I'd guess WG14 has considered these questions, but I haven't until now :). 1 Answer Sorted by: 1 Your code is ok. Best to cite C11 s7.24.2.1 here: The memcpy function copies n characters from the object pointed to by s2 into the object pointed to by s1. A bug can cause them never to be reassigned. My below code where I'm calling a stored procedure is giving a null pointer exception. which version of SonarQube are you using? Search for vulnerabilities resulting from the violation of this rule on the CERT website. My question is; is my solution incorrect? How can we prove that the supernatural or paranormal doesn't exist? 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. 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?) Doing so will cause a NullPointerException to be thrown. You're in a company-managed project. 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>. sonar_etReines-CSDN 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. rev2023.3.3.43278. null(java.lang.NullPointerException) . Null pointers should not be dereferenced (#42) Issues - GitLab Is there a proper earth ground point in this switch box? Interactions/interfaces with C can't use references. Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. I would also guess that pointers that point to the one-past-the-end of an array are also invalid. 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. the Java one). 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). I'd guess null pointers are not valid, even though they point to 0 bytes. Issues Components. What is generic pointer? The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). Which @NotNull Java annotation should I use? It could be non-null the first time but not the second time, sonar does not know this. References, C++ FAQ res.getBody() == null || res.getBody().getServiceResult() == null). https://stackoverflow.com/questions/47534436/, https://stackoverflow.com/questions/47534436/, java - Jenkins groovy : Error: java. I say "theoretical" because I have not successfully produced strings of this length in testing. The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Finally my method is returning a response with value of restTemplate. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 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. Passing a null pointer tomemcpy() would produce undefined behavior, even if the number of bytes to copy were 0. Pointer is so confusing : Stack with singly linked list in C - Stack C# static code analysis: Null pointers should not be dereferenced Products In-IDE IDE extension that lets you fix coding issues before they exist! [PATCH v2] vsprintf: Do not have bprintf dereference pointers 11 Sep, 2006. Is there a proper earth ground point in this switch box? Aaron:I suspect we are talking past each other. On many platforms, dereferencing a null pointer results inabnormal program termination, but this is not required by the standard. Does a summoned creature play immediately after being summoned by a ready action? For example the following program doesn't compile. 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. SonarLint: A "NullPointerException" could be thrown; "getBody()" can return null. While the engine is in practice already able to explore code from other files if needed (relying solely on bytecode), we restrain this approach to a limited set of well-known methods from standard libraries, for which we know that behaviors are correctly produced. [SONARJAVA-2808] - Jira - SonarSource I reordered that code example to do all the checks before allocations. It also uses the unsigned type size_t to pass the length parameter, ensuring that negative values are not passed to func(). In some situations, however, dereferencing a null pointer can lead to the execution of arbitrary code [Jack 2007,van Sprundel 2006]. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? LANG.MEM.NPDLANG.STRUCT.NTADLANG.STRUCT.UPD, Null pointer dereferenceNull test after dereferenceUnchecked parameter dereference, Can detect violations of this rule. A reference to null should never be dereferenced/accessed. 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. Issues Components. C# static code analysis: Null pointers should not be dereferenced The solution that I recommend is not work with null returns or variables on Java, try to avoid it. Null Dereference | OWASP Foundation Connect and share knowledge within a single location that is structured and easy to search. C static code analysis: Null pointers should not be dereferenced 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. Just because something is a pointer does not mean you should call delete . Trying to understand how to get this basic Fourier Series. util.regex.Matcher, java - Swing .getParent() . This sounds indeed like a bug in the flow when an exception is raised. Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. Null pointers should not be dereferenced. 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. With their flexibility, void pointers also bring some constraints. Hi Andreas, Thanks for the feedback. I believe that dereferencing NULL should not crash the system, should not allow a write to a NULL pointer area, but should always set errno, If I am a hacker, could I trap a null failure that would force a memory dump. 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. Phew, we're agreed here. But when length of A is 1, the control never reaches the else block. assert(!invalid(p)); // or whatever, bool invalid(const void *p) { 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. Basically, yes. Why are physically impossible and logically impossible concepts considered separate in terms of probability? Made code more compliant with other rules. Note that 7.1.4 explicitly states that a null pointer is not a valid pointer argument. PS: I also tried the code in android studio which uses Lint and got no warnings. Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. Passing ownership of something also requires pointers. I added a comment to explain that SIZE_MAX is the limit of size_t. (I think you cover that in a different rule.) And fwstr > is dereferenced in the following codes. [squid:S2259] False positive - "Null pointers should not be dereferenced" Sonar is ok. Automated Detection Null pointer dereferences can happen in path-dependent ways. This rule applies to all null pointers, regardless of which function returned them. EXP01-J. Do not use a null in a case where an object is required Solution 1, it looks like, today's solution tomorrow's problem. 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. 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). How can we let this pass? [4] 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. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. SonarQube null pointers should not be dereferenced on try/catch ", 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". How to use Slater Type Orbitals as a basis functions in matrix method correctly? The issue arises when dereferenced pointers are used. context.RaiseException , (/) See the "Null pointer checks may be optimized away more aggressively" section inhttps://gcc.gnu.org/gcc-4.9/porting_to.htmlas an example with one common implementation. 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. name result . Callable statement giving Null Pointer Exception - Oracle Forums Software Engineering Institute What is a NullPointerException, and how do I fix it?,What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? The above check can't hurt, as I guess you could have a system with a 32-bit size_t that had a ton of memory and had some crazy banking/selector scheme with pointers. As for today, the SE engine is able to explore non-overridable methods (static, for instance), when declared in the same file being analyzed. So we have to check all the arguments before performing any actions. How can this new ban on drag possibly be considered constitutional? Note that it doesn't know how to check for non-heap, non-stack. Sonar detects that res.getBody() can be null when you do the check res.getBody()==null. The solution that I recommend is not work with null returns or variables on Java, try to avoid it. A NULL pointer can be dereferenced when signatures are being verified on PKCS7 signed or signedAndEnveloped data. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. How to fix int cannot be dereferenced? Explained by Sharing Culture At See "Clever Attack Exploits Fully-Patched Linux Kernel" [Goodin 2009] for an example of a code execution exploit that resulted from a null pointer dereference. 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. That is, sets equivalent to a proper subset via an all-structure-preserving bijection. It could be non-null the first time but not the second time, sonar does not know this. 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]. We cannot understand how there could be a null pointer exception at the reported line. 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. This issues is displayed by SonarQube. What is null pointer exception in android Smartadm.ru Is the God of a monotheism necessarily omnipotent? A null pointer in this position causes the read system call to fail with -EINVAL ("Invalid argument"). NullPointerException is thrown when program attempts to use an object reference that has the null value. Share Improve this answer Follow answered Oct 5, 2017 at 16:27 I am a student implementing stack with singly linked list using C, following a book called Fundamentals of Data Structures in C.. When B is null, The control reaches inside the main if block only when length of A is 1. So you can declare a string t and then add characters to the string with a plus sign : t += 'a'; The code you are having issue with is just moving the pointer to the next character which the foreach is already doing. 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. A value is checked here to see whether it is null, but this value can't be null because it was previously dereferenced and if it were null a null pointer exception would have occurred at the earlier dereference. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Essentially, this code and the previous dereference disagree as to whether this value is allowed to be null. Original Java Specification Request (JSR) - Java Community Process Reports. 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 pointers should not be dereferenced #1155 - GitHub In order to fix this, just do the following: If you are absolutely sure that res.getBody() stays null and is also not modified by another thread, you could also use a //NOSONAR comment in order to suppress the warning. In the first compliant example it's useless to do allocation if the essential pointer user_data is NULL. Connect and share knowledge within a single location that is structured and easy to search. Find null smart pointer dereferences with the Clang Static Analyzer Java Specification Participation Agreement version in use: 2.0. So no checking of the length is necessary (besides preventing integer overflow, which the compliant solution does). versions used (SonarQube, Scanner, language analyzer) 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. 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! Now (sonarqube java analyzer version 4.3.0.7717) it's supported and works fine. https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx Yeah, I suspect once it's possible to allocate 2+gigs contiguously in amainstream install of a modern OS, we'll see a frenzy of new vulnerabilities come out. 412-268-5800, If an argument to a function has an invalid value (such as a value outside the domain of the function, or a pointer outside the address space of the program, or a null pointer, or a pointer.