How can we prove that the supernatural or paranormal doesn't exist? minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). EXP01-J. Do not use a null in a case where an object is required isEmpty(Collection collection) Is the God of a monotheism necessarily omnipotent? Iflengthhas the value1, the addition yields 0, and png_malloc() subsequently returns a null pointer, which is assigned to chunkdata. That is only true if possibleNumbers contains no element.. BTW: none of these warnings are shown by . Accessing or modifying a null object's field. [PATCH] drm_edid-load: Fix a missing-check bug in drivers/gpu/drm/drm Callable statement giving Null Pointer Exception - Oracle Forums False fault 'Null pointers should not be dereferenced' using Optional Status: Dormant. Small typo nit: "such as if i t pointed to freed memory" meant to say "if it" instead (removing whitespace). Im having trouble understanding your problem. 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. specifies the length of the array for a function. 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. A common memory-leak idiom, is reallocating storage and assigning its address to a pointer that already points to allocated storage. 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. That's true. Software project. (from res.getBody().getServiceResult() ). This is indeed an obvious False Positive from the rule. Is it plausible for constructed languages to be used to affect thought and control or mold people towards desired outcomes? My below code where I'm calling a stored procedure is giving a null pointer exception. 1. Introduction - Understanding and Using C Pointers [Book] Using platform-specific means (e.g. How can we prove that the supernatural or paranormal doesn't exist? Issues Components. Null - When a variable is declared as being a pointer to type void, it is known as a generic pointer. Perhaps this could be done with a special constraint that will notify the SE engine that we learned from a Debug.Assert call. We resolved it by adding our tools path in the white list, and repackaging it. 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. Calls to extension methods are not reported because they can still operate on null values. Recovering from a blunder I made while emailing a professor. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Should trycatch go inside or outside a loop? VB.NET static code analysis: Null pointers should not be dereferenced Dereferencing a null pointer results in undefined behavior. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Using Kolmogorov complexity to measure difficulty of problems? C# static code analysis: HTTP responses should not be vulnerable to 2008-2023 SonarSource S.A., Switzerland. C static code analysis: Null pointers should not be dereferenced C static code analysis Unique rules to find Bugs, Vulnerabilities, Security Hotspots, and Code Smells in your C code All rules 311 Vulnerability 13 Bug 74 Security Hotspot 18 Code Smell 206 Quick Fix 14 Tags "memset" should not be used to delete sensitive data Vulnerability Could I capture, and I would be able to glean much security information from the dump? Setup is effortless and analysis is automatic for most languages, Fast, accurate analysis; enterprise scalability. The alert is related to the sonar rule : Null pointers should not be dereferenced. 4. Software Engineering Institute Correct; a null pointer is not a valid pointer for the C library functions. What is a NullPointerException, and how do I fix it?,What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? in above code, 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. 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. Obviously the value of that pointer could have changed since the . If malloc() fails, it returns a null pointer that is assigned to c_str. Key here (explains table format and definitions), EXP34-C = Union( CWE-690, list) where list =. Clearly the standard enumerates 1 case of undefined behavior, but makes no special mention of n=0. , . Also, the term 'pointer' is bad (but maybe it comes from the FindBugs tool): Java doesn't have pointers, it has references. We can see that at obj.run(), obj can not be null, but is pointed out by Sonar. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to bypass security measures. 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). After that, you call res.getBody() again. The idea is not to guarantee validity, but to catch a substantial number of problems that could occur. Which @NotNull Java annotation should I use? Does Counterspell prevent from any further spells being cast on a given turn? [squid:S2259] False positive - "Null pointers should not be dereferenced" 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. 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. [4] All rights are expressly reserved. uninitialized reference-type class members. Basically, yes. 1 Answer Sorted by: 1 Your code is ok. Find null smart pointer dereferences with the Clang Static Analyzer . IDE extension that lets you fix coding issues before they exist! (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). Pointers in C Explained - They're Not as Difficult - freeCodeCamp.org One could argue that all code examples would be redundant with the first pair. NULL vs Uninitialized pointer - An uninitialized pointer stores an undefined value. In case the hash algorithm used for the signature is known to the OpenSSL library but the implementation of the hash algorithm is not available the digest initialization will fail. rev2023.3.3.43278. Sonar is ok. Sonar can't determine that the helper method did the null validation. Whoops, you're right. How to deal with "java.lang.OutOfMemoryError: Java heap space" error? And the semantics, as I said, are different. Doing so will cause a NullReferenceException to be thrown. SonarJava. Then the reading of the buffer via bstr_printf() will then look at the pointer to process the final output. Shouldn't the function check all pointers before dereferencing them or passing them to another function? What does "Could not find or load main class" mean? Null pointer should not be dereferenced , By explicitly teaching the C++ standard class behaviors we can make the Analyzer to find more bugs related to modern C++ code. It's still illegal. If you call connect() function, it better do the connection, but failing simply because some ptr is NULL is not good behaviour -- failures should . This compliant solution eliminates the null pointer deference by initializing sk to tun->sk following the null pointer check. There are other problems with this code, as is noted in the rule. 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). 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. Ah, gotcha. At Extended Description NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions. raiseException() return, Sonar When c_str is dereferenced in memcpy(), the program exhibits undefined behavior. Goal points to memory allocated to the process) and what exactly was allocated there after the public key was freed, this may cause a segmentation fault or even execute code, which could again cause a segmentation fault, but might potentially be under the attacker's control. Whats the grammar of "For those whose stories they are"? At this point we define size as strlen(input_str) + 1. A reference to null should never be dereferenced/accessed. SonarQube - Null Pointer Dereference Issue java simonsirak (Simon Sirak) June 14, 2018, 1:18pm 1 Hi! I added a comment to explain that SIZE_MAX is the limit of size_t. [RSPEC-2259] - Jira 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. 3.7. The same problem we will have with "Add at least one assertion to this test case." The null concept refers to the idea that a pointer can hold a special value that is not equal to another pointer. which version of SonarQube are you using? 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. Interactions/interfaces with C can't use references. In this noncompliant code example, input_str is copied into dynamically allocated memory referenced by c_str. () 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. The return value from strchr() is often NULL, but the dev might know that a specific strchr() function call will not return NULL. Making statements based on opinion; back them up with references or personal experience. Find centralized, trusted content and collaborate around the technologies you use most. Things go fine now. Which version of SonarJava plugin do you have? There are many ways to resolve this. A pointer is simply a variable that contains a memory address. 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. 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 get rid of NullPointerException - freeCodeCamp.org 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 With their flexibility, void pointers also bring some constraints. Automated Detection Null pointer dereferences can happen in path-dependent ways. That interpretation of the standard is not supported universally. C# static code analysis: Null pointers should not be dereferenced Products In-IDE IDE extension that lets you fix coding issues before they exist! Just because something is a pointer does not mean you should call delete . But passing 0 to memcpy() is not one of them. 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 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. You can use Optional instead. The SonarJava SE engine is however, by default, not configured to explore methods declared in other files (in your case, your utility class CheckUtils). In this case, the difference is the assumption thatmalloc() always returns non-nullfor the second NCCE, whereas the first NCCE has themalloc() abstracted away. To learn more, see our tips on writing great answers. validated for null in your method declaration with it: 2008-2023 SonarSource S.A., Switzerland. Thanks for contributing an answer to Stack Overflow! [PATCH v2] vsprintf: Do not have bprintf dereference pointers (In contrast, the case of passing 0 bytes to malloc is addressed in C11.) When and how should I use a ThreadLocal variable? How handle the initialization of "responseDto" without "null" because is throwing the issue on sonar. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 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?) The expected result here is solve the issue with sonarqube. 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. Now, you can find the list of whitelisted methods here. The issue of passing n=0 to memcpy() is distinct from null or invalid pointers. Search for vulnerabilities resulting from the violation of this rule on the CERT website. @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. In the first compliant example it's useless to do allocation if the essential pointer user_data is NULL. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? This code also violates ERR33-C. Detect and handle standard library errors. parsing /proc/self/maps under linux) one might find out whether the pointer points into mapped memory, but this is still not a guarantee of validity because it is very coarse-grained see again the above example. I have checked on multiple . There is no guarantee that subsequent invocations are returning the same value, thats why issue is raised. Why does the second compliant example permit using possibly-null pointers? I think "res.getBody() == null" checks null first so it should go to return line, not reach to next if condition. OpenSSL Releases Security Update - NHS Digital At worst, it could expose debugging information that would be useful to an attacker, or Thered be huge value in jumping onto the latest version of the ecosystem (notably SonarQube), and benefit from all latest analyzers (e.g. Even if the object is null in this case, it will not give an exception and will print ' null ' to the output stream. 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. Report False-positive / False-negative [LTS] The new SonarQube LTS is here: SONARQUBE 9.9 LTS, SonarQube - Null Pointer Dereference Issue. Privacy Policy, Detect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories. Maybe one of these methods is already doing what your methods is doing, and could be considered as replacement. The user_data pointer could be invalid in other ways, such as pointing to freed memory. Pointer members in structs are not checked. The only potential null is the return value of list(). Some Interesting Facts: 1) void pointers cannot be dereferenced. 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. S2259: Null pointers should not be dereferenced java tsubasa (Jiaoyang Ma) January 11, 2019, 6:57am 1 versions used (SonarQube, Scanner, language analyzer) SonarQube Version 6.7.2 (build 37468) SonarJava Version 5.9.2 (build 16552) minimal code sample to reproduce (with analysis parameter, and potential instructions to compile). When should pointers be checked for NULL in C? Connect and share knowledge within a single location that is structured and easy to search. This solution also ensures that theuser_data pointer is not null. Powered by Discourse, best viewed with JavaScript enabled. The standard will simply copy 0 byteswhich is essentially a no-op. All content is copyright protected. 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. Making statements based on opinion; back them up with references or personal experience. 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. SonarQube Version 6.7.2 (build 37468) . Is there a proper earth ground point in this switch box? For the time being, I would unfortunately recommend to mark as False Positive the issue. Does it just mean failing to correctly check if a value is null? 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). Pittsburgh, PA 15213-2612 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 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. IMHO, the rule title should be changed to something less general. PS: I also tried the code in android studio which uses Lint and got no warnings. The libpng library allows applications to read, create, and manipulate PNG (Portable Network Graphics) raster image files. The final NCCE is actually more insidious than it seems at first. SonarLint: A "NullPointerException" could be thrown; "getBody()" can return null. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Why void pointer cannot be dereferenced? Explained by Sharing Culture C static code analysis: Null pointers should not be dereferenced 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. When exploring such methods, the engine then deduces behaviors regarding null-checking (among other things). How do you ensure that a red herring doesn't violate Chekhov's gun? It also adds assertions to document that certain other pointers must not be null. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? Thanks for contributing an answer to Stack Overflow! Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? 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?) My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? Doing so will cause a NullReferenceException to be thrown. Finally my method is returning a response with value of restTemplate. 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(). So the SIZE_MAX check was unnecessary. very old code or C code being worked into c++ may have functions that expect the user to delete the data. Using Kolmogorov complexity to measure difficulty of problems? 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. I believe in this case, either expression would work. ii. 3.Null pointers should not be derefer enced/accessed. Good question! 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. (I think you cover that in a different rule.) Note that it doesn't know how to check for non-heap, non-stack. Passing ownership of something also requires pointers. In C/C++ speak, 'dereferencing' simply means getting the object that a pointer . You can compare a pointer with NULL to test for the special condition. I would also guess that pointers that point to the one-past-the-end of an array are also invalid. 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. Thanks for the feedback. How to tell which packages are held back due to phased updates. Aaron:I suspect we are talking past each other. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Not the answer you're looking for? As for copy vs pointer/reference - it depends. Solution 1, it looks like, today's solution tomorrow's problem. Appropriate typecasting is necessary. Null Dereference | OWASP Foundation Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA.