt that "length" of zero is a valid parameter, and although there no copy, but we see memory allocation. In C/C++ speak, 'dereferencing' simply means getting the object that a pointer . Doing so will at best cause abrupt program termination, without the When you have a variable of non-primitive type, it is a reference to an object. rev2023.3.3.43278. Description The program can potentially dereference a null pointer, thereby raising a NullPointerException. Is there a solution to add special characters from software and how to do it, Acidity of alcohols and basicity of amines.